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IASS 2016 Annual International Symposium
Technical Program

Remark: The presenter of each paper is marked with "*".
Technical Program:   SIMPLE version   DETAILED version with abstract
Author Index:   HERE

Session Schedule

Monday, September 26, 2016

Ito HallGallery-1Sanjo MainMain FoyerRoom 001Room 002Room 201Room 202Room 203
8:00 - 9:00
OS  Opening Ceremony
9:00 - 10:10

Coffee Break
10:10 - 10:30
AW  TAC and Awards
10:30 - 13:00

13:00 - 14:20
CS1M  WG15: Morphology -1
14:20 - 16:20
CS1Y  Design of 21st century -1
14:20 - 16:20
CS1A  WG8: Metal Roofs -1
14:20 - 16:20
CS1B  New Materials and New Construction Methods -1
14:20 - 16:20
CS1C  WG6: Tension & Membrane Structures -1
14:20 - 16:20
CS1D  WG12+18: Timber & Environment -1
14:20 - 16:20
CS1E  Shell -1
14:20 - 16:20
CS1F  Seismic -1
14:20 - 16:20
CS1G  Conceptual Design -1
14:20 - 16:20
Coffee Break
16:20 - 16:40
CS2M  WG15: Morphology -2
16:40 - 19:00
CS2Y  Design of 21st century -2
16:40 - 19:00
CS2A  WG8: Metal Roofs -2
16:40 - 19:00
CS2B  New Materials and New Construction Methods -2
16:40 - 19:00
CS2C  WG6: Tension & Membrane Structures -2
16:40 - 19:00
CS2D  WG12+18: Timber & Environment -2
16:40 - 19:00
CS2E  Shell -2
16:40 - 19:00
CS2F  Seismic -2
16:40 - 19:00
CS2G  Conceptual Design -2
15:50 - 17:50
Reception Party
19:00 - 20:30

Tuesday, September 27, 2016

Ito HallGallery-1Sanjo MainMain FoyerRoom 001Room 002Room 201Room 202Room 203
8:00 - 9:00
PS1  Plenary Session -1
9:00 - 10:00

Coffee Break
10:20 - 10:40
PS2  Plenary Session -2
10:20 - 12:40

12:40 - 14:00
CS3M  WG15: Origami -1
14:00 - 16:00
CS3Y  Form Finding & Optimization -1
14:00 - 16:00
CS3A  WG8: Metal Roofs -3
14:00 - 16:00
CS3B  New Materials and New Construction Methods -3
14:00 - 16:00
CS3C  Tension Structures -1
14:00 - 16:00
CS3D  Timber & Environment -1
14:00 - 16:00
CS3E  Shell -3
14:00 - 16:00
CS3F  Seismic -3
14:00 - 16:00
CS3G  Conceptual Design -3
14:00 - 16:00
Coffee Break
16:00 - 16:20
CS4M  WG15: Origami -2
16:20 - 18:40
CS4Y  Morphology
16:20 - 18:40
CS4A  Flex Structures
16:20 - 18:40

CS4C  Tension Structures -2
16:20 - 18:20
CS4D  Timber & Environment -2
16:20 - 18:20
CS4E  Shell -4
16:20 - 18:20
CS4F  Seismic -4
16:20 - 18:20
CS4G  Deployable Structures -1
16:20 - 18:20
WG Meetings (if necessary)
18:40 - 20:00

Wednesday, September 28, 2016

Technical Tour
9:00 - 17:00

Thursday, September 29, 2016

Ito HallGallery-1Sanjo MainMain FoyerRoom 001Room 002Room 201Room 202Room 203
8:00 - 9:00
PS3  Plenary Session -3
9:00 - 10:20

Coffee Break
10:20 - 10:40
PS4  Plenary Session -4
10:40 - 12:40

Lunch on Seminar "Typology and Structural System, Through Shell Structures on Earth and Mars" by Clouds Architecture Office (Masayuki Sono)
12:40 - 14:00
CS5M  WG15: Graphic Statics
14:00 - 16:00
CS5Y  Project & Construction -1
14:00 - 16:00
CS5A  WG13+15: Bending Active and Flexible Structures -1
14:00 - 16:00

CS5C  Tension Structures -3
14:00 - 16:00
CS5D  Metal Roofs -1
14:00 - 16:00
CS5E  Membrane Structures -1
14:00 - 16:00
CS5F  Computational Methods-1
14:00 - 16:00
CS5G  Deployable Structures-2
14:00 - 16:00
Coffee Break
16:00 - 16:20
CS6M  Form Finding & Optimization -2
16:20 - 18:20
CS6Y  Project & Construction -2
16:20 - 18:20
CS6A  WG13+15: Bending Active and Flexible Structures -2
16:20 - 18:20

CS6C  Tension Structures -4
16:20 - 18:40
CS6D  Metal Roofs -2
16:20 - 18:20
CS6E  Membrane Structures -2
16:20 - 18:20
CS6F  Computational Methods -2
16:20 - 18:20
CS6G  Deployable Structures -3
16:20 - 18:20
Conference Dinner (Asakusa View Hotel)
19:00 - 21:00

Friday, September 30, 2016

Ito HallGallery-1Sanjo MainMain FoyerRoom 001Room 002Room 201Room 202Room 203
8:00 - 9:00
CS7M  Form Finding & Optimization -3
9:00 - 11:00
CS7Y  WG17: Historical Structures
9:00 - 11:00
CS7A  WG13: Bio-inspired Control of Structures
9:00 - 11:00

CS7C  WG20: Teaching Shell & Spatial Structures
9:00 - 11:00
CS7D  Metal Roofs -3
9:00 - 11:00
CS7E  Membrane Structures -3
9:00 - 11:00
CS7F  Snow, Wind & Disarster
9:00 - 11:00
CS7G  Towers & Coolings
9:00 - 11:00
Coffee Break
11:00 - 11:20
CS8M  Form Finding & Optimization -4
11:20 - 13:20
CS8Y  Historical Structures
11:20 - 13:20
CS8A  WG13: Computational Methods
11:20 - 13:20

CS8C  Teaching of Shell and Spatial Structures
11:20 - 13:20
CS8D  Presevation & Temporary Structures
11:20 - 13:20
CS8E  Membrane Structures -4
11:20 - 13:20
CS8F  Disaster & Applications
11:20 - 13:20
CS8G  New Approaches
11:20 - 13:20
13:20 - 14:40
CS9M  Hangai Prize Presentation
14:40 - 16:20

Coffee Break
16:20 - 16:40
CC  Closing Session
16:40 - 17:30

List of papers

Remark: The presenter of each paper is marked with "*".

Monday, September 26, 2016

Session OS  Opening Ceremony
Time: 9:00 - 10:10 Monday, September 26, 2016

OS-1, ID 1549 (Time: 9:00 - 9:30)
TitleOpening Address
AuthorKen'ichi Kawaguchi (University of Tokyo)
Keywordspatial structures

OS-2, ID 1550 (Time: 9:30 - 9:50)
TitleTorroja Medal Conferral
AuthorJack Christiansen, Rene Motro

OS-3, ID 1551 (Time: 9:50 - 10:10)
TitleHonorary Membership Conferral
AuthorShiro Kato, Pieter Huybers

Session AW  TAC and Awards
Time: 10:30 - 13:00 Monday, September 26, 2016

AW-1, ID 1555 (Time: 10:30 - 11:20)
TitleIASS Technical Activities
AuthorCarlos Lazaro (Universidad Politecnica de Valencia, Spain)

AW-2, ID 1552 (Time: 11:20 - 11:50)
Title[Plenary] Tsuboi Award 25 Years
AuthorYoshiaki Tsuboi (Tokyo University of Fine Arts, prof. em., The eldest son of late prof. Yoshikatsu Tsuboi)
Keywordspatial structures, Tsuboi
AbstractThe Tsuboi Award honors the memory of Professor Yoshikatsu Tsuboi (Japan, 1907-1990), former President and Honorary Member of the IASS, and his outstanding contributions to structural and architectural design. Tsuboi Awards are awarded annually in two categories: (A) For the most meritorious paper published in the Journal of the IASS in the preceding calendar year. (B) For the most outstanding paper presented and published in the Proceedings of the previous year's annual IASS Symposium. The history of 25 years of The Tsuboi Award is presented by Professor Yoshiaki Tsuboi, together with the conferral of this year.

AW-3, ID 1553 (Time: 11:50 - 12:05)
Title[Plenary] Hangai Prize Conferral
AuthorNaoko Hangai (MESCO, The widow of late prof. Yasuhiko Hangai)
KeywordHangai, Spatial structures
AbstractMy late husband, Yasuhiko Hangai had been involved in the IASS activities for long years, until he passed away from a disease in 1998. He was a University professor, and loved to work and talk with young people. The Hangai Prize was established by his friends and co-workers with the aim of encouraging young researchers. Every year four prize winners are selected through screening of the applicants’ research papers.This year, we have the fourteenth award ceremony. I really appreciate that the Hangai Prize committee has been taking care of the Hangai Prize for long years. I hope this prize contributes to the prolific research works in the IASS.

AW-4, ID 1558 (Time: 12:05 - 13:00)
Title[Plenary] The Challenge of Modern Architecture - Homage to Mr. Yasuhiko Hangai -
AuthorToyo Ito (Toyo Ito & Associates, Architects, Japan)
Keywordarchitecture, modern architecture, Toyo Ito, Hangai
AbstractHuman beings used to live by the river for water resources. Their bodies are like a branch of the river taking in water. Human beings used to truly be a part of nature. However, people living in the modern world now think that one can live under any environment as long as they carry a bottle of water. They believe that human beings can be independent from nature. The same is true with architecture. People used to live in a cave or on a tree but they came out from the cave or down from the tree and build their houses on the ground. They began to use geometry to create architecture they created a new order that is independent from the natural world. From the ancient Greece until this very day, people have been proud of this ability. The history of architecture can be perceived as the history of geometry.

Session CS1M  WG15: Morphology -1
Time: 14:20 - 16:20 Monday, September 26, 2016
Location: Ito Hall

CS1M-1, ID 1009 (Time: 14:20 - 14:40)
TitlePlane Snub Tessellations
Author*Christopher Kitrick (Qualcomm, Inc., U.S.A.)
KeywordTessellation, Geodesic, Plane, Snub
AbstractClass III hexagonal geometries are unique due to their chiral symmetry but the skew topology introduces additional computational complexity making their use in constructed shells rare. In nature though class III tessellations are very common at the microscopic level. In 2015 Kitrick [1] presented a general solution for deriving plane hexagonal tessellations applicable to Class I and II geodesic geometries. These classes are intrinsically symmetric and allow the solution to be resolved within the Schwarz spherical triangle. Class III geometries do not fall neatly within the Schwarz triangle and present an initial condition problem that is addressed in this paper allowing plane hexagons to be effectively derived for this unique class. Shells consisting of only plane hexagons offer advantages with respect to face and edges for both single and dual layer shells.

CS1M-2, ID 1050 (Time: 14:40 - 15:00)
TitleDesign of Scissor System from a Given Source Shape into a Specific Target Shape
Author*Wenwen Jia, Jianguo Cai, Jian Feng (Southeast University, China), Daneil Sang-hoon Lee (The Royal Danish Academy of Fine Arts, Schools of Architecture, Denmark)
Keywordscissor structure, topology, geometry, optimization, fabrication
AbstractIn this paper we focus on producing a scissor structure that deploys from a given source shape into a specific target shape.The first step is topology construction, the number of scissor units is determined, and the number of revolute joints in the scissor structure is decided, which change the DOFs of the structure. Then the geometry of the scissor structure is optimized in order to better approximate the two states by the algorithm method fmincon in MATLAB optimization toolbox. Finally, physical deployable objects are fabricated according to the designed scissor structures by using manual assembly.

CS1M-3, ID 1162 (Time: 15:00 - 15:20)
TitleMultistable Slit Caps
Author*Paul Maximilian Sobota, Keith A. Seffen (University of Cambridge, U.K.)
KeywordMultistability, Post-buckling analysis, Föppl-von Kármán plate theory, Analytical solution
AbstractMultistable shells are structures that have more than one stable state of self-stress. We demonstrate for the first time that an initially stress-free, hemispherical cap with isotropic behaviour can gain at least three additional stable shapes and, hence, states of self-stress, if it is sliced partially along a given axi-symmetrical meridian. The usual initial and inverted configurations are only slightly affected by slicing. The other configurations are elicited by extra deformations about the inverted shape, which now performs a pre-stressing role. The experimental results are confirmed by finite-element simulations, and it is shown that initially rotationally symmetric structures can gain three stable configurations. Motivated by this, a simplified analytical approach using Föppl-von Kármán plate theory is undertaken to analyse the bistable properties of shallow spherical segments. It is shown that the boundary conditions have a dominating influence on the occurrence of multistability.

CS1M-4, ID 1066 (Time: 15:20 - 15:40)
TitleStructural exploration of a fabrication-aware design space with Marionette Meshes
Author*Romain Mesnil, Cyril Douthe, Olivier Baverel, Christiane Richter (Ecole des Ponts et Chaussées, Université Paris-Est, Laboratoire Navier (UMR 8205), France), Bruno Leger (Bouygues Construction, France)
Keywordfabrication-aware design, geometry, mechanics, optimisation, PQ-mesh
AbstractThis paper presents a new methodology for generating doubly-curved shapes covered with planar facets. The proposed method, called marionette method relies mainly on descriptive geometry, and it is shown that specifying appropriate projections, e.g. plane view and elevations, defines uniquely a free-form shape. This methodology is highly intuitive and can be used in real-time, mainly because only linear systems of equations are solved. The design-space offered by the marionette method is extremely large, and easily parameterized. Some applications show the potential of this technique for the parameterization of a fabrication-aware design space for structural optimization.

CS1M-5, ID 1282 (Time: 15:40 - 16:00)
TitleMechano-adaptive space frame generation based on ellipsoid packing
Author*Alessandro Felder (The Royal Veterinary College, U.K.), Harri Lewis (Mule Studio, U.K.), Daniel Piker (Foster and Partners, U.K.), André Pereira (University of New South Wales, Australia), Xavier De Kestelier (Foster and Partners, U.K.)
Keywordspace frames, optimisation, lightweight, bone-inspired, computational design
AbstractWe present an algorithm to automate the generation of volume-filling space frames adapted to an input mechanical stress field. Our approach relies on local rules, inspired by the fact that vertebrate bones’ local responses to the mechanical environment produce globally strong, yet lightweight, structures. Noticing the anisotropy of trabecular bone, we choose ellipsoids aligned to the principle stress directions as basic units of our approach. The ellipsoids’ local interactions are based on simple engineering principles designed to encourage mechanically advantageous configurations, such as smaller ellipsoids in regions of high stress and more elongated ellipsoids in regions of more anisotropic stress. The final structure results from connecting ellipsoid centre points along stress directions. We show that for a representative case our structures can achieve an improved performance, quantified by deflection and buckling analysis, compared to traditional space frames, despite using significantly less material.

Session CS2M  WG15: Morphology -2
Time: 16:40 - 19:00 Monday, September 26, 2016
Location: Ito Hall

CS2M-1, ID 1408 (Time: 16:40 - 17:10)
Title[Keynote] Intuitive and implicit design parametrization for analysis and design by the Vertex Morphing Method
AuthorKai-Uwe Bletzinger (Technical University of Munich, Germany)
Keywordparametric design, shape optimization, form finding, shape morphing, implicit splines
AbstractThe Vertex Morphing method, a consistent surface control approach for shape optimization is presented. This method introduces a control field and a map that relates it to the geometry field. The optimization problem is solved in the control space and the map is defined such that both surface smoothness and mesh regularity criteria are satisfied simultaneously and synchronously in the geometry field. The control field is discretized with the same discretization as the one of the geometry, which leads to the richest design space possible for optimization of a discrete geometry. The capabilities of the Vertex Morphing method are evaluated within an adjoint based CFD shape optimization workflow. Several engineering cases mainly from automotive industry are tested. The method has shown significant success in performance, efficiency and robustness even for problems with extreme geometrical complexities and millions of design parameters for applications in structural as well as fluid mechanics and their combination.

CS2M-2, ID 1323 (Time: 17:10 - 17:30)
TitleAn alternative method for topology optimization, applied to nodes of free form space frame structures
Author*Ioannis Mirtsopoulos (Swiss Federal Institute of Technology, Switzerland), Andrew Borgart (Delft University of Technology, Netherlands)
Keywordstructural optimization, topology optimization, free form, spatial structure, space frame structure
AbstractThis paper presents an alternative structural optimization methodology for topology optimization, applied to generate free form spatial structures nodes, based not on the mean compliance or the total strain energy, but on the calculation of the dilatation and the distortion energy separately. This is done by determining for each element its geometry of distortion through volume change and skewness. This Python algorithm is based on the idea of discretizing an arbitrary cubical domain into numerous elements and step-by-step removing the inefficient elements of the initial assumed design domain. Throughout all iterations, the dilatation and distortion energy of each element are monitored and based on the total strain energy, their young's modulus is altered. Currently, the operations done are only related to removing inefficient parts, meaning that young's modulus values intend to get decreased by the script. Subsequently, there is no possibility of later re-activating any element prior indicated as inefficient.

CS2M-3, ID 1045 (Time: 17:30 - 17:50)
TitleDeployment Simulation of a Scalable Planar Gossamer Space Structure with Miura-ori Pattern
Author*Jianguo Cai, Ruijun Ma, Jian Feng, Yifan Ding (Southeast University, China)
Keywordorigami, membrane, deployment
AbstractThe deployment behaivor of a scalable planar gossamer space structure with Miura-ori patten is studied in this paper. The variable Poisson's ratio model, which is used to model the wrinkling of membranes, is firslty introducted. A 1-m quadrant shaped membrane is chosen to study the deployment behaivor of membranes with Miura-ori pattern. Moreover, the effects of geometrical parameters, such as the angle between the valley crease and the mountain crease, the length of the basic Miura-ori element, are also investigated. Then the numerical analysis of the deployment of a pantographic foldable mast based on scissor-link elements, which is used to active the deployment of the membrane, is carried out. Furthermore, the influence of the imperfection, including the size and the shape of the imperfection, are also discussed. Finally, a prototype, which consists of two foldable mast and a triangular membrane, is constructed to valid the concept and design.

CS2M-4, ID 1044 (Time: 17:50 - 18:10)
TitleDevelopment of Kinetic Origami Canopy using Tapered Miura Folding Patterns
Author*Zheng Ren (Southeast University, China), Daniel Sang-hoon Lee (The Royal Danish Academy of Fine Arts, Schools of Architecture, China), Jianguo Cai, Jian Feng (Southeast University, China)
KeywordCurved Configuration, Form Finding, Miura-ori, Geometric Analysis, Rigid Foldability
AbstractThe main objective of the paper is to design a configuration of revolution hyperboloid of one sheet for the canopy of the workshop conducted in Denmark. The design aims to create a novel curved configuration, and it is also required to achieve ideal light penetration quality. This paper has the specific interests in the design development of lighting structures with basic form finding principles of Miura-ori, which is of certain significance in creating architectural space. Various radially foldable systems composed by Miura-ori units are studied by many researchers. In order to obtain a curved shape for the cover of the canopy, the geometry of Mirua-ori configuration with variable angles is firstly studied. Then design and parameter analysis of hyperbola is conducted, and the configuration is built according to geometric analysis. Finally, the rigid foldability of the system is studied.

CS2M-5, ID 1374 (Time: 18:10 - 18:30)
TitleMethod for customizing deployment motion through modifying Poisson’s ratio
Author*Janette Fernelius, Alden Yellowhorse, Spencer Magleby, Larry Howell (Brigham Young University, U.S.A.)
KeywordCustomizing, Deployment, Motion
AbstractApplying engineering principles to origami-based mechanical systems enables the control of certain properties, such as flexibility, bending stiffness, and deployment motion. Determining Poisson’s ratio for deployable, rigid-foldable tessellation origami patterns provides a method to optimize the deployment motion of deployable structures and mechanisms that incorporate such patterns. Rigid-foldability requires that the mechanism can move between deployed and compact states without twisting or stretching the panels between creases (Tachi [1]). Mathematically modelling Poisson’s ratio for these patterns enables engineers to select and modify tessellation fold patterns based on their potential behavior relative to engineering needs. This paper presents and discusses a method for calculating Poisson's ratio in terms of degree-of-deployment and is demonstrated for five origami tessellations. Modifications of the unit cell geometry of the tessellation are discussed and illustrate a method of tailoring patterns to obtain the desired deployment motion. Application of the mathematical models is also discussed.

CS2M-6, ID 1383 (Time: 18:30 - 18:50)
TitleGeometrical basis and mechanical characteristics of a fractal hexagon dome
AuthorShuichi Asayama (Tokyo Denki University, Japan), Toshifum Mae (Oita National College of Technology, Japan)
Keywordfractal, hexagon, dome, mophology, space structure

Session CS1Y  Design of 21st century -1
Time: 14:20 - 16:20 Monday, September 26, 2016
Location: Gallery-1

CS1Y-1, ID 1159 (Time: 14:20 - 14:50)
Title[Keynote] Hinged Folded Festival Pavilion–Membrane Bearing in Lightweight Dismountable Structures
Author*Manfred Grohmann (School of Architecture, University of Kassel/Bollinger + Grohmann Ingenieure, Germany), Philipp Eisenbach, Moritz Rumpf, Cynthia Ward (School of Architecture, University of Kassel, Germany)
KeywordFolded structures, Membrane action, Lightweight, CNC fabrication, Dismountable pavilion
AbstractLightweight and dismountable structures are valuable examples in future building industry. Not only due to aesthetical reasons but also in order to use material in a resource conserving way. An increasing speed of changes of user demands of the built environment results in the exertion of temporary structures ensuring not only a quick installation but also an unpretentious de- and reassembly. Folded structures as well as tessellated freeform structures with a load bearing behaviour reduced to membrane action allow the application of fully hinged connections at the adjacent edges of the surfaces. In consequence the construction of the joints can be simplified to modular low-tech systems with no constraints to the global geometry of the architectural design. A one-semester student project entitled ´Burning Man and Friends´ at the School of Architecture of the University of Kassel worked on the paradigm stated above in an educational setting.

CS1Y-2, ID 1027 (Time: 14:50 - 15:10)
TitleComputational systems for design and production of complex geometries with large-format roll-bent aluminum plates
Author*Ragunath Vasudevan (schneider+schumacher Parametrik GmbH & Co.KG, Germany), Mark Fahlbusch (Bollinger+Grohmann Ingenieure, Germany), Michael Schumacher (schneider+schumacher Planungsgesellschaft, Germany), Klaus Bollinger (Bollinger+Grohmann Ingenieure, Germany), Michael Grimm (Arnold AG, Germany)
KeywordComplex Geometries, Parametric design & production, Geometry-Structure hybrid, Roll-bent plates, computational systems
AbstractThis paper describes the process of design and production of the aluminum sculptures that are part of the office building complex “die Welle” in Frankfurt/Main, Germany. The sculptures were executed by Arnold AG. It describes the process in which these complex geometries were designed using parametric tools in 3D modelling, which was then linked to the structural stability analysis in the same parametric system in order to activate structural stability through the geometry of the individual surfaces. The size and complexity of the geometries of each plate was far beyond normal accepted limits for a 4-roll plate bending process. Hence these sculptures show that parametric systems can be used effectively to create objects that may not be possible otherwise.

CS1Y-3, ID 1017 (Time: 15:10 - 15:30)
TitleStability of large-span aluminum reticulated domes with assemble connections
Author*Huihuan Ma, Yuqi Jiang, Feng Fan (School of Civil Engineering, Harbin Institute of Technology, China)
Keywordaluminum alloy, semi-rigid joint, reticulated shell, Stability analysis
AbstractBased on the bending stiffness curves of the improved TEMCOR joints, the finite element models of single-layer aluminum reticulated shells with semi-rigid joints are established. Parametric analysis of the reticulated shells is carried out using ANSYS. The parameters considered in the numerical simulation are bending stiffness, ratio of rise to span, asymmetric load distribution and initial imperfections. The influence of the different parameters on the critical loads and joint stiffness status is identified. Finally, formulae are derived for the calculation of critical loads of the shells which will be useful for design and application of single-layer aluminum reticulated shells with semi-rigid joints.

CS1Y-4, ID 1417 (Time: 15:30 - 15:50)
TitleExpanding the theory of accommodaptive architecture
Author*Johan Bernard (Jeroen) da Conceição van Nieuwenhuizen (University of Technology Eindhoven | supported by Avans University of Applied Sciences and MoveYou, Netherlands)
Keywordadaptive, accommodating, accommodaptive, flexible, structure
AbstractElaborating on the paper presented at the IASS2015 congress a further expansion of the theory how to build accommodaptive architecture is sought for. A focus towards buildings materialized with biobased materials is quantified and fit into the accommodaptive theory responding to the current paradigm shift (smaller footprint, Cradle to Cradle, Super Use, Re-Use, adaptivity, Trias materials) the building industry is undergoing.Part of the theoretical framing is the evaluation of accommodaptive details created by MoveYou of more than 20 different building systems (A). Next to that the first outlines and outcome of a tool (Flexibiliteit Calculator), created to quantify adaptability and accommodation into money (A.B.A. Hameetman) is described (B). The literature review is completed (C) and coupled to the outcomes of a Master course tutored on the University of Technology Eindhoven. Possible options to improve these building systems to make them more adaptive are described (D).

CS1Y-5, ID 1200 (Time: 15:50 - 16:10)
TitleComputer-controlled fabrication of a freeform stone vault
Author*Cristian Calvo Barentin, Matthias Rippmann, Tom Van Mele, Philippe Block (ETH Zurich, Switzerland)
Keyworddigital fabrication, CNC, CAM, 5-axis stone cutting, freeform vault
AbstractThis paper reports on the computer-controlled fabrication process of the individual stone blocks of the Armadillo Vault, an expressive funicular masonry vault constructed and exhibited at the 15th International Architecture Exhibition - la Biennale di Venezia. It focuses on the strategies followed to translate the digital model of the compression-only vault into a series of unique stone pieces, by addressing geometric, fabrication and time constraints.

Session CS2Y  Design of 21st century -2
Time: 16:40 - 19:00 Monday, September 26, 2016
Location: Gallery-1

CS2Y-1, ID 1516 (Time: 16:40 - 17:00)
TitleAdaptive Building Structures - Two Case Studies
Author*Gennaro Senatore, Philippe Duffour (University College London, U.K.), Pete Winslow (Expedition Engineering, U.K.)
Keywordadaptive structures, structural optimisation, shape control, embodied energy, metal spatial structures
AbstractThis paper demonstrates how adaptive design techniques can be employed to save over 40% of the whole life energy from large scale 3D structures. Using previously developed optimisation methodologies (details published elsewhere) two case studies are investigated: a long span arch bridge and an office tower supported by an exo-skeleton structural system. Assuming some statistical distribution for the occurrence of the loads, the whole energy (embodied and operational) can be minimised by only using activation for large load events. The purpose of the case studies described in this paper is to study: 1) the analysis of performances of adaptive structures in terms of mass and energy savings for both strength and stiffness governed design problems; 2) the scalability of the design process to complex spatial configurations. Both case studies confirmed that even on large complex structures, significant energy savings can be achieved, the more so for stiffness governed structures.

CS2Y-2, ID 1430 (Time: 17:00 - 17:20)
TitleDynamic Characteristics according to Natural Frequency Ratio between Dome Structure and Substructure
Author*Young-Rak Lee, Joo-Won Kang (Yeungnam University, Republic of Korea)
KeywordRibbed-dome, Latticed-dome, Substructure, Natural frequency, Natural Mode
AbstractThis thesis is a study on dynamic response characteristics according to natural frequency ratio between the upper structure and substructure of dome structures. A study investigates the dynamic response changes of dome structure according to property changes of substructure. The upper structure of shape variables sets up half-open angle and is modeled as ribbed-dome and latticed-dome. By standarding the first natural frequency of the upper structure having no substructure, the first natural frequency of substructure is changed as identical ratio. The natural mode shape and frequency were analyzed through eigenvalue analysis.

CS2Y-3, ID 1165 (Time: 17:20 - 17:40)
TitleStatistic analysis and the effect of orthotropic mechanical property on application of CFRP tendons
Author*Qinghua Han, Lichen Wang, Jie Xu, Yan Lu (Tianjin University, China)
KeywordCFRP tendons, Statistical analysis, experimental research, transverse mechanical property
AbstractThe use of carbon fiber reinforced polymer (CFRP) tendons instead of steel cables is a promising method for improving the overall performance of cable structures. However, compared with CFRP sheet, research of the CFRP tendons is insufficient. In this paper, the state of the art of the applications and researches of CFRP in engineering structures is summarized and analyzed according to the statistics results of academic papers. Based on statistics results, the research hotspots, problems, and developments of applications of CFRP tendons are proposed and summarized. At last, some new researches of the CFRP tendons about its orthotropic mechanical property are introduced and analyzed.

CS2Y-4, ID 1432 (Time: 17:40 - 18:00)
TitleVibration Control Performance Evaluation of Multiple Smart TMDs for an Arch Structure
Author*Lyeong-Kyeong Lee (Yeungnam University, Republic of Korea), Hyun-Su Kim (Sunmoon University, Republic of Korea), Joo-Won Kang (Yeungnam University, Republic of Korea)
KeywordSpacial arch structure, Seismic response control, Multiple smart TMD, Genetic algotirhm
AbstractMultiple smart tuned mass dampers (MSTMDs) were proposed in this study for vibration control of spatial structures. An arch structure was used as an example structure because it has primary characteristics of spatial structures and it is a comparatively simple structure. MSTMDs were applied to the example arch structure and the seismic control performance were evaluated based on the numerical simulation. The analytical results showed that the MSTMDs effectively decreased the dynamic responses of the arch structure subjected to earthquake loads compared to the conventional multiple TMDs.

CS2Y-5, ID 1424 (Time: 18:00 - 18:20)
TitleThe Effects of the Frame Section Shapes according to Geometrical Shape for Single-layer Lattice Dome
Author*Hwan-Mok Jung (Deptartment of Achitecture design, Kyungdong University, Republic of Korea), Seok-Ho Yoon (Deptartment of Civil Engineering, Kyungdong University, Republic of Korea), Cheol-Hwan Kim (Deptartment of Architectural Engineering, Kyungpook National University, Republic of Korea), Sung-Won Yoon (Seoul National University of Science and Techology, Republic of Korea), Dong-Woo Lee (I’ST Co., Ltd, Structure Engineering Group, Republic of Korea)
KeywordFrame Section Shapes, Geometrical Shape, Single-layer Lattice Dome
AbstractThe purpose of this study is to verify the reinforcement effect of buckling member and the stability effect of the frame section shapes according to geometrical shape for single layer latticed dome with 3-way grid.

Session CS1A  WG8: Metal Roofs -1
Time: 14:20 - 16:20 Monday, September 26, 2016
Location: Sanjo Main

CS1A-1, ID 1141 (Time: 14:20 - 14:40)
TitleReliability analysis of buckling load of reticulated domes of a circular plan under uniform snow load
AuthorShiro Kato (Toyohashi University of Technology, Japan), Takanori Oya (Tomoe Corporation, Japan), Toshimasa Yanagisawa (Toyohashi University of Technology, Japan), Kazuki Nakazawa, *Yoichi Mukaiyama (Tomoe Corporation, Japan), Shoji Nakazawa (Toyohashi University of Technology, Japan)
KeywordSingle layer reticulated dome, Snow load, Buckling strength, Load factor, Reliability index
AbstractThe present paper discusses on the relationship between the reliability index and global load factor which are both the key factors in design for buckling of single layer reticular domes. The load is restricted in this study to dead and uniform snow loads. Firstly an approximate formula for nominal buckling load is presented, then followed by a proposal for reliability performance function to evaluate the failure probability. The performance function is solved to derive the relationship between the reliability index and snow load factor for design. The relationship is then transformed to the relationship between the reliability index and global load factor. Several discussions about the results are given from a viewpoint of anti-buckling design with focusses on the effect of the imperfection for design.

CS1A-2, ID 1004 (Time: 14:40 - 15:00)
TitleSeismic Response Evaluation of Lattice Shell Roofs Using Seismically Isolated Bearings
Author*Toru Takeuchi, Takashi Miyazaki, Toshiyuki Ogawa (Tokyo Institute of Technology, Japan)
KeywordLatticed Shell, Seismically Isolated, Response Evaluation, Amplification Factor
AbstractSeismic isolation bearings are known to be effective at reducing the seismic response of latticed shell roofs. Although simple response evaluation methods have been proposed, they are limited to the condition that the elastic stiffness of the isolated layer is much lower than that of the supporting substructure, or that the weight of the substructure is relatively light. In this paper, simple seismic response evaluation methods for cylindrical lattice shell roofs are presented for the transverse as well as the longitudinal directions. In addition, methods are proposed for seismically isolated roof structures including isolated bearings with high initial stiffness and heavy substructures. Friction pendulum bearings are assumed for isolated bearings, and two different analytical models are compared for evaluating the response.

CS1A-3, ID 1138 (Time: 15:00 - 15:20)
TitleA Study on Evaluation of Dynamic Buckling Strength and Reliability of Single Layer Reticular Domes under Severe Earthquake Motions
Author*Toshimasa Yanagisawa, Shiro Kato, Shoji Nakazawa (Toyohashi University of Technology, Japan), Feng Fan (Harbin Institute of Technology, China)
KeywordSingle layer reticular dome, seismic load, dynamic buckling strength, reliability index, safety factor
AbstractThe present paper discusses on reliability of single layer reticular domes under seismic loads. First, on a basis of the mathematical formula derived previously by the authors for dynamic buckling load under dead load and seismic forces, the performance function for reliability is proposed. Secondly, a scheme for numerically obtaining the reliability index is formulated in terms of seismic acceleration intensity together with related probabilistic variables of yield stress, Young’s modulus and others. Finally, the reliability index is calculated by AFOSM method, and the relationship between the reliability index and the design load factor is clearly investigated for a certain reference period for seismic forces.

CS1A-4, ID 1016 (Time: 15:20 - 15:40)
TitleInfluence of Connection Stiffness and of Imperfections on the Stability of a Grid Shell
Author*Christian Stutzki, John Knowles, David Miklosi (STUTZKI Engineering, Inc., U.S.A.)
KeywordGridshells, stability, connections
AbstractThis presentation is about the robustness vs. sensitivity of two grid shells currently under construction. The stability of grid shells is influenced by many factors, like slenderness of the members, shallowness of the overall geometry, building tolerances, stiffness of boundary conditions, bending capacity of connections, and loads. This concept is applied to the current grid shell even though the shapes are not perfect spherical domes but domes with elliptical footprint. The connection technology is discussed in depth, and how additional bending stiffness of the connections reduces the sensitivity, and increases the robustness and the reliability. The connection technology, in form of bolted connections between the beam-type members and the nodes has a beneficial impact of construction cost and construction time, as will be shown in detail. The detail design of the connection is also discussed in view of low-cycle fatigue, a frequent reason for failures of buildings in seismic areas.

CS1A-5, ID 1352 (Time: 15:40 - 16:00)
TitleElasto-plastic seismic response behavior and evaluation of allowable deformation of single layer lattice domes with geometric initial imperfection
Author*Tomohiko Kumagai, Daiki Yamana (Meiji University, Japan), Toshiyuki Ogawa (Tokyo Institute of Technology, Japan)
Keywordsingle layer lattice dome, elasto-plastic seismic response behavior, geometric initial imperfection, plastic rotational angle, evaluation of allowable deformation
AbstractIn this paper, the elasto-plastic dynamic response behavior of the single-layer lattice domes with geometric initial imperfection subjected to earthquake motions in the horizontal and vertical directions is investigated by numerical analysis. In addition, the allowable plastic deformation of domes is evaluated by focusing attention on the nodal rotation angles and the rotational angles at center of members. Methods of analyses are a natural vibration analysis and a dynamic response analysis which takes into account the geometrical and material nonlinearities. From the numerical results, it is concluded as follows. 1) The initial yield accelerations of lattice domes with geometric initial imperfections which are similar to the shapes of the predominant vibration modes with short wavelength decrease compared with those of lattice domes without imperfection. 2) The allowable deformation of plastic rotational angles at center of members is evaluated with 0.025rad for the domes in this examination.

CS1A-6, ID 1176 (Time: 16:00 - 16:20)
TitleElasto-plastic behaviour of long-span steel structures for snow load
Author*Yuichiro Ishinabe, Ryoki Kameyama, Hajime Nakajima (Nihon University, Japan)
Keywordsnow load, return period, snowproof design, steel structures, metal structures
AbstractDuring 14th to 16th of February in 2014, a number of steel buildings were damaged by heavy snow in the capital region of Japan. As for long-span steel roofs (e.g. gymnastic hall), some cases of complete collapse were reported. In this paper, first of all, snow load is analyzed based on the fact of this disaster. And then, focusing of some structural types of steel roof, the elasto-plastic behaviour is examined through numerical analyses in order to obtain fundamental information for snowproof design of steel structures. Static elasto-plastic analyses of some type of steel roofs are carried out. The characteristics as a snowproof structure are examined. In this paper, 3 types of 30m-span girder that support roof are focused, (1) single wide flange, (2) truss structure, (3) beam string structure.

Session CS2A  WG8: Metal Roofs -2
Time: 16:40 - 19:00 Monday, September 26, 2016
Location: Sanjo Main

CS2A-1, ID 1078 (Time: 16:40 - 17:00)
TitleThe application of free-form grid shells as protective shelters in archaeological sites
AuthorOrnella Iuorio, *Eiki Homma, Konstantinos Tsavdaridis (University of Leeds, U.K.)
Keywordarcheological sites, conceptual design, dynamic relaxation method, free-form finding, genetic algorithm
AbstractThe challenge of preserving archaeological sites by the adoption of grid shells is investigated in this paper. Archaeological remains often require protection from external agents, especially environmental threats. In fact, when covered by soil, they are preserved effectively under certain equilibrium conditions. Nonetheless, when exposed to the outer environment they can easily deteriorate. Therefore, a shelter or enclosure may be provided for protection. When a large area requires protection, steel structures such as portal frames or two-dimensional trusses are extensively employed. These have a heavyweight character and require deep foundations, the construction of which is substantially limited in archaeological sites, and increases the risk of damage during erection. Through the development of an extensible free-form grid shell design with a minimum weight, maximum stiffness and constructability approach, the potential application of shelters for archaeological sites is evaluated. This study involves a parametric investigation and considers the worst-case scenario conditions

CS2A-2, ID 1264 (Time: 17:00 - 17:20)
TitleBuckling strength of steel tubular members related to semi-rigidity of gusset-plate connection for spatial structures
Author*Takanori Oya (TOMOE Corporation, Japan), Shun-ichi Takagi, Jun-ya Okazaki (Tomoe Corporation, Japan), Shiro Kato (Toyohashi University of Technology, Japan)
Keywordtubular member, buckling stress, semi-rigid, experiment, design formula
AbstractA steel tubular member with gusset plate connection has been often applied in spatial structures, commonly for single layer and double layer lattice structures. In some cases, the buckling length of the tubular members tends to be longer than the distance between both end nodes. Then the buckling capacity of the spatial structures is much influenced totally by the rigidity of gusset plate, however, there is only a few number of studies concerning the effects to buckling capacity. First, this paper reports a series of buckling experiments for the effect of the gusset plate connection with different plate thickness, and secondly discusses the results from a viewpoint of buckling strength of the steel tubular member with gusset plate connection for design based on comparison with analytical studies. Finally, the present paper clarifies that a certain thickness for the gusset or rib-reinforcing to the gusset is much effective to improve the buckling strength of the member.

CS2A-3, ID 1015 (Time: 17:20 - 17:40)
TitleNumerical analysis on hysteretic behavior of aluminum alloy gusset joints
AuthorLinlin Liu, *Xiaonong Guo, Renpeng Wang, Yongfeng Luo, Zhe Xiong (Tongji University, China)
Keywordaluminum alloy gusset joints, hysteretic behavior, skeleton curve, ductility ratio, energy dissipation coefficient
AbstractAluminum Alloy Gusset joints (AAG joints) have been widely used in single-layer reticulated shells in recent years. To reveal more information on the hysteretic behavior, a numerical study on AAG joints under cyclic out-of-plane moment is presented in this paper. One sixth of the joint was modelled numerically considering the symmetry of geometry and load conditions. It is shown that the behavior of AAG joints in the whole loading process can be roughly divided into 5 phases: elastic stage, bolts slipping stage, the yielding stage, the peak stage and failure stage. The failure modes include the buckling of member web and the block tearing of gusset plate. Hysteretic curves are plump in general and significantly influenced by the bolts slipping. The energy analysis indicated that the inelastic deformation was the main energy dissipation mechanism. AAG joints can provide ideal ductility and large energy dissipation under cyclic out-of-plane bending moment.

CS2A-4, ID 1094 (Time: 17:40 - 18:00)
TitleAlgorithms Behind Building Envelopes
Author*Dimitry Demin (algotecture.net, Singapore)
Keywordfaçade design, glass envelopes, BIM, parametric design, algorithmic architecture
AbstractIn recent years, an interdisciplinary approach for engineering and constructing design of complex geometry building envelopes has been growing. In this context the aim of this paper is to present an overview of computational design tools in the context of computer-automated design process of feasible buildings.

CS2A-5, ID 1006 (Time: 18:00 - 18:20)
TitleStability and serviceability design for tilting footbridges supported by cable-arch systems
AuthorQilin Zhang, Xiaoqun Luo (Tongji University, China), Debao Li (Shanghai Tonglei Civil Engineering Co. Ltd., China)
Keywordstablility, serviceablity, cable-arch, footbridge

Session CS1B  New Materials and New Construction Methods -1
Time: 14:20 - 16:20 Monday, September 26, 2016
Location: Main Foyer

CS1B-1, ID 1020 (Time: 14:20 - 14:40)
TitleExperiences with new space structures materials
Author*Stefan Reich (Anhalt University of Applied Sciences, Germany), Jan Ebert (Technische Universität Dresden, Germany)
Keywordspace grid structure, loadbearing glass, roof, in-plane loaded glass
AbstractSpace grid structures experienced their summit the third quarter of the last century. The structural principles were described and thousands of steel space grid structures built. Nowadays advancement of space grids only happen in the use of new materials replacing structural elements. In 2016, the authors are pleased to announce that since seven years a new type of space grid structures perfectly have fulfilled its task in the German capital Berlin.The structure bases on a steel double layer grid, but all members in the compression layer are replaced by glass panes. The glazing serves either as the primary load bearing system or roof covering. The glass pane corners are fixed in steel knots and transfer in-plane forces via adjustable high performance plastic blocks.The structure has been monitored since seven years and proofed the designed long time characteristics of proper plastic materials within a new, sophisticated space grid structure.

CS1B-2, ID 1054 (Time: 14:40 - 15:00)
TitleMulti-transformable and Non-Rigidly Folding of Kresling Cylindrical Origami
Author*Ruijun Ma, Jianguo Cai, Jian Feng, Ya Zhou (Southeast University, China)
Keywordorigami, multi-transformable, cylinder, rigid foldability, deployable/foldable structures
AbstractRigid origami is seen as a fundamental model in many self-folding machines. A key issue in design rigid origami is the foldability. The kinematic and foldability of Kresling origami, which based on an origami pattern of the vertex with six creases, are studied in this paper. The description of the movement of the single-vertex is firstly discussed. Based on the quaternion rotation sequence method (QRS method), the loop-closure equation of the vertex with six creases is obtained. Then the multi-transformable behavior of the single vertex is investigated. Furthermore, the rigid foldability of origami patterns with multi-vertex are investigated with an improved dual quaternion method, which is based on the checking of the folding angle and the coordinates of all vertices. It can be found that the Kresling cylinder is not rigidly foldable.

CS1B-3, ID 1068 (Time: 15:00 - 15:20)
TitleDesign of a new type of interlocking brick and evaluation of its dynamic performance
Author*Anooshe Rezaee Javan, Hamed Seifi, Shanqing Xu, Yi Min Xie (RMIT University, Australia)
Keywordinterlocking structure, osteomorphic brick, dynamic behavior, impact force
AbstractDespite the increasing interest in topological interlocking structures made of identical elements, only one type of interlocking brick has been extensively studied so far, with very limited focus on their dynamic behaviour. In this paper, a new design of interlocking brick was proposed, which had a symmetrical geometry with four curved side surfaces to be interlocked with adjacent elements. The dynamic mechanical behavior of the new brick was numerically investigated and compared to that of the existing interlocking brick and the monolithic plate. The deformation patterns and the energy absorption capacity of interlocking structures were also studied. The results showed that the newly designed interlocking brick had intermediate contact forces and much more uniform load and stress distribution during the impact. Moreover, its energy absorption capacity was the largest.

CS1B-4, ID 1071 (Time: 15:20 - 15:40)
TitleBending stiffness of three layered plates of a rectangle shell made of flat plates and bolts, and Improvement of model figure by minimizing the sum of curvatures between the elements
Author*Shigehiro Morooka (Tokai University, Japan)
Keywordshell, flat plate, bolt, stiffness
AbstractThe author has proposed the construction method to make a shell surface made of flat plates and bolts. In this method, two or three bending plates are superposed and fixed. As we know, we can easily bend a flat plate in one direction, and superposing two or three plates bending in different directions makes clearance between the plates, and we cannot easily estimate the stiffness of this curvature. The first purpose of this paper is to estimate the bending stiffness especially for seismic design. To estimate the stiffness by using the thickness of the plates, I made a FEM model and changed the plate thickness to accord the vibration frequency of small assembled model. The second purpose is to reduce the difference between drawings and the assembled model. To reduce the difference, I changed nodal positions to reduce sum of squares of curvatures and checked its validity.

CS1B-5, ID 1109 (Time: 15:40 - 16:00)
TitleStructural engineering for a low-rise, single-layer lattice frame using H-section steel main members
Author*Masahiro Uekusa, Hiroyuki Matsuzaki, Hideyuki Ito, Akihisa Yamamoto (Takenaka Corporation, Japan)
KeywordLow-rise single-layer lattice, JIS standard H-section steel, buckling analysis, 3D-CAD, analysis for the construction and the erection
AbstractA low-rise single-layer lattice frame using H-section steel as the main members was adopted for the gymnasium roof structure for the 2 buildings of the Main Arena and Sub-arena of the "St.Margaret's School Gymnasium 2014", to reduce the construction cost, to meet the requirements of the architectural scheme, and to improve productivity. However there were no precedents for the application of H-section steel as the main members, so there were many issues to be resolved. This paper describes the methods to resolve these issues at each stage of structural design and construction planning.

Session CS2B  New Materials and New Construction Methods -2
Time: 16:40 - 19:00 Monday, September 26, 2016
Location: Main Foyer

CS2B-1, ID 1268 (Time: 16:40 - 17:00)
TitleComfortable space achieved by functional ETFE film
AuthorHirosi Aruga (Asahi Glass Co., Ltd., Japan), *Seiji Mastuda (AGC Green-Tech Co.,Ltd., Japan)
KeywordETFE, durability
AbstractThe membrane structures using the ETFE film are applied as sport facilities. The category of "the film for membrane structure" was established to construction materials of Japanese Building Standard Act Article 37 in October, 2014. 60µm ETFE film has been used as greenhouse covering materials in Japan from 1987, and after 28 years later, films are working now. ETFE is superior to PVF, PVdF and ECTFE in weather durability and bending property. But 10% modulus and bending property is different depending on composite of co-polymer and molecular weight. Sun light (UV, Visible, and NIR) can pass through more than 90% transmittance, so ETFE film cannot make comfortable space for human activity because it is too hot and too bright. We have developed the transmittance & reflection controlled ETFE films by colored, UV-blocking, NIR-blocking, and silver ink. We report how to produce functional ETFE film and these durability.

CS2B-2, ID 1278 (Time: 17:00 - 17:20)
TitleComplex concrete casting: knitting stay-in-place fabric formwork
Author*Mariana Popescu, Matthias Rippmann, Tom van Mele, Philippe Block (ETH Zurich, Switzerland)
Keywordknitted fabric formwork, textile reinforcement, stay-in-place formwork, complex concrete geometry
AbstractThe paper presents initial results of research focused on developing a novel type of formwork for concrete based on pre-stressed fabric formwork principles. It aims at creating geometries that are fabricated in one piece by knitting technical fibers, which could ultimately be used as reinforcement for concrete. This approach would result in a spatial textile that minimises the need for patterning, sewing, welding or gluing compared to a conventional approach to fabric formwork and textile reinforcement based on woven fabrics. It makes it possible to create directional material properties aligned to the internal force flow. This paper presents an overview of the proposed prefabrication technique and exemplifies its feasibility through small-scale experiments.

CS2B-3, ID 1302 (Time: 17:20 - 17:40)
TitleCrafted variation in FRP: Resilience by fabric materiality
Author*Arielle Blonder, Yasha Jacob Grobman (Technion Institute of Technology, Israel)
Keywordfabric, architecture, FRP, self organisation, resilience
AbstractThe basic principle of living matter, being structured as fibres and matrix, is often taken as a reference for the design of FRP materials.. Biological design principles, such as self-organisation and variation stand in contrast to standard design and fabrication of architectural FRP and therefore call for alternative processes. Introducing the concept of Fabric Materiality, the research suggests an alternative fabric based approach to design and fabrication that relies on textile’s inherent attributes. Through a case study, the paper examines the potential of developing a resilient FRP structure by employing principles extracted from the biological resilient model of a bird’s nest, relying on the integration of Fabric materiality. Transposing these principles into a FRP structure faces the challenge of structured randomness at the structure level and crafted variation at the component level. The resulting structure is extremely light, self-supportive and resists lateral loads, is varied and demonstrates resilient properties.

CS2B-4, ID 1319 (Time: 17:40 - 18:00)
TitleGrammar-based Rhombic Polyhedral Multi-Directional Joints and Corresponding Lattices
Author*Zhao Ma (Massachusetts Institute of Technology, U.S.A.), Pierre Latteur (Université catholique de Louvain, Belgium), Caitlin Mueller (Massachusetts Institute of Technology, U.S.A.)
Keywordpolyhedra, lattice, joint, puzzle, drones
AbstractThis paper presents a new type of joint derived from traditional Chinese and Japanese wooden puzzles. A rule-based computational grammar for generating the joints is developed based on the relationship between the three-dimensional shape and its two-dimensional “net”. The rhombic polyhedra family, cube, rhombic dodecahedron, and rhombic triacontahedron are fully explored in the paper as they are the central part of the joints and is enclosed by all the elements around. This paper also presents lattices derived from these joints, and provides structure analysis to compare the structural performance of these lattices. The non-orthogonal lattices provide new way of looking at lattice structures and also provide new challenges and opportunities for designing assembly techniques by hand, robotics, and drones.

CS2B-5, ID 1413 (Time: 18:00 - 18:20)
TitleFoldfinding- a novel approach to the design and fabrication of folded structures
Author*Tal Friedman (Tal Friedman Architecture & Design, Germany)
Keywordfolded structures, origami, thin shell, self supporting, computational optimization
AbstractThe paper describes the design and fabrication process of a folded Origami inspired pavilion created from Composite Aluminum boards. It is a case study of a novel general approach for folded structures. The project tries to incorporate traditional Origami folding techniques in the realm of architecture by introducing a fabrication method which does not only resemble Origami in its exterior form but is also fabricated in a similar fashion by folding the material to its final position. An approach was developed in order to produce an adaptable system that would incorporate construction details and optimize itself for fabrication restraints and material thickness using digital algorithms. When folded to its predetermined form, the structure would prove to be a self supporting thin shell monocoque without the need for a sub structure while incorporating a cantilever on both ends. The project was analyzed with a designated FEA approach developed for the project.

Session CS1C  WG6: Tension & Membrane Structures -1
Time: 14:20 - 16:20 Monday, September 26, 2016
Location: Room 001

CS1C-1, ID 1018 (Time: 14:20 - 14:40)
TitleAn extension of the Natural Force Density Method to quadrangular elements
AuthorFagner Lopes Fernandes, *Ruy M.O. Pauletti (Polytechnic School of the University of São Paulo, Brazil)
KeywordNatural Force Density Method, Membrane Structures, Shape finding
AbstractThe Force Density Method (FDM), first proposed by Linkwitz and Scheck in 1974 is a convenient alternative for finding configurations of cable nets and membranes, since it provides viable geometries in a single linear equilibrium analysis. The Natural Force Density Method (NFDM) is an extension of the FDM to the shape finding of membrane structures, which preserves the linearity of the original method and overcomes the difficulties of the original method to deal with irregular meshes. It was first suggested by Pauletti in 2006 [1], [2], based on a triangular membrane element introduced by Argyris in 1974. The original NFDM required the use of meshes composed exclusively of triangular elements. This paper presents an extension of the method to quadrangular elements, considering an equivalent assembling of flat triangular elements and compares several results obtained with fully triangulated meshes, as required by the original NFDM.

CS1C-2, ID 1085 (Time: 14:40 - 15:00)
TitleOn the General Purpose Computational Program for Nonlinear Analysis of Tensile and Membrane Structures
Author*SeungDeog Kim (Semyung University, Republic of Korea)
KeywordNonlinear analysis, Membrane structure, Form finding, Seoul dome, NASS
AbstractSpatial structures have to be analyzed by considering geometric nonlinearity, and the nonlinear problem is very sensitive to initial conditions. The efficiency of a computer program depends on the possibility of convergence and the speed in nonlinear procedure. This study introduces NASS, short for Nonlinear Analysis for Spatial Structures - not a commercial nonlinear analysis program under development. NASS, the first of its kind, is being developed for both soft and hard structures to get nonlinear solutions and to target a general purpose computational program. Using examples NASS ability in both soft and hard structures is proved.

CS1C-3, ID 1091 (Time: 15:00 - 15:20)
TitleShaping of conoid membrane structures with unequal biaxial stresses: a summary
Author*Slade Gellin (Buffalo State College, U.S.A.), Ruy M. O. Pauletti (University of Sao Paulo, Brazil)
Keywordshaping, conoid, biaxial
AbstractA summary of the work done for over a decade on the shaping of conoid membrane structures with unequal biaxial stresses is presented in an order that reflects, in hindsight, the body of knowledge accumulated on the subject. Critical results from the previous work are presented with a new point of view that reflects this evolution of understanding of the subject.

CS1C-4, ID 1112 (Time: 15:20 - 15:40)
TitlePrestressing force distribution and static behavior analysis of wheel-spoke crossed cable structures
Author*Zongyu Hu (Tongji University, China), Jun Wang, Jida Zhao (China Academy of Building Research, China)
Keywordwheel-spoke crossed cable structures, prestressing force distribution, static behavior
AbstractA new type of spatial cable-strut structure called wheel-spoke crossed cable structure (WSCCS), which is originated from traditional wheel-spoke cable structure (WSCS), is proposed. Based on different topology and connection method, WSCCSs can also be divided into five different structural types. Method for prestressing force distribution analysis of WSCCSs is put forward. In order to analyze the static behavior of WSCCSs, five calculation models with variation of geometric parameters in each structural type are introduced, and are analyzed under different load cases by ANSYS. The results show that WSCCSs have an excellent load-carrying capacity and good global structural rigidity, and have broad application prospects.

CS1C-5, ID 1122 (Time: 15:40 - 16:00)
TitleMembrane stadium projects in Japan - development, characteristic and maintenance -
Author*Akihiro Noguchi, Yoshihito Saito, Kenji Ohya, Jun Kitamura (Taiyo Kogyo Corporation, Japan), Masao Saitoh (Nihon University, Japan)
Keywordcurved membrane, flat membrane, tension membrane, pre-stress, maintenance
AbstractIn anticipation for the 2002 FIFA World Cup games joint hosted by Japan and Korea, many stadiums were constructed in Japan. Out of the ten newly constructed stadiums, six featured membrane roofing structure. This paper introduce the membrane structure stadiums in Japan, from those mainly focused around 2002. To verify the reason for applying membrane roofing to stadiums, the characteristics of the stadiums with membrane roofing and its heat and light environment is explained. In addition, the future of membrane roofing on stadiums is discussed. The stadium membrane’s current condition and the inspection situation is reported to show the maintenance condition after 16 years from completion.

CS1C-6, ID 1048 (Time: 16:00 - 16:20)
TitleStaged constructional study and detail connection analysis for cable membrane roof structures
AuthorWenrui Liu, Xiaoqun Luo, Qilin Zhang (Tongji University, China), Debao Li (Shanghai Tonglei Civil Engineering Co. Ltd., China)
Keywordcable-membrane system, construction analysis, cable clamp connection

Session CS2C  WG6: Tension & Membrane Structures -2
Time: 16:40 - 19:00 Monday, September 26, 2016
Location: Room 001

CS2C-1, ID 1196 (Time: 16:40 - 17:00)
TitleDesert city bubble roof
Author*Santiago Guerra, Julio González, Guillermo Capellán (Arenas&Asociados, Bridge Designers, Spain), José María Lastra (Lastra&Zorrilla, Arquitectura Textil, Spain)
KeywordRoof, ETFE, Tensigrity, Form Finding
AbstractDesert City Ltd, Spanish pioneer xeriscaping company is settling its Headquarters office in San Sebastián de los Reyes, Madrid (Spain). The building is composed by two volumes connected by walkways, having the main building a 1,575 m2 (37 m x 42 m) exhibition cactus courtyard intended to be covered by a light a permeable roof. What better solution than an ETFE foil roof to provide a perfect showroom inside a bubbling greenhouse? The roof consists in a rigid steel frame with four longitudinal steel beams as Primary Structure. The void between beams is filled with ETFE cushions reinforced with Transverse Tensigrity Beams, made-up by cables and steel strut-masts due to the span, 9.5 m that those ETFE cushions must cover between the longitudinal beams. These masts, observed from the courtyard will provide a sensation in the spectators of a sea of scattered cactus spikes floating inside Cumulus Clouds.

CS2C-2, ID 1198 (Time: 17:00 - 17:20)
TitleA comparison of alternative form finding methods in ixCube 4.10 program
AuthorRenan Prandini, *Ruy M.O. Pauletti (Polytechnic School at the University of São Paulo, Brazil)
KeywordForm finding, FDM, NFDM, URS
AbstractThis paper presents a comparison of three different form finding methods available in ixCube 4.10, a specialized software for the design and analysis of membrane structures. A variety of membrane models with different geometry are evaluated, considering the computer time, resulting geometry, and tension distribution, as provided by the Force Density Method (FDM), the Natural Force Density Method (NFDM) and Updated Reference Strategy (URS).

CS2C-3, ID 1416 (Time: 17:20 - 17:40)
TitleStability of Cable-stayed Masts in Tensioned Fabric Structures
Author*Sudarshan Krishnan (University of Illinois at Urbana-Champaign, U.S.A.)
KeywordCable stay, buckling, prestress, mast, column
AbstractStayed-columns or masts have found application in both flexible and rigid structures. Tensioned fabric structures use them as the principal compression members to provide equilibrium to the high tension forces from fabric membrane and cables. The stiffness of a mast has to be large enough to overcome instability due to buckling. The transformation of a tube section by adding cross-arms and prestressed stays substantially increases the load-carrying capacity of tall and slender masts. The use of cables, the presence of prestress and inherent nonlinearities, all contribute to the intricate behaviour of stayed-masts. For some stayed-masts, the anti-symmetric (or two-lobe) mode may govern design, which is uncharacteristic when compared to regular column design. There is still a lot to be learned, recognized and understood about the behaviour of stayed masts. By understanding their behaviour, structural designers can benefit from using a lightweight compression member with enhanced strength and stiffness.

CS2C-4, ID 1469 (Time: 17:40 - 18:00)
TitleCable-nets and Tensioned Membrane Structures: Insights from the Form-finding Process
Author*Jienan Zhang (Sowlat Structural Engineers, U.S.A.), Sudarshan Krishnan (University of Illinois at Urbana-Champaign, U.S.A.)
Keywordcable-net, structural behaviour, form-finding, prestress, membrane
AbstractCable-nets and tensioned membrane structures demonstrate unique behaviour due to their flexibility. Geometrical nonlinearities play a significant role in both form-finding and force analysis. Advancements in solution methods to nonlinear problems and commercially available programs have made parametric studies an efficient endeavour. This paper provides insights about the parametric effects in structural behaviour during the form-finding process for cable-nets and membrane structures. A series of hypar and cone forms were investigated were examined; the effects of different prestress levels and span-to-height ratios were studied. The behaviours are compared and observations are presented. The form-finding analysis was done using the program RFEM that employs the Updated Reference Strategy (URS) based on iterative regularization of the stiffness matrix during the process. This work is a prelude to the ongoing parametric study on structural behaviour of prestressed configurations under external loads.

CS2C-5, ID 1003 (Time: 18:00 - 18:20)
TitleDynamic analysis of a tensioned bamboo roof
Author*Reyolando Brasil (Federal University of ABC, Brazil), Marcia Yamamoto Sato (University of São Paulo, Brazil)
Keywordtensioned roof, bamboo, wind, dynamics, random vibrations
AbstractWe present a nonlinear random time domain analysis of a 3D hyperbolic paraboloid tensioned latticed bamboo roof. Fluid-structure interaction forces are divided in one concerning average wind velocity, another related to fluctuation around average, of random nature. The computer program solves vector equations of motion via the Central Difference Method. Masses and damping are considered lumped. We compute large displacements and restoring forces at each time step, using an appropriate bamboo stress-strain relationship. We simulate wind by superposition of harmonic loads with randomly set phase angles and amplitudes taken from Davenport PSD bands. The results are a large series of displacements and member tractions for determining characteristic design values, using Gumbel probability density function. This is a Monte Carlo type simulation.

Session CS1D  WG12+18: Timber & Environment -1
Time: 14:20 - 16:20 Monday, September 26, 2016
Location: Room 002

CS1D-1, ID 1535 (Time: 14:20 - 14:50)
TitleAnalysis of the Spatial Configurations of 17 Basic Wooden Frames using the Theory of Material and Skeletal Energy
Author*Norihide Imagawa (Tokyo Denki University, Japan)
Keywordthe theory of material and skeletal energy, structure design, material, wood, global warming
AbstractThroughout the 40 years of my career, I have worked with various types of architectural construction materials from over 25 countries, and used them in the diverse spatial structures of over 2500 design projects. Once materials are adapted to spatial skeletons and completed as an architectural structure, deterioration begins due to natural forces of nature (gravity, earthquake, typhoon, etc.). This theory of material and skeletal energy explicates how materials function in spatial skeletons under various environmental conditions, in quantitative form. In this research, wood is the primary structural material, which is procurable across the globe, easy to process and ecological. Furthermore, the theory analyzes the energy volume of material used for architecture as a whole and the energy between material and skeleton; and it may act as a guide toward better solutions to global warming (reduction of CO2), one of the most important themes in the twenty first century.

CS1D-2, ID 1312 (Time: 14:50 - 15:10)
TitleEngineered timber - innovative approaches for its structural enhancement
Author*Martin Trautz (Chair for Structures and Structural Design, RWTH Aachen University, Germany)
Keywordglue-laminated timber, continuously-threaded-screws, load-introduction-tests, load-deformation-behavior, Digital Image Correlation
AbstractTimber is a natural and early time building material which is very closely connected traditional workmanship. At the same time, it is also a modern material, because it is efficient and sustainable - as it binds carbon-dioxin. The evolution of manufacturing processes of man-made materials like screws and their combination with timber, e.g. as reinforcement, allows for a much more efficient utilization of this natural material than before and broadens its application in structural engineering and beyond. This paper presents innovative approaches to investigate the material behaviour of timber and to enhance its structural performance using continuously-threaded-screws as reinforcement or joining element. Hereto, results of stress and –strain-distribution investigations in loaded specimens based on Digital Image Correlation (DIC) are presented. Based on visualizations, which provide a first time overall view of the strain-distributions in timber elements, loaded through continuously-threaded-screws, conditions were derived for dimensioning and the bond-behaviour of screw-reinforced timber.

CS1D-3, ID 1489 (Time: 15:10 - 15:30)
TitleTECH Transportable Emergency Cardboard House
Author*Jerzy F. Latka (Delft University of Technology, Netherlands)
Keywordemergency, architecture, cardboard, paper, structures
AbstractTransportable Emergency Cardboard House is lightweight, sustainable and energy efficient cardboard structure designed to be used as an emergency house for a refugees and victims of natural and human-made disasters. The structure of the house is composed of materials based on paper . The project aims to create small easy to transport and build by non-professionals housing, education or health-care units. Usage a common products from paper industry allows to create cheap and energy efficient in whole life-cycle structures: the production process (recycled material), transportation (lightweight), assembly (no need for heavy equipment), usage (better insulated that given contemporary solutions) and demolition (recycling of the used components). TECH is designed to be produced off-side and transport to the site in form of components. The project was a design task of the Bucky Lab students at TU Delft during summer semester 2014/15. The prototype of TECH was constructed at TU Delft campus.

CS1D-4, ID 1257 (Time: 15:30 - 15:50)
TitleDesign of a grid shell glulam structure connection using glued-in steel rods
Author*Guirong He (Tongji Architectural Design (Group) Co., Ltd., China), Minjuan He (Department of Structural Engineering, Tongji University, China)
Keywordglulam, grid shell structure, glued-in steel rods connection, bearing capacity, bending stiffness
AbstractThis paper presents the connection design of a large-span glulam restaurant building, where the building roof is a typical grid shell structure supported by alternating V-shaped columns on top of basement. In order to meet the requirements of structural lateral stiffness and architectural appearance, a new type of glued-in steel rods connection was designed, in which the steel plates were completely inserted in glulam beams. According to foreign and domestic relevant specifications, the behavior of this type of connection, including capacity and stiffness, is researched theoretically and experimentally. The results of experiments and design calculations are compared to validate the design method, and that the glued-in steel rods connection has high bearing capacity and enough bending stiffness.

CS1D-5, ID 1238 (Time: 15:50 - 16:10)
TitleBreathable Carapace – Designing Climate-Adapted Filtering for Precipitation, Airflow and Luminance
Author*Daniel James Prohasky, Nicholas Williams, Jane Burry (RMIT University, Australia)
Keywordcomplex vault, complex geometry, solar performance, precipitation, passive ventilation
AbstractThis paper includes a brief description of the influence of physical fabrication processes on the design of a breathable cladding system. We combine knowledge from the fields of geometrical panelisation of freeform surface geometry and contemporary approaches to digital fabrication, with applications from wind studies and thermal comfort literature. Methods and processes involved in the design of an environmentally-driven cladding system are examined through detailing the case study cladding system for the Smart Nodes prototype pavilion. The parametric system logic for panelisation is cellular at the macro and micro scale. It responds to local climate and immediate microclimatic fluctuations. It does this through the articulation of its cells and passively functioning sub-cell structures. The design solution presented as a case study for the design methodology is a flexible system that can be applied in various climates for free-form open-air shelters.

Session CS2D  WG12+18: Timber & Environment -2
Time: 16:40 - 19:00 Monday, September 26, 2016
Location: Room 002

CS2D-1, ID 1079 (Time: 16:40 - 17:00)
TitleAre today's design and construction practices more environmentally compatible?
Author*Petr Vegh (exp Services Inc., Canada)
KeywordEnvironmental compatibility
AbstractThe environmental pollution of the atmosphere, soil and water resulted from the rapid and uncontrolled growth of industry and population which took place in the decades after the Second World War and in a variety of forms still continues until the present day. This growing pollution prompted new trends in engineering and architecture which would attempt to address the problems associated with these negative impacts on the environment. Since approximately the mid 1990’s various initiatives and measures have been put forth in an attempt to make current construction practices more environmentally compatible or, as the terms are sometimes used, sustainable or “greener”. The paper examines some aspects of three three structural systems widely used in Canada and the US as well as selected design and construction practices currently used in Canada and attempts to discuss how and if their Environmental Compatibility has changed and potentially improved since the 1990’s.

CS2D-2, ID 1421 (Time: 17:00 - 17:20)
TitlePreliminary Research on Thermal Performance and Energy Saving Effect of a Void Space of a room with a Retractable Membrane Ceiling
Author*Junbin Ma, Ken'ichi Kawaguchi (The University of Tokyo, Japan)
KeywordRetractable Membrane Ceiling, Indoor Thermal Environment, Energy Saving Effect, Detached Housing, Opening Ceiling Space
AbstractRecently in Japan, membrane is often employed as safer ceiling for large span building because of its material advantages of lightweight and soft property. Furthermore, membrane ceiling may improve the indoor thermal environment and energy efficiency by separating air flow, which was already studied through field measurement in large span indoor swimming pool [1]. The aim of this paper is to represent another case of this effect with field test in detached housing with opening ceiling space. The filed measurement of membrane ceiling in real detached housing was conducted to investigate the ability of blocking air flow from the living space to ceiling space in winter with air conditioner. The temperature difference between the top and bottom of membrane ceiling is measured to investigate the ability of blocking air flow, and the air temperature in living space was measured to study its effect on indoor thermal environment.

CS2D-3, ID 1487 (Time: 17:20 - 17:40)
TitleMulti-Scalar Modelling for Free-form Timber Structures
Author*Paul Poinet, Paul Nicholas, Martin Tamke, Mette Ramsgard Thomsen (CITA: Centre for Information Technology and Architecture, Denmark)
Keywordmulti-scalar modelling, glue-laminated timber, segmentation, discretization, optimization
AbstractThis paper describes a new conceptual and computational framework that employs Multi-Scalar Modellingtechniques in order to overcome the problem of big data management and to enable a moreintegrative digital workflow during the geometrical discretization of spatial structures.The research explores the design probe of free-form structures composed of glue-laminated timber beamsand looks at the different types of data that need to be shared among each discipline and across multiple scales from which different levels of resolution can be defined.A particular focus lies in the segmentation strategy of glue-laminated timber structures that depend onstructural requirements and the different types of constraints related to fabrication, transportation and assembly. Where current working practices decouple segmentation processes within a discrete digitalworkflow, this research aims to integrate and negotiate the different parameters that drive the samesegmentation strategy within a continuous environment.

CS2D-4, ID 1320 (Time: 17:40 - 18:00)
TitleSimulation and analysis of an irregular cable-supported thin timber shell roof structure
Author*Yongliang Sun (Tongji Architectural Design (Group) Co., Ltd., China), Minjuan He (Department of Structural Engineering, Tongji University, China)
Keywordthin timber shell, cable-supported structure, glulam, structural analysis
AbstractDimension lumber and plywood panel are widely applied to the light wood structures. Meanwhile, the application of the cable-supported structures is popular due to their lightweight and aesthetic features. The cable-supported thin timber shell introduced in this article is combined by dimension lumber, plywood panel, and the cable-supported structure. Such roof shell system is very light and its high strength cable under the roof shell could provide enough bending strength and stiffness for the whole roof system. The roof of the building is shaped as an irregular 3-dimensional curve, which is almost 10 meters high and covers about 2,500 m2. The structural analysis shows that the cable-supported thin timber shell could provide enough strength and stiffness for the whole roof system. Some additional buckling analysis of the roof shell is also performed due to its irregular shape.

CS2D-5, ID 1032 (Time: 18:00 - 18:20)
TitleProduction system of wooden space frame architecture
Author*Hiroyuki Miyahara (Graduate School of Engineering, Osaka University, Japan), Katsuhiko Imai, Kiyoshi Shogatsudani (Forest Engineering & Economics Lab. Co. Ltd., Japan), Yoshinori Fujita, Ryosuke Kanki (Yoshinori Fujita & Associates, Architects, Japan), Osamu Saitoh (Hakuyo-do (White Hawk), Economic Journalist, Japan), Masumi Fujimoto (Graduate School of Engineering, Osaka City University, Japan), Michihiro Kita (Graduate School of Engineering, Osaka University, Japan)
KeywordWooden structure, Space frame, Production system, Truss structure, Formian
AbstractThis paper presents the innovative production system of the wooden space frame (KiTruss) it includes form generation of KiTruss, generation of the common data file that most programs accesses, structural analysis, fabrication system, construction methods and quantity survey & estimation. A fabrication system where unskilled local people can participate in fabricating members was developed. The fabrication of space frame member is generally considered a work requiring advanced technology, but this fabrication system does not need any advanced technology. As the system is designed to hide the technology to the people, they can fabricate it easily. This is the idea of the so-called ‘local consumption of locally produced products.’ Because of the ease of assembly of the KiTruss members on the construction site, even the workers of local construction companies can construct them without any difficulties. As a result, the utilization of local labour and material contributes to the local economy.

CS2D-6, ID 1119 (Time: 18:20 - 18:40)
TitleGeodesic Lattice Shell Methodologies
Author*Mark Cabrinha (California Polytechnic State University, U.S.A.)
KeywordShell, geodesic, timber, parametric, form-finding
AbstractThis paper outlines a working methodology for wood lattice shell structures developed through a three-step parametric workflow process combining readily available form-finding while employing non-uniform lattice spacing developed through a geodesic network. This digital process is combined with empirical testing of physical wood members as a material feedback loop in the form-finding process. The motivation of this parametric process is to off-load detailed calculations of form-finding and geodesic analysis to the tool, such that attention can be placed in conceptual design to other design criteria such as spatial development and environmental response while maintaining the structure, elegance and economy of lattice shells.

Session CS1E  Shell -1
Time: 14:20 - 16:20 Monday, September 26, 2016
Location: Room 201

CS1E-1, ID 1073 (Time: 14:20 - 14:50)
Title[Keynote] Deformation analysis of the second cornice of Hagia Sophia
Author*Takashi Hara (National Institute of Technology, Tokuyama College, Japan), Kenichiro Hidaka (Osaka University, Japan)
KeywordHagia Sophia, heritage structure, vibration, FEM
AbstractHagia Sophia, Istanbul, was constructed in 537. The building shows particular characteristics. Huge dome was supported by the arches, the tympanum and the piers. To stabilize them, the semi domes, the buttress and the pendentives were arranged. These are also supported by other complex structures. Hagia Sophia has been survived under several earthquake attacks. In this paper, the structural behavior of Hagia Sophia was analyzed by use of vibration record of the structure. The vibration record was measured by the micro tremor meters. The vibration characteristics of the total building were analyzed by combining the vibration records. Then, the deformation characteristics and the dynamic behavior of the second cornice were investigated. Applying the finite element method to solve the structure of the second cornice, the structural behaviors were clarified and the cause of the particular deformation was investigated.

CS1E-2, ID 1089 (Time: 14:50 - 15:10)
TitleDesign and Modelling of Heinz Isler’s Sicli Shell
Author*Chu Chun Chuang, John Chilton (University of Nottingham, U.K.)
KeywordHeinz Isler, concrete shells, conceptual design, form finding, optimization
AbstractIn 1969 a thin concrete shell roof designed by the master shell builder Heinz Isler was erected for the fire extinguisher manufacturer Sicli, SA, in Geneva, Switzerland. From this research carried out at the Heinz Isler Archive at ETH Zürich, it was found that more, previously unrevealed, alternative proposals and physical models were employed to accomplish this project. This paper describes an investigation of the original physical modelling process of the Sicli shell and discusses the infinite potential of form-finding methods for shaping a good shell. Four alternative free-form design schemes proposed by Isler for the Sicli shell, in addition to the final chosen hanging cloth modelling approach, are introduced and discussed. The actual construction details of the Sicli shell will be reviewed with regard to both architectural and engineering perspectives. In conclusion, more research to be carried out on the valuable legacy of Isler’s form-finding techniques is suggested.

CS1E-3, ID 1167 (Time: 15:10 - 15:30)
TitleExplorations in Structural Geometry: Jack Christiansen’s Segmental Hyperbolic Paraboloids
Author*Tyler Sprague (University of Washington, U.S.A.)
Keywordshells, thin shell concrete, structural geometry, modern architecture, concrete
AbstractJack Christiansen has been rightly recognized as one of the top thin shell concrete designers in the modern period. At the core of his shell investigation was the geometrical combination of the warped, hyperbolic paraboloid shell segments into large-scale structural forms. This paper will focus on three signature hyperbolic paraboloid shell structures that Christiansen designed between 1958 and 1969, and describe their structural geometry in depth. These structures - a small-scale multipurpose room, a high school auditorium and an exhibition dome – collectively portray his personal method of structural investigation and spatial creativity. Starting small, Christiansen designed shells with a distinctly different spatial condition than other designers like Felix Candela, and would later take the hyperbolic paraboloid shell to even longer spans. These three projects set the stage for Christiansen’s design of the Seattle Kingdome, the largest freestanding concrete dome in the United States.

CS1E-4, ID 1213 (Time: 15:30 - 15:50)
TitleSunflower shell: a way to change the energy
Author*Daniela Oropeza, María José Portillo (Universidad Autónoma de Querétaro, Mexico), Edgardo Rocha (Grupo Uehara, ingenieros y arquitectos, Mexico)
Keywordsunflower, shell, solar cells, sun path, passive systems
AbstractThis research presents an analysis about shells intended to be focused in the climatic design with the purpose of take advantage of the sun radiations [1] that can be taken in Querétaro City, Mexico. For this design was selected sunflower concept. Each part of the structural shell approach has a solar collection system, so the solar cells can provide of electric energy to the setting up of the structure. Also, the design of the structure must be lightweight and mobile in the cover. Finally, this structure is intended to increase the wide usage of passive systems and renewable energy that can contribute to minimize the climatic impact. Furthermore, it will provide a shaded area wherever the facility could be placed for example a yard or a parking lot. Keywords: climatic design, sun radiation, sunflower, structural shell, solar cell, Vogel Model, passive systems, renewable energy.

CS1E-5, ID 1288 (Time: 15:50 - 16:10)
TitleAn approach on form-diversity of free-form shells generated from numerical hanging models
Author*Qingpeng Li, Andrew Borgart (Delft University of Technology, Netherlands), Yue Wu (Harbin Institute of Technology, China)
Keywordform-finding, free-form shells, form-diversity, numerical hanging models
AbstractBased on its structural principle, the form of a hanging model is self-forming and capable of transferring its self-weight and loads solely by means of tension, and when it is turned upside down a pure compression model arises. Isler designed many shells by using this kind of models but with relatively limited structural forms. Recently, these models can be simulated by numerical methods, and this brings a more convenient and efficient approach to generate diverse structural forms in a very short time. The structural form and its mechanical behavior can be influenced by five categories of parameters used to describe the initial structural system. Therefore, an approach on form-diversity can be presented by varying these parameters. This paper uses the Non-linear Finite Element Method to generate the equilibrium shape of the hanging model, and thus several examples are shown to illustrate the specific procedures and results of the form-diversity approach.

Session CS2E  Shell -2
Time: 16:40 - 19:00 Monday, September 26, 2016
Location: Room 201

CS2E-1, ID 1042 (Time: 16:40 - 17:00)
TitleStudy on Ultimate Stability Bearing Capacity of Single-Layer Reticulated Shell with Member Initial Imperfection
Author*Zaigen Mu, Yuqing Yang (University of Science and Technology Beijing, China), Yanfeng Xu, Ming Gan (Beijing Institute of Architectural Design, China)
Keywordsingle-layer reticulated shell, initial imperfection, geometric nonlinearity, stability bearing capacity, eigenvalue buckling
AbstractBearing capacity of single-layer reticulated shell is always controlled by ultimate stability bearing capacity. Single-layer reticulated shell belongs to imperfection sensitive structures that small initial imperfections in members may greatly reduce them critical load. In the process of processing, transportation and installation, initial bending will be inevitably produced. As a result of these imperfections, the ultimate bearing capacity of the compression bars sharp decrease. Therefore member initial imperfections must be considered when analyzing stability of single-layer reticulated shell. In this paper, taking Shenzhen Stadium as project background, the ultimate stability bearing capacity of single-layer reticulated shell with member initial imperfections is analyzed. Eigenvalue buckling and nonlinear buckling analysis by ABAQUS is compared with perfect structure stability bearing capacity. By analyzing ultimate stability bearing capacity of single-layer reticulated shell and differences of stability bearing capacity from perfect structure, the very useful references are provided for design and construction of Shenzhen Stadium.

CS2E-2, ID 1057 (Time: 17:00 - 17:20)
TitleShape optimization of free-form shells consisting of developable surfaces
Author*Keigo Nakamura, Makoto Ohsaki, Jinglan Cui (Kyoto University, Japan)
Keyworddevelopable surface, free-form shell, shape optimization, Bézier surface
AbstractA method is presented for optimization of free-form shells consisting of developable surfaces. The surface is modelled as 2×1 or 3×1 tensor product Bézier surfaces. The developability conditions are assigned numerically as constraints for the optimization problem for minimizing the strain energy under self-weight as the mechanical performance. The control points of the Bézier curves are considered as design variables. A new continuity condition of normal vector of surface is proposed for connecting ruled surfaces. Optimal solutions are found using a nonlinear programming approach, and a finite difference approximation is used for sensitivity analysis. The effectiveness of the present approach is confirmed through various examples and the characteristics of the optimal shapes are discussed.

CS2E-3, ID 1063 (Time: 17:20 - 17:40)
TitleMechanic behavior of elliptic paraboloid cable-braced grid shells with different joints
Author*Ruo-qiang Feng, Xi Wang (The Key Laboratory of Concrete and Prestressed Concrete Structures of the Ministry of Education, Southeast University, China), Wei-jia Xu (Shanghai General Metal Structure Engineering Co., Ltd, China), Min Ma (Guangdong Electric Design Power Institute, China), Yang Liu (Guangzhou Urban Planning &Design Survey Research Institute, China)
Keywordbolted joints, stability, grid shell, mechanic behavior, buckling load
AbstractThe mechanic behavior of joints has a significant effect on the mechanic behavior of cable-braced grid shells. Taking elliptic paraboloid cable-braced grid shells as an example, the mechanic behavior of cable-braced grid shells with different joints was studied in this paper. The main conclusions are as follows. The rotational stiffness and ultimate load of bolted joints are below those of improved bolted joints. As a result, the buckling load of the elliptic paraboloid cable-braced grid shells with bolted joints is lower than that of the elliptic paraboloid cable-braced grid shells with improved bolted joints. The distribution of the maximal compression stress of the tubes was similar to that of the structural displacement when the cable-braced grid shell collapsed. The joint stiffness of the grid shells should be greater than 20% of the rigid joint stiffness.

CS2E-4, ID 1263 (Time: 17:40 - 18:00)
TitleEffects of CFRP reinforcement for thin-walled steel cylinder subjected to bending and shear loading
AuthorAkira Tsujioka, *Yukihiro Matsumoto, Duong Nguyen Ngoc (Toyohashi University of Technology, Japan), Hitoshi Nakamura (Tokyo Metropolitan University, Japan), Takahiro Matsui (Toray Industries, Inc., Japan)
Keywordthin-walled steel cylinder, steel tank, CFRP reinforcement, bending shear loading
AbstractIn recent years, the use of CFRP has been widely introduced by various researchers. For example, CFRP is used to the high pressure vessel or shell tank. In this paper, the effect of CFRP reinforcement for thin-walled steel cylinder under bending shear load has been studied in order to investigate seismic performance by finite element analysis. Firstly, variation of buckling behavior and the effect of CFRP reinforcement are investigated. Secondly, the effect of CFRP reinforcement has been evaluated through AIJ design recommendation. Finally, the design formula of buckling load having CFRP reinforcement has been proposed.

CS2E-5, ID 1363 (Time: 18:00 - 18:15)
TitleApplication and research of stainless steel in structural scheme of high energy physics equipment
Author*Zongyi Wang (Wuhan University, China), Qinglin Jiang (Jiangsu Dongge Stainless Steel Ware Co., Ltd, China), Yuanqing Wang (Tsinghua University, China), Xinxi Du (Wuhan University, China), Ligang Zhang (Jiangsu Dongge Stainless Steel Ware Co., Ltd, China)
Keywordstainless steel, neutrino central detector, structural scheme, latticed shell
AbstractStainless steel is widely used in the high energy physics equipment, due to its high strength, corrosion resistance and low background. Neutrino central detector (NCD) is a typical kind of high energy physics equipment. In this paper, three NCDs (SNO, Daya Bay and Borexino) are intensively introduced. Among them, Daya Bay NCD, which is the first neutrino detector in China, adopts the structure of cylindrical acrylic vessel and stainless steel tank. SNO NCD adopts the structure of an acrylic ball and a single-lay stainless steel latticed shell. Borexino chooses the combination of nylon vessel and stainless steel sphere. Subsequently, the Jiangmen Underground Observatory (JUNO) and Jinping NCD are presented. An alternative scheme of an acrylic ball supported by a double-layer stainless steel latticed shell for the JUNO is proposed and the mechanical analysis on the shell is conducted. Eventually, the design of the small model of Jinping detector is introduced.

Session CS1F  Seismic -1
Time: 14:20 - 16:20 Monday, September 26, 2016
Location: Room 202

CS1F-1, ID 1024 (Time: 14:20 - 14:40)
TitleFormulation of release conditions for TMDs with initial displacement and its application to an arch model
Author*Susumu Yoshinaka, Riki Yoshida, Yoshiya Taniguchi (Osaka City University, Japan)
KeywordVIbration control, Tuned mass damper, Arch model
AbstractTMDs show high control performance for harmonic responses, but have limited capacity under transient responses. To control transient responses effectively, we propose a TMD with initial displacement. In our previous study, we proposed design formulas for impulse loading. These formulas are based on the principle that under restricted structural initial conditions giving a specific TMD initial displacement, the first modal response is eliminated while the the second modal response with high modal damping is only oscillated. In this paper, we formulate an equation for initial conditions to release initial TMD displacement, and show that by dividing one TMD into multiple TMDs with different natural frequencies, the restricted initial conditions to release a TMD can be altered. Then, to confirm the applicability of the proposed method to spatial structures, we study the control effect of TMDs with initial displacement attached to an arch model.

CS1F-2, ID 1037 (Time: 14:40 - 15:00)
TitleCollapse Mechanism of Wide-area Suspended Ceiling in School Gymnasium
Author*Tomohiro Sasaki (National Research Institute for Earth Science and Disaster Resilience, Japan), Atsushi Aoi (Takenaka Corporation (former National Research Institute for Earth Science and Disaster Resilience), Japan), Koichi Kajiwara (National Research Institute for Earth Science and Disaster Resilience, Japan), Hiroyuki Tagawa (Mukogawa Women’s University (former National Research Institute for Earth Science and Disaster Resilience), Japan), Daiki Sato (Tokyo Institute of Technology (former National Research Institute for Earth Science and Disaster Resilience), Japan)
KeywordSuspended Ceiling, Collapse Mechanism, Seismic Design, school gymnasium, Full-scale shake table experiment
AbstractIn the 2011 off the Pacific coast of Tohoku Earthquake, many suspended ceilings and other suspended equipment fell down due to the lack of their resistance to earthquakes. To mitigate severe damage to ceiling system caused by earthquakes, new seismic design code for suspended ceiling system was issued by the Ministry of Land, Infrastructure, Transportation and Tourism. However, the mechanism why and how suspended ceiling system falls down during earthquakes has not yet been clarified. In order to clarify the collapse mechanism of wide-area ceiling system and development of its countermeasure, new research project was launched and first series of full-scale shake-table experiments of wide-area ceiling system in school gymnasium was conducted. Based on experimental results, collapse mechanism of nonseismic ceiling was clarified and it was found that failure mechanism of the seismically designed ceiling depends on the ratio of strength of ceiling braces and its metal joints.

CS1F-3, ID 1039 (Time: 15:00 - 15:20)
TitleVibration tests of cylindrical lattice shell using active vibration control
Author*Ken’ichi Minowa (Nippon Institute of Technology, Japan), Masayuki Hattori (Former, Tokyo Institute of Technology, Japan), Toshiyuki Ogawa (Professor Emeritus, Tokyo Institute of Technology, Japan)
KeywordCylindrical lattice shell, Active vibration control, Vibration test, Voice coil motor, Acceleration feedback
AbstractActive vibration control for shell and spatial structures is studied for the purpose of reducing their seismic responses. For example, in Ref. [6], the active vibration control tests of arch structure with piezoelectric films have been performed. The study shows that the active vibration control can make the reductions in the response displacement and acceleration compatible. However, it is difficult to use the piezoelectric films to existing structures due to their small force. Also, the active vibration control is desired to apply for not only arch structures but also lattice shells. Therefore, this paper deals with the active vibration control for cylindrical lattice shells using voice coil motors, as shown in Fig. 1. To confirm the control effects, vibration tests are performed. Figure 8 shows the distributions of the maximum response acceleration. As a result, the seismic responses are reduced by about 40% without amplifying all the vibration modes.

CS1F-4, ID 1046 (Time: 15:20 - 15:40)
TitleMobility of conventional slide bearings supporting steel roofs
Author*Tetsuo Yamashita, Naoki Wada (Kogakuin University, Japan)
KeywordBearing, Friction, Mobility, Stability
AbstractThis paper discusses about mobility of conventional slide bearings supporting steel spatial roofs on the lower concrete structures. In many city gymnasiums in Japan, a steel roof is installed on the lower concrete frame. To avoid stress due to thrust or thermal stress, the bearings supporting the steel roof on the concrete column are designed to be mobile. Some of such conventional slide bearings suffered damage during the 2011 Tohoku Great Earthquake. However, some destroyed bearings showed no abrasion of moving. On the observation, we conducted further experimental study to investigate the mobility of actual slide beraings. It is found that the friction between the washer of anchor bolts and the top surface of base plate, which has been neglected so far, greatly influences the mobility. Moreover a quantitative condition for stable slide is formulated.

CS1F-5, ID 1056 (Time: 15:40 - 16:00)
TitleMaximum axial force and bending moment of slanted beam, gable arch and circular arch subject to earthquake motion
Author*Juri Nemoto, Koji Yamada (National Institute of Technology, Toyota College, Japan)
Keywordslanted beam, gable arch, circular arch, response analysis
AbstractIn this report, a simple method is proposed to estimate the maximum axial force and the maximum bending moment of a slanted beam, a gable arch and a circular arch subject to earthquake motions. Structures are a slanted beam, a gable arch and a circular arch whose span are 30, 50, 70m. Input motions are 5 artificial motions with the phases of observed earthquake motions. We discuss the ratios of the maximum axial forces and bending moments by comparison of the maximum axial forces and bending moments subjected to dead loads. As a result, the scale factor is constant to estimate the axial force subject to earthquake motions from the axial force subject to dead load. The scale factor is a linear function to estimate the bending moment subject to earthquake motions from the bending moment subject to dead load.

CS1F-6, ID 1069 (Time: 16:00 - 16:20)
TitleTopology optimization of supporting structures for seismic response reduction of spatial structures
Author*Yuji Miyazu (Hiroshima University, Japan), Makoto Ohsaki (Kyoto University, Japan), Seita Tsuda (Okayama Prefectural University, Japan)
Keywordarch, latticed dome, flexible supporting structure, topology optimization, seismic response
AbstractA flexible supporting structures reducing seismic responses of two types of spatial structures, an arch and a latticed dome, are proposed. The supporting structures of the arch and the latticed dome are modeled as two- and three-dimensional truss structures, respectively, and their topology and cross-sectional areas are optimized solving nonlinear programming problems. The optimization problem of the arch is divided into two small optimization problems to obtain the optimal solution efficiently. It is demonstrated through time-history response analysis that the flexible supporting structure can reduce the seismic response of the roof structures, and installing viscous dampers into the supporting structure is effective to further reduction of the responses.

Session CS2F  Seismic -2
Time: 16:40 - 19:00 Monday, September 26, 2016
Location: Room 202

CS2F-1, ID 1129 (Time: 16:40 - 17:00)
TitleComparison Study of Elasto Plastic Behavior on Static and Dynamic Responses for Single Layer Lattice Domes
Author*Yoshiya Taniguchi, Tomoya Matsui, Susumu Yoshinaka (Osaka City University, Japan)
Keywordsingle-layer lattice dome, vertical loading, seismic motion, allowable sesmic level, elasto plastic behavior
AbstractIn this paper, the relationships between static load-carrying capacity and seismic resistant capacity are focused on, that is, the comparison study is carried out about elasto plastic behavior of both responses. The purposes is to establish an evaluation method of allowable maximum earthquake acceleration, which may bring a structure into an ultimate state. The both elasto plastic behavior is analyzed for single layer lattice domes under vertical loading, which is a static vertical uniform load and a vertical seismic motion. The relationships between equivalent velocity of static absorbed energy and vertical deformations are focused on as a static elasto plastic behavior. The other relationships is the maximum earthquake input acceleration and the equivalent velocity of strain energy of domes as a dynamic elasto plastic behavior. Consequently, the change of slopes between the elastic and plastic ranges may be concerned with each other.

CS2F-2, ID 1140 (Time: 17:00 - 17:20)
TitleA study of seismic risk evaluation consideration of overturning furniture for middle and low rise buildings
Author*Keita Saito (Research Institute of Architecture, Japan), Takaya Higuchi (MHPS Engineering Co. , Ltd, Japan), Shoji Nakazawa (Toyohashi University of Technology, Japan)
Keywordseisemic risk, BCP, seismic fragility curve
AbstractThe purpose of this paper is the analysis in the parallel damage evaluation of buildings and the furniture in the building when structural durability is changed. Targeted structure is middle and low-rise office building in the steel frame. This paper sets the Qu/Qun (the horizontal load bearing capacity; Qu / the required held horizontal yield strength; Qun ) as the analysis parameters. In this study, it performs a response value evaluated by the seismic response analysis, the damage evaluation of the building itself is analyzed by earthquake losses calculated by the Seismic Risk Analysis. Moreover, the effect of the furniture in the building is analyzed by the evaluation of overturning ratio.As a result of damage evaluation of building and furniture in the parallel analysis and increased the Qu/Qun. Increased Qu/Qun affect for reducing building damage , on the other hand it does not improve for the overturning ratio of furniture.

CS2F-3, ID 1170 (Time: 17:20 - 17:40)
TitleThe total seismic loss ratio of a power plant with equivalent pendulum tuned mass damper system
AuthorXiaofeng Sun, *Zhan Shu, Minjuan He (Tongji University, China)
KeywordPerformance based analysis and design, Pendulum-type tuned mass damper, Mass varying system, Fragility function, Total loss ratio
AbstractThe presented study implements the performance-based analysis and design methodology to assess the seismic vulnerability of a coal-fired power plant and to optimally design its equivalent pendulum-type tuned mass damper (PTMD) system such that the direct losses due to earthquake damages are minimized. A full scale numerical model of the tested specimen is developed and its vibration characteristics are validated against previous shaking table test results. In order to quantify the system level damage states of the structure, a total loss ratio (TLR) is proposed to link the component level losses with the total repair cost of the original structure. Based on the fragility functions derived for the structure when subject to near-field and far-field ground motions, the TLRs are computed for various PTMD designs. The optimal PTMD design could refer to the derived cases with the minimum TLR.

CS2F-4, ID 1179 (Time: 17:40 - 18:00)
TitleProposal for the seismic retrofitting method for wood-frame houses using earthquake-proof shelter
Author*Mizuki Ichikawa, Yuki Ozawa (Shibaura Institute of Technology, Japan), Kentaro Ide (Konoike Construction Co. Ltd., Japan)
Keywordearthquake-proof shelter, wood-frame house, seismic retrofitting method
AbstractIn Japan, there are tens of millions of wood-frame houses. It is said that about 25 percent of them don’t have enough strength for large seismic forces. On Hanshin-Awaji Great Earthquake Disaster in 1995, more than six thousands of people were killed by collapse of wood-frame houses. A means to protect the people from large earthquake disaster is inserting earthquake-proof shelters in these houses. However, there is a large disadvantage that the safety of people can’t be assured if they don’t exist in the shelter at the moment the earthquake occurs. In this paper, a new method of improving the seismic performance by connecting the shelters with the wood-frame of existing houses is proposed. It is necessary to simulate the overturn motion of the shelters by horizontal load because in most cases the shelters aren’t fixed to the existing houses.

CS2F-5, ID 1206 (Time: 18:00 - 18:20)
TitleControl of the dynamic collapse mechanism of double layer truss walls by means of fuse type connections
Author*Koichiro Ishikawa, Yusuke Hara (University of Fukui, Japan)
Keywordtruss wall, seismic responce analysis, damage control, earthquake resistant capacity, dynamic collapse mechanism
AbstractThis study deals with the dynamic Elasto-plastic analysis considering a member buckling and damage-control structures such as partial cylindrical aluminum alloy truss wall structures induced by the plastic elongation of the steel bolt within the joint connection. The purpose of this study is to investigate the dynamic collapse mechanism within the joint connection bolt tensile collapse type structure system caused by the bolt plastic elongation due to an axial tension stress. The effect of the member buckling and the yield elongation of the steel bolt on the seismic response of the out of the plane is shown in comparison with the response of the plane of the wall structure subjected to the plane direction horizontal earthquake motions. The earthquake evaluation method is also proposed considering the dynamic collapse mechanism. A validity of the proposed method is shown by means of the accuracy between the analysis and the estimation.

CS2F-6, ID 1216 (Time: 18:20 - 18:40)
TitleDamping Evaluation of Spherical Pre-stressed Concrete Shell by Filtering and Half-power Bandwidth Method
Author*Kiyoshi Shingu, Kiyotoshi Hiratsuka, Norio Kondo, Toshihiro Irie (Nihon University, Japan)
Keyworddamping ratio, spherical concrete shell, half-power bandwidth method, filter design, impact vibration examination
AbstractDamping phenomena of vibration of structures is well-known as one of important natures. Measures on damping ratios of the structures have been carried out based on microtremor observation or impact vibration examination (IVE), because damping ratios of structures are not able to be evaluated theoretically. The authors carried out IVE of a spherical pre-stressed concrete shell which was for the planetarium in Narashino city in 2011. The accuracy of evaluated damping ratio at that time was not sufficient because of the large deviation of damping ratios. In this research, the band-pass filtering process is applied to results measured by IVE, and then the filter design is devised. The damping ratio is evaluated by the half-power bandwidth method. The deviation of damping ratios of the shell obtained by using the proposed method becomes small, and the damping ratio of the shell by the IVE is verified around 2.0%.

Session CS1G  Conceptual Design -1
Time: 14:20 - 16:20 Monday, September 26, 2016
Location: Room 203

CS1G-1, ID 1092 (Time: 14:20 - 14:40)
TitleArchitectural Form and Structural Concepts Combined in Practice; an Approach to Spatial Structural Design in the case of Timber Gridshells
Author*Bendik Manum (Faculty of Architecture and Fine Art, Norwegian University of Science and Technology, Norway), Anders Rønnquist (Department of Structural Engineering, Norwegian University of Science and Technology, Norway), Nathalie Labonnote (SINTEF Building and Infrastructure, Norway)
Keywordstructural architectural design, kinematic grid shell, network bridge
AbstractBased on teaching architecture and structural engineering and working with students on projects also built in real, this paper discusses the two professions’ approaches to design, presents the design development in the case of timber gridshells and comments on the potential of combining architects’ and engineers’ profession specific design competences more in general. In the case of conceptual structural design presented, master students examined kinematic gridshells, resulting in an innovative modular timber gridshell parametrically designed and constructed as a 10x10x4m pavilion. Then, a master student of engineering examined the structural potential of the concept in the case of a bridge. Aiming at synergies across the professions, the studies combined parametric tools developed by architects with engineers’ more specific structural analyses. As the two professions work together, the design process resulted in a shell-bridge proposal fusing the architectural elegance of the pavilion with the structural integrity required in a bridge.

CS1G-2, ID 1115 (Time: 14:40 - 15:00)
TitleApplication of pentagonal space bar structures
Author*Jan B. Obrêbski (Faculty of Civil Engineering, Warsaw University of Technology, Poland)
Keywordpentagonal space bar structures, shaping, bar patterns, convex, conczve
AbstractThe structures with pentagonal contour can be used as independent roof or a part of UNIDOM type domes. In the paper are discussed some possible proposals for such structures with different bar patterns. It is continuation of author’s previous works presented partially on international conferences: IASS, SEWC, SEMC and LSCE. The system of UNIDOM space bar structures was investigated firstly on models, using children plaything, and next by Zometool kit. There is possible to construct even complicated domes, composed from two kinds of bars and one node, only. The elementary substructures can be designed as: plane single- or double-layer (triangular, rectangular and pentagonal, the last can be convex or concave) with possible theirs any combinations. It permits to obtain many architectural effects. The UNIDOM type dome has principal nodes located in vertexes of rhombiicosidodecahedron, with coordinates not positioned in regular net of points, but substructures are regular.

CS1G-3, ID 1181 (Time: 15:00 - 15:20)
TitleResearch on static properties and stability of super-large span Kiewitt type mega-latticed structure
Author*Qingwen Zhang, Feng Fan (Harbin Institute of Technology, China)
Keywordsuper-large span, Kiewitt type mega-latticed structure, stability performance
AbstractThis paper does some researches on whether several common rigid space structures are suitable for super-large span structure. Static behaviors of double-layer reticulated shell structure, local triple-layer reticulated shell structure, Ribbed type mega-latticed structure and Kiewitt type mega-latticed structure are compared and the results show that Kiewitt type mega-latticed structure is the most economic type in terms of steel consumption with the same span and load. According to the structural configuration of the structure analyzed through CAD 3D modeling, the geometrical connections of the main structure are studied in detail and the structural form parameters are put forward. The static behaviors, optimum of rod sections and stability analysis of Kiewitt type mega-latticed structure are studied based on the program firstly developed which can create the new structure automatically according to APDL parametric language. Finally the stabilities of the structure are studied by both linear and nonlinear methods and the load-displacement path is got through the Arc-length Method.

CS1G-4, ID 1185 (Time: 15:20 - 15:40)
TitleOn the Configuration of 1.5-Layer Space Frames
Author*Pei-Shan Chen (Kyushu Institute of Technology, Japan)
Keywordspace frame
AbstractA 1.5-Layer Space Frame, which is invented by the author, is a bar-linked structure configured with one-layer of chords and diagonal members. Unlike a conventional double layer space frame, the 1.5-Layer Space Frame has no lower chords, or when it is oriented upside down, no upper chords. Unlike a single layer space frame, the diagonal members are mounted onto the chords (a latticed shell) and efficiently strengthen it so that the entire structure can be constructed in subtle curvatures or as a plane. The present paper introduces the ontology and methodology for assembling a 1.5-Layer space frames with Lap-units, Crossing-units, Triple connecting and units of polygon Pyramids, etc. Furthermore, the author demonstrates that all the proposed configuration patterns are stable and able to be used for practical structural design. In addition, the author demonstrates the relation between the vertical displacement and the depth of a 1.5-Layer Space Frame.

CS1G-5, ID 1243 (Time: 15:40 - 16:00)
TitleResearch on stability of a 800m double-layer spherical reticulated shell structure of Kiewitt type
Author*Yu Zhang, Qingwen Zhang, Miaofan Li (Harbin Institute of Technology, China)
Keywordsuper-large span, double-layer spherical reticulated shell, Kiewitt type, stability analysis
AbstractThis paper focused on the stability of 800m double-layer spherical reticulated shell structure of K6 type, based on nonlinear complete-process analysis method. A comparison was made of the buckling mode, critical load, and plastic development distribution of response by 124 examples. It summarized the reasonable values of parameters such as the span to depth ratio, rise-span ratio, initial geometrical imperfections, and unsymmetrical distribution of loads, for pyramidal system and geodesic type. And the ultimate bearing capacity was accurately obtained by considering geometric nonlinearity, material nonlinearity and initial curvature of the members. Through various parameters analysis, it gets the regularity of the plastic stability of the K6 double-layer spherical reticulated shell, which provides the basis for the selection of the super large span double layer lattice shell.

CS1G-6, ID 1250 (Time: 16:00 - 16:20)
TitleHyparActive: A Design Exploration Tool for Multi-segment HyPar Shells
Author*Winston Davis, Tyler Sprague, Brian Johnson (University of Washington, U.S.A.)
Keywordexploration, simulation, performance analysis, conceptual design, hypar
AbstractShell structures may offer efficient solutions to contemporary design problems, but designer familiarity with them has been in decline. Modern fabrication techniques have rekindled interest, but it is hampered by the difficulty of balancing form manipulation and structural analysis concerns. In this paper we describe HyparActive, a software tool developed specifically to help designers explore shells during conceptual design. HyparActive provides simple 3D form-manipulation tools and visual FEA feedback in the same digital model. The tool allows users to define, manipulate and visualize a parametric form consisting of multiple hyperbolic paraboloid (hypar) shell segments. The quick feedback means the designer can interactively explore how form and stress distributions interact, informing design decisions and enhancing their design "intuition." This research project investigates the challenges of developing an interactive modeling tool and the benefits of including performance analysis in the conceptual design phase.

Session CS2G  Conceptual Design -2
Time: 15:50 - 17:50 Monday, September 26, 2016
Location: Room 203

CS2G-1, ID 1304 (Time: 15:50 - 16:10)
TitleDesign applications of non-flat thick origami
Author*Christopher Perry (Carnegie Mellon University, U.S.A.)
KeywordOrigami, Linkages, Thick-Foldability, Environments, Design
AbstractThe needs of humans are constantly changing over the course of days, weeks, and seasons; the built environment needs not only to accommodate this, but also to reflect and embody it. In this paper we look at several methods for designing thick rigid origami with the hope of inspiring desirable kinetic architecture for the transformable environment. In order to inform our decisions about form we must look to how people interact with the spaces they occupy, and how we might foster a meaningful relationship between people and their environments. Understanding thick origami allows us to focus on how we want to interact with a mechanism, so that the geometries may be an emergent property of human interaction.

CS2G-2, ID 1316 (Time: 16:10 - 16:30)
TitleThe effect of performance feedback and optimization on the conceptual design process
AuthorNathan Brown, *Caitlin Mueller (Massachusetts Institute of Technology, U.S.A.)
Keywordconceptual design, design tradeoffs, interactive design, performance feedback, behavioral study
AbstractMany recent contributions in computational structural design have argued that design quality can be improved when performance feedback and guidance are part of the conceptual design process. However, the effect of multi-objective feedback and guidance tools has not been studied extensively. This paper presents the results of an educational study that tests the direct relationship between conceptual design tools and the simulated performance of resulting designs. In the study, students were tasked with designing a restaurant canopy roof using a series of increasingly performance-driven computational design tools. Although there was no consensus on preferred workflows or aesthetic preferences, the average designs chosen using real time feedback or directed optimization performed significantly better in terms of deflection and emissions than those chosen through free exploration. Overall, this research establishes a link between design tools and performance outcomes, while strengthening the argument for further integration of performance feedback into early stage design processes.

CS2G-3, ID 1332 (Time: 16:30 - 16:50)
TitleDesign of a novel tensile shading system with cellular structure using coated textiles
AuthorSalvatore Viscuso, Alessandra Zanelli (Politecnico di Milano, Italy)
KeywordPerformative design, Tensile fabric, Shading system
AbstractThe paper deals with a novel textile component for shading curtain walls, and methods for manufacturing it. Starting from the state of the art of textile façade systems, a new cellular structure based on the “Kirigami Honeycomb” pattern is presented, which has the double advantage of a reduced and variable thickness on the transversal façade section and the double-curved large span porous frontal skin. The new component, called “Textile Voronoi”, aims to provide on-site a multi-adaptable honeycomb pre-fabricated panel that can be differently stretched on the façade, alternating crowded parts with more opened ones. The cellular structure also allows reducing the amount of structural elements compared to current structural textile skins, due to the tensional balance between each cell of the matrix. The paper demonstrates that is feasible to get customized cross-section (thickness) of the shading systems and contemporarily a wide dimensional variation of the frontal cells in the façade.

CS2G-4, ID 1361 (Time: 16:50 - 17:10)
TitlePerformative Wood – Digital Production of Individualized Joints by Wood Constructions using Robotic Arms
Author*Baris Cokcan (Chair for Structures and Structural Design - RWTH Aachen University, Germany), Johannes Braumann (Robots in Architecture, Austria), Sigrid Brell-Cokcan (Chair for Individualized Production - RWTH Aachen University, Germany), Martin Trautz (Chair for Structures and Structural Design - RWTH Aachen University, Germany)
KeywordWooden Structure, Individualized Production, Computational Method
AbstractNew digital design methods allow architects to easily create and plan free-formed buildings. However it is common that just before production starts contractors need a significant additional effort and data processing to enable the production. In projects with complex geometric aspects, people casually refer to “File to Factory”, which should facilitate the production process. However, we believe that this does not reflect reality: A close collaboration is needed between architects and e.g. carpenters to effectively understand and use joinery machines to directly link design with the production of wooden joints. Our goal is to involve architects in different material production processes and to provide a material-based technology transfer. It is here that multifunctional machines such as industrial robots offer a new alternative for digitally controlled production methods and can also serve as information carriers. The large scale project “Düzce Teknopark” makes a clear statement regarding this production integrated design methodology.

CS2G-5, ID 1439 (Time: 17:10 - 17:30)
TitleConcept Design on Deployable Facade by Hybrid-Typed Scissors System
Author*HyeWon Jung (Semyung University, Republic of Korea), SunWoo Park (Korea National University of Arts, Republic of Korea), SeungDeog Kim (Semyung University, Republic of Korea)
KeywordFacade Design, Scissors System, Tessellation, Pattern
AbstractRecently, the interest in the smart buildings is increasing in the architecture field. Among them, a research of facade design using a transformable system that can adjust the effect of the external environment is in progress. One of a typical example of the deployable system is a Scissors system that can change shape by using the geometric conditions of a unit member. Scissors system is a high-tech structural system which can construct the deployable plan and curved space by using the SLE (Scissors-Like Element) consisted of two Bar and Pivot. If the facade is designed by applying Scissors system, it is possible to maximize the performance and aesthetic effect of the structure by using a shape change of the line member. This paper presents a study of deployable facade design applying hybrid-typed Scissors system. A new deployable pattern of facade design is developed by combining Angulated Scissors system and tessellation pattern.

CS2G-6, ID 1476 (Time: 17:30 - 17:50)
TitleA Study on Instability Characteristics of Double-layered Dome Structures by Quasicrystal grid
Author*KyoungSu Lee (Semyung University, Republic of Korea), Tony Robbin (Artist, U.S.A.), SeungDeog Kim (Semyung University, Republic of Korea)
KeywordQuasicrystal, Instability, Double-layer Dome, Polyhedron, Dome structure
AbstractThis paper is a study on the proposal and possibility of analysis to apply as building structures of Quasicrystal system. Quasicrystal is the quasi-crystalline material, which is the intermediate material of the crystalline material and non-crystalline material. Quasicrystal is a structures that is ordered but not periodic, the basic form is a rhombus. These studies in the field of chemistry will proceed actively studied, in the field of construction a situation that still insufficient research. Therefore, in this paper, we presents the analysis of Quasicrystal system, and the research on the applicability of as dome structures. This paper described some examples of polyhedron form, and method of applying Quasicrystal system. Also, we grasped the flow of the load and forces through analysis of the basic polyhedron applied Quasicrystal system, and applied to dome structures of the expanded form.

Tuesday, September 27, 2016

Session PS1  Plenary Session -1
Time: 9:00 - 10:00 Tuesday, September 27, 2016

PS1-1, ID 1567 (Time: 9:00 - 9:20)
Title[Plenary] Long Span Structures in Thin Shell Concrete
Author*Jack Christiansen (PE,SE,NAE,Arch., U.S.A.)
Keywordconcrete shells, thin shell concrete, long span structures
AbstractSeven long span structures of thin shell design and construction built in the 2nd half of the 20th century are discussed and illustrated. Also, a schematic design for a very large roof is included with a cost estimate.

PS1-2, ID 1571 (Time: 9:20 - 10:00)
Title[Plenary] Forms and Forces - Visible and Invisible
Author*René Motro (Emeritus Professor, University of Montpellier, France)
Keywordtensegrity, form, force, complexity, simplicity
AbstractWhen dealing with Shell and Spatial Structures, it is necessary to work at several levels and at least to have a good understanding of forms and forces, two linked worlds, one visible the other no. In many cases forms and forces are coupled, and, from idea to realization, the first stage, conceptual design, requires form-finding studies. Designers have to “make forces visible” in their personal mind. Simultaneous approaches can be useful; scientific, artistic and symbolic. The experience of the author is based, more or less, on these three approaches. The presented studies use simultaneously these approaches in terms of paintings, symbolic analogies and scientific methods. Five topics are evoked in this paper. Actors and projects are the source for motivation and inspiration. Complexity of problems necessitate tools, but methodology is an inevitable prerequisite: simplicity is the best guide. Three research fields are addressed: morphology, surface spatial structures, and tensegrity systems.

Session PS2  Plenary Session -2
Time: 10:20 - 12:40 Tuesday, September 27, 2016

PS2-1, ID 1561 (Time: 10:20 - 11:40)
Title[Plenary] International Design Competition for Young Generation, New National Stadium Japan
AuthorYudai Honma (University of Tokyo)
KeywordNational Stadium
AbstractThe selected five proposals from the competition of "The Design Competition for Young Generation" are presented. Winner 1: Lukas Ingold, Pierluigi D‘Acunto and Patrick Ole Ohlbrock (ETH Zurich, Chair of Structural Design) Winner 2: Yohei Yokosuka (Kagoshima University) Winner 3: Takenaka Corp. Osaka Head Office, Designing dept. TAMA-SUDARE team Winner 4: Mauricio Loyola Vergara and Alexander Antoni Niewiarowski (Princeton University) Winner 5: Motoi Masubuchi (freelance), Ryo Fukumoto (YAMAHIRO, plus+bauplanung GmbH) and Andrey Bachevskiy (freelance)

PS2-2, ID 1562 (Time: 11:40 - 12:40)
Title[Plenary] Panel Discussion “Spatial Structures in the 21st Century”
Author*Hiroshi Ohmori (Nagoya University (Prof.em.), Japan), Hiroshi Naito (The University of Tokyo (Prof.em.), Japan), William Baker (Skidmore, Owings & Merrill, U.S.A.), Ken'ichi Kawaguchi (The University of Tokyo, Japan), Knut Stockhusen (Schlaich Bergermann Partner, Germany)
KeywordNational Stadium Japan, competition, spatial structures, 21st century
AbstractReflecting the results of the young generation's competition, "Spatial Structures in the 21st Century" will be discussed. Critiques from the jury to the selected proposals: Winner 1: The design by three rings which is floating in the air is impressive. The suggestion constituting all mainly on the tension is so beautiful and so innovative. This delicate expression also leads to Japanese culture which is seen in the structure of the bamboo-and-paper umbrella namely “Karakasa”. Even though there were some proposals by wires as the structure in the first actual competition, there was no plan which was such clear, lucid, and was beautiful. Since the proposal has quite clear structure and enough void to surrounding environment, it will be greatly contributed to ease the feeling of pressure from this huge facility. To realize the proposal, the visibility for the field from the seat, the resistance for the wind, or how to manage the partial maintenance should be validated. Winner 2: The development of digital computational tools raise the generation of people who are skilled with these tools and trying to apply them to explore the new form of structures that have been becoming possible to be designed by using these tools. In this proposal a simple optimization of minimum volume is firstly applied and then the member arrangement is refined by another principle, which minimizes the member length and leads to geodesic pattern of members. The final structural form exhibits interesting pattern with geodesic lines. These arrangements of structural members following continuous geodesic lines which run through the curved surface of the roof and give special visual peculiarity to the roof structure. That is the most appreciable point of this proposal, although the construction efficiency is not considered at all. Winner 3: The roof structure of this proposal for stadium is composed of what we call Tama-Sudare Frames which is a structural system having flexible configuration through the combination of smaller straight members and tension members together with pin joints connecting them. Smaller ready-made members connected with tension rods realize structural system without rigid joints with low cost as well as extremely high transportability. While individual frames are highly flexible and laterally unstable, structural stability is secured by crossing the frames with each other in a certain angle. The rigidity and the stability as a whole structure are also achieved through the tension rings which connect the Tama-Sudare Frames. Only a few kinds of members are required to construct the frame, that is, several types of square steel pipes, one type of rod together with three types of pin joints. Simple construction process is also clearly shown. Good proposal having gentle external appearance with small members which do not exceed the scale of the surrounding trees around the stadium. Winner 4: The challenge for the designers of the early 21st century is how to harness today's powerful computational and graphic tools to produce a design that is beyond just a superficial form. This proposal, the Mountainous Gridshell, is an excellent example of how art & science can be merged using 21st century tools. Geometry is central to design; it is where architecture and structure meet. This project demonstrates how sophisticated, modern optimization tools can be used to develop the topology, shape and size of the structure that both compliments and informs the esthetic goals. The result is a design solution that is both good structure and interesting architecture. The design approach went beyond the structural and aesthetic criteria to also systemically address major issues that range from ventilation to avoiding excessive shading of the playing pitch to constructability concerns. The design also addresses the important topic of sustainable structures and cultural relevance by using wood as the primary material. Winner 5: This is a proposal of a retractable flexible membrane roof system. Although folding roof membrane to perimeter ring is not a new idea, a unique unfolded geometry of the membrane roof is proposed in this idea. The membrane shape is cleverly fitted to the ridge and valley cables of the so-called Geiger type cable dome, which are arranged to support the structure and to guide the movement of the membrane. Roof membrane is not a single sheet but prepared as the regularly arranged long inflatable strips, which will be pressurized when it is fully unfolded, in order to accommodate to the geometric incompatibility. Minimum expression of the stadium with foldable roof and stadium bowl is also impressive. The difference between oval and circular plans is not well described.

Session CS3M  WG15: Origami -1
Time: 14:00 - 16:00 Tuesday, September 27, 2016
Location: Ito Hall

CS3M-1, ID 1116 (Time: 14:00 - 14:20)
TitleIntroduction of Monolithic Origami with Thick-Sheet Materials
Author*Nathan A Pehrson, Spencer P Magleby (Brigham Young University, U.S.A.), Robert J Lang (Lang Origami, U.S.A.), Larry L Howell (Brigham Young University, U.S.A.)
KeywordOrigami, Thick-Sheet, Monolithic, Folding
AbstractRecent interest in origami-based engineering design has illuminated opportunities for new products and has also introduced and many challenges. One such challenge is the inability to fold thick-sheet engineering materials using crease patterns which assume zero thickness. Several approaches have been developed which assist in accommodating the thickness of materials. Introduced in this work is a unique method to accommodate the thickness of materials in origami engineering without the need for assembly of its panels and joints. This fabrication out of monolithic thick-sheet materials is viable due to the incorporation of compliant mechanisms formed from the sheet. A general approach to apply the proposed method is described. An optimization of joints is used due to interference at a vertex. The thickness accommodation method and optimization are applied to a simple degree-four-vertex crease pattern in detail. As further proof of concept, the method is demonstrated on an origami square-twist crease pattern.

CS3M-2, ID 1132 (Time: 14:20 - 14:40)
TitleInvestigation for absorption energy performance of pairing origami structures
Author*Yang Yang, Maria Savchenko, Chie Nara, Ichiro Hagiwara (Meiji University, Japan)
KeywordPairing Origami Structure, Reversed Spiral Cylindrical (RSC) Structure, Absorbing Energy Performance, Tachi-Miura polyhedron (TMP), Nojima polyhedron (NP)
AbstractFormally we have discussed the collapse easiness of two pairing structures: Nojima polyhedron (NP) and Tachi-Miura polyhedron (TMP), for the applicability of empty beer cans made of the aluminum material. This paper is focused on the investigation of the absorbing energy performance and the crushing modes. We consider the application of these pairing origami structures to expect to be used as the collision energy absorber of vehicles with the steel material. The impact analyses are performed by using dynamic explicit finite element program LS-DYNA. Moreover, we compare the collapse characteristics of the investigated structures with the conventional rectangular cross section structure and reversed spiral cylindrical origami structure (RSC).

CS3M-3, ID 1168 (Time: 14:40 - 15:00)
TitleTunable static and dynamic behavior of triangulated cylindrical origami
Author*Hiromi Yasuda, Mia Lee, Jinkyu Yang (University of Washington, U.S.A.)
AbstractWe present unique static and dynamic behavior of cylindrical origami in triangular patterns. This cylindrical origami structure composed of triangular facets can support both axial and rotational motions under external excitations. To analyze the folding mechanism, we model each triangular facet as linear spring network to accommodate its deformations. We first examine the force-displacement relationship of a single unit cell. Our analysis results show transitions between monostable and bistable configurations by altering initial geometrical parameters. Based on this single cell analysis, we conduct dynamic analysis on a 1D chain of multiple unit cells stacked vertically in various arrangements to investigate its coupling of axial and rotational motions. This multi-cell analysis demonstrates the tunability of wave propagation in the 1D chain as well as frequency band structure formation. By leveraging their unique static/dynamic mechanisms, the origami-based mechanical structures have great potential for engineering applications, e.g., deployable aerospace structures.

CS3M-4, ID 1187 (Time: 15:00 - 15:20)
TitleDesign of a composed origami-inspired deployable shelter: modeling and technological issues.
Author*Giulia Curletto, Luigi Gambarotta (Polytechnic School, University of Genoa, Italy)
KeywordOrigami, Foldable Structures, Modular Shelter, Form-Finding, Parametric Modeling
AbstractA novel and efficient approach to the design of foldable architectural structures based on rigid Origami is here proposed to obtain lightweight constructions. This kind of structures are made by rigid thin plates, easily assembled and transportable. In particular, a composed Origami in-plane structure is developed, testing two different typology of folding solutions. The model has been developed by applying parametric design, which allows to vary the geometric parameters to assess the sensitivity of the structural response, with the aim of finding the best structural morphology. Manufacturing issues have been integrated in this process to develop a feasible construction. Thin panels of composite material Hylite® have been considered as particularly interesting to develop a model in which panel’s core material can provide a hinge function, suitable to be used for deployable structures.

CS3M-5, ID 1431 (Time: 15:20 - 15:40)
TitleRigid folding analysis of offset crease thick folding
Author*Jason S. Ku, Erik D. Demaine (MIT, U.S.A.)
Keywordorigami, folding, thickness, rigid folding, configuration space
AbstractThe offset crease method is a procedure for modifying flat-foldable crease patterns in order to accommodate material thickness at creases. This paper analyzes the kinematic configuration space for the family of non-spherical linkage constructed by applying the offset crease method. We provide the system of equations that describes the parameterized configuration space of the linkage, and we visualize the two-dimensional solution space using appropriate projections onto the five-dimensional state space. By analyzing the projections over the space of flat-foldable crease patterns, we provide evidence that the flat and fully-folded states generated by the offset crease method are connected in the configuration space. We also present software for designing and constructing modified crease patterns using the offset crease method.

CS3M-6, ID 1239 (Time: 15:40 - 16:00)
TitleCurved folded cone assemblies
Author*Rupert Maleczek, Günther Filz, Christian Scheiber (Institute of Design | unit koge. Faculty of Architecture, University Innsbruck, Austria), Moritz Heimrath, Clemens Preisinger (die angewandte, Austria)
Keywordorigami, curved folding, assembly strategy, structural folding, , computational design
AbstractInspired by the work of David Huffman, especially his research on cones, this work investigates one particular strategy to generate freestanding structures from assemblies of folded cones. The reflective folding strategy described by Huffman is adapted to generate stable elements consisting of folded sheet material that are assembled into a larger structure. After discussing a general approach of cone assemblies a particular strategy named stacked cones, to generate double-layered structures is explained in detail on a scale one prototype entirely fabricated from paper.

Session CS4M  WG15: Origami -2
Time: 16:20 - 18:40 Tuesday, September 27, 2016
Location: Ito Hall

CS4M-1, ID 1246 (Time: 16:20 - 16:40)
TitleFace to Face: Varieties and Properties of Coplanarly Joined Multilayer Tessellations
Author*Yves Klett, Peter Middendorf (Insitute of Aircraft Design, Universität Stuttgart, Germany)
KeywordOrigami, Tessellation, Multilayer, Kinematics, Lightweight
AbstractWe present a comparatively simple way to realize multi-layered, rigidly foldable structures by face-to-face joining of kinematically congruent, offset tessellations. A number of relevant tessellation types can be assembled efficiently by joining coplanar faces. The resulting structures preserve the characteristic kinematics of the constituting layers, but exhibit different mechanical and other properties when compared to single-layer tessellations. Different geometric setups are presented, and the kinematic and mechanical as well as other properties of the resulting metamaterials will be discussed.

CS4M-2, ID 1291 (Time: 16:40 - 17:00)
TitleFolded bike shell-ter: Application of oricrete design and manufacturing method
Author*Jan Dirk van der Woerd, Rostislav Chudoba, Josef Hegger (Institute of Structural Concrete, RWTH Aachen University, Germany)
KeywordOrigami, Textile Reinforced Concrete, folded plate structures, shells, light-weight construction
AbstractIn the present paper, we use the oricrete design and manufacturing method to produce two different folded shell elements. They can serve as a protecting shelter for a bicycle for example. With the method spatial structures are made out of a flat plate of textile reinforced concrete by means of folding. Both strucutres are made on the basis of an identical plate. As crease pattern the Yoshimura pattern was chosen. The first design is characterized by sharp folding angles up to 110 degrees and is singly curved. The second design is characterized by double curvature. The previously developed modeling tool oricreate capturing the rigid-folding kinematics, foldability constraints and energy potentials has been used to support the form-finding process and the technical design of the folding procedure. The paper provides a detailed report on the whole design and manufacturing process. The potential of the methodology for further applications is discussed.

CS4M-3, ID 1318 (Time: 17:00 - 17:20)
TitleZero-Area Reciprocal Diagram of Origami
AuthorErik Demaine, Martin Demaine (Massachusetts Institute of Technology, U.S.A.), David Huffman (University of California, Santa Cruz, U.S.A.), Thomas Hull (Western New England University, U.S.A.), Duks Koschitz (Pratt Institute, U.S.A.), *Tomohiro Tachi (University of Tokyo, Japan)
Keywordorigami, reciprocal diagram, rigid foldability, morphology
AbstractWe propose zero area reciprocal diagram as a graphical tool for the design of rigid foldable mechanisms. First, we interpret the meaning of zero-area reciprocal diagram as the second order approximation of rigid foldability of origami crease pattern. We further show the equivalence to rigid foldability for special cases of single vertex origami and an origami pattern with flat foldable degree-4 vertices. We also show design examples with approximated rigid folding, which has a potential engineering applications.

CS4M-4, ID 1477 (Time: 17:20 - 17:40)
TitleTilt-up concrete dome skeleton construction by 
Rotational Erection System (RES), part 1
Author*Yoshinobu Miyamoto (Aichi Institute of Technology, Japan), Takaaki Itoh (Toyota T&S Construction Co., Ltd., Japan), Hiroaki Harada (Nikken Sekkei Ltd., Japan)
Keywordorigami, kirigami, pop-up, tilt-up, concrete
AbstractWe propose a novel construction method for dome skeleton using Tilt-up concrete and Rotational Erection System (RES) (Miyamoto [3]). The construction procedures are 1) setting the edge form and rebar on the level floor pad, 2) casting structural concrete, 3) hoisting up the hub on the temporary support, 4) tilting-up the arms and fastening them to the hub. We studied the two types of structural configuration with a) intersecting arms and b) dual layer arms [Figure 1]. The preliminary structural analysis suggested that the 30m span domes are feasible with conventional concrete materials.

CS4M-5, ID 1480 (Time: 17:40 - 18:00)
TitleMERLIN: A MATLAB implementation to capture highly nonlinear behavior of non-rigid origami
Author*Ke Liu, Glaucio H. Paulino (Georgia Institute of Technology, U.S.A.)
Keywordorigami, nonlinear analysis, bar-and-hinge model
AbstractArisen from the geometric arrangements of panels and creases, unique mechanical properties such as foldability endow origami with promise for developing novel tunable and functional structural systems. To promote engineering applications of origami, a simplified but effective approach for investigation of the nonlinear mechanical behavior of non-rigid origami structures is essential. We propose a fully nonlinear, displacement-based formulation, for constructing quasi-static finite element analyses of origami structures based on a previously established bar-and-hinge simplification. The formulation leads to an efficient and robust numerical approach for predicting large displacements and large local deformations of origami structures. Comparison between actual paper-made models and numerical simulations hints the ability of the proposed approach in capturing key features of origami deformation. Thus the current work builds up a connection between theory and practice of origami structures, which has the potential to impact design, education, and applications of origami.

CS4M-6, ID 1517 (Time: 18:00 - 18:20)
TitleDesign of single/double curved honeycomb cores based on origami techniques
Author*Kazuya Saito, Akinobu Fujimoto, Lijun Wang, Yoji Okabe (The University of Tokyo, Japan)
KeywordHoneycomb, Kirigami, Origami, Sandwich Structure
AbstractThe authors of this paper researched a new honeycomb design and manufacturing method called “kirigami honrycomb.” Resembling origami, kirigami honeycomb allows a single flat sheet of material with periodic slits to be folded into a honeycomb shape. The advantage of this method is that it can be extended to manufacture 3D (non-flat) honeycomb. This is achieved only by changing the crease patterns of original sheets. First, this paper describes a method for designing single-curved honeycomb panels using the kirigami technique. This method can facilitate arbitral W-direction (the mechanical direction in a normal honeycomb) shape changes in honeycomb structures. Then, a novel crease pattern conversion method is proposed, through which L-direction shape changes can be created in a Kirigami honeycomb. Finally, we introduce the developed relevant manufacturing equipment and provide some relevant prototypes.

CS4M-7, ID 1483 (Time: 18:20 - 18:40)
TitleFeasibility of a knowledge-based engineering framework for the AEC industries
Author*Maarten Joep Mathot (Delft University of Technology, Netherlands), Jeroen Coenders, Anke Rolvink (White Lioness technologies, Netherlands)
Keywordanalysis, automation, KBE, framework, reasoning
AbstractThis paper presents the development of a new computational framework with which expert analysis knowledge can be captured, stored and dynamically retrieved when required to determine the performance of a building design with respect to user-defined requirements. By subdividing the engineer’s and designer’s knowledge into discrete steps, and storing these steps in a database along with a description of the context in which the knowledge is to be applied, a searchable knowledge base is created. Given a context consisting of a BIM model and one or more building requirements for which metrics are to be provided, the applicable knowledge can be iteratively retrieved from the knowledge base. Through this computational reasoning an analysis is acquired as a chain of logically connected analysis steps. Foreseen benefits of use of the framework include safekeeping and disclosure of AEC expert’s knowledge and automation of analyses without loss of analysis transparency.

Session CS3Y  Form Finding & Optimization -1
Time: 14:00 - 16:00 Tuesday, September 27, 2016
Location: Gallery-1

CS3Y-1, ID 1031 (Time: 14:00 - 14:20)
TitleDesign of tree-type support structure of free-form shell generated using fractal geometry
Author*Jinglan Cui (Kyoto University, Japan), Guangchun Zhou (Harbin Institute of Technology, China), Makoto Ohsaki (Kyoto University, Japan)
KeywordFractal Geometry, B-spline Curves, tree-type Support Structure
AbstractIn this study, we propose a method of optimizing a tree-type support structure, considering the aesthetic effect, to evolve the structure to a rationalized form. The initial shape is generated using the fractal geometry, and the B-spline curve is used to generate the boundaries and cave of the free-form shell. It is shown in the numerical examples that the strain energy of overall structure can be reduced by optimizing the shape of the tree-type structure.

CS3Y-2, ID 1035 (Time: 14:20 - 14:40)
TitleAnalysis of traditional Chinese arched architecture with graphical statics
Author*Lijing Yang (Chongqing University, China)
Keywordgraphical statics, conceptual structural design, traditional Chinese architecture, masonary arch
AbstractThis paper describes arch, a spatial structure form of traditional Chinese architecture, and compares the characteristics of different arch forms using graphical statics. The section form of arch has undergone an incessant development from the semi-circular arch to the dual-core circular arch and three-centered circular arch, and even parabolic arch. To evaluate the stability and efficiency of different forms of arch, different methods have been developed based on experiment and calculation. Graphical statics, including funicular polygon and force polygon and based on graphic force flow thought, is a suitable tool for architect to analyze and find reasonable structural form. This paper tries to use the graphical statics to explain the performance of three different forms of masonry arch in Chinese traditional architecture in detail. Further, it can be used to optimize the form according to the force drew in force polygon, and get the optimum solution.

CS3Y-3, ID 1043 (Time: 14:40 - 15:00)
TitleShape optimization of compression structures
Author*Petra Gidak, Mario Uroš, Damir Lazarević (Faculty of Civil Engineering, University of Zagreb, Croatia (Hrvatska))
Keywordform finding, kinematic constraints, tension-compression analogy, force density, compression structures
AbstractFinding the form of structures consisting primarily of compressive elements is not always an easy task. In order to facilitate the design process of compression structures, the shape of a mirrored tensile structure can therefore be adopted, based on the traditional tension-compression analogy. Adding kinematic constraints to the original definition of the force density method, fixing the length of each structural element, the procedure may be applied iteratively until given conditions are satisfied Fresl et al [1]. Beside fixed element length, different kinematic constrain can be used in the sense of wanted element forces. Moreover, for some elements one can define wanted length and for others target tensile force. This paper will investigate different forms of compressive structure as a result of form finding with tension - compression analogy using diverse kinematic constraints applied to the same layout of tension elements.

CS3Y-4, ID 1080 (Time: 15:00 - 15:20)
TitleParametric design and optimization of shell structures using the Natural Force Density Method
Author*Márcio Sartorelli Venâncio de Souza, Ruy Marcelo de Oliveira Pauletti (Polytechnic School of the University of São Paulo, Brazil)
Keywordforce density, natural force density, shell, grasshopper, karamba
AbstractIn this paper, we present the development of a NFDM plugin for Rhino/Grasshopper environment, that allows quick and robust parametric generation of bending-free shapes, either reticulated or continuous, which we subsequently optimize using other Grasshopper plugins (Karamba and Galapagos). Even though convergence of genetic algorithm is usually slower that of gradient optimization methods, we found that the combination of NFDM shape generation and genetic algorithms offers a robust and overall quick procedure to select efficient yet formally appealing shell geometries.

CS3Y-5, ID 1118 (Time: 15:20 - 15:40)
TitleForm-finding of spatial grid structures with volume constraints
AuthorChao Ding (Zhejiang University, China), *Hamed Seifi, Yi Min Xie (RMIT University, Australia)
Keywordform finding, inverse hanging method, volume constraint
AbstractThe conventional inverse hanging method has been widely used for the form-finding of structures. However, the simulation results may vary significantly due to different initial models and material properties. It is difficult to choose one specific design shape from all the possible solutions. A modified hanging method is proposed in this paper to search for the stiffest design for a structure from arbitrary initial models with a given volume constraint. A variety of 2D and 3D examples are presented to demonstrate the effectiveness of the proposed method. It is shown that the proposed optimization procedure is capable of substantially enhancing the performance of the structure while the target volume is kept constant.

CS3Y-6, ID 1120 (Time: 15:40 - 16:00)
TitleMulti-objective Optimization for Free Form Surface Shell Using Swarm Intelligence with Decent Solutions Search
Author*Kodai Nagata (Daiken Sekkei, Inc./ Kagoshima University, Japan), Toshio Honma (Kagoshima University, Japan)
KeywordStructural Morphogenesis, Multi-objective Optimization, Swarm Intelligence, Decent Solutions, Diversity of Solutions
AbstractIn this paper, a structural morphogenesis for free form surface shells using the particle swarm optimization (PSO) and the artificial bee colony (ABC) which are one of the swarm intelligence (SI) is shown. These procedures categorized to the multipoint search algorithm are important as the computational procedure of acquiring a lot of diversified design variables. The genetic algorithms with immune system (ISGA) has already been proposed as an optimization method obtaining decent solutions. The decent solutions have comparatively high evaluation including Pareto optimal solutions and local Pareto optimal solutions. We have already shown a new scheme for PSO and ABC with searching manipulation of decent solutions using a technique concerning ISGA algorithm. Here, our schemes are applied to the multi-objective optimization problem for free form surface shell structure. From the numerical results, the acquisition of various decent solutions is shown by using our computational procedures.

Session CS4Y  Morphology
Time: 16:20 - 18:40 Tuesday, September 27, 2016
Location: Gallery-1

CS4Y-1, ID 1064 (Time: 16:20 - 16:40)
TitleSystematization of structural form of curved suspension bridges
Author*Fumiya Murano (IHI Infrastructure Systems Co., Ltd., Japan), Yoshiaki Kubota (Kyoto University, Japan)
Keywordcurved suspension bridge, systematization, structure and form, form finding by experiment
AbstractA curved suspension bridge offers multiple advantages including low weight, adaptability to various terrains, conservation of raw materials, and elegant architectural forms. However, it remains difficult to conceive the basic form of a curved suspension bridge because of the various three-dimensional forms possible and the currently immature knowledge of this system. Therefore, this study set out to clarify the relationship between the structure and the form of a curved suspension bridge and to systematize the fundamental underlying principles. In this study, we regarded curved suspension bridges as consisting of “curved girders,” “main cables and hangers,” and “pylons and back stay cables,” and clarified the relationship between the structure and the form for each of these components by conducting a mechanical analysis and practical experiments.

CS4Y-2, ID 1297 (Time: 16:40 - 17:00)
TitleFlexural mechanics of creases in thin metallic strips
Author*Martin G. Walker, Keith A. Seffen (Department of Engineering, University of Cambridge, U.K.)
KeywordCreasing, Folding, Shells
AbstractThe presence of mechanically formed corrugations in thin metallic shells has been shown to have a dramatic effect on mechanical behaviour. Currently, the majority of research has concentrated on the opening characteristics of a folded crease as part of an origami structure; surprisingly little study has been done on the flexural mechanics of a crease bent along its axis. We address this behaviour here. For analysis purposes, it is common to treat the crease line as a singular elastic rotational hinge. We examine this assumption for creases in thin metallic strips by endowing the crease with a finite, but small, geometry and approaching the singular limit. We show that when the crease dimensions are on the order of the shell thickness, the crease does not open appreciably and therefore stretching along the crease line must occur. A simple mathematical model is developed which matches practical flexural behaviour well.

CS4Y-3, ID 1157 (Time: 17:00 - 17:20)
TitleApplication of a net-shaped mechanism system in structural morphology
Author*Guigang Tu, Changyu Cui, Xiaodong Liang (Harbin Institute of Technology, China)
Keywordshape optimization, mechanism system, self-adapting function
AbstractThis study explores an innovative method in structural morphogenesis. It is based on the self-adapting function of a net-shaped mechanism system. A net-shaped mechanism system was developed first by adopting B-spline curves for the member geometry, followed by an equation of the control points motions which constrains the length of each member within the net-shaped system so they remain unchanged as the shape is adapted. This equation is solved using the generalized inverse matrix theory together with a principle of maximized gradient of potential energy increment with the system shape variation. An iterative process is used to find the final shape of the mechanism system, which corresponds to an optimized structural shape featuring a predominant axial force and a small bending moment under the specific loading pattern applied to the mechanism system.

CS4Y-4, ID 1158 (Time: 17:20 - 17:40)
TitleApplication of a linkage mechanism system in structural morphology
Author*Guigang Tu, Changyu Cui, Xinyue Chang (Harbin Institute of Technology, China)
Keywordshape optimization, mechanism system, self-adapting function
AbstractThis study explores the structural morphogenesis method of frame structures based on the self-adapting function of a linkage mechanism system that searches for the reasonable shape of a frame structure. In deriving an equation for shape changing a number of 'element groups' in a mechanism system are predefined such that each 'element group' must have a constant summation of element (rod) lengths. This equation is solved using the generalised inverse matrix theory together with the principle of the maximised gradient of potential energy increment with the variations in the system shape. An iterative process is used to find the final shape of the mechanism system which corresponds to an optimised structural shape that features a predominant axial force and a small bending moment under a specific loading pattern applied to the mechanism system. A control norm is proposed to seek a reasonable frame structure shape that is consistent with the designer’s intentions.

CS4Y-5, ID 1103 (Time: 17:40 - 18:00)
TitleTopology optimization of 3D structures using improved ESO method
Author*Yohei Niiuchi (Graduate School of Systems Engineering, Kindai University, Japan), Shinya Matsumoto, Daiji Fujii (Faculty of Engineering, Kindai University, Japan)
KeywordTopology optimization, ESO method, Voxel finite element method, Three dimensional structure, Computational Morphogenesis
AbstractIn this paper, an improved ESO (Evolutionary Structural Optimization) method for topology optimization is applied to biomimetics in architecture. In the proposed method (hereinafter called IESO), the idea of BESO method and the idea of extended ESO method are combined. However, IESO method is one-directional approach similar to the earlier ESO method, that is, it does not have the additional algorithm of elements. Therefore, this method is computationally efficient, and moreover more natural morphology can be obtained in comparison with SIMP method. Also, if a finishing algorithm is added to this method, it is possible to obtain the result which the objective function is better than SIMP method. Several numerical examples will be shown in order to demonstrate the effectiveness of the proposed method, and the effectiveness for the application to biomimetics.

CS4Y-6, ID 1482 (Time: 18:00 - 18:20)
TitleSome Morphological Aspects of Configurations
AuthorHoshyar Nooshin (Emeritus Professor, University of Surrey, U.K.), *Omidali Samavati (Consulting Engineer, Iran)
KeywordStructural morphology, Classification of structural forms
AbstractIn the present paper, to begin with, the attention is focused on a number of basic characteristics of the configurations. These characteristics concern such morphological aspects as ‘curviance’ and ‘connectivity’. The term ‘curviance’ means the ‘way in which a configuration is curved’ and the term ‘connectivity’ means the ‘way in which the components of a configuration are interrelated’. The morphological characteristics discussed in the paper are then used in considering the constitution of a proposed classification for the lattice spatial structural forms. In this classification system, it turns out that the ‘curviance’ is the main factor that governs the constitution. Also, at the next level, for the configurations that have the same curviance, it is the pattern that governs the classification. Then comes such aspects as the ‘geometric proportions’ involved and the ‘frequency’ of the pattern that are considered as the distinguishing features for the classification.

CS4Y-7, ID 1514 (Time: 18:20 - 18:40)
TitleGraphical limit state analysis of hyperstatic structures
Author*Jean-François Rondeaux, Denis Zastavni (Université catholique de Louvain (UCL/LOCI), Belgium)
Keywordgraphic statics, limit analysis, plastic theory, hyperstaticity, load factor
AbstractThis paper suggests a methodology that applies Graphic Statics to the limit state analysis of bended structures within the framework of Plastic Theory. For rather simple statically indeterminate bended structures like beams or frames it shows that this approach could be an alternative method to classical algebraic methods – like applications of the Principle of Virtual Works – for evaluating the structural safety. By application of the Lower Bound Theorem of Plasticity, a ‘safe’ value for the collapse load factor can be graphically determined by means of specific constructions of the reciprocal Form and Force Diagrams that is expressed as a scale factor applicable to the latter in order to transform it into a collapse Force Diagram. The advantages of this methodology are outlined in case of analysing geometrically complex existing structures.

Session CS3A  WG8: Metal Roofs -3
Time: 14:00 - 16:00 Tuesday, September 27, 2016
Location: Sanjo Main

CS3A-1, ID 1099 (Time: 14:00 - 14:20)
TitleBuckling strength maximization approach for free-form of single layer reticulated shells
Author*Yuji Takiuchi, Shiro Kato, Shoji Nakazawa (Toyohashi University of Technology, Japan)
Keywordfree-form, buckling, strength, single layer reticulated shell, optimization
AbstractIn this paper, a scheme of shape optimization is proposed for obtaining the maximum strength of free-form steel reticulated shells. In order to discuss the effectiveness of objective functions with respect to the strength, several different optimizations using GA are applied to shallow steel single layer reticulated shells. The objective functions to be searched and compared are, respectively, strain energy minimization, linear buckling load maximization, initial yield load maximization, and buckling strength maximization. The buckling strength as a target for the fourth optimization is evaluated based on Modified Dunkerley Formula. With respect to the obtained free-forms based on the four optimization schemes, elasto-plastic buckling behaviour is investigated. From comparison, it is confirmed that the strain energy minimization approach is rather effective to obtain a large buckling strength, while the other three approaches are much effective in obtaining high buckling strength.

CS3A-2, ID 1139 (Time: 14:20 - 14:40)
TitleBuckling behavior of two-way single layer lattice dome stiffened by diagonal braces
Author*Takayuki Iwamoto (Tomoe Corporation, Japan), Shiro Kato, Shoji Nakazawa (Toyohashi University of Technology, Japan)
Keywordmetal spatial structures, lattice shells, single layer, elasto-plastic buckling, diagonal stiffening
AbstractThe present study focuses on a two-way lattice dome stiffened by diagonal braces aiming to grasp elasto-plastic buckling behaviour of the dome under dead and non-uniform snow loads assuming that it is supported elastically by roof eaves and substructures. The results reveal the following characteristics.The eaves around the lattice dome provided as a tension ring are much effective to secure the sufficient horizontal stiffness in order to avoid excessive stresses in the diagonal braces, resulting in increase of buckling strength. The diagonal braces of even a small sectional area at the central region of the dome work aplendidly to upgrade the buckling strength. At the initial loading stage, the diagonal braces will not work for vertical loadings, however, these braces begin to bear tensile stresses on account of shear deformation appearing after large displacements in the dome and effectively upgrade the buckling performance.

CS3A-3, ID 1283 (Time: 14:40 - 15:00)
TitleEffect of Accordion Force Limiting Device on stability behavior of double layer grids
Author*Maryam Poursharifi, Mohammad Reza Chenaghlou, Karim Abedi (Sahand University of Technology, Iran)
KeywordForce limiting device, Double layer grid
AbstractSpace structures have many advantages such as light weight, mass production, ease of erection as well as economic matters. Beside these advantages, space structures suffer from sudden collapse in brittle manner because of compression member’s failure. In order to modify the behaviour of space trusses, force limiting devices can be applied to critical compression members. In this study, an innovative type of force limiting device is introduced which is designed based on buckling restrained braces and accordion metallic damper. This device called Accordion Force Limiting Device (AFLD). One whole steel Accordion Force Limiting Device is designed, constructed and tested. A parametric study is carried out to study the effect of AFLD, considering loading patterns, aspect ratio as well as length to depth ratio in double layer grids. Results indicate that regardless of loading patterns as well as varying geometric properties applying AFLD to critical compression members cause great behavior improvement.

CS3A-4, ID 1150 (Time: 15:00 - 15:20)
TitleStudy on accumulated deflection due to plastic deformation steel moment frames of gymnasiums
Author*Ryo Iwasawa, Tetsuo Yamashita, Shungo Manjo (Kogakuin University, Japan)
Keywordgymnasiums, finite element analysis, Static incremental analysis, H-section steel frame, accumulated deflection
AbstractWhen subjected to cyclic horizontal earthquake load, large accumulated deflection arises at the crown of steel moment frames. This paper discusses the mechanism and a quantitative evaluation on this deflection. We performed FEM analysis of some steel moment frames subjected to cyclic horizontal and constant vertical loads. All of the models caused yield of the panel zones. It is found that the accumulated deflection especially increases when a plastic hinge occurs on only one end of the girder. Based on this mechanism, we developed an equation to estimate the vertical deflection and verified by comparing with the FE analysis.

CS3A-5, ID 1301 (Time: 15:20 - 15:40)
TitleEffect of member length imperfection on stability behavior of double layer pellevated dome
AuthorRamin Vaezi Vazna, *Karim Abedi (Sahand University of Technology, Iran)
Keywordlack of fit, double layer pellevated domes
AbstractTo construct a space structure with hundreds of members and joints without any imperfection is almost an impossible work. Previous studies shows that these structures are sensitive to the different types of imperfections. The behavior of double layer space structure is dependent on their axial load- axial displacement response of compressive members. The lack of fit in the members of double layer space structures is the most common form of imperfection. Consequently, this type of imperfection in the compressive members will change the behavior of these structures. This study presents an investigation into the effects of lack of fit imperfection on double layer pellevated dome’s members by carrying out nonlinear static and dynamic analysis. Since there have been deterministic investigation, the critical members of the structure recognize at first and after that, imperfection applied to them and by doing nonlinear static and dynamic analysis, the effect of this kind of imperfection had been investigated.

CS3A-6, ID 1386 (Time: 15:40 - 16:00)
TitleExperimental research on the aging behaviors of PVDF-coated fabrics from Qingdao ETSONG Stadium
Author*Yunting Li, Bin Yang, Qilin Zhang (Tongji University, China)
KeywordPVDF-coated fabrics, natural ageing, artificial ageing, mechanical property
AbstractThis paper investigates effect of natural ageing on mechanical properties of PVDF-coated fabrics Ferrari 1302T, which is removed from Qingdao ETSONG Stadium through experiments. Surface coating of the PVDF-coated fabrics is checked with scanning electron microscopy. In addition, the aged coated fabrics are compared with the new ones through experiments in terms of brightness, uniaxial force at failure, tear strength, bonding strength and Young’s modulus. Results show that there are some microfractures on the top surface of the aged coated fabrics. The force at failure of aged coated fabrics in warp direction and in warp direction is lower than that of the new coated fabrics. Compared with force at failure, tear strength decreases more. Bonding strength of the aged coated fabrics decrease to some extent and the failure mode indicate the bonding still meets the corresponding requirement.

Session CS4A  Flex Structures
Time: 16:20 - 18:40 Tuesday, September 27, 2016
Location: Sanjo Main

CS4A-1, ID 1180 (Time: 16:20 - 16:40)
TitleStructural Morphogenesis for Tunnel-Shaped Frame Structure by Using Genetic Algorithms
Author*Daisuke Wada, Koichi Tanaka (AZUSA SEKKEI Co., LTD., Japan), Toshio Honma (Kagoshima University, Japan)
Keywordstructural optimization, genetic algorithms, steel structure, arch frame, bending moment minimization
AbstractIn this paper, we introduce the example of the building that was designed by structural morphogenesis and constructed. The target building is TOTO MUSEUM facilities that have a tunnel-shaped form. We apply genetic algorithms (GA) to the structural morphogenesis of the tunnel-shaped frame structure. We focus on the stress of long term load for objective function. In the numerical result, we show the solution forms of structural morphogenesis with some design constraints. Optimization method use the standard genetic algorithms (SGA). The design variable is the coordinates position of the nodal points. Optimization is the single objective optimization problem of setting the objective function of the bending moment minimization. The numerical result is obtaining the solution forms of the tunnel-shaped frame structure with constraints of building height and space volume. We search for the curved shape that these obtained forms are advantageous in the structure, the design and the function.

CS4A-2, ID 1355 (Time: 16:40 - 17:00)
TitleStructural design of the crematorium in Kawaguchi
Author*Toshiaki Kimura, Yoshiyuki Hiraiwa, Mutsuro Sasaki (Sasaki Structural Consultants, Japan)
Keywordfree-curved RC surface, computational morphogenesis, NURBS, strain energy
AbstractThis paper reports the under construction project of the crematorium which has the free-curved RC surface, designed by Toyo Ito Architects and Associates. In the structural planning, structural system of this building consists of the RC rigid frame with the shear wall, steel column and free curved RC surface. With respect to free curved RC surface, the scheme of computational morphogenesis is utilized. By using this scheme, the configuration of free curved RC surface which is satisfied with a certain structural rationality and an architect’s aesthetics has been obtained. With respect to the construction, the form work of the the free-curved RC surface is planned by using method which 3D modeling technique has been applied.

CS4A-3, ID 1214 (Time: 17:00 - 17:20)
TitleTilt-up concrete dome skeleton construction by
 Rotational Erection System (RES), part 2
AuthorYoshinobu Miyamoto (Aichi Institute of Technology, Japan), *Takaaki Itoh (Toyota T&S Construction Co., Ltd., Japan), Hiroaki Harada (Nikken Sekkei Ltd., Japan)
Keywordorigami, kirigami, pop-up, tilt-up, concrete
AbstractWe propose a novel construction method for dome skeleton using Tilt-up concrete and Rotational Erection System (RES) (Miyamoto [1]). The construction procedures are 1) setting the edge form and rebar, 2) casting structural concrete, 3) hoisting up the hub on the temporary support, 4) tilting-up the arms and fastening them to the hub and 5) installing the stay cable or rod adjusting the their tension and removing the support under the hub (Figure 1, 7). The preliminary structural analysis suggested that 30m span domes are feasible with conventional concrete materials.

CS4A-4, ID 1531 (Time: 17:20 - 17:35)
TitleExperimental and Numerical Studies on Bending Behavior of Origami Creases
Author*Zelun Qian, Jianguo Cai, Jian Feng (Southeast University, China)
Keywordorigami, crease, Bending Behavior
AbstractIn this paper, the bending behavior of the creases of the origami, is studied numerically and experimentally. Three type of creases, normal (standard) crease, continuous cut crease (the cut traverses partially, but continuously, the paperboard thickness), discontinuous cut creases are tested. The numerical analysis are carried out and the comparison of between experimental and numerical results are studied. After that, more parameters are studied using the numerical study. The experimental curves, which is obtained for the different crease types subject to loading and unloading cycle, are idealized in three classes of simplified constitutive law, in order to grasp their very distinctive behavior.

Session CS3B  New Materials and New Construction Methods -3
Time: 14:00 - 16:00 Tuesday, September 27, 2016
Location: Main Foyer

CS3B-1, ID 1414 (Time: 14:00 - 14:30)
Title[Keynote] DBFstudio - Evaluation and development of research topics through the application of advanced fabrication technologies
AuthorStefan Neudecker, Jörg Petri, Hendrik Lindemann, *Harald Kloft (Institute for structural design, Technische Universität Braunschweig, Germany)
Keywordrobotic fabrication, teaching, robotic, generative production, fiber reinforcement
AbstractThe DBFstudio (Digital Building Fabrication - Studio) is a teaching framework that has been created to introduce early stage ITE research topics to students. The idea is to explore these topics from a different perspective through the work with the students. The format offers access to the possibilities of robotics in the context of architecture and building techniques with tasks that combine, material, digital processing and manual craft techniques.

CS3B-2, ID 1422 (Time: 14:30 - 14:50)
TitleMagnetically Controlled Concrete 3D Printing
Author*Sandra Manninger, Matias del Campo (Taubman College, University of Michigan, U.S.A.)
Keyword3D printing, Large Format 3D printing, concrete shells, concrete spatial structures
AbstractThe aim of this paper is to present the results of explorations in robotic construction methods executed at the University of Michigan. It discusses an approach to solve the problem of slumping in large format 3D printing spatial concrete structures or shells without molds. This paper describes a material approach introducing magnetic forces in order to control the deposition of the concrete.

CS3B-3, ID 1502 (Time: 14:50 - 15:10)
TitleBio-Based Composite Pedestrian Bridge – Part 1: Design and Optimisation
Author*Joris Smits, Rafail Gkaidatzis (Delft University of Technology, Netherlands), Rijk Blok, Patrick Teuffel (Eindhoven University of Technology, Germany)
KeywordBio-based, FRP, Design, Optimisation, structural
AbstractThe Bio-based composite bridge is a 3TU project which aims to design and realize a 14m span pedestrian bridge made from fibre-reinforced polymers (FRP) that have a high percentage of bio-based content. The bridge will be installed over the river Domel, at the campus of the Eindhoven University of Technology (TU/e) in the Netherlands. The present paper investigates the design potentials and challenges of bio-based fibre-reinforced polymers, which is a relatively new material in architectural and structural bridge design. Along with the design possibilities of the material, the paper presents the entire design process followed from conceptual stage to detailing, focusing on the evaluation of different structural typologies and the optimization of selected geometry.

CS3B-4, ID 1504 (Time: 15:10 - 15:30)
TitleBio-Based Composite Pedestrian Bridge – Part 2: Materials and Production Process
AuthorMark Lepelaar (NPSP BV, Netherlands), Alwin Hoogendoorn (Centre of Expertise Biobased Economy & Avans University of Applied Science, Netherlands), Rijk Blok, *Patrick Teuffel (Eindhoven University of Technology, Netherlands)
KeywordBio-based, FRP, Testing, Production
AbstractThe Bio-based composite bridge is a 3TU project which aims to design and realize a 14m span pedestrian bridge made from fibre-reinforced polymers (FRP) and which is introduced in part 1 of this paper. Part 2 will focus on various studies about bio-based materials, which are suitable for structural applications: this includes bio-based resins, bio-based fibres, bio-based core materials as well as bio-based coatings. In order to understand the mechanical behaviour of different material combinations various tests (tension, compression, bending as well as moisture absorption) are carried out. In addition different production processes are evaluated to find the optimal technique for the selected design and material choices.

CS3B-5, ID 1544 (Time: 15:30 - 15:50)
TitleMasonry construction with drones
Author*Pierre Latteur, Sebastien Goessens (Louvain School of Engineering, EPL, Belgium), Caitlin Mueller (MIT, U.S.A.)
KeywordMasonry, drone, droxel, digital fabrication, additive manufacturing
AbstractThis paper presents new research in the area of construction of building-scale structures using unmanned aerial vehicles, commonly called drones. The work follows up on a previous paper presented at the 2015 IASS Symposium by Latteur et al. [1], which focused on the feasibility of drone-based construction systems with an emphasis on localization systems and building system units. Since then, the project has continued with a focus on masonry block structures, with new developments in block design, computational modelling and design tools for drone-built structures, and tests with a custom-built 40-kg payload quadracopter drone.

Session CS3C  Tension Structures -1
Time: 14:00 - 16:00 Tuesday, September 27, 2016
Location: Room 001

CS3C-1, ID 1040 (Time: 14:00 - 14:20)
TitleThe Dynamic Behaviors of the Roof of the Gymnasium 2 of Yoyogi Stadium
Author*Chie Matsuo, Mamoru Kawaguchi (KAWAGUCHI & ENGINEERS, Japan)
KeywordYoyogi Stadium, eigenvalue analysis, elastic response analysis
AbstractThe dynamic behaviors of the roof of the Gymnasium 2 of Yoyogi Stadium are reported on the basis of elastic response analyses. Firstly, the static analysis has been carried out, and the results are compared with the values reported elsewhere [1]. Secondly, the eigenvalue analysis has been carried out, and the resulting natural periods are compared with those measured on the actual roof. Finally, the elastic response analyses have been carried out. The response accelerations in the horizontal and the vertical directions are compared at the corresponding points of the roof. The dominant natural modes for different load directions are pursued from the distribution of the maximum response acceleration, and the stress states of the suspended roof trusses are examined.

CS3C-2, ID 1059 (Time: 14:20 - 14:40)
TitleSuper-stability of symmetric prismatic tensegrity structures based on group representation theory
Author*Masaki Okano, Jingyao Zhang (Nagoya City University, Japan)
Keywordtensegrity, dihedral symmetry, super-stability, prismatic, self-equilibrium
AbstractTensegrity structures are prestressed pin-jointed structures composed of struts and cables. To check stability of tensegrity structures, it’s preferable to check super-stability since it is the strongest stability criterion. In this paper, we discuss the super-stability of prismatic tensegrity structures which have dihedral symmetry. In previous studies, these structures were proved to be super-stable if horizontal cables connect adjacent nodes. However, these proofs are incomplete. Therefore, we complement the proof for super-stability of symmetric prismatic tensegrity structures in this study.

CS3C-3, ID 1060 (Time: 14:40 - 15:00)
TitleResearching on a cylindrical tensegrity structure
Author*Heping Liu, Jinsong Geng, Ani Luo, Chengxu Wu, Pengfei Cao, You Lu, Shenshen Zhao (Harbin Engineering University, China)
Keywordtensegrity, connection matrix, force density, minimum mass, cylindrical structure
AbstractTensegrity structure has advantages of light weight, simple shape of the members and easy building etc. In the paper, a cylindrical tensegrity structure is presented and researched. At first, based on a cylindrical origami structure, the method of arranging the bars and strings of the cylindrical tensegrity structure is presented. Then the connectivity matrix is set up. The mathematical model is set up further. Length of the members is obtained further and a model of the cylindrical tensegrity structure is built. The model proves the stability of the structure and feasibility of designing it. The force equilibrium equation of the structure is obtained further. Optimization method is applied to get the minimal mass and section sizes of the members. Through researching in the paper, the method for designing a kind of new tensegrity structure is obtained and configuration of the tensegrity structure is enriched.

CS3C-4, ID 1061 (Time: 15:00 - 15:20)
TitleResearching on the influence of tensegrity structure axial splicing interface parameters on rigidity
Author*Jinsong Geng, Ani Luo, You Lu, Wei Tian, Penghao Sun, Xiaodong Hao (Harbin Engineering University, China)
KeywordAxial splicing tensegrity structure, Finite element method, Unit overlap ratio, Adjacent unit deflection angle
AbstractThis paper focuses on the influence of axial splicing interface parameters of the tensegrity structures on mechanical properties and rigidity of the structure. At first, the finite element method is applied to introduce the rigidity matrix, and deform it according to the constraint conditions and outer forces. In addition, establish the mathematical model of the structure and realize the automatic configuration based on axial splicing interface parameters. Finally, taking a double-unit structure for an example, obtain the relationship between interface parameters and rigidity. Through this paper, the most reasonable value range of unit overlap ratio and adjacent unit deflection angle of the axial splicing tensegrity structure are determined, which provides related research of tensegrity structure with the theoretical support.

CS3C-5, ID 1104 (Time: 15:20 - 15:40)
TitleStudy on glass structure using prestressing -Application to arch-shaped structure and understanding of basic structural characteristics-
Author*Ayana Tomisawa, Akira Okada, Naoya Miyasato, Shuzo Hiroishi, Shuntaro Shino (Nihon University, Japan)
Keywordannealed glass panel, string, cables, hybrid construction, initial tensile force
AbstractGlass is used as a finishing material and is considered safe only in regard to bearing the wind load and self-weight of the glass panel. However, glass can be applied as a structural element by taking advantage of the high compressive strength of the glass which can allow for more attractive, constructive spaces. The authors suggest several hybrid constructions which combine structures which support annealed glass panels with strings such as cables as one of the methods to make use of compressive strength of glass. The most important characteristic of this structure is to add compression to the glass panel through the initial tensile force introduced into the string. This paper proposes an arch-shaped frame which is suitable for a relatively large span.

CS3C-6, ID 1428 (Time: 15:40 - 16:00)
TitleA unified formulation for redundancy of cable-strut structures considering the effect of pre-stresses
Author*Jinyu Zhou, Wujun Chen, Bing Zhao, Chengjun Gao (Shanghai Jiao Tong University, China)
Keywordredundancy, cable-strut system, principle of minimum potential energy, distributed static indeterminacy, distributed kinematic indeterminacy
AbstractAn understanding of the redundancy is necessary to evaluate the robustness of a structure to progressive collapse frequently caused by unexpected events. However, such an understanding is limited by a lack of universal assessments for redundancy of a cable-strut assembly at pre-stressed configuration. To this end, a redundancy evaluation of cable-strut structures was improved by incorporating the effect of component pretension on structures. A nonlinear governing equation was established in the updated Lagrangian formalism, and then a linearization method for simplifying the strain energy was adopted to release the numerical complexity. Based on this reasonable linearization, a unified analytical formulation for elastic and geometric redundancies was derived using the principle of minimum potential energy; a theoretical comparison was made to clearly interpret the difference. Furthermore, two examples were investigated using this evaluation, to demonstrate the use of the proposed redundancy index and to provide insight into structural properties affecting robustness.

Session CS4C  Tension Structures -2
Time: 16:20 - 18:20 Tuesday, September 27, 2016
Location: Room 001

CS4C-1, ID 1231 (Time: 16:20 - 16:50)
Title[Keynote] Parametric Analysis on Static Behavior of Annular Crossed Cable-truss Structure
AuthorRenjie Liu, *Suduo Xue, Xiongyan Li (Beijing University of Technology, China), Marijke Mollaert (Vrije Universiteit Brussel, Belgium)
KeywordTensile spatial structures, New structural system, Disproportionate collapse, Parametric Analysis
AbstractThe Annular Crossed Cable-Truss Structure (ACCTS) is a new type of tensile spatial structure with a configuration suitable to cover large-span stadiums. Its configuration has potential to perform well in disproportionate collapse resistance. However, static behavior of the ACCTS hasn’t been investigated in depth. In this paper, parametric analysis was carried out. Geometric parameters and pretension of structural system were considered. With the results it is found that pretension, the number of connections on the outside ring beam and the sag height ratio influenced the structural stiffness the ACCTS obviously and can be used to adjust the structural stiffness during the structural design. It is also observed that the rise height ratio has little effect on the structural stiffness but can be used to adjust the curvature of the top layer to make the tensile membrane well tensioned.

CS4C-2, ID 1222 (Time: 16:50 - 17:10)
TitleThe analysis of configuration and structural stability of 8-bars tensegrity prism
Author*Pengfei Cao, Ani Luo, Chengxu Wu, Jinsong Geng, You Lu (Harbin Engineering University, China)
Keyword1122334455, 5544332211
AbstractThis article focus on the construction method and criteria for geometrical stability of the tensegrity prism with 8 bars. According to geometric parameters of the tensegrity, mathematical model of the tensegrity can be built up with the use of generalized coordinate matrix of the nodes and connection matrix. Then, according to forces in member and force density in member, the criteria for geometrical stability of the structure is analyzed by building the force equilibrium equation. After the equilibrium equation is analyzed, stable tensegrity prism and corresponding variation range of geometrical parameters will be found. The method used in this article can be used when other basic tensegrity structure are analyzed.

CS4C-3, ID 1235 (Time: 17:10 - 17:30)
TitleExperimental study on the response of a suspendome subjected to the sudden failure of hoop cables
Author*Xiaoxiang Wang, Hongbo Liu, Zhihua Chen (Tianjin University, China)
KeywordSuspendome, Cable rupture, Cable sliding, Dynamic response, Dynamic amplification factor
AbstractSuspendome is a kind of highly efficient prestressed structure system. In this study, two tests were conducted on a 10:1 scaled-down suspendome model to investigate the dynamic response and mechanical changes. A special rupture device was invented to realize the sudden failure of cable. The internal force variations of different members were measured and dynamic member-moving procedures around the break region were captured by high-speed video camera. The internal forces of the members near the breaking point experienced large vibrations at the breaking moment. In traditional structural design, the dynamic amplification factor (DAF) value is usually considered as 2.0. However, owing to complex nonlinear effect, the value 2.0 would be unsafe when experienced sudden failure of hoop cables in suspendome structures. It is suggested that refined finite element dynamic analysis should be considered and model test could be conducted to obtain a more precisely result.

CS4C-4, ID 1258 (Time: 17:30 - 17:50)
TitleAnalysis of the response of suspen-dome structure at elevated temperatures
Author*Ye-Hua Wang, Zu-Yan Shen, Yuan-Qi Li (State Key Laboratory of Disaster Reduction in Civil Engineering, Tongji University/Department of Strucutral Engineering, Tongji University, China)
Keywordsuspen-dome structure, structural response, elevated temperature, fire resistance
AbstractThe suspen-dome structure, as a highly effective structural system, is extensively used in Japan and China. In the same time, the fire accidents of suspen-dome structure are sometimes occurred. However, the research on fire resistance of the structure is relatively limited. In this paper, geometrically and materially nonlinear finite element analysis of the response of suspen-dome structure at elevated temperatures simulating the fire condition is conducted to research the fire resistance of the structure. The results show that the deformation mechanism of the suspen-dome structure at elevated temperature appears the feature of expansion-to-fall, and variational rules of the forces of the members of the structure appears that the axial force firstly increase and then decrease with the temperature increasing. Then according to the analytical results, a failure criterion of suspen-dome structure at elevated temperature is proposed based on vertical strut buckling or cable relaxing.

CS4C-5, ID 1287 (Time: 17:50 - 18:10)
TitleAnalysis of new type of cable dome with rigidly cladding in arena of Tianjin University of Technology
Author*Qing Ma, Zhihua Chen, Xiangyu Yan (Tianjin University, China)
Keywordcable dome, rigid roof, purlin system, integral model
AbstractThe largest cabledome in China mainland is presented in this paper. The cabledome is built for the roof of arena of Tianjin University of Technology. It was arranged in ellipsoid plane with major axis of 102m and minor axis of 82m. A type combined Geiger and Levy form was adopted in the arrangement of cables. The outmost were in Geiger form and inner ones in Levy form. It was covered with membrane in the center and metal cladding in the periphery, so purlin system is applied to support the roof. Influence of purlin system and concrete structure are discussed.

Session CS3D  Timber & Environment -1
Time: 14:00 - 16:00 Tuesday, September 27, 2016
Location: Room 002

CS3D-1, ID 1033 (Time: 14:00 - 14:30)
Title[Keynote] Fatigue and creep characteristics of wooden space frame joint
Author*Katsuhiko Imai (Forest Engineering & Economics Lab. Co. Ltd., Japan), Hiroyuki Miyahara (Graduate School of Engineering, Osaka University, Japan), Shizuo Tsujioka (Department of Architecture, Fukui University of Technology, Japan), Kiyoshi Shogatsudani (Forest Engineering & Economics Lab. Co. Ltd., Japan), Tadatoshi Furukawa (Graduate School of Environmental Studies, Nagoya University, Japan), Masumi Fujimoto (Graduate School of Engineering, Osaka City University, Japan)
KeywordFatigue, Creep, Wooden structure, Space frame, Truss structure
AbstractAs the wooden space frame system (KiTruss) grew in performance remarkably well because of recent developments and became comparable to steel space frames, KiTruss can be applied to outdoor use under wind load such as stadium roofs, observation towers, monuments, advertising towers and communication antennas for mobile phones. It can be also for used under long term large vertical loads such as wide span structures in regions of heavy snowfall and pedestrian bridges. This paper presents fatigue and creep characteristics of the KiTruss joint under tensile load. Both for repeated and long-term vertical loading, it was shown through the experiments that the KiTruss joint had excellent safe strength and deformation resistance against repeated and long-term loading. There is no previous research on the fatigue and creep characteristics of wooden space frame joints.

CS3D-2, ID 1481 (Time: 14:30 - 14:50)
TitleReinforcement of glulam with ab intio embedded steel sheets for high-performance joints
AuthorChristoph Koj, Martin Trautz, *Andrija Pranjic (Chair of Structures and Structural Design, RWTH Aachen University, Germany)
Keywordglulam, glued-in steel sheets, reinforcement, timber construction, joints
AbstractIn engineered timber construction glued connections are superior to mechanical fasteners, yielding a significantly higher strength and stiffness. The Chair of Structures and Structural Design at RWTH Aachen University in cooperation with the Institute of Building Materials Research (ibac) and three industrial partners is researching a way to embed steel sheets ‘ab initio’, that means within in the glulam production process. The embedded thin steel sheets serve as local reinforcements to boost the strength of bolt and steel plate connections and create high-performance joints. After the evaluation of suitable steel-glue-combinations, the effects of sheet geometry, climatic exposure, long term loads and installation methods have been examined. Additionally the glulam production process was analysed to determine suitable slots in the process to integrate the embedding of the steel sheets. Finally the developed connections are tested on construction-size tension and bending joints, proving the potential of this innovative reinforcement and joining method.

CS3D-3, ID 1249 (Time: 14:50 - 15:10)
TitleThe structural design of a timber two directional parallel chord truss
Author*Keisuke Nomura (Tokai University, Japan), Katsuo Nakata (K. Nakata & Associates, Japan)
KeywordTimber, Spatial structures, Structural design
AbstractIn this paper, report on the structural design of a timber two directional parallel chord truss, which limited the material, section and length. And report about it mock-up loading experiment. The timber-truss was applied to the roof at Gojo gymnasium in Nara of Japan. Until the second floor was a reinforced concrete structure, the roof was a hybrid structure of steel and timber-truss. The plane of the arena was a long axis about 56.8m, short axis about 50.8m. Keel beam and four sides of the roof was a steel frame. And others were covered with timber-trusses. As for the truss, the unit of T-type comprises a top chord wood and a web, the units rotate a direction 90 degrees and are jointed, and a bottom chord intersects perpendicularly and is jointed to the web of the unit.

CS3D-4, ID 1266 (Time: 15:10 - 15:30)
TitleDesign of Timber Suspension Roof Pretensioned to Reduce Deformation under Snow Load
Author*Shohei Furuichi (Jun Sato Structural Engineers Co., Ltd., Japan), Jun Sato (The University of Tokyo, Japan)
Keywordtimber, suspension roof, snow load, pretension
AbstractTimber, usually used in compression or bending, has a rather high tensile strength and can be a good material for tensile structures. This paper presents structural design of a junior high school with a timber suspension roof. As it snows heavily around the site, reducing the deformation under snow load was one of the main themes of structural design. For this purpose, steel beams were placed on the roof orthogonal to the timber beams and tension rods were set between the steel beams and the foundation. The rods introduce pretension which acts as a concentrated load on the timber beams equivalent to the distributed snow load. Under snow load, the rods lose pretension corresponding to the amount of snow, meaning the total load on the timber beams remains roughly the same, therefore the deformation is suppressed small. This pretensioning system also works to reduce the influence of unbalanced snow load.

CS3D-5, ID 1178 (Time: 15:30 - 15:50)
TitleExperimental study on single layer two-way grid spherical dome composed of prefabricated wooden truss system with tension rod members
Author*Masumi Fujimoto (Osaka City University, Japan), Katsuhiko Imai (Forest Engineering & Economics Lab. Co. Ltd., Japan), Atsuo Takino (Graduate School of Humanities and Sciences, Nara Women's University, Japan), Zhonghao Zhang (Northeast Agricultural University, China)
Keywordsingle layer, two-way grid, spherical dome, wooden truss system, tension rod member
AbstractIn this study, we treat a single layer two-way grid spherical dome composed of wooden prefabricated truss system with tension rod members to get the new structural data. The effect of tension members on the structural behaviour of the two-way grid shell had been shown through experimental studies. Two-way grid members are Japanese cypress round timbers; tension rod members are PC bar. Loading patterns are the concentrated centre load and the asymmetrical concentrated. The initial axial force of tension member is determined by engineering judgement. The difference between manufactured member length and nominal member length correspond macroscopically to the introduced axial forces of tension members. From loading experiments, the buckling load of grid shells and the rigidity of load displacement relation increase through the increase in introduced initial axial force. The effect of tension member initial axial force on load deformation behaviour of single layer grid shell is confirmed. 55

Session CS4D  Timber & Environment -2
Time: 16:20 - 18:20 Tuesday, September 27, 2016
Location: Room 002

CS4D-1, ID 1470 (Time: 16:20 - 16:40)
TitleComposite timber-concrete floor: Experimental and theoretical verification
Author*Lukáš Surovec, Miloš Slivanský (Slovak University of Technology in Bratislava, Slovakia)
Keywordcomposite, timber, concrete, floor, experimental
AbstractThis paper contains results of experimental research executed on composite timber-concrete floor. Original two-storey family house that is about 80 years old is in reconstruction by September 2014. Composite floor was built on the original brick walls of the first storey after removal of the original roof structure. New floor consists of timber beams with dimensions 100/220 mm, with regular spacing 740 mm and span about 5.3 m. On these beams 18 mm thick cement bonded particleboards (CETRIS) were put and fixed with nails. These sheets created the decking for the 70 mm thick concrete deck. Measurement of deformations and stresses was performed immediately after removing the temporary supports. Obtained experimental results were compared to the theoretical calculation models.

CS4D-2, ID 1276 (Time: 16:40 - 17:00)
TitleModular Kinematic Timber Gridshell; a Simple Scheme for Constructing Advanced Shapes
Author*Steinar Hillersøy Dyvik, John Haddal Mork (Faculty of Architecture and Fine Art, Norwegian University of Science and Technology, Norway), Magnus Nilsen, Marcin Luczkowski (Department of Structural Engineering, Norwegian University of Science and Technology, Norway)
KeywordTimber post formed Gridshell, Timber Structure, Digital Form Finding, Full scale prototype, Segment Lath
AbstractThis paper explains the construction scheme of a modular post formed gridshell. The scheme uses timber modules connecting laths of 900 mm length into a 2-layer module. The scheme and the module are designed to efficiently handle both Form Finding, Fabrication and Raising, and they are tested through the construction of a full scale pavilion in Trondheim, Norway.

CS4D-3, ID 1306 (Time: 17:00 - 17:20)
TitleDesign theory of Haraichi Kindergarten based on Japanese traditional structural detailing
Author*Kuniaki Ito (Prof. Emeritus of Tohoku Univ. and Architect, Japan), Junichiro Matsumoto (J. Matsumoto Design Office, Japan), Toshimi Kushida (TOJU Industry Co.Ltd, Japan)
Keywordlaminated wood, same thickness members, modular co-ordination, three dimensional truss, glued-in rod
AbstractThis laminated wood structure for a kindergarten is based on the same housing-design method of “Shinkabe; wooden column-exposed wall construction” which has been used for the Japanese traditional wooden houses for a long time. This kindergarten, in spite of containing relatively wide span rooms like school gymnasium, class rooms and meeting room has no big size members. Not only from the view point of artistic detailing but also in economical and modular co-ordination factors, laminated wood columns and beams are one-side same thickness members (width size 12cm). To obtain the necessary performance as the kindergarten , they are used frequently as the members of part of Three Dimensional Truss or those of Rigid Rahmen frame using reliable glued-in rod connection.As a result, we could achieve a long-span school gymnasium having high-side light, deep eaves and walls with smooth suface. They were necessary to assure for children to be active,

CS4D-4, ID 1342 (Time: 17:20 - 17:40)
TitleA Nature Inspired Design Philosophy of Spatial Structures
AuthorKang-geun Park (Korean Association for Spatial Structures, Republic of Korea), *Dong-woo Lee (I'ST Co., Republic of Korea), Sang_Ju Lee (I'ST Co., Ltd, Structural Engineering Group, Republic of Korea)
Keywordnature inspiration architecture, bio-eco architectural design, temperature control systems, large span spatial structures, bio-eco-friendly material
AbstractThis study is to find the design concept of nature inspiration architecture for the design philosophy of large span spatial architectures that seeks solutions for nature-friendly building design. It has been commonly noted that the nature inspiration architecture was designed by aesthetic, ecologic, sustainable and geometric buildings, thus, this paper will be investigated present spatial buildings which embrace nature inspiration techniques, bio-sustainable design and effective temperature control system of spatial structures. The bio-eco architecture which replicates a structure of nature in order to create innovative design and techniques will be surveyed, and bio-mimetics applications play an important role in the developments of new design concept. And then it will be shown how to design a nature-friendly architecture, how to control the interior temperature of building from extreme hot or cold weather as well as how to design the retractable roof of spatial structures.

CS4D-5, ID 1107 (Time: 17:40 - 18:00)
TitleStudy on jointing system of torus double-layer lattice structures consisting of rectangular section members
Author*Yuki Taniguchi, Yoshiya Taniguchi, Hitoshi Okuyama (Graduate school of Osaka City University, Japan)
Keywordlattice structures, timber, joints variations, contact of cross section, web members
AbstractThis paper highlights the joints geometry of timber lattice structures consisting of rectangular section members to abandon such the screw jointing technology. Torus shape [2] is adopted as a building shape to reduce jointing variations. The two curvatures and depth determine the geometry of a basic structural unit. In the timber lattice structures developed, the compressive axial member forces are directly delivered by the contact of cross sections. It should be noted that if the double-layer lattice structures have two curvatures, the web members must be twisted to be connected to the top and bottom nodes. The difference of such member chord angles is also investigated.

CS4D-6, ID 1255 (Time: 18:00 - 18:20)
TitleExperimental study on new jointing system for timber lattice structures by direct contact of member cross sections in the fiber direction
Author*Hitoshi Okuyama, Yoshiya Taniguchi, Yuki Taniguchi (Osaka City University, Japan)
Keywordtimber lattice structure, jointing system, Experimental study, new jointing system, direct contact of cross sections
AbstractIt may be important to use timbers from thinning, to maintain forest in a good condition. The timbers from thinning are usually irregular goods because of their shorter length or smaller cross section. Lattice structures have been often adopted in overcoming this disadvantage. Former timber lattice structures may mostly stand on the technology of industrial steel truss systems. In this paper, a new concept is introduced in the transmission of member axial forces. The compressive member axial forces are directly delivered by the contact of cross sections, that is, timbers are mutually contacted through cross sections. The other tensile and shear forces are mainly delivered by steel plates hidden in timbers with drift pins. This basic technology itself may be not innovative, however it may be sufficient to abandon the conventional manner in realizing timber lattice structures with a screw jointing system.

Session CS3E  Shell -3
Time: 14:00 - 16:00 Tuesday, September 27, 2016
Location: Room 201

CS3E-1, ID 1365 (Time: 14:00 - 14:20)
TitleThe effect of dents on the buckling and post-buckling behavior of cylindrical shells with stepwise variable thickness
AuthorSara Pourkhorshidi, *Karim Abedi (Sahand University of Technology, Iran)
Keywordcylindrical shells, pressure loading
AbstractThin-walled cylindrical shells with stepwise variable thickness in height, are the most prevalent structural components in the petrochemical industry. During service life, these structures may be exposed to some geometrical imperfections, such as dents. Previous studies show that the stability behavior of cylindrical shells under pressure load is strongly dependent on the nature and magnitude of the imperfections. Some experimental studies have been carried out regarding the effect of dents on these structures. This study presents an investigation into the effects of dent on the buckling and post-buckling behavior of stepwise graded cylindrical shells. For this purpose, a graded cylindrical shell in actual dimensions has been designed in double and triple layers and modelled in ABAQUS, then some vertical and horizontal dents have been made in different places. The stability behavior of the imperfect cylindrical shells has been evaluated under the peripheral pressure loading.

CS3E-2, ID 1370 (Time: 14:20 - 14:40)
TitleThin-walled textile reinforced concrete shells: analysis of combined effect of anisotropic strain hardening and imperfect geometry
AuthorEhsan Sharei, *Rostislav Chudoba, Alexander Scholzen, Josef Hegger (RWTH Aachen University, Germany)
KeywordTextile-reinforced concrete, Thin-walled shells, Geometrical nonlinearity, Geometrical imperfection, Finite-element analysis
AbstractConstruction of lightweight shell structures with complex geometries has been facilitated in recent years thanks to the advances in new composite materials such as textile reinforced concrete (TRC). Due to the non-corrosiveness of textile reinforcement, much thinner cross sections compared to steel reinforced concrete can be designed. TRC exhibits strain hardening and anisotropy under tension, which has to be considered in the mechanical description of the material behaviour. Furthermore, thin-walled TRC elements exposed to dominant compressive stresses are susceptible to buckling and instability. Geometrical imperfections may also considerably affect the load bearing capacity of the shell structures. In this paper we apply the previously presented strain hardening anisotropic damage model to study the structural behaviour of thin-walled TRC barrel vault shell. The model provides the possibility to investigate the combined effect of the material behaviour, geometrical nonlinearity and geometrical imperfections on load bearing capacity of the shell structures. The model predictions are validated using a full-scale test of the barrel vault shell.

CS3E-3, ID 1403 (Time: 14:40 - 15:00)
TitleA numerical model for computing the lateral pressure on an airformed dome caused by granular materials
AuthorYichen Gao, *Guozhi Qiu, Jinghai Gong (Shanghai Jiao Tong University, China)
Keywordairformed dome, concrete shell, lateral pressure, hypoplasticity
AbstractAirformed domes, which are often used for industrial storage, have been introduced into China in the recent years. The existing design standards only list the lateral loads caused by granular materials for a silo, and does not list the ones for a dome. This paper proposes a numerical model for computing the lateral pressure for both silos and domes, using the Von Wolffersdorff hypoplastic model to describe the behavior of the granular material. The dome wall is considered to be elastic and the foundation is consider to be infinitely rigid. Both the interaction between dome wall and granular material and the one between foundation and granular material have been set up, using surface to surface contact with Coulomb friction law. The numerical model turns out to be helpful for computing the lateral pressure on an airformed dome caused by granular materials.

CS3E-4, ID 1420 (Time: 15:00 - 15:20)
TitleElasto-plastic buckling strength of lattice shells shape-optimized for bending strain energy or linear buckling load
Author*Shiun Ohuchi, Kenji Yamamoto (Tokai University, Japan)
KeywordSingle layer lattice shell, Elasto - plastic buckling, Shape optimization, Bending strain energy, Linear buckling load
AbstractThe spatial structures of compression resistance type, such as lattice shells, enable large spans by the mechanical effects of curvature. Because of the advancement of construction technology in recent years, it is possible to build structures with complex shapes. As achievable structural shapes are increased, determination of the structural shapes becomes more important. From this background, the shape optimizations are often applied to the shape determination of lattice shells. However, the buckling strength of shape-optimized lattice shells is not necessarily fully examined in the previous studies. In this study, the shape optimizations of the lattice shells in which the bending strain energy and the linear buckling load are the objective function are performed, and the elasto-palstic buckling strength of the optimal shapes are investigated in detail.

CS3E-5, ID 1505 (Time: 15:20 - 15:40)
TitleDa Vinci’s Bridge in ice and other ice structures with an inflatable mould
Author*Arno Pronk, Maarten Arntz, Lex Hermens (TUe, Netherlands)
Keywordice shell, ice composite, membrane mould
AbstractThe starting point for the construction of the largest bridge in ice was based on a design made by Leonardo Da Vinci. The original design from the 16th century was designed to span the Golden Horn in Istanbul. This design would have had a span of 240 metres and a width of 24 metres. The bridge would have had the largest span at that time if the sultan of Turkey had approved the design. This design was the inspiration for this project, a bridge made out of ice with the largest span until now. Arno Pronk and two master students (Roel Koekkoek and Thijs van de Nieuwenhof) started this project in continuation of the previous ice-building projects, Sagrada Familia in Ice 2015 and Pykrete dome 2014.

Session CS4E  Shell -4
Time: 16:20 - 18:20 Tuesday, September 27, 2016
Location: Room 201

CS4E-1, ID 1515 (Time: 16:20 - 16:40)
TitleGlass Hybrid Structures - Towards Novel Lightweight Transparent Building Envelopes
Author*Oliver Englhardt, Vlad Silvestru, Georg Kolany (Graz University of Technology, Austria)
Keywordglass, steel, hybrid, adhesives, stability
AbstractThis paper focuses on transparent self-carrying building envelopes using the hybrid load-bearing behavior of glass-metal-structures. The main idea on which the project is based is the activation of the in-plane load bearing capacity of the glass panes. Increasing requirements regarding the energetic and sustainable performance of building envelopes coupled with high geometrical complexity and the demand for maximal transparency lead to façade concepts, where the involved elements and materials are used at the highest possible level according to their properties. An optimized structural behavior for glazed building envelopes is the main theme of the research project Glass Building Skins. This requires complex investigations of load-paths between the metal frame and the glass pane of one element as well as between several elements, selection of suitable materials for proper load-transfer as well as consideration of building physics related aspects.

CS4E-2, ID 1520 (Time: 16:40 - 17:00)
TitleStudy on Direct Construction Method utilizing Hanging Net for Small-scale Isler-type Shell Structures
Author*Yuki Ozawa (Shibaura Institute of Technology, Japan), Hotsuki Wada (Tokyo Institute of Technology, Japan)
KeywordShell structure, Heinz Isler, Suspended Surface
AbstractShell stuructures are very excellent system from the point of view of material efficiency. On the other hand, the construction process requires a great deal of time. It is a reason that shell structures have declined since the latter half of the twentieth century. Heinz Isler, a Swiss engineer, developed form finding methods from experimental studies using suspended surface and he had realized large amout of shell structures since 1970s. But its construction system is not very different from normal shell construction process. Therefore, it is difficult to apply his methods to the present time. In this paper, an easy construction method for Isler-type shell structures is proposed. The main points of this system is to make a rigid suspended surface directly by making use of hanging net. In this system, it is fully feasible to realize small-scale shell structures with a span of 10-15m without any formwork.

CS4E-3, ID 1117 (Time: 17:00 - 17:20)
TitleFree-form structures from semi-precast planar concrete elements
Author*Romuald Tarczewski, Michal Swieciak (Wroclaw University of Technology, Poland)
Keywordfree-form surfaces, planarization, concrete structures, semi-precast stay-in-place elements
AbstractThe paper presents a concept of construction of free-form shell on a precast stay-in-place formwork (e.g. Filigran or similar). Thin reinforced concrete slabs with built-in tension and shear reinforcement, with the topology obtained by the modified VSA algorithm are hinge-connected along the edges, to form a self-stable polyhedral surface. The upper layer of concrete is casted on site. This method allows implementation of the free-form structures resulting in significant cost savings due to reducing or even eliminating the formwork and a shorter execution time.

CS4E-4, ID 1194 (Time: 17:20 - 17:40)
TitleUltimate strength of reinforced concrete shell of free form of a square plan supported by four corners
Author*Ryo Hara (Nakanihon Engineering Consultants Co., Ltd., Japan), Shiro Kato, Shoji Nakazawa (Toyohashi University of Technology, Japan), Toshio Honma (Kagoshima University, Japan)
Keywordconcrete shell, free form, ultimate strength, tensile strength of concrete, initial imperfection
AbstractElastic-plastic buckling analysis is conducted for a reinforced concrete shell of free form of a square plan, which is stiffened by edge beams and supported by four corners. The intrinsic problem of the imperfection sensitivity of ultimate strength of the shell is studied in the case of not only gravity load but also earthquake loads. Moreover, the influences of cracking of concrete to the ultimate strength load is focused, in which cracking and tensile strength of concrete is considered in evaluating the ultimate strength, because the tensile strength plays an important role in ultimate strength and also because the deterioration of tensile strength is an important factor of aging concrete shells. The present study reveals how much concrete tensile strength and initial imperfections influence the ultimate strength of a free form shell by discussing in detail its failure mechanism.

CS4E-5, ID 1427 (Time: 17:40 - 18:00)
TitleDevelopment of floor system using RC curved and folded surfaces
Author*Atsushi Mutoh, Akihiro Masuda, Takaaki Itoh (Meijo University, Japan)
KeywordReinforced-concrete shell, floor slab, curved surface, folded surface, pre-cast concrete
AbstractIn this paper, high-efficiency slab system employing reinforced concrete curved or folded surface is proposed for floor slabs. In this study, an examination result to enable a high load carrying capacity at light weight is shown by applying several curved and folded surfaces to a floor slab. In particular, a floor-slab system using a novel double slab with a fused shell structure and pre-cast technology is proposed. The structural performance of the proposed floor-slab system is examined by a numerical simulation with the conventional flat slab and a void slab. In general, a large-span slab requires the installation of joists, as well as increased formwork and work to arrange reinforcing bars on the construction site. A lack of skilled workers and high cost are potential shortcomings for the use of large-span slabs. The proposed concept ensures the strength and rigidity in the mechanical rationality of the shell and reduces the complexity of construction by a pre-cast in factory production. In addition, it is possible to eliminate the need for a ceiling and provide a space design utilizing a curved surface corresponding to indirect lighting.

Session CS3F  Seismic -3
Time: 14:00 - 16:00 Tuesday, September 27, 2016
Location: Room 202

CS3F-1, ID 1217 (Time: 14:00 - 14:20)
TitleOptimal damper distribution for seismic retrofit by using Hybrid Genetic Algorithm implementing non-linear response analysis
Author*Kazuhiro Fujishita (Tokyo Institute of Technology, Japan), Fatih Sutcu (Istanbul Technical University, Turkey), Ryota Matsui, Toru Takeuchi (Tokyo Institute of Technology, Japan)
KeywordStructural Optimization, Genetic Algorithm, Response Control Retrofit, Existing RC Building
AbstractIn this study, a method to determine elasto-plastic damper distribution in RC buildings by employing hybrid-GA in dynamic response analysis program with the multi degree of freedom shear spring model is proposed. Hybrid-GA includes Simple Genetic Algorithm (SGA) and the Hill-climbing method for local search. It is observed that the obtained optimal damper distribution shape for each seismic wave were almost identical on each model. Previously, the authors proposed a damper distribution method of the response control retrofit for RC buildings by using equivalent linearization (EL method). Finally, the comparison of the results for the proposed optimization method with hybrid-GA and the EL method is represented and the effectiveness of damper distribution with EL method is validated.

CS3F-2, ID 1236 (Time: 14:20 - 14:40)
TitleTest of a Hybrid Wall Model
Author*Calin Grigore Radu Mircea, Mihai Mulea (Technical University of Cluj-Napoca, Romania)
Keywordhybrid wall, testing, seismic design, prefabrication, self-centering
AbstractThe paper presents aspects of a research performed on a precast hybrid wall model. A full scale hybrid prefabricated wall model was tested to static cyclic loading. The connection was designed for the peak ground acceleration 0.25g and a normalized axial force of 5 %, corresponding to a connection over the base foundation of a shear wall structure of a multistory building. An innovative concept was implemented, by using mild unbounded mild special reinforcement, with guided yielding response. The test revealed a reasonable seismic performance of the proposed concept performance in the terms of load-lateral drift, shear/flexural strength, ductility, energy dissipation, damping and joint opening with load. Despite the lack of bond that usually concentrates the stress in the rebars in the critical sections, the model showed a good seismic capacity. A promising post-collapse behavior should be also noticed.

CS3F-3, ID 1240 (Time: 14:40 - 15:00)
TitleA modified approach for the nonlinear seismic response analysis of pre-tensioned cable-supported building envelopes
Author*Yang Xiang, Yongfeng Luo, Zuyan Shen (Tongji University, China)
Keywordpre-tensioned cable net, cable-supported curtain wall, equivalent linear method, overall stiffness, nonlinear seismic response
AbstractThe pre-tensioned cable-supported building envelope is being adopted more and more in design of modern buildings. This paper proposes a linearized procedure for the nonlinear seismic response analysis of cable-supported building envelopes. Firstly, an energy-based parameter is established to demonstrate the overall structural stiffness of a cable-supported system with irregular geometrical topology. Secondly, the modal equivalent single degree of freedom (ESDF) systems are established. It is revealed that the stiffening characteristic of a cable-supported system is generally the same as that of a Duffing system. Thirdly, based on a linearized approach, the relationship between the equivalent linear stiffness (ELS) of the nonlinear ESDF system and its peak displacement response is derived. Finally, the ESDF responses are determined via a non-iterative procedure based on the design response spectra recommended by seismic design codes. Moreover, the effectiveness of the proposed approach is illustrated by a numerical example.

CS3F-4, ID 1259 (Time: 15:00 - 15:20)
TitleDesign and Construction of Tension Structure on Viscoelastic Dampers directly connected to Tension Strings
Author*Akira Morita (MHS Planners, Architects & Engineer, Japan), Yoshinao Konishi, Lei Xu (Nippon Steel & Sumikin Engineering Co., LTD., Japan)
Keywordtension strings, effective mass ratio, energy dissipative brace, viscoelasticity, disc spring
AbstractIn this report, gymnasium roof is a gable shape structure. This is the compound structure which Beam String Structure resists the load in the vertical direction and energy dissipative brace resist the load in the horizontal direction. This paper analyzes damper effect of steel roof with dampers composed of viscoelasticity and disc spring. These dampers are installed vertically against the energy dissipative braces to reduce the response to earthquake and the fatigue caused by wind. Tension strings such as cable or rod have the additional stiffness function as a compression member by sustaining initial tension. When dampers are placed vertically, it is necessary to use a mechanism capable of holding the initial tension of the tension strings. Therefore, the disc spring was chosen to retain the initial tension. The viscoelasticity is used for the damper effect. This report verified Viscoelastic Dampers.

CS3F-5, ID 1373 (Time: 15:20 - 15:40)
TitleStudy on dynamic characteristics and seismic performances of latticed shell string structure with inner and outer truss
Author*Yun-long Yao, Guang-ying Ma (Shandong University (Weihai), China), Shi-lin Dong (Space Structures Research Center, Zhejiang University, China)
Keywordlatticed shell string structure, modal analysis, multi-dimensional seismic excitation, seismic analysis
AbstractThis study proposes a new type of annular space latticed shell string structure with inner and outer truss torus that can reduce the space occupied by the roof structure and be easily laid by a rigid roofing material. Three types of annular space latticed shell string structure, namely, ribbed, sunflower and schwedler patterns, are presented. Ribbed latticed shell string structure with a span of 100 m was taken as an example, the modal analysis and the time-history analysis were performed and the seismic behavior under one-dimensional and multi-dimensional seismic excitations were studied. The effects of the heights of radial cables, the curvatures of latticed shell, the radial supports and the horizontal truss torus on seismic performances of this structure were also investigated. The results revealed some characteristics of modal and earthquake response of the structure. The research results could be referenced by structure designers.

CS3F-6, ID 1169 (Time: 15:40 - 16:00)
TitleDevelopment of a Long Stroke Damper with Torus
Author*Tomoyasu Taguchi (Okabe Co.,Ltd., Japan), Ken'ichi Kawaguchi, Tomoki Kawai (The University of Tokyo, Japan), Akimitsu Nishino (Okabe Co.,Ltd., Japan)
KeywordDamper, base-isolated buildings, vibration-controlled buildings, long stroke, torus
AbstractThis report focuses on the development of a simplified light-weight damper consisting of a “torus,” a “shaft,” and a “cylinder.” The shaft passes through the torus, which is inside the cylinder. When the shaft and the cylinder produce relative displacement, the torus rolls. The damper uses the generated rolling resistance for attenuation. This report describes a simplified light-weight damper and performance tests that confirm its effectiveness.

Session CS4F  Seismic -4
Time: 16:20 - 18:20 Tuesday, September 27, 2016
Location: Room 202

CS4F-1, ID 1381 (Time: 16:20 - 16:40)
TitleInfluence of half open angle of cylindrical lattice shell roofs on seismic response control effects by plural TMDs
Author*Takuya Shimoyama, Tomohiko Kumagai (Meiji University, Japan), Toshiyuki Ogawa (Tokyo Institute of Technology, Japan)
Keywordcylindrical lattice shell roof, plural TMDs, half open angle, response reduction effect, parallel multi-mass system
AbstractTMD is fit for the vibration control of spatial structure because it is possible to install TMDs by a single supporting point. However, there are few studies dealing with the vibration control of spatial structures by installing a plurality of TMDs which target a single mode for plural modes (Kumagai et al. [2]). Moreover, influence of half open angles of cylindrical lattice shell roofs on vibration control effects by plural TMDs have never been examined. Therefore, this paper is intended as an investigation of seismic response reduction effects by plural TMDs for cylindrical lattice shell roofs which have different half open angles. First, the selection method of controlled modes is proposed. Next, the response reduction effects by plural TMDs for cylindrical lattice shell roofs which have different half open angles are examined. Finally, the response estimation by energy absorption of TMDs is attempted.

CS4F-2, ID 1410 (Time: 16:40 - 17:00)
TitleApplication of Endurance Time method in dynamic analysis of double layer barrel vaults
AuthorSajad Hajinia, Mohammad Charkhtab Basim, *Mohammad Reza Chenaghlou (Sahand University of Technology, Iran)
Keywordresponse-history analysis, Endurance Time method, spatial structures, barrel vaults
AbstractCareful evaluation of structures under earthquake hazards is an issue that has always faced challenges because of the complexity involved in using analysis methods. The Endurance Time (ET) method, as an analytical assessment tool, can be used to provide estimations of structural responses with affordable computational demand. In the ET method, structures are analyzed under specially designed intensifying acceleration functions and their response at various excitation levels is estimated by each single response-history analysis. Computational demand in this method is much less compared to other response-history analyses. In this study, application of the ET method in seismic assessment of double layer barrel vaults is investigated. The advantages and shortcomings of the proposed method are investigated by comparing the results from the ET method and common response-history analysis using ground motions. It can be concluded that the results, having much less computational demand, has good compliance with classical response-history analyses.

CS4F-3, ID 1438 (Time: 17:00 - 17:20)
TitleEvaluation method of earthquake resistant capacity of double layer truss wall based on the dynamic collapse mechanism
Author*Koichiro Ishikawa, Takenori Ito (University of Fukui, Japan)
Keywordtruss wall, buckling, dynamic analysis, earthquake resistant capacity, estimation method
AbstractThis study deals with the dynamic elasto-plastic behavior considering a member buckling of double layer partial cylindrical steel truss walls. The study also focuses the dynamic collapse mechanism of the truss wall on the member buckling chain due to a compression stress. It is known in the double layer plate type truss wall that the member buckling chain induces the brittle collapse behavior of the structure soon after the member buckling occurs. The evaluation method is presented in the study that the partial cylindrical truss wall improves on the earthquake resistant capacity enough to avoid the sudden brittle dynamic collapse by the deformation effects of the radius direction. The estimation method of the maximum response of the horizontal displacement at the top of the wall is also proposed by the equivalent natural period and the earthquake response spectrum.

CS4F-4, ID 1454 (Time: 17:20 - 17:40)
TitleSeismic response evaluation of HP lattice shells with supporting substructures
Author*Kazuya Nitta, Tomohiko Kumagai (Meiji University, Japan), Toshiyuki Ogawa (Tokyo Institute of Technology, Japan)
KeywordHP lattice shell, Supporting Substructure, Free vibration characteristics, Seismic response behavior, Seismic response evaluation
AbstractA hyperbolic paraboloidal (HP) shell with straight edge lines is generated by translating a straight line with varying the tilt of line. The various shapes are created by the combinations of these HP shells. They are used on many places. Free vibration characteristics and seismic response behavior of the HP lattice shells which are constructed by steel frame are investigated by numerical analyses. In addition, the seismic response evaluation method for HP lattice shells based on the previous studies is proposed. From the results, in free vibration characteristics of HP lattice shells, the effective mass ratio of mode with shape of antisymmetric 1st wave increases according to an increase of the half open angles of members. The maximum response accelerations on the ridge line are represented by symmetric half wave in a horizontal direction and antisymmetric 1st wave in a vertical direction regardless of seismic waves.

CS4F-5, ID 1527 (Time: 17:40 - 18:00)
TitleAnalysis on seismic damage resilience of single-layer lattice shells based on safety margin
Author*Zheng He, Tingting Liu (School of Civil Engineering, Dalian University of Technology, China)
Keywordultimate seismic strength, seismic damage resilience, collapse margin ratio, single-layer lattice shells, optimal selection range
AbstractThe ultimate seismic strength and seismic damage resilience are important indicators for assessing seismic performance level. Resilience is introduced for quantifying the ability of highly redundant l single-layer lattice shells with certain level of damage due to earthquakes to restore or retain their original seismic capacity. Essentially, it is a kind of safety margin coefficient regarding numerical calculation based on seismic damage. Because of defects caused by randomness of earthquakes, collapse margin ratio can be considered as a seismic capacity index in consideration of influences affected by various earthquakes. Due to various grid forms and non-uniqueness of failure modes, there is not a simply direct proportionality between strength and resilience which are research motivation this article aims at. That is, a precondition for improving seismic resilience is to guarantee the certain level seismic capacity, which gained extensive economic benefit to limit the optimal selection range.

CS4F-6, ID 1083 (Time: 18:00 - 18:20)
TitleElastic analysis of the steel structure of Beijing CBD Cultural Center based on ABAQUS
Author*Zelin Li, Yuanqing Wang (Tsinghua University, China), Weibiao Yang, Weihua Chang (Beijing Institute of Architectural Design, China)
KeywordBraced steel frame structure, finite element analysis, ABAQUS, modal analysis, response spectrum analysis
AbstractBeijing CBD Cultural Center is located in Chaoyang District, Beijing, China. It is constructed by using a braced-steel-frame structural system. Challenges of its structure are mainly resulted from large-spans, large-cantilever spans and large-openings in the floor system. For buildings which possess either complex shapes or complex structural arrangements, at least two different mechanical models are required for structural analyses and comparisons. This paper presents details of using Abaqus to develop a 3-dimensional finite element (FE) model for undertaking elastic analyses of the dynamic behavior of this building, including modal analysis and response spectrum analysis. Indicators such as the natural vibration period and drift ratio have been examined and compared with the results obtained from Midas Gen. It can be concluded from the FE analysis results that ABAQUS is adequate for the structural analyses. However, it should be noted that the stiffness in local area of the structure is too small.

Session CS3G  Conceptual Design -3
Time: 14:00 - 16:00 Tuesday, September 27, 2016
Location: Room 203

CS3G-1, ID 1446 (Time: 14:00 - 14:20)
TitleA Parametric Modelling Process for the Integration of Architecture and Structure in Large Multi-functional Sports Hall Design: a Case Study
Author*Wang Pan (South China University of Technology & Delft University of Technology, Netherlands), Yimin Sun (South China University of Technology, China), Michela Turrin, Sevil Sariyildiz, Joop Paul (Delft University of Technology, Netherlands)
Keywordparametric modeling process, large multi-functional sports hall, functional space, large-span structure, design exploration
AbstractThe integration of architectural (functional spaces) and structural design is especially crucial for the conceptual design of large multi-functional sports halls, due to the strict regulations for functional spaces, the requirement of large-span structure, and the complex interrelationships between these two aspects. This on-going research aims at developing a computational method to support this integration during the conceptual design of large sports hall. This paper proposes a parametric modelling process to support a design exploration which is an important part of the computational method. A typical and simplified large multi-functional sports hall is used as an example case to demonstrate this process.

CS3G-2, ID 1464 (Time: 14:20 - 14:40)
TitleDesign Conception of Steel Truss Foundation for Wind Turbine Towers
Author*Junling Chen, Ming Wu (Tongji University, China)
Keywordwind turbine, foundation, steel structure, truss, design conception
AbstractThe simplest and traditional foundation form of wind turbine tower is the RC slab foundation. Its design reference period is determined to be 50 years according to Code for Design of Building Foundation (GB50007)[1]. However, the service life of wind turbine is usually only 20 years. So most of wind turbines built in 1990s have to be demolished in recent years although the service life of RC foundation still has 30 years. In order to obtain the higher wind energy, the original foundation cannot be reused due to the increasing of unit capacity of wind turbine. Therefore, these disused RC wind turbine foundations will make a great influence on the local environment. So a novel foundation consisting of 16 steel trusses around the insert ring with a RC slab at the bottom is proposed in this paper. A detailed three-dimensional finite element (FE) model of the steel foundation system is developed by the commercial software ANSYS to analyze its performance under operational load case and extreme load case. The numerical results show that the proposed steel foundation has good economic efficiency and is worth to be researched further.

CS3G-3, ID 1525 (Time: 14:40 - 15:00)
TitleDesign and research on complex sculpture class space structure
Author*Yaxiong Liang, Xiuli Wang, Guozu Zheng, Chang Wu (School of Civil Engineering, Lanzhou University of Technology, China), Shou-li Zhang (Infrastructure Department, People's Hospital of Gansu Province, China)
KeywordComplex spatial structure, Sculpture, Design and analysis, MSTCAD, 3D modeling
AbstractThe structure of Yongchang county culture square theme sculpture was analyzed as a whole by using software MSTCAD. In case of incomplete architectural drawings, according to the scale model structure model is established by using the total station to measure the coordinates of the key points, it provides a new idea for the modeling of similar structure. Mechanical properties of structures under wind load and earthquake effect were analyzed. The mechanical properties of the structure in the wind load and seismic analysis shows that: Structure vibration mode is more complex and there is coupling effect between the higher order modes; Whole structural deformation is larger, but it can meet the requirements of normal use; The spatial structure of the overall stiffness, good stability, is the preferred structure scheme. The research results can provide reference for the complicated space structure design.

CS3G-4, ID 1539 (Time: 15:00 - 15:20)
TitleBiomimetics and structural morphology: case studies
Author*Irmgard Lochner-Aldinger (Biberach University of Applied Sciences, Germany)
Keywordtopology optimization, structural design, biomimetics, lightweight structures
AbstractThis paper presents developments in the field of biomimetically inspired structural geometries. The combination of biomimetic studies and the application of methods of topology optimization was subject to previous studies [1], where a general approach to structural morphology, based on elements of classical structural analysis such as columns - beams - slabs - shells etc, was linked to the methods of topology optimization. The aim of this project is to combine the classical structural theory and analysis to new methods of structural design. The studies carried out relate to the research projects of Frei Otto and the research project "Natürliche Konstruktionen" (structures in nature) as pursued in the project "SFB 230" [2].The studies initiate a classification of structural systems according to their geometries and their loading / stress conditions. Structural geometries are derived according to their stress conditions.

CS3G-5, ID 1412 (Time: 15:20 - 15:40)
TitleStructurally informed decision-making by means of Data Visualisations during the Conceptual Design Phase
Author*Lennert Loos (Vrije Universiteit Brussel, Belgium), Kenny Verbeeck (Ney & Partners, Belgium), Lars De Laet (Vrije Universiteit Brussel, Belgium)
KeywordStructural Design, Performance Aided Design, Conceptual Design, Data Visualisation, Dashboard Approach
AbstractThis paper presents a new approach for comparing different structural design alternatives based on data visualisation in the conceptual design phase. The aim of the proposed methodology is to focus on the overall structural behaviour and to include non-numeric architectural parameters. By having the information of all different design proposals at hand, the designer is able to make informed design decisions. Previous research will be discussed in order to introduce this new approach. It turns out that the use of data visualisation and dashboards enriches the design process and that the informed decision-making process is facilitated. What is presented in this paper is part of ongoing research and is focussing on the concept of the new approach and its research context. To have a clear understanding of this research context, an overview of terminology, difficulties of the current design process, and research topics with similar goals are discussed.

CS3G-6, ID 1518 (Time: 15:40 - 16:00)
TitleMultivariate Interactive Visualization of Data for Multi-Objective Design Space Exploration
Author*Andre Chaszar (TU Delft / O-Design, Netherlands), Peter von Buelow (U Michigan, U.S.A.), Michela Turrin (TU Delft, Netherlands)
Keywordgenerative design, optimization, data visualisation
AbstractThis paper describes recent developments in an ongoing research effort to develop a method, ParaGen, which combines parametric form generation with multi-performance optimization and exploration. Here we focus on how the system is augmented with data visualization capabilities which enhance the understanding of relationships between design parameters and performance, and thus aid the exploration of design alternatives. These capabilities are applicable also to spatial structures, and we illustrate their use with an example of a long-span gridshell dome.

Session CS4G  Deployable Structures -1
Time: 16:20 - 18:20 Tuesday, September 27, 2016
Location: Room 203

CS4G-1, ID 1030 (Time: 16:20 - 16:40)
TitleExtended variations of 2D-deployable linked panel unit
Author*Masao Takatsuka (Nagoya University, Japan)
Keyworddeployable structures, space structures, structural concept, conceptual design
AbstractThis paper proposes a new concept of a deployable structure which is required for transportation and construction of space structures such as a Solar Power Satellite. The objective of the present study is to investigate the possibility of a deployment system which enhances its deployment reliability in space. This paper presents two types of variations of our previously proposed ‘linked panel unit’ and their rigid body motions. The first one is a multi-degree-of-freedom system of the ‘linked panel units’ composed of square panels, in which each unit can be deployed independently. The second one is a multi-degree-of-freedom system composed of triangle panels, which can be folded, deployed, and extended two-dimensionally. These new systems may improve the problem of the previous 2D-extended ‘linked panel units’ that is a single-degree-of-freedom system which has a risk that the deployment cannot be completed by only one malfunction in the structure.

CS4G-2, ID 1049 (Time: 16:40 - 17:00)
TitleEnumeration of Folding Patterns of Flat-folding Structures with Single Vertex by using Branch-and-Bound Method
Author*Jingyao Zhang (Nagoya City University, Japan), Hidekazu Taguchi (Fukumi Construction Co., Ltd., Japan)
KeywordFlat-folding, Enumeration, Folding pattern, Branch-and-Bound Method
AbstractWe present in this paper an efficient method, based on the concept of bound-and-branch method, to enumerate all feasible folding patterns for a specific crease pattern consisting of only one vertex. It is demonstrated by examples that the proposed method is more efficient and more systematic than the conventional methods.

CS4G-3, ID 1090 (Time: 17:00 - 17:20)
TitleDynamic analysis for a deployable structure considering the effect of pre-stress
Author*Minger Wu, Jiangling Rao, Gang Ma (Tongji University, China), Fuling Guan (Zhejiang University, China)
Keyworddeployable structure, modal analysis, transient dynamics analysis, fundamental frequency
AbstractWith the development of aerospace science and technology, small satellites have become an important part of space systems. Equipped with deployable structure as a working platform on a small satellite will broaden the function of the small satellite. Because the mass and volume of small satellites are very small, the attitude adjustment ability is limited. The dynamic characteristics of deployable structure has a great influence on the state attitude control in orbit of small satellites. This paper conducts the dynamic analysis for a single-layer deployable truss structure driven by elastic components. Through the modal analysis, the nonlinear transient dynamics analysis and the fundamental frequency measuring experiment, the dynamic characteristic of the deployable structure is investigated.

CS4G-4, ID 1152 (Time: 17:20 - 17:40)
TitleCurvature in Kirigami Sheets
Author*Spencer Wilson, Keith Seffen (University of Cambridge, U.K.)
Keywordkirigami, morphing, origami, embedded
AbstractKirigami design differs from origami by allowing cuts and material removal in addition to folding. This work explores the use of kirigami as a basis for transforming flat sheets into 3D shapes. By formulating the principles of kirigami with topology and differential geometry, a framework is developed for transforming a sheet between flat and curved configurations by “suturing” cuts in a sheet. This framework is demonstrated by designing and analyzing a kirigami unit cell. We find that this unit cell is a type of plane symmetric 6R linkage. We analyze the linkage and illustrate two possible tessellations. Planar design suitable for standard subtractive machining processes ensures the manufacturability of the structures. We expect this system to find applications in morphing structures and robotics where transitions between curvature states are desired.

CS4G-5, ID 1230 (Time: 17:40 - 18:00)
TitleA perturbation procedure for prediction of bifurcation points on kinematic path
Author*Toku Nishimura, Nana Shirai (Kanazawa Institute of Technology, Japan)
Keywordkinematic bifurcation, perturbation method, Deployable structure, eigenvalue problem, singular value decomposition
AbstractDeployable structures are investigated in space engineering and others. If the structures change distinct shapes, a critical form has been existed in the movement. At the critical form, there may be a bifurcation point called kinematic bifurcation point. The bifurcation concerned with kinematics is identified by the change of the rank of compatibility matrix A or equilibrium matrix AT. Nishimura has proposed the strategy to predict critical points in the fundamental stability problems. A significant feature of this strategy is the application of a perturbation method to eigenvalue problem. The non-zero eigenvalues of ATA or AAT are equal to the signular values of A. Since ATA or AAT are symmetric matrices, the perturbation procedure is applicable to eigenvalue problem for ATA or AAT. In this pater, we present a methodology to predict the kinematic bifurcation points using a perturbation procedure. And we verify the availability of the methodology.

Thursday, September 29, 2016

Session PS3  Plenary Session -3
Time: 9:00 - 10:20 Thursday, September 29, 2016

PS3-1, ID 1570 (Time: 9:00 - 9:40)
Title[Plenary] Overview of analysis schemes for buckling strength, seismic resistance and reliability index of reticulated shells
AuthorShiro Kato (Prof. em. Toyohashi University of Technology, Japan)
AbstractThe present overview concerns, first, an analysis scheme for buckling load of column based on Dunkerley formula where plastic load and elastic buckling load are both applied. Second, the scheme is extended to reticulated shells under static loads. Third, the discussion is also extended to evaluate the seismic resistance considering the effects of dynamic responses. Fourth, the overview focusses an approximate scheme to evaluate probability distributions, average and standard deviation, for both the elasto-plastic bucklnig load and seismic resistance. Fifth, a numerical scheme, AFOSM, is adopted to numeriaclly calculate the values of failure probability of both buckling under snow loads and collapse due to severe earthquake motions. Finally, questuions about relationship between reliability index and global snow load factor are aroused by showing an imcompatible situation of studies for reticulated shells, followed by necessity of risk analysis to secure the function of facilities during and after severe earthquakes.

PS3-2, ID 1569 (Time: 9:40 - 10:20)
Title[Plenary] Polyhedra and the Like
Author*Pieter Huybers (Delft University of Technology, Netherlands)
KeywordGeometry, Polyhedron, isohedron, structures, space frames
AbstractDuring his employment at the Delft University of Technology the author investigated the appropriate use of materials in building technique. This resulted in the design of glass fibre reinforced plastics (GRP) for load bearing structures, emergency housings, and in the end to space structures of relatively great spans or height made of roundwood. This paper refers mostly to his work since his retirement in the year 2000. This was mainly concerned with the roundness of convex uniform polyhedra. and this resulted in a study on isohedra where all faces have the same distance from the centre. This aspect was used for the construction of the outer skin of soccer balls, where the roundness of form is particularly essential. A few other solutions for this application are shown, so as for world maps with the most correct representation of the original aspect ratio.

Session PS4  Plenary Session -4
Time: 10:40 - 12:40 Thursday, September 29, 2016

PS4-1, ID 1565 (Time: 10:40 - 11:30)
Title[Plenary] New National Stadium Japan - the Architectural Concept -
Author*Kengo Kuma (KENGO KUMA & ASSOCIATES, Japan)
Keywordstadium, wood
AbstractI have built architecture with wood and shadow as a theme. Trees need shadow. Tress generate shadow. Then animals gather under the shadow. They protect themselves from strong sunlight, ultraviolet rays and strong rain. Of the works of ours from Asakusa Culture and Tourism Center to FRAC Besancon and, further to the new national stadium, our protagonist has always been wood and shadow as a set, which also plays a role as mediator between humans and nature. What we are doing now is to revive wood in modern architecture. Same attempts are being carried out in many parts of the world. It has been proved that wood can play a dual role as a mediator and a shelter to deal with the nature. Restoring wooden architecture in the current context will give a great and positive impact on people’s lives worldwide. I believe that is the task assigned to all architects of our time. (Portrait photo by The Courier)

PS4-2, ID 1566 (Time: 11:30 - 12:00)
Title[Plenary] Structural design of the New National Stadium
AuthorOsamu Hosozawa, *Taro Mizutani, Shinichiro Kawamoto (Taisei Corporation, Japan), Hiroaki Kobayashi (Azusa Sekkei Co., Ltd., Japan)
KeywordOlympic, National Stadium, hybrid members, wood
AbstractThe New National Stadium is a facility to be built as a main stadium of the Tokyo Olympic and Paralympic Games in 2020. Based on the concept of “The Forest Stadium”, the new stadium will establish a network of green and water in Gaien (the Outer Garden of Meiji Jingu Shrine) and sports activities. In this paper, we will report the outline of the structural concepts, such as the simple structure in consideration of the construction period, the cantilever roof structure with the hybrid members using wood and steel, and the response controlled structure by Soft First Story System with high seismic performance.

PS4-3, ID 1575 (Time: 12:00 - 12:20)
Title[Plenary] Tokyo Aquatics Centre
Author*Ikuhide Shibata, Mitsutake Tanigawa (Arup, Japan), Tatsuya Kataoka, Takuya Sone (YAMASHITA SEKKEI INC., Japan), Yasuhiko Asaoka (OBAYASHI CORPORATION, Japan)
KeywordAquatics center, base isolation
AbstractThis facility is, first of all, a venue for swimming competitions of the 2020 Tokyo Olympic Games. "How to realize an excellent Olympic facility" was prioritized for the planning. The next focus was planned on "how to hand down the great inheritance of the 2020 Tokyo Olympics to future generation." Based on these concepts, the planning for this facility started with the following five basic concepts. Concept of the Olympic facility (20,000-seat transfer mode) * To realize the "best environment for competitions" to facilitate new worlds record * To realize "the best viewing environment as an Olympic/Paralympic venue * To convey "Japan" to the world with the design and the engineering Concept for the legacy facility (5,000-seat legacy mode) * To hand the "memories" of the Olympic and Paralympic Games to future generations * To realize "Mecca for swimming open to the public" integrated with the Tatsumi Seaside Park

PS4-4, ID 1576 (Time: 12:20 - 12:40)
Title[Plenary] Basic Design of Ariake Arena
AuthorHiroshi Ito, Hiroki Yoda, Chikamasa Okuno, Masari Kawai, Tatsuya Hanada (Kume Sekkei Co., Ltd., Japan)
KeywordAriake Arena
AbstractBasic design of Ariake Arena (venues at the Tokyo Olympic Paralympic Games) is completed. Tokyo Metropolitan Government (TMG) is developing a new permanent arena of 15000 seats as facilities for sports and events. Ariake Arena has decided to be used for volleyball venues at the Tokyo Olympic Games, and Wheelchair Basketball venue in Tokyo Paralympic Games in 2020. Ariake Arena site is located in Ariake Kita(North) district at Tokyo Waterfront City. The major concept of development is Legacy Use. Main Structure System is R/C Moment Frame structure, and taking into account the construction period (In time for the Olympic Games) most of R/C members are planned in pre-cast. Main Arena Roof is steel truss system using wood beams, and has Seismic Isolation System. Core Frame are arranged at 4 corners to resist the seismic load of roof structure. For use in various applications, we have set a large load for the loading conditions (in particular lifting load from the roof). This load is determined in reference to the set load of the suburbs of other arena. Because of considering such a large lifting load and using seismic Isolation System, member of the roof is determined by the long-term load. Because Core Frames for seismic load are only exist in 4 corners, it is fairly large percentage of the horizontal brace occupied in the steel frame of roof amount. Therefore, by adopting the seismic isolation system for roof, there is a merit to reduce the steel of roof. In addition, Isolation System is effective for temperature load of such a long span structure. By using Isolation System, acceleration of roof is 75% decreased, and story shear force of core frames is 80% decreased. References [1] Towards 2020 -Building the Legacy-, Tokyo Metropolitan Government, Coordination Section, General Coordination Division, Bureau of Tokyo 2020 Olympic and Paralympic Games Preparation, April 2016 http://www.2020games.metro.tokyo.jp/taikaijyunbi/torikumi/legacy/index.html [2] Documents of Advisory Council of New Permanent Venues of Metropolitan http://www.2020games.metro.tokyo.jp/taikaijyunbi/torikumi/facility/simonkaigi/index.html

Session CS5M  WG15: Graphic Statics
Time: 14:00 - 16:00 Thursday, September 29, 2016
Location: Ito Hall

CS5M-1, ID 1155 (Time: 14:00 - 14:20)
TitleForm-finding explorations through geometric transformations and modifications of force polyhedrons
Author*Juney Lee, Tom Van Mele, Philippe Block (ETH Zurich, Switzerland)
Keyword3D graphic statics, polyhedral reciprocal diagrams, discrete spatial structures, generative design, spatial equilibrium modeling
AbstractThis paper introduces a new structural modeling methodology to generate equilibrated, discrete three-dimensional structures—with both compression and tension elements—through geometric transformations and modifications of force polyhedrons. By exploring the geometric properties of polyhedral reciprocal diagrams used in three-dimensional graphic statics, the proposed approach provides a significant amount of control of spatial structures during conceptual design. The presented design examples will demonstrate how this method can be used to discover new three-dimensional structural typologies without any biases towards conventional solutions. They also provide an alternative design strategy for two-dimensional problems.

CS5M-2, ID 1203 (Time: 14:20 - 14:40)
TitleEfficient and elegant three dimensional experimental form, from two dimensional forces
Author*Edmond Saliklis (California Polytechnic State University San Luis Obispo, U.S.A.)
Keywordstress function, form finding, funicular, graphic statics
AbstractThis paper documents experimental and numerical explorations of form finding that arose from a combination of mathematical insights coupled to aesthetic considerations. Such form finding occurred through the Airy Stress Function, which has been studied previously from a purely theoretical point of view. Previously it was shown that the Airy Stress Function could be used to provide a polyhedral form diagram for problems that cannot be solved using the standard graphic statics approach. In this current study, we constructed such a polyhedron, made up of planar faces. A continuous Airy Stress Function allowed for automatic form finding, whether or not the three dimensional surface was modeled as faceted or as smoothly continuous. Another uniqueness of this current paper is that the form was also constructed at an experimentally tractable scale of 2.3m by 1.2m in plan, and 1.8m in height, using the Catalan vaulting technique of masonry construction.

CS5M-3, ID 1334 (Time: 14:40 - 15:00)
TitleVector-Based 3D Graphic Statics (Part I): Evaluation of Global Equilibrium
Author*Pierluigi D'Acunto, Patrick Ole Ohlbrock (ETH Zuerich, Switzerland), Jean-Philippe Jasienski (UCLouvain, Belgium), Corentin Fivet (EPF Lausanne, Switzerland)
Keyword3D graphic statics, global equilibrium, 3D resultant, funicular structure, projections
AbstractThe evaluation of the equilibrium of a system of forces that fulfils specified boundary conditions is a core question of theory of structures. This paper reviews three methods, related to procedures introduced at the end of the 19th century, to evaluate the global equilibrium in three dimensions using graphic statics. The paper is specifically focused on one of these methods, which is grounded on the use of projections. Based on this method, a given system of forces can be reduced to three skew resultants, which are parallel to three initially chosen unit vectors. The three resultants can be composed into two resultants thanks to the construction of a simple 3D auxiliary structure or reduced to one resultant and a couple. Given the three resultants, the reactions at the supports can be evaluated according to specified boundary conditions in both cases of externally statically determinate and indeterminate systems.

CS5M-4, ID 1343 (Time: 15:00 - 15:20)
TitleVector-Based 3D Graphic Statics (Part II): Construction of Force Diagrams
Author*Jean-Philippe Jasienski (Structures & technologies, LOCI, UCLouvain, Belgium), Pierluigi D'acunto, Patrick Ole Ohlbrock (Chair of Structural Design, Institute of Technology in Architecture, ETH Zürich, Switzerland), Corentin Fivet (Structural Xploration Lab, ENAC, EPF Lausanne, Switzerland)
Keywordgraphic, statics, vectors, 3D
Abstract2D graphic statics is based on two interdependent diagrams, namely the form and the force diagrams. To each edge of the first one corresponds a pair of vectors in the second one that can be generally overlapped as a single element. In the case of vector-based 3D graphic statics, the reciprocity between the two diagrams is normally not attained due to the impossibility of overlapping all pairs of vectors in the force diagram. This paper explains how to construct the force diagram in three dimensions while proposing a solution to deal with the non-overlapping pairs of vectors. This procedure applies to any class of pin-jointed spatial frameworks. Alternative ways of assembling the force diagram are suggested and a specific double-layered configuration is described. The 3D force diagram defined here can be regarded as a direct extension of the 2D force diagram and can be effectively used for early design explorations.

CS5M-5, ID 1335 (Time: 15:20 - 15:40)
TitleVector-Based 3D graphic statics (Part III): Designing with Combinatorial Equilibrium Modelling
Author*Patrick Ole Ohlbrock, Pierluigi D'Acunto (ETH Zuerich, Switzerland), Jean-Philippe Jasienski (UC Louvain, Belgium), Corentin Fivet (EPF Lausanne, Switzerland)
Keywordequilibrium, combinatorial state, topology, force-pattern-based design, form-finding
AbstractThis paper presents an extension of the graphic-statics-based framework called Combinatorial Equilibrium Modelling (CEM). CEM allows for the generation of topologically and combinatorially different spatial equilibrium solutions in the early explorative design phase. In addition to the form and the force diagrams, CEM introduces a topological diagram, which enables the possibility to easily adjust the connectivity of the structure, the combinatorial state (tension-compression) as well as the static action (product of each element’s length and its corresponding force magnitude) of its inner forces. Thanks to its planarity, the topological diagram is always visually readable, comprehensible and easy to control, even in case of complex spatial structures. This innovative approach has the potential to find novel spatial networks in which the intrinsic structural properties can be controlled by the designer with simple visual operations.

CS5M-6, ID 1376 (Time: 15:40 - 16:00)
TitleReciprocal constructions using conic sections & Poncelet duality
Author*Marina Konstantatou, Allan McRobie (University of Cambridge, U.K.)
Keywordgraphic statics, projective geometry, reciprocal diagrams, Maxwell, Rankine
AbstractGraphic Statics offer a geometrical framework for the design & analysis of structural systems with reciprocity between the ‘form’ and ‘force’ diagrams being a fundamental notion. In this paper we provide a detailed illustration and explanation of Maxwell’s reciprocal construction for 2-dimensional trusses through a 3-dimensional paraboloid of revolution. Even though Maxwell briefly mentions this method there is no record of the detailed construction. The main focus of this research is placed on the synthesis of Poncelet duality in projective geometry and of reciprocity in graphic statics resulting in the definition of a generalised dual statement for the construction of reciprocal diagrams (Maxwell 2D & Rankine 3D). This is based on the construction of their higher dimensional discrete Airy stress functions, using conic sections. We generalise the construction for other conics, such as the sphere and ellipsoid, and we extend the definition for 3-dimensional trusses and corresponding higher-dimensional conic sections.

Session CS6M  Form Finding & Optimization -2
Time: 16:20 - 18:20 Thursday, September 29, 2016
Location: Ito Hall

CS6M-1, ID 1151 (Time: 16:20 - 16:40)
TitleParametric Finite Element Contact Analysis and Optimization for Topologically Interlocking Joinery Using Design of Experiments
AuthorSawako Kaijima, *Zack Xuereb Conti, Amir Hosein Sakhaei, Martin L Dunn (Singapore University of Technology and Design, Singapore)
KeywordInterlocking Joinery, Design of Experiments, Contact Analysis, Sensitivity Analysis
AbstractThe paper presents an approach to parametric finite element contact analysis and optimization of Topologically Interlocking Joineries (TIJs) utilizing the Design of Experiments (DOE) statistical technique. TIJs can be viewed as a design principle to join structural elements without metallic fasteners by using topology/geometry and contact mechanisms to create interlocking structures. Simulations of such joints require full 3D finite element models with contact interactions, which are computationally expensive thus time consuming to execute optimizations. In this context, we suggest the application of DOE to perform an efficient search through the design/variable space. This paper presents a case study on a TIJ called Basra Splice. This study revealed variable sensitivity that was not discovered in our previous paper (Kaijima [12]). Moreover, DOE helped us gain further insights into the relationship between the geometrical variables and the structural behavior of the TIJ by estimating variable sensitivities and variable correlations.

CS6M-2, ID 1174 (Time: 16:40 - 17:00)
TitleImplementation of Self-Organization Algorithm by GAE and Application to Uniform Member Length Problem
Author*Eriko Shimada (Graduate School, Nihon University, Japan), Kazuo Mitsui (Nihon University, Japan)
KeywordSelf-Organization, GAE, Uniform member length, Morphogenesis, Framed structure
AbstractThis paper presents an effective method to optimize structural forms by self-organization algorithm. Self-Organization is phenomenon which autonomously generates an orderly state from a random state and can be seen in nature. It can be seen in the field of structural optimization as example of application for optimization too. In order to show the effectiveness of the self-organization algorithm for structural form optimization, framed structures with the nodes that are limited to movement on a given surface are analyzed by using our method as examples of uniform of member length problems. Moreover, the method is extended, and the extended method is applied to the minimization of strain energy problem. The methods is implemented by “Grasshopper” which runs within “Rhinoceros”.

CS6M-3, ID 1182 (Time: 17:00 - 17:20)
TitleMorphogenesis of free-form shells considering multiple load conditions
Author*Yue Wu, Yi Xia, Qingpeng Li (Harbin Institute of Technology, China)
KeywordFree-Form shell, shape optimization, multiple load conditions, load evaluations
AbstractAs free-form shells can be designed to satisfy architectural purposes by complex and irregular shapes, they have been widely used by architects. Moreover, many researches which study and find the optimum shape of free-form shells have appeared. However, these studies mainly focus on finding the optimum shape under certain load condition and ignore the influence caused by different loads, which may have hidden safety troubles in specific condition. Therefore, multiple load conditions should be considered in the optimization method of free-form shells. In order to solve this problem, three aspects should be investigated.The first one is to evaluate the effectiveness or the result caused by each load condition.The second one is the formulating of the function to calculate weight factors.The last one is to optimize the free-form shell based on the former formulation to find a reasonable shape under multiple load conditions.At last, several numerical examples are showed.

CS6M-4, ID 1193 (Time: 17:20 - 17:40)
TitleGradient-based optimization of closest-fit funicular structures
Author*Pierre Cuvilliers, Renaud Danhaive, Caitlin Mueller (Massachusetts Institute of Technology, U.S.A.)
Keywordform finding, funicular structures, optimization, closest fit, force density method
AbstractThe aim of this research is to solve an inverse form-finding problem: construct funicular, axial-only structures as close as possible to a target surface defined by the designer. The scope is limited to grid-like, node-and-branch only networks, which can be solved efficiently using the force density method (FDM). This problem is formulated as a least-squares nonlinear optimization problem, and is solved using the constrained nonlinear solvers implemented in MATLAB. Two nonlinear constrained solving methods, interior-point and trust-reflective region, are found to be the fastest with a large convergence domain. The first and second-order derivatives of the objective function are found analytically. Lastly, the problem is shown to have several degeneracies; one in particular cannot be removed with physical arguments and leads to new insights in the numerical form finding of funicular surfaces.

CS6M-5, ID 1233 (Time: 17:40 - 18:00)
TitleStructural morphogenesis for asymmetric free-form grid shell Using NURBS with manipulation of decent solutions search
Author*Yusuke Okita (Tohata Architects & Engineers, inc., Kagoshima University, Japan), Toshio Honma (Graduate School of Science and Engineering, Kagoshima University, Japan)
KeywordStructural morphogenesis, Genetic algorithms (GA), Diversity of solution, Decent solutions, Free-form grid shell
AbstractThis study presents the effectiveness of a structural morphogenesis for free-form grid shells with manipulation of decent solutions search. The decent solutions are composed by the solutions of comparatively high evaluation containing a global optimal solution and local optimal solutions. The use of the decent solutions satisfying a structural rationality will stimulate designer's ideas. In this paper, the genetic algorithm with immune system (ISGA) to obtain the decent solutions is applied to a structural morphogenesis for an asymmetric free-form grid shell. The curved shape decision and the member selection for the grid shell are described with NURBS representation. The obtained forms in the structural morphogenesis for the grid shell are influenced by the order of NURBS. Especially in decent solutions search, it is important to understand this influence. The property and the influence for the order of NURBS on decent solutions search with geometric constraint are clarified from numerical results.

CS6M-6, ID 1251 (Time: 18:00 - 18:20)
TitleShape optimization of latticed shells consisting of ruled surface
Author*Shinnosuke Fujita (Tokyo Institute of Technology, Japan), Makoto Ohsaki (Kyoto University, Japan), Kazuya Seki (Azusa Sekkei, Japan)
KeywordRuled surface, Shape optimization, Bézier curve, Non-linear programming
AbstractA shape optimization method is presented for latticed shells using ruled surface.Boundary shape is defined using two Bezier curves, and the points with the same parameter value are connected by a line to model a ruled surface.The locations of control points of the Bezier curves are considered as design variables of the optimization problem. The total strain energy is minimized under constraints on material volume.In this optimization problem, not only vertical loads but also horizontal loads are considered.While the optimal shape is expected to have a large stiffness, it does not necessarily have enough capacity for the stress limit.Therefore, we solve another optimization problem considering strain energy and stress constraint. The effectiveness of the proposed approach is confirmed through numerical examples, and the characteristics of the optimal shapes are discussed.

CS6M-7, ID 1135 (Time: 18:20 - 18:40)
TitleIsogeometric analysis based on Bézier extraction of NURBS for topology optimization
Author*Qui X Lieu, Thang T Pham, Jiho Kim, N-Il Kim, DongKyu Lee, Kihak Lee, Jaehong Lee (Department of Architectural Engineering, Sejong University, Republic of Korea)
KeywordTopology optimization, SIMP approach, Isogeometric analysis (IGA), Bézier element, Bernstein basis functions
AbstractThis paper presents an effective approach using isogeometric analysis (IGA) based on Bézier extraction of non-uniform rational B-splines (NURBS) to perform topology optimization. By employing Bézier extraction operator, the localized NURBS basis functions constructed by the Bernstein basis functions are identical to all C0 continuous Bézier elements. It thus provides an element structure for implementation more easily than the conventional IGA and supplies capacity of local refinement to one. Density value at the center of each Bézier element is considered as design variable based on the modified Solid Isotropic Material with Penalization (SIMP) approach. The proposed sensitivity filter considering more neighboring element sensitivities of material volume shows its efficiency in eliminating the numerical instabilities in topology optimization. Moreover, optimized designs show highly discrete design variables in terms of solid and void materials without employing any project schemes. Numerical benchmark tests are presented to illustrate the effectiveness of the present method.

Session CS5Y  Project & Construction -1
Time: 14:00 - 16:00 Thursday, September 29, 2016
Location: Gallery-1

CS5Y-1, ID 1041 (Time: 14:00 - 14:20)
TitleComenius bridge in Jaromer, Czech Republic
Author*Vladimir Janata, Jindrich Beran, Miloslav Lukes, Jiri Lahodny (EXCON, a.s., Czech Republic), Petr Nehasil (Mott MacDonald CZ, s.r.o., Czech Republic)
Keywordfootbridge, prestressed tendon, beam string structure, sustainability, strain gauge
AbstractNew Comenius Bridge in Jaromìø for pedestrians and cyclists of length 61m and width 4,5m, connects historical centre of the town with the right bank of the river. It was built instead of the original bridge from the year 1886 destroyed by flood in 2013. Sufficient height of level of deck of the bridge above the flood level enabled to realize unusual subtle triangular prestressed beam-string structure with central compressed beam which won the architectural competition. Due to the requirement to refurbish historical abutments the bridge acts as a simple beam on them. Three corner tendons are prestressed to ensure favorable redistribution of internal forces in the structure and to deform the structure opposite to the deflection from vertical loading. The structure is hot-dip galvanized without any additional painting.

CS5Y-2, ID 1088 (Time: 14:20 - 14:40)
TitleSpace-frame structure with Steel forging connections
Author*Takashi Kurata (Nippon Steel & Sumikin Engineering Co., Ltd., Japan), Takeo Haijima (Azusa Sekkei Co. Ltd., Japan)
KeywordConnection, Steel Forging, Single Layer Frame, Moment Frame
AbstractSpace-frame structures require structural safety and beautiful architectural space. The key element is the connections. Steel forging connections are important design requirements; however they are rarely used for buildings in Japan. This paper presents design examples and describes the potential of spaceframe structures using steel forging at connections. The design examples are the Satellite Building and Glass Dome in the expansion project of Tokyo International Airport international Passenger Terminal, which opened in September 2014.

CS5Y-3, ID 1101 (Time: 14:40 - 15:00)
TitleConstruction of Suita City Football Stadium
Author*Masahito Ohno, Hisato Okude, Hirokazu Nozawa, Takashi Inoue (Takenaka Corporation, Japan)
Keywordspacial structure, 3D truss structure, roof isolation structure, construction, jack down
AbstractIn a 2014 article we described the structural design for the roof structure of the Suita Stadium. In the present article we report on the construction of the stadium (Ohno [1]). Since the Suita Stadium construction project was funded by donations from individuals and corporations, there was a strong need to ensure the efficient use of the fund. We had to pursue cost-effectiveness not only when determining the sectional design of structural members composing the roof, but also when choosing materials used in the construction of temporary structures. In developing the erection plan we tried to maximize the sizes of field-assembled pieces, in order to minimize the number of mega supports for the steel roof and the number of welding operations needing to be performed in high places. This paper provides a description of the roof structure design and reports on how the steel frame roof structure was constructed.

CS5Y-4, ID 1102 (Time: 15:00 - 15:20)
TitleSteel Frame Construction for the Yawaragi Mori no Stadium
Author*Junichiro Tsutakabe, Yutaka Soga, Mitsuo Asano (Takenaka Corporation Design Department, Japan)
Keywordspace truss, Parametric Design, BIM, CAD/CAM
Abstract“Yawaragi Mori No Stadium” is a building with a large membrane roof which consists of space truss steel frames. Arch shaped roof structure realizes wide spans of 147.5m at the maximum, 125m in general area, respectively. Space trusses are applied to the arch structure, considering buckling restraint against compressive force and assembly accuracy control at the construction stage. Structural design of the building was conducted by “Parametric Design” method, which produced three-dimensional analysis model applying some parameters and functions. The method was highly effective for achieving both the low roof height and reasonable substructure, due to the optimization of the balance between the rise and the thrust force. To complete the building in an ultra-short period of 9.5 months (60% of normal construction period), besides getting consensus among designers, structural engineers and construction technicians about the complicated roof shape, improved efficiency of both design and construction should be needed.

CS5Y-5, ID 1125 (Time: 15:20 - 15:40)
TitleTokorozawa Station: Use of upside down quadrangular conical columns as attractive structural frames and joints for a large spatial structure
Author*Yusuke Sugiyama, Osamu Hosozawa, Katsuhiro Ootake (Taisei Corporation, Japan)
KeywordSteel structure, joints, construction, simulation, large roof
AbstractThis study considers the upside down quadrangular conical columns (hereafter referred to UDQCC) used for conventional construction of joints in the large roof of the station building concourse formed by a large spatial frame.To ensure that the columns supporting the large roof would provide a sense of stability to the space, the UDQCC stretching overhead in three dimensions in a Y shape were placed starting from a height of 5m from the concourse floor level. Tapered steel tubes were used at both ends of the 4 diagonal columns to create an aesthetically beautiful structural frame design.This reduces the distance between binding beam supports and makes it possible to use an economical cross-section for the columns and binding beams, resulting in a supple and attractive design.

Session CS6Y  Project & Construction -2
Time: 16:20 - 18:20 Thursday, September 29, 2016
Location: Gallery-1

CS6Y-1, ID 1137 (Time: 16:20 - 16:40)
TitleStructural Design of Two buildings with Large Spaces
Author*Shunsuke Okayama (Kanebako Structural Engineers, Japan), Yoshiharu Kanebako (Kanebako Structural Engineers/Kogakuin University, Japan)
KeywordStructural design, Large spaces, Steel truss, Diagonal grid
AbstractIn this paper, the structural design of two buildings located at the station square of the local city is introduced. It is common that two buildings have large spaces. At an exhibition hall, we designed economical and unique shaped steel truss that is connected to architectural design by using diagonal grid. At a convention hall, we designed economical steel structure of large space in 1st floor by using large wall girders in upper floor. The design of the ceiling is important recently in Japan. In this building, the ceiling is supported by the steel secondary members those are connected with steel truss members.

CS6Y-2, ID 1197 (Time: 16:40 - 17:00)
TitleSafe and cost effective hybrid joints for single-layer braced dome construction in Mexico
Author*Humberto Uehara Guerrero, Edgardo Rocha (Universidad Autónoma de Querétaro, Mexico)
Keywordhybrid joint, cactus-shaped bamboo dome, lightness, aesthetics, elephant foot tree trunk-shaped fog-water collector
AbstractOver the past twenty years, many types of joints have been developed to connect structural elements and all of them have been suited to their particular construction requirements. Mero; Unistrut; Triodetic, Tuball joint; Octatube are some examples of joints that have been widely applied in the construction of tubular single-layer and even multiple – layer domes all over the world. However, most of the joint hardware produced so far has been fabricated utilizing casted steel as a single material, which is expensive in México. The hybrid joint herein introduced is composed of three materials: steel; high strength plastic and rubber.In 2002, the author won a design competition for a crystal dome design that should have fulfilled four major requirements: safety, economy, lightness and aesthetics, and he was commissioned to build the aforementioned dome in Querétaro city, México that covered the atrium of “Boulevares Shopping Plaza”, with plan dimensions 20.00 m X 30.00 m. and 3.00 m height.

CS6Y-3, ID 1253 (Time: 17:00 - 17:20)
TitleStructural Design of a Building with Shell and Flat Slab Hybrids
Author*Ken Noda (Kanebako Structural Engineers, Japan), Yoshiharu Kanebako (Kanebako Structural Engineers / Kogakuin University, Japan)
Keywordstructural design, shell and flat slab hybrid, undulating surface, load dispersion, stress transfer
AbstractThis paper is the structural design proposal for a complex building with undulating surfaces. The complex is one building that consists of four lines of hill-like roofs, called “waves”, which are intertwined with each other. Moreover, this site has soft ground that includes many artifacts to be preserved as a cultural heritage. The main issues in the structural design were as follows: 1. Design of shapes considering both architectural aesthetics and structural rationality; 2. Implementation of systems which properly transmit seismic forces among the waves; and 3. Prevention of damages to the artifacts beneath the site.The authors propose a structural system with a curved surface on distributed supports. It has a hybrid behavior between shell and flat slab. This hybrid system realized load dispersion by using thin slabs and slender columns, and achieved the construction of the building on the soft ground.

CS6Y-4, ID 1339 (Time: 17:20 - 17:40)
TitleLarge Roof Structure with Diamond Shaped Trusses
Author*Yumi Sakaguchi, Osamu Hosozawa, Kohei Shimamura, Sachiho Hanazato (Taisei Corporation, Japan)
Keywordtruss, large roof, sport facilities
AbstractThis project was part of the relocation and new construction of the farm main ballpark and related facilities for “Fukuoka SoftBank Hawks Farm” (the minor league team), necessitated by the aging of their existing facilities. This paper describes an outline of the indoor practice ground in the facilities.The indoor practice ground described here has a plan shape of 64 m×64 m, a height of 23 m. The structural form of the large roof includes a parallel chord truss with a diamond shape in plan in the center of the roof, with steel tubes extending from the peripheral frame to the lower chord level of the 4 corners of the diamond shaped truss, so that the diamond shaped truss is suspended. Vertical braces were provided in the 4 corners of the building to provide resistance to horizontal forces.

CS6Y-5, ID 1369 (Time: 17:40 - 18:00)
TitleDesign of Japan’s Largest Covered Waste Disposal Site
Author*Yuki Toyoshima, Osamu Hosozawa, Kohei Shimamura, Yumi Sakaguchi (Taisei Corporation, Japan)
KeywordStructural cable, Keel truss, sliding construction method
AbstractA combination of keel trusses and cable structure was adopted as the structural scheme for a building that needed to have the minimum number of columns over the floor area, as a result of its use as a covered waste disposal site. For safety and constructability the slide forming method was adopted, which is also effective for reducing the construction period.

CS6Y-6, ID 1053 (Time: 18:00 - 18:20)
TitleRibbon Chapel -Two interlinking spirals-
Author*Ikuhide Shibata (Arup, Japan), Hiroshi Nakamura (Hiroshi Nakamura & NAP Co., Ltd, Japan)
KeywordSpiral, Tuned Mass Damper, Base Isolation System, Herical Curve, Geometric Engineering
AbstractThe site is on the edge of a cliff overlooking the serene Seto Inland Sea in Japan. It’s an iconic design that from a far looks like a sculpture. It's a small wedding chapel in a resort hotel. Two directionally opposing spiral staircases ascending and becoming one at the top, symbolizing two paths ending in a marriage. The structure can be regarded as a coil spring that twists and expands outward while moving up and down with pressure from above. Our solution to stabilize the movement was to have four connections where the inner and outer spirals meet. That creates a basic structural concept of hoops and a 3D bracing system which allows an overhang of the spiral. We installed the Base isolation system to reduce the seismic force and to increase durability. Therefore the structure is a seemingly totally independent, floating spiral staircase with un-intrusive vertical support posts.

Session CS5A  WG13+15: Bending Active and Flexible Structures -1
Time: 14:00 - 16:00 Thursday, September 29, 2016
Location: Sanjo Main

CS5A-1, ID 1400 (Time: 14:00 - 14:20)
TitleBespoke materials for bespoke textile architecture
Author*Martin Tamke, Yuliya Baranovskaya, Anders Holden Deleuran (CITA - The Royal Danish Academy of Fine Arts, Schools of Architecture, Design and Conservation, Denmark), Filipa Monteiro (AFF a. ferreira & filhos, sa / Fibrenamics -Universidade do Minho, Portugal), Raul Manuel Esteves Sousa Fangueiro (Fibrenamics -Universidade do Minho, Portugal), Natalie Stranghöhner, Jörg Uhlemann (University Duisburg-Essen, Germany), Michel Schmeck, Christoph Gengnagel (UDK Berlin, Germany), Mette Ramsgaard Thomsen (The Royal Danish Academy of Fine Arts, Schools of Architecture, Design and Conservation, Denmark)
KeywordMembrane Materials, Form Finding, Simulation, Testing, Customisation
AbstractMembrane architecture uses currently off the shelf materials and produces the shapes and details through cutting and laborsome joining of textile patterns. This paper discusses investigations into an alternative material practice - knit - which engages bespoke membrane materials. A practice which allows for customised and graded material properties, the direct fabrication of shaped patterns and the integration of detailing directly into the membrane material. Based on two demonstrators built as hybrids of bespoke CNC knit and bending active GFRP rods this paper discusses the affordances and procedures, which this new practice of digital fabrication of membrane material requires. The central focus is set on the interaction between the involved disciplines and the emerging iterative process of design, material specification, prototyping, evaluation, (re-)design and (re-)specification. We discuss how design and engineering practices change, when material properties move from given and constant into the area of design and gradient.

CS5A-2, ID 1522 (Time: 14:20 - 14:35)
TitleExtending Geometric and Structural Capacities for Textile Hybrid Structures with Laminated GFRP Beams and CNC Knitting
Author*Sean Ahlquist (Taubman College of Architecture and Urban Planning, University of Michigan, U.S.A.), Julian Lienhard (str.ucture GmbH, Germany)
Keywordtextile hybrid, cnc kitting, bending-active, membrane structures, GFRP laminated beams
AbstractA textile hybrid structure is defined by the interaction of bending-active elements and tensile (form-active) surfaces. The bending-active capacity is ideally captured with the use of GFRP rods, given their ideal ratio of high strength to low bending stiffness. This research addresses the challenges in advancing the geometric properties and structural behavior of bending-active glass-fiber reinforced polymer (GFRP) rod structures. To overcome the geometric and structural limitations of single cross-section GFRP rod systems, this research introduces the use of laminated GFRP beam structures through composite forming with custom knitted sleeves. This paper will show how the material method allows for more complex differentiated geometries to be realized, and the inclusion of bending-active stiffness at the scale of the whole system greatly increases structural capacities for the overall textile hybrid architecture.

CS5A-3, ID 1146 (Time: 14:35 - 14:55)
TitleActively-bent plywood floor frame with in-plane curvature
Author*Alfonso Garcia, Juan Monjo (Technical University of Madrid, Spain), Hiroyasu Sakata (Tokyo Institute of Technology, Japan), Ramón Sastre (Technical University of Barcelona, Spain), Yoshihiro Yamazaki (Tokyo Institute of Technology, Japan)
Keywordplywood, active bending, floor frame, in-plane curvature, prestressed structure
AbstractDeformation is often the critical parameter for wooden structures subjected to bending. The cross section of these structural elements could easily comply with strength criteria but not with those concerning stiffness. This issue is even more decisive dealing with long-term behaviour. In order to increase the stiffness of a wooden horizontal floor frame, this paper proposes to introduce elastically bent elements made from standard plywood but placed with in-plane curvature. These actively-bent components are coupled to some others to define joists as tie-arch groups. Due to the form finding process all the elements acquire prestress: bending stress for the curved elements and tension prestress for the ones that remain straight. Also camber can appear. Comprehensive parametric study is performed by varying the key parameters characterizing the geometry of the solution. Finally, the knowledge achieved during the parametric study will be used to establish a final proposal.

CS5A-4, ID 1012 (Time: 14:55 - 15:15)
TitleOptimization of locations of slot connections of gridshells modeled using elastica
Author*Makoto Ohsaki (Kyoto University, Japan), Kazuya Seki (Azusa Sekkei, Japan), Yuji Miyazu (Hiroshima University, Japan)
Keywordgridshell, elastica, optimization, simulated annealing, slot joint
AbstractAn optimization method is presented for gridshells, which are generated by bending beams through forced displacements at supports. The target shape of a curved beam is defined as an elastica, which is the shape of a buckled beam-column with large deflection. The length of beam of the initial configuration on the ground is computed from the target shape. It is shown that the interaction forces at hinges between perpendicularly connected beams are reduced by designing the curve as elastica. The interaction forces are further reduced by assigning hinge+slot joints that can move along a member. A heuristic approach called simulated annealing is used for optimizing the locations of hinge+slot joints. It is shown in the numerical examples that maximum forces at joints are effectively reduced by appropriately placing a small number of hinge+slots.

CS5A-5, ID 1161 (Time: 15:15 - 15:35)
TitleScale effect in bending-active plates and a novel concept for elastic kinetic roof systems
Author*Kenryo Takahashi, Axel Körner, Valentin Koslowski, Jan Knippers (Institute of Building Structures and Structural Design (ITKE), University of Stuttgart, Germany)
KeywordBending-Active Structure, Kinetic Structure, Deployable Structure, Convertible Roof
AbstractThis paper presents the understanding of scale effects in bending-active structures and a strategy for increasing the span to employ them for elastic kinetic roof systems. The aspect of scalability and the stability during the deformation in bending-active structures are not often regarded. Regardless of the self-similarity of bending, the problem can be identified as the increase of compressive stresses that could easily cause the instability in a scaled structure both during its active deformations and under external loading.The paper therefore proposes a concept of bending-active structures with built-in tension cable elements, which should improve the stability of the structure in a larger scale. A novel concept of elastic kinetic roofs shall be presented in accordance with comparative feasibility studies of bending-active plates for their structural behaviours in scales both at deformed and loaded configurations.

CS5A-6, ID 1398 (Time: 15:35 - 15:55)
TitleLow cost double curvature: Geometrical and structural potentials of rectangular, cold-bent glass construction
Author*Philipp Eversmann (ETH Zurich, Switzerland), Eike Schling (TU München, Germany), André Ihde (TU München, Pfeifer Seil- und Hebetechnik GmbH Memmingen, Germany), Christian Louter (TU Delft, Netherlands)
Keywordcold-bending, glass, double-curvature, optimisation, FE-Analysis
AbstractThe realization of doubly curved façades often requires large investments in fabrication equipment and produces additional waste through subtractive fabrication processes and non-reusable molds. In glass construction, elastic bending techniques can be used for small curvatures. This paper continues previous research of the authors on bending rectangular glass elements into irregularly curved panels. First, we analyze the stresses occurring in cold bent glass during assembly, thus defining a particle-spring model which is able to compute approximate stresses in real-time during the bending procedure. In a second step, we compare the structural performance of the bent glass with that of flat panels using FE-analysis. Finally, we illustrate the implementations on multi-panel façade layouts. We analyze the dependencies between curvature, gap-tolerance and panelization. We present a method to minimize gap-tolerances by optimizing the distribution of surface curvature. Our results highlight the structural and geometrical potentials and possible applications for curved glass construction.

Session CS6A  WG13+15: Bending Active and Flexible Structures -2
Time: 16:20 - 18:20 Thursday, September 29, 2016
Location: Sanjo Main

CS6A-1, ID 1473 (Time: 16:20 - 16:40)
TitleSimulating Pneumatic Erection of Strained Grid Shells via Dynamic Relaxation
Author*Gregory Quinn, Christoph Gengnagel (Department for Structural Design and Technology, Berlin University of Arts, Germany), Kai-Uwe Bletzinger (Department for Structural Analysis, Technical University of Munich, Germany)
KeywordPneumatic, Erection, DR, Grid shell, Active bending
AbstractThe central research question of this work asks “can pneumatic falsework be used to erect strained grid shells?” In order to begin to answer this question, a bespoke simulation method was developed in the Rhinoceros 3D / Grasshopper software environment making use of the Kangaroo2 Dynamic Relaxation solver alongside substantial customisations using Python and C# programming scripts. A series of 2D mechanically calibrated case studies were conducted which simulate the incremental inflation of a membrane cushion of substantial tensile stiffness but zero bending stiffness in combination (colliding) with a beam featuring significant bending stiffness and relatively low self weight. The method features very low membrane utilisation stresses (up to 35%) and bending stresses climb gradually such that overstressing of the beams is avoided entirely demonstrating the effectiveness of the method. The importance of external and internal tethering cables for restraint and the significance of an initial ‘trigger’ pressure are highlighted.

CS6A-2, ID 1494 (Time: 16:40 - 17:00)
TitleCalibrated and interactive modelling of form-active hybrid structures
AuthorGregory Quinn (Department for Structural Design and Technology (KET), Berlin University of Arts, Germany), Anders Holden Deleuran (Centre for Information Technology and Architecture (CITA), Royal Danish Academy of Fine Arts, Schools of Architecture, Denmark), Daniel Piker (Robert McNeel & Associates, England, U.K.), Cecilie Brandt-Olsen (Department of Civil Engineering, The Technical University of Denmark, Denmark), Martin Tamke, Mette Ramsgaard Thomsen (Centre for Information Technology and Architecture (CITA), Royal Danish Academy of Fine Arts, Schools of Architecture, Denmark), *Christoph Gengnagel (Department for Structural Design and Technology (KET), Berlin University of Arts, Germany)
KeywordHybrid, Kangaroo, Calibrated, DR, Structure
AbstractForm-active hybrid structures (FAHS) couple two or more different structural elements of low self weight and low or negligible bending flexural stiffness (such as slender beams, cables and membranes) into one structural assembly of high global stiffness. They offer high load-bearing capacity at a fraction of the weight of traditional building elements and do so with a clear aesthetic expression of force flow and equilibrium. The design of FAHS is limited by one significant restriction: the geometry definition, form-finding and structural analysis are typically performed in separate and bespoke software packages which introduce interruptions and data exchange issues in the modelling pipeline. The mechanical precision, stability and open software architecture of Kangaroo has facilitated the development of proof-of-concept modelling pipelines which tackle this challenge and enable powerful materially-informed sketching. Making use of a projection-based dynamic relaxation solver for structural analysis, explorative design has proven to be highly effective.

CS6A-3, ID 1293 (Time: 17:00 - 17:20)
TitleNon-prismatic bending and torsion beam elements for form-finding by dynamic relaxation
Author*Maryanne Wachter, Andrew Liew, Tom Van Mele, Philippe Block (Block Research Group, Institute of Technology in Architecture, ETH Zurich, Switzerland)
Keywordbending-active, form finding, dynamic relaxation, non-prismatic beams, torsion
AbstractThis paper evaluates the use of the 4-DoF beam-element formulation proposed by Du Peloux et al. [7], for modelling non-prismatic beam sections for form finding by dynamic relaxation. While non-standard sections have posed a problem for economic fabrication in the past, the rise of bespoke prefabrication opens up the possibility to create custom structural elements for bending-active structures. Tapered beam profiles can be formed from glass fibre-reinforced polymers (GFRP) by pultrusion, with consistent material properties. Given this construction potential, an extended numerical approach is presented that includes a linear weighting scheme at the element nodes and explores the required element discretization to achieve an accurate simulation of tapered members with different cross sections. The effects of bending alone and coupled bending with torsion for the non-prismatic beam elements are then compared to results achieved using standard beam elements in the finite element software ABAQUS.

CS6A-4, ID 1353 (Time: 17:20 - 17:40)
TitleA review on geometrically exact models for very flexible rods
Author*Carlos Lazaro, Salvador Monleon, Juan G. Bessini, Jose Casanova (Universidad Politecnica de Valencia, Spain)
Keywordgeometrically exact rods, bending active structures, large rotations, large displacements, Reissner-Simo beam model
AbstractThis paper reviews the fundamentals of the geometrically exact beam theory −or Reissner-Simo beam theory− and the most relevant associated finite element implementations. Reissner-Simo’s theory is able to model the mechanical behaviour of slender structural members involving arbitrarily large displacements and rotations. Rod centreline displacements and cross sectional rotations are used as model variables; the exact mathematical treatment of rotations is achieved by handling them as elements of the special orthogonal group. The choice of suitable parametrizations of the rotations, and the difficulties and specificities of finite element implementations of this theory are reviewed. Numerical examples using the author’s implementation are presented, and finally the potential for future applications for form finding of bending active structures is pointed out.

CS6A-5, ID 1008 (Time: 17:40 - 18:00)
TitleInflatable cushions, active bending and the elastica
Author*Slade Gellin (Buffalo State College, U.S.A.), Romuald Tarczewski (Wroclaw University of Technology, Poland)
Keywordactive bending, inflatable cushions, elastica
AbstractThis paper continues the theoretical study of the deformed shape of inflatable cushion structures. The classic problem of the elastica can be applied as an appropriate theoretical model when these structures are under active bending loads. Comparisons with experimental results are made so that the bending stiffness of the structure can be determined. Approximate expressions for the key parameters are derived.

CS6A-6, ID 1153 (Time: 18:00 - 18:20)
TitleNew shapes for elastic gridshells covered by planar facets
Author*Cyril Douthe, Romain Mesnil, Hugo Orts, Olivier Baverel (Ecole des Ponts ParisTech, France)
KeywordPQ-mesh, elastic gridshell, circular mesh
AbstractElastic gridshells are structures made of flat two-way grids which are deformed elastically before they are braced and which afterwards mechanically behave like continuous shells. Gridshells present some advantages in terms of manufacturing, lightness and time of assembly. Their covering remains however a technical issue. The present article proposes hence an alternative method to cover them by planar quadrilateral facets, which could also be used as natural bracing if connected properly. It relies on the duality between a certain family of circular meshes with a unique radius and some Tchebycheff nets. The approach is versatile and allows for the design of a large variety of shapes from two curves in space. Real time numerical tools are developed for open and closed curves as well as a strategy for umbilical points.

CS6A-7, ID 1411 (Time: 18:20 - 18:40)
TitleSurface approximation/population by self-locking, bending active modules from coupled straight and curved line z-folded elements
Author*Günther H. Filz, Ines Kumric (Faculty of Architecture, Institute of Design | unit koge. Structure & Design, University of Innsbruck, Austria), Vladimir Razenj (Mathematician, Solid Works (retired), U.S.A.)
Keywordbending active modules, coupled straight and curved line folding, self-locking snap-action mechanism, architectural geometry
AbstractIn the context of the realized “Z-Snap-Pavilion” the authors (Filz and Kumric [4]) described the principles on how to achieve a transition from planar, zip-assembled sheet elements into 3dimensional bending active, modular structures by z-folding one or more pairs of coupled straight and curved lines. The category of how spatial configurations can be locked is dependent on the number and position of z-folded, coupled straight and curved lines on the sheet element. Particular attention lies in the self-locking snap-action mechanism, achieved by collars. This paper looks into the freedoms and limits in the genesis and variety of forms of spatial objects utilizing described z-folding strategies. Simultaneously we are aiming for surface approximation/population by controlling the geometrical setup and/or additive arrangement of spatial elements. This will be proved by the realization of a full scale paper/cardboard structure as well as its architectural qualities.

Session CS5C  Tension Structures -3
Time: 14:00 - 16:00 Thursday, September 29, 2016
Location: Room 001

CS5C-1, ID 1434 (Time: 14:00 - 14:30)
Title[Keynote] The research progress and prospect of cable-supported structures in china
Author*Zhihua Chen (Department of Civil Engineering, Tianjin University, China), Xiaoxiang Wang, Hongbo Liu, Qing Ma (Tianjin University, China)
KeywordCable-supported structures, Cable, Cable-strut joint, Equivalent friction Element, Engineering application
AbstractCable-supported structures can be classified as cable-supported plane structure, separable cable-supported spatial structure and inseparable cable-supported spatial structure, according to different mechanical characteristics and force transferring principles. Cable-supported plane structure includes beam string and truss string structure, and inseparable cable-supported spatial structure contains suspendome, cable-supported barrel vault, cable-supported concrete roof, cable-supported arch-dome and cable-supported latticed shell and etc. Then the research progress of structural behavior of beam string structure and suspendome structure are introduced in this paper. Cable is the key structural component in cable-supported structures and its mechanical properties can influence the bearing behaviors and safety evaluation of cable-supported structures. Therefore a brief discussion and key issues of cable researches are presented here. Besides, researches on two advanced cable strut joints for cable-strut or member-strut connections are also introduced. In the end, a brief overview of the overall development of cable-supported structure and some future works are presented.

CS5C-2, ID 1341 (Time: 14:30 - 14:50)
TitleMechanical Characteristics of Large Span Spoked Wheel Systems
Author*Kang-geun Park (Korean Association for Spatial Structures, Republic of Korea), Dong-woo Lee (I'ST Co., Republic of Korea), Sang-Ju Lee (I'ST Co., Ltd, Structural Engineering Group, Republic of Korea)
Keywordgeometrical nonlinear behavior, large span cable spoked wheel system, self-equilibrium structures, opposite curvature, upper bearing cable, lower stabilizing cable
AbstractThe study is carried out to get the geometrical nonlinear behavior of large span cable spoked wheel system is defined as a self-equilibrium structure which consists of a compressive outer ring and radial cable trusses. The advantage of this cable system is the roof weight dramatically can reduce, the self-equilibrating effect and lightness are efficiently utilized to the large span roof of sports arena. A large span cable spoke wheel system is too flexible, cable roofs are stabilized by connecting by hangar cables for the upper bearing cable and lower stabilizing cable with strongly pre-stressed. A cable truss system is formed by cables with reverse curvature, double cable arrangement is more efficiently as a load bearing system, pre-tensioning strongly makes the structural stiffness. With the sets of cables having opposite curvature to each other, a cable truss is able to carry vertical load in both upward and downward direction.

CS5C-3, ID 1359 (Time: 14:50 - 15:10)
TitleForm-finding Analysis for Stabilized and Stiffened Structural System Using Tension Members
Author*Shingo Komikado, Yohei Yokosuka, Toshio Honma (Kagoshima University, Japan)
KeywordRigid Body Displacement, Self-equilibrated Axial Force, Total Potential Energy
AbstractWe organize the stable structures with prestress, which are separated into compression and tension groups, and propose structural model and form-finding analysis. Characteristic of the proposed model is simple mechanism to divide compression/tension members, and only tension members are used to stabilize and stiffen the structural form. In this paper, we indicate mechanical property of the solution form obtained by the form-finding analysis to focus on the total potential energy. Next, by using the geometrically nonlinear analysis with prestress in FEM, we compare structural forms which have different number of statically indeterminacy, and verify mechanical behavior and solution space under vertical and horizontal loads. Furthermore, we verify the model that structural members and nodal points are increased, and compare the grouping for tension members. From these results, we show the possibilities of stable structures with prestress obtained by the form-finding analysis.

CS5C-4, ID 1419 (Time: 15:10 - 15:30)
TitlePreliminary Investigation of Joint Behavior in A Tensegrity Structure
Author*Pujin Wang, Ken’ichi Kawaguchi, Tatsuhiko Hashiba, Keisuke Mizutani (The University of Tokyo, Japan)
Keywordtensegrity, full-scaled, truncated pentagonal cone, joint behavior, hemisphere joint
AbstractIn general, structural behavior of tensegrity structures under load is often calculated with representing members as simple line members. However, in the construction phase, it is necessary to consider the thickness of members and the real dimension of the connections. This leads us to pay attention to the rigid body motions of members, especially the rotation of the straight members around its axis. In this paper, the conventional compression members calculated as truss members are reconsidered as beam elements having six degrees of freedom. Then the angle change of the members during construction is studied. The upper part joints in the structure are designed as hemispheres, relative calculations are also necessary.

CS5C-5, ID 1543 (Time: 15:30 - 15:50)
TitleState of the art products and materials for long span tension structures
Author*Igor Siotor (Pfeifer Cable Structures, Canada), Thomas Hermeking (Pfeifer Cable Structures, Germany)
KeywordTension structure, cable structures, fixed lengt cables, fatigue resistance, force measurement
AbstractThe understanding of tensile technology has arguably revolutionized the engineering and construction of long span structures, specifically the design of lightweight bridges. Various materials have been used as tension members carrying most if not all loads in all sorts of bridge-like structures for thousands of years, i.e. rope walkways in Chinese mountains. Later, in mid centuries iron chains have been used to carry much heavier loads of bridges and draw platforms. All sorts of hemp (and other natural fibers) ropes were utilized for smaller temporary structures, in mining and in the sail ship industry, of course. In modern times, one of the pioneers in engineering long span tension structures was Eng. John Roebling. His first wire rope suspension aqueduct was built in Pittsburgh in 1844-1845 and was, arguably the “game changing” use of new material for long span structures.

Session CS6C  Tension Structures -4
Time: 16:20 - 18:40 Thursday, September 29, 2016
Location: Room 001

CS6C-1, ID 1496 (Time: 16:20 - 16:40)
TitleDouble-Layer ellipsoidal tensegrity structures: Geometric investigation and parametric representation
Author*Katherine Liapi, Adreana Papantoniou (University of Patras, Greece), Chysostomos Nousias (Aristotle University of Thesaloniki, Greece)
Keywordtensegrity, ellipsoid, double layer, square tesselation, mercator projection
AbstractThe paper presents a method that renders possible the development of double layer ellipsoidal tensegrity structures composed of square-base units. Existing methods for the development of single or double curvature tensegrity structures can be only used to generate networks of vaulted, spherical and spiral geometry composed of identical tensegrity units. To generate the ellipsoidal geometry the investigation of the distribution of a four- square pattern, that represents the lower level of an assembly of four units, not necessarily identical, on an ellipsoid has been first addressed. An application of the Mecrator projection technique has been used for this. At a subsequent stage, the development of the second layer of the ellipsoidal tensegrity structure has been investigated. A parametric method that uses an algorithm that generates the distribution of the square based tensegrity units on the surface of a sphere first, and of an ellipsoid afterwards, has also been developed and discussed in the paper.

CS6C-2, ID 1509 (Time: 16:40 - 17:00)
TitlePostelastic Analysis of biconvex and biconcave prestressed suspension cable trusses
AuthorStanislav Kmet, *Marek Mojdis (Faculty of Civil Engineering, Institute of Structural Engineering, Technical University of Kosice, Slovakia)
KeywordCable trusses, Geometrically nonlinear analysis, Postelastic analysis, Finite-element analysis
AbstractThe paper deals with geometrically nonlinear analytical solutions for postelastic response analysis of biconvex and biconcave prestressed suspension cable trusses subjected to a uniformly distributed load. The cable trusses are composed of top and bottom prestressed cables which are anchored at each end. Between the top and bottom cables are placed numerous vertical or diagonal ties or either vertical and diagonal ties or vertical spacers. These types of constructions offer an economical and efficient alternative to many structural problems, for example projects that require coverage of large areas. In the article are derived analytical equations which provide a straightforward determination of the intensity of vertical uniformly distributed loads applied over the entire span of a structure, as well as the accompanying forces and vertical deflections corresponding to the postelastic behavior of cable trusses.

CS6C-3, ID 1536 (Time: 17:00 - 17:20)
TitleRenovation of Nature of structure (Tensegrity) art -No.2: Proposal of repair methods and joint detail-
Author*Masahide Imagawa (ISGW Co., Ltd., Japan), Norihide Imagawa (Tokyo Denki University, Japan), Shoudai Sueyoshi (ISGW Co., Ltd., Japan)
KeywordTensegrity, tension structure
AbstractProposed by the repair method based on the current situation survey and analysis of the Art of Nature of structure (tensegrity) and the joint detail in Part 2. From survey results, the wire must be replaced has been confirmed such as broken wires, wires tension is increased or decreased and the wire exceeds the long-term allowable tension. In this renovation, because there is a need for the proposed renovation how to do while maintaining the existing shape, propose a repair method to achieve it.

CS6C-4, ID 1537 (Time: 17:20 - 17:40)
TitleRenovation of Nature of structure (Tensegrity) art -No.1: Comparison and consideration of the original design and deterioration survey results-
Author*Shoudai Sueyoshi (ISGW Co., Ltd., Japan), Norihide Imagawa (Tokyo Denki University, Japan), Masahide Imagawa (ISGW Co., Ltd., Japan)
KeywordTensegrity, tension structure
AbstractThis paper report on the renovation of the Art of Nature of structure (Tensegrity), which was designed in collaboration of Mr. Norihide Imagawa and Mr. Kenneth Snelson. After this work is completed, has passed about 15 years, it was conducted a survey of the current state of the shape, tension and deterioration state. In part 1 is considered to compare the state of tension obtained from the survey results and the tension state by the analysis of the shape of the original design.

CS6C-5, ID 1545 (Time: 17:40 - 18:00)
TitleA linear method for form-finding of irregular prism tensegrity
AuthorMohammad Moghaddas, *Kok Keong Choong (School of Civil Engineering, Universiti Sains Malaysia, Malaysia), Jae-Yeol Kim (Department of Architectural Engineering, Hyupsung University, Republic of Korea)
Keywordirregular prism tensegrity, form-finding, member length relation
AbstractPrism tensegrity has the major advantage of simple combining ability where a single layer prism system can be easily extended to multi-layer tensegrity structure. Such obvious advantage presents designers with the flexibility to experiment with different shapes of structure using tensegrity system. In order to achieve that, a form-finding method which is accurate and fast is desirable. In this paper, a linear method is presented by combining the force equilibrium with length relation conditions. This linear approach can be used for form finding of both symmetrical and unsymmetrical prism tensegrity systems. In the proposed approach, force equilibrium and member length relations are linked together through trigonometric relations. Through the incorporation of the trigonometric relation in form finding equation, the calculation of lengths and force ratios in prism tensegrity structure becomes linear. The applicability of the approach is shown using examples of prism tensegrity structures which are symmetry and unsymmetry.

CS6C-6, ID 1546 (Time: 18:00 - 18:20)
TitleForm-finding of human spine inspired biotensegrity
AuthorChai Lian Oh, *Kok Keong Choong (School of Civil Engineering, Universiti Sains Malaysia, Malaysia), Toku Nishimura (Department of Architectural Engineering, Kanazawa Institute of Technology, Japan), Jae-Yeol Kim (Department of Architectural Engineering, Hyupsung University, Republic of Korea)
Keywordbiotensegrity, human backbone, form-finding
AbstractBiotensegrity is a concept introduced to study interaction of forces within biological systems at microscopic and macroscopic levels. Past studies have claimed that human spine has superior load bearing capacity due to mechanical interaction between the vertebrae column and the surrounding tensional muscles. However, mathematical proof of a biotensegrity model representing human spine is yet to be established. The objectives of this paper are to: (a) develop a biotensegrity model mimicking human spine architecture and (b) establish an algorithm for form-finding of the biotensegrity model inspired by the human spine. The idea of tensegrity mast incorporating all characteristic feature of human spine which is used in the development of the human spine inspired biotensegrity model is presented. The iterative process used in form-finding process for the human spine inspired biotensegrity model is also described.

CS6C-7, ID 1121 (Time: 18:20 - 18:40)
TitleForm-finding of Tensegrity Structures using Frequency Constraints
Author*Seunghye Lee, Thao An Huynh, Sumin Kim, Dieu Thi Thanh Do (Sejong University, Republic of Korea), Ho-Soo Kim (Cheongju University, Republic of Korea), Jaehong Lee (Sejong University, Republic of Korea)
KeywordTensegrity, Form-finding, Stiffness Method, Genetic Algorithm, Self-stress state
AbstractA form-finding method of tensegrity structures is a process of finding an equilibrium configuration and a key step in a design of the tensegrity. Over the past few years, several studies have been made on form-finding methods of the tensegrity structures, however, these methods are limited in the tensegrity systems with multiple self-stress states. The purpose of this study was to present a numerical method for form-finding of tensegrity systems with a single states or multiple states of self-stress by using the natural frequencies of the structures. To obtain both mechanical and geometrical parameters of tensegrity structures, “The maximum stiffness status of the structure can be determine when the fundamental frequency of the structure is maximized” philosophy was employed. A genetic algorithm is then performed to draw the maximum fundamental frequency of the tensegrity structures.

Session CS5D  Metal Roofs -1
Time: 14:00 - 16:00 Thursday, September 29, 2016
Location: Room 002

CS5D-1, ID 1058 (Time: 14:00 - 14:20)
TitleNumerical Research on Bearing Capacity of 6061-T6 Aluminum Alloy Columns under Axial Compression at Elevated Temperatures
Author*Xiaonong Guo, Weijia Huang, Shouchao Jiang (Tongji University, China)
Keywordaluminum alloy columns, coefficient of stability, bearing capacity at elevated temperatures
AbstractThis paper presented a numerical investigation on the bearing capacity of domestic 6061-T6 aluminum alloy columns under axial compression at elevated temperatures. Firstly, based on the existing test data, finite element (FE) models of aluminum alloy columns with rectangular and circular hollow sections were developed. The FE models were accurately calibrated on the basis of the available experimental results. Secondly, a finite element analysis on the bearing capacity of domestic 6061-T6 aluminum alloy columns with thirty four cross-sections was conducted and 2108 numerical points were obtained. Subsequently, according to the finite element results, formulae to estimate the coefficient of stability of aluminum alloy columns at elevated temperatures were proposed. Finally, the proposed column curves were compared with test data and column curves of different codes. It is showed that the proposed column curves were well applicable to the aluminum alloy columns at elevated temperatures.

CS5D-2, ID 1062 (Time: 14:20 - 14:40)
TitleNumerical Research on Bearing Capacity of aluminum alloy gusset joints at Elevated Temperatures
Author*Kun Wang, Xiaonong Guo, Zhe Xiong (Tongji University, China)
KeywordAlloy Gusset joints (AAG joints), Finite Element models at elevated temperatures, Bearing Capacity
AbstractAluminum Alloy Gusset joints (AAG joints) have the advantages of simple form and ease of erection, they have been widely used in single-layer reticulated shells. Numerous studies have been conducted to investigate the bearing capacity of AAG joints at ambient temperature. However, the available research results on the bearing capacity of AAG joints at elevated temperatures are very limited. In order to reveal the bearing capacity of AAG joints at elevated temperatures, finite element models of AAG joints at 25℃, 100℃, 200℃ and 300℃ were established by using the nonlinear finite element software, ABAQUS. The failure modes of AAG joints at elevated temperatures were inquired. The bearing capacity of block tearing and bearing capacity of buckling within the central area at elevated temperatures were obtained. The research results indicated that the bearing capacity of block tearing was related to the tensile strength of aluminium alloy at elevated temperatures.

CS5D-3, ID 1082 (Time: 14:40 - 15:00)
TitleFinite element analysis on the stability behavior of 7A04 high-strength aluminum alloy angle columns under axial compression
Author*Zhongxing Wang, Yuanqing Wang (Tsinghua University, China), Xiaoguang Hu, Haijun Xing (China Electric Power Research Institute, China)
Keywordhigh-strength aluminum alloy, column, overall stability, finite element analysis, parametric analysis
AbstractIn order to investigate the stability behavior of 7A04 high-strength aluminum alloy angle column under axial compression, a finite element (FE) mode was presented in the current paper. Results of the FE model are verified by experimental results. By the verified FE model, a parametric analysis of more than one hundred columns has been conducted to study the effects of initial imperfections, material strength and width-to-thickness ratio. It is found from the FE model that, there are three kinds of failure modes of the specimens including local buckling (λ<30), flexural-torsional buckling (λ=30~60) and flexural buckling (λ=80~100). It is shown from the parametric analysis, when the slenderness ratio is about 80, the influence of imperfection on stability resistance is the greatest; the nominal yield stress doesn’t make visible effects on the thin-walled columns and long columns; with slenderness ratio increases, the effect of width-to-thickness ratio becomes insignificant.

CS5D-4, ID 1133 (Time: 15:00 - 15:20)
TitleCyclic shear tests of steel hexagonal latticed plates part1: Experiment overview
Author*Hiroyuki Oyobe, Tetsuo Yamashita, Ryosuke Miyazawa (Kogakuin University, Japan)
Keywordhexagonal latticed plate, overall buckling, member buckling, out-of-plane deformation
AbstractIn recent years, steel latticed plates are used as facades of some innovative buildings for great transparency of light and aesthetical design. However, there is few studies on seismic capacity when used as earthquake-resisting walls. Now the authors are focusing hexagonal latticed plates for stability in the inelastic shear deformation and great energy dissipation capacity. Experiments and analysis on the inelastic shear behavior of four hexagonal latticed plates were performed. In Part I, experiments of the four steel latticed plates are to be described.

CS5D-5, ID 1134 (Time: 15:20 - 15:40)
TitleCyclic shear tests of steel hexagonal latticed plates Part II: Evaluation of test result using FEA
Author*Ryosuke Miyazawa, Tetsuo Yamashita, Hiroyuki Oyobe (Kogakuin University, Japan)
Keywordhexagonal latticed plate, out-of-plane deformation, generalized slenderness
AbstractIn part II, detailed analysis on the cyclic loading test using finite element analysis (FEA) is demonstrated. First, the hinges occur at the ends of vertical members and the actual fracture points show good agreement with the points where the accumulated plastic strain concentrates. Second, it is found that bending moment is predominant in the hexagonal grid plates by observing the MN instruction curves on the vertical and diagonal members. However, the axial stress in the voronoi and anisotropic hexagonal grid plates is larger than that in the regular hexagonal plates. It is guessed that the larger axial stress gives some influence on the larger out-of-plane deformation observed in the experiments of these plates. Moreover, we consider that the generalized slenderness can be the index to determine the boundary of onset of significant out-of-plane deformation. The boundary lies between 0.23 and 0.28.

Session CS6D  Metal Roofs -2
Time: 16:20 - 18:20 Thursday, September 29, 2016
Location: Room 002

CS6D-1, ID 1234 (Time: 16:20 - 16:40)
TitleFrom complex shape to simple construction: fast track design of "the future of us" gridshell in Singapore
Author*Catherine Poirriez (Passage Projects, Singapore), Thomas Wortmann (Advanced Architecture Laboratory Singapore University of Technology and Design, Singapore), Roly Hudson (Universidad de los Andes, Bogota, Colombia), Yacine Bouzida (Passage Projects, Singapore)
KeywordConstruction, Steel structure, Gridshell
AbstractThe “future of us” exhibition celebrated Singapore’s Golden Jubilee. The visitors of the exhibition experienced a stunning play of light and shade cast by a metal lattice, composed of a main steel structure that supports 11000 perforated aluminium panels, spanning approx. 50m and rising to 16m. From start of design to completion of installation was only 5 months. This document describes how the boundaries of simplicity have been pushed during all the steps of the project, by using basics construction concepts and compromises in order to meet the challenge of building a free form complex structure on time. The choice of structural system, the rationalization of the geometry, the material used, the choice in type of connections as well as solutions for the interfaces between the structural framing and the façade participated in building a simple complex structure.

CS6D-2, ID 1211 (Time: 16:40 - 17:00)
TitleStudy on analysis method for behavior of single-layer reticulated domes subjected to external blast loading
Author*Xudong Zhi, Shaobo Qi, Qingwu Shao, Feng Fan (Harbin Institute of Technology, China)
Keywordlong-span spatial structures, blast loading, scaled-down experiments, failure modes, AUTODYN
AbstractLong-span spatial structures are commonly used as landmarks of modern cities and can be potential targets of terrorist attacks. Because of this risk, it is important to study the dynamic behavior of spatial structures under blast actions. The aims of this paper are to (i) test the accuracy of the numerical approach for simulation of structural dynamic responses based on the explicit dynamic finite element software AUTODYN, (ii) verify the existence of failure modes of single-layer reticulated domes under external blast loading using numerical analysis based on scaled-down experimental results (iii) compare and evaluate several numerical simulation methods for studying the dynamic responses of domes under external blast loading. Our main finding is that the damage conditions of the single-layer reticulated dome under external blast loading can be well-predicted and multi-parameter analysis can be performed using an adaptive range of different numerical simulation methods.

CS6D-3, ID 1215 (Time: 17:00 - 17:20)
TitleExperimental study on inelastic response of bearings supporting steel roofs for cyclic loading
Author*Naoki Wada, Tetsuo Yamashita (Kogakuin University, Japan)
KeywordEarthquake damage, Roof bearing, Anchor bolts, Base mortar, Shear strength
AbstractThis paper is about the cyclic loading tests of conventional pin bearings supporting steel roofs on the concrete lower structures. Such roof bearings suffered severe damage in the Pacific coast of Tohoku Earthquake that occurred in 2011. The typical damage was crack or crush of the base mortar, and break of the anchor bolts. We conducted cyclic tests to observe the fracture behaviour and the load-bearing properties of the bearings. The strength of the bearing was lower than the yield shear strength and the maximum shear strength of the anchor bolts, which was calculated according to the AIJ recommendation. The base mortar was severely crushed before reaching the yield shear strength due to inelastic bending of the anchor bolts. So far shear force has been considered dominant in anchor bolts. But it was found that the restoring force curve could be precisely enveloped by horizontal component of the axial force.

CS6D-4, ID 1219 (Time: 17:20 - 17:40)
TitleA study of the history of the corrugated metal plate used in architecture and the prospection of this material
Author*Haining Li, Shuhei Endo (Graduate School of Engineering, Department of Architectural Engineering, Kobe University, Japan)
Keywordcorrugated metal plate, architecture, design, history, prospection
AbstractIn this study, we attempted to organize the history of the corrugated metal plate, find out the usage of it in each period since its invention, and then we summarized the historical assessment and the prospection of this material. The corrugated metal plate has been recognized generally as an exterior material which is cheap and functional. However, in this study we found out that it also has been used effectively in terms of design. Especially, After the World War II, the thickness of the plate was standardized into two series (the series 1 which is thinner, and the series 2 which is thicker). Cases using the thicker type for the structure also appeared after the war, including the Kenji Kawai House. In this paper, we collected typical cases in each period, and described the style and the usage of the corrugated metal plate in design.

CS6D-5, ID 1232 (Time: 17:40 - 18:00)
TitleEffect of joints eccentricity of web members on load-carrying capacity for parallel chord truss beams
Author*Ryosuke Takaoka, Yoshiya Taniguchi, Susumu Yoshinaka (Osaka City University, Japan)
Keywordrigid-jointed truss, joints eccentricity, shear failure
AbstractIt is well known that, to prevent flexural moments in truss members, they should be connected without joint eccentricity. Joints should be strong enough to transmit axial forces. Various industrialized joints have been developed for use in steel structures. We have studied a new jointing system for timber lattice structures. In designing timber structures, most designers wish to conceal steel jointing systems. Simpler jointing systems could be devised if some joint eccentricity were allowable. This study considers the effect of joint eccentricity on the load bearing capacity of parallel chord truss beams. A numerical study was carried out with the parameter of web member eccentricity to demonstrate the lowering of buckling loads and peak loads.

CS6D-6, ID 1076 (Time: 18:00 - 18:20)
TitleRefined Finite Element Analysis on the Static Performance of Tubular Truss
Author*Lei Gu (China Construction Steel Structure Corp. Ltd., China), Jin Hui (Shenzhen Graduate School, Harbin Institute of Technology, China), Jinghui Liang (Bureau of Public Works of Shenzhen Municipality, China), Fang Wu (Shenzhen Eastern Development(Group) Co., Ltd., China)
Keywordtubular truss structure, tubular joint, joint stiffening, multi-scale model
AbstractIn this paper, plane tubular truss model and space tubular truss model, with tubular joint, were built using the SHELL181 element of ANSYS. The comparison between these refined finite element method and traditional analysis those used the BEAM189 element was concluded and the refined results revealed the plastic stress distribution and joint failure mode of tubular truss at the limit of damage, then the parametric analysis based on different joint stiffening methods was studied. The research indicated that using joint plate to strengthen or increasing the tube-wall thickness of main chord to 1.5-2 times, the tubular joint can be considered as rigid joint, but the defection of inner clapboard was not obvious.

Session CS5E  Membrane Structures -1
Time: 14:00 - 16:00 Thursday, September 29, 2016
Location: Room 201

CS5E-1, ID 1010 (Time: 14:00 - 14:20)
TitleTensile Membrane Structures and the Education of the Architect
Author*Mauricio Soto-Rubio (University of Calgary, Canada), Alexander Michalski (str.ucture GmbH, Germany)
KeywordTensile Membrane Structures, Cable Net Structures, Education, Lightweight Structures, Textile Architecture
AbstractThis paper reviews the methodology employed to teach the design of tensile membrane structures in architecture schools and highlights the importance of developing a deep understanding of the behavioural properties of materials as well as the technical issues related with the structural analysis, construction, and installation of tensile membrane structures. To illustrate this process, the paper showcases the tensile membrane structures seminar completed at the California College of the Arts in San Francisco, where students developed, designed, and calculated a complex membrane structure for the entrance area of the college.

CS5E-2, ID 1074 (Time: 14:20 - 14:40)
TitleDesign and damping measurement for a framework membrane structure that combines cross arches and cables
Author*Katsuhiro Ootake, Osamu Hosozawa (Taisei Corporation, Japan)
Keywordmembrane, cables, arches, damping, measurement
AbstractA framework membrane structure has been designed combining cross arches formed from steel tubes, type B membrane material, and cables, as the roof over an indoor pool. In addition in order to determine the damping properties of the type B membrane material, microtremor measurements and artificial excitation measurements were carried out on the steel structure of the cross arches on their own before and after initial tensioning the membrane. Similar results were obtained for the measurements before initial tension of the membrane and the analysis, with a primary natural frequency of about 11.05 Hz. As a result of estimating the damping factor by the RD method[6], it was estimated that the damping factor was a maximum of 1.72 %. After initial tension of the membrane, the results showed that the estimated damping factor was a maximum of 4.85 % at the frequency 12.80 Hz.

CS5E-3, ID 1086 (Time: 14:40 - 15:00)
TitleAn Experimental Study on Stress Relaxation of ETFE Film Structure by Stretch Fabrication
Author*EulSeok Jeong (Semyung University, Republic of Korea), Masaya Kawabata (Yokohama National University, Japan)
KeywordETFE film, Stretch Fabrication, Stress Relaxation, viscosity behavior
AbstractThis paper proposes the stretch fabrication of ETFE film to verify the applicability of ETFE films to tensile membrane structures. In previous work, a stretching method that is able to increase the yield strength of ETFE film to film’s plastic region during panel installation was proposed, and the effectiveness of stretch fabrication was confirmed. In this paper, to investigate the possibility of application on tensile membrane structures, a stretch fabrication test is carried out, and it is verified that it is possible to increase the yield strength of the film membrane structures. And then, post-aging tension measurement is conducted at the experimental facilities, and the visco-plastic behavior resulting from stress relaxation is investigated with respect to tensile membrane structures.

CS5E-4, ID 1106 (Time: 15:00 - 15:20)
TitleTensegric membrane structure with radiated struts
Author*Yi-Hsuan Tu, Chia-Ho Lin (National Cheng Kung University, Taiwan)
KeywordTensegrity, Membrane
AbstractThe geometrical characteristics and the mechanics of the tensegric membrane system with parallel struts are studied in this paper. It was found that the spacing between parallel struts decreases as the membrane curves from a plane to a vault. Tension occurs in the membrane when the decrease is restrained. Therefore, the pre-tension in the membrane and the force equilibrium can be derived from the final rotation angle and the incremental rotation angle with a given strut arrangement. The relationships between the pre-stress and the strut length, spacing, overlap ratio, number, and the final rotation angle were studied. It was found that the pre-stress significantly decreases as the strut number increases. In order to simplify the pre-stress application, a torus dome with radiated struts that enables a concentrated pre-stressing mechanism at the center was proposed. Non-stretch waterproof fabric was used as the membrane material, and a half-scaled model was designed and built.

CS5E-5, ID 1126 (Time: 15:20 - 15:40)
TitleBehavior of tensile membrane structure with spring-strut using ETFE film under strong winds
Author*Yugi Ohga, Akira Okada, Naoya Miyasato, Shuzo Hiroishi (Nihon University, Japan), Rina Nakagawa (Japan ERI Co., Ltd., Japan)
KeywordETFE film, Mebrane structure, Horn-shaped membrane, Strong winds, Wind tunnel test
AbstractSpring-strut type membrane structures, in which a membrane is pushed up by struts with embedded springs, maintain stress on the membrane which does not allow stress relaxation. In the case of this structure using ETFE film with low spring stiffness, it is necessary to consider the dynamic response of the film’s surface. In this paper, the authors focus on a horn-shaped membrane structure under strong winds. From wind tunnel tests, the wind pressure coefficient is provided under uniform flow and turbulence flow. In addition, static and dynamic response analyses using results obtained from wind tunnel tests are calculated.

Session CS6E  Membrane Structures -2
Time: 16:20 - 18:20 Thursday, September 29, 2016
Location: Room 201

CS6E-1, ID 1226 (Time: 16:20 - 16:50)
Title[Keynote] Development of a super-pressure balloon with a diamond-shaped net for high-altitude long-duration flights
Author*Daisuke Akita (Tokyo Institute of Technology, Japan), Yoshitaka Saito, Ken Goto (JAXA/ISAS, Japan), Kyoichi Nakashino (Tokai University, Japan), Takuma Matsuo (Meiji University, Japan), Kiyoho Matsushima, Hiroyuki Hashimoto (Fujikura Parachute Company Ltd, Japan), Shigeyuki Shimadu (Nakada Industrial Company, Japan)
KeywordHigh-altitude balloon, Super-pressure balloon, Long-duration flight
AbstractHigh-altitude balloons for scientific observations are required to fly for long-duration to obtain sufficient amount of data. The long-duration flight can be achieved with a super-pressure balloon. The super-pressure balloon increases the pressure tightness by decreasing the local curvature radius of the balloon film usually with many ropes between the poles of the balloon. However the increase in the number of the ropes also increases the fabrication cost of the balloon. Therefore, instead of the many ropes, we proposed to cover a balloon with a diamond-shaped net. The new super-pressure balloon has been developed since 2010 through ground inflation tests, numerical simulations, and flight demonstrations, gradually enlarging the size of the balloon. Our goal is to fly a payload of 900 kg to higher than 37 km altitude for several months with a 300,000 m3 balloon. In this paper, we will introduce the development of the new super-pressure balloon.

CS6E-2, ID 1223 (Time: 16:50 - 17:10)
TitleField measurement research on wind pressure characteristics and wind-induced vibration characteristics of Expo Axis cable-membrane structure
Author*Zhaoyang Li (Tongji University, China), Shaoquan Zhang (Shanghai Tonglei Civil Engineering Technology Co., Ltd, China), Bin Yang, Qilin Zhang (Tongji University, China)
Keywordfield measurement, cable-membrane structure, wind filed, wind pressure characteristics, wind-induced response
AbstractIn order to deeply investigate the wind pressure characteristics and the wind-induced vibration characteristics of cable-membrane structure, a monitoring study on the Expo Axis cable-membrane structure was carried out. The wind speed, wind pressure and wind-induced response were measured simultaneously. The wind pressure characteristics and the structure’s dynamic characteristics were analyzed based on the monitoring data. It shows that the spectra of fluctuant wind speed measured are basically in agreement with von Karman spectrum. The probability density distribution of wind pressure has some non-Gauss property. With the change of wind direction wind pressure coefficient by field measurement and wind tunnel test has the same trend. The acceleration RMS and power spectral density vary with the wind direction. The acceleration RMS increases with the increase of mean wind speed. Added mass and structure mass ratio varies in 0~8 and regular changes with wind direction.

CS6E-3, ID 1261 (Time: 17:10 - 17:30)
TitleAdded mass estimation of curved membranes vibrating in still air
Author*Yuan-Qi Li (Department of Strucutral Engineering, Tongji University/State Key Laboratory of Disaster Reduction in Civil Engineering, Tongji University, China), Yi Zhou (School of Civil Engineering, Southwest Jiaotong University, China), Zong-Ya Xu (Department of Strucutral Engineering, Tongji University, China)
Keywordmembrane structure, added mass, curved membrane
AbstractAdded mass has significant effect on wind-induced vibration of membrane structures. At present, research on the added mass of membrane structures is still limited. Li, et al [1] tested the vibration of circular flat membrane in still air with varying air pressures, and a simplified added mass model based on the vibration mode shapes of flat membranes was proposed. However, the research work just focused mainly on flat membrane structures. The purpose of this paper was to investigate the added mass of curved membranes in still air and verify the suitability of the proposed simplified added-mass model for curved membranes.

CS6E-4, ID 1267 (Time: 17:30 - 17:50)
TitleDeflation behavior of an air-supported membrane structure with a dome shape under vertical loading
AuthorQiang Qing, Xiao Guo, Qingsong Li, *Jinghai Gong (Department of Civil Engineering, Shanghai Jiao Tong University, China), Zhongli Li (Beijing Z&T Fabric Architecture Technology Co.,Ltd, China)
KeywordAir-supported structure, Loading deflation, Residual pressure, Membrane wrinkling, experiment
AbstractThis paper presents experimental investigation and numerical simulation of the deflation behavior of an air-supported structure of dome shape under vertical loading. There loading cases, including 0kN, 160kg, and 320kg of sandbags, were applied on the hemispherical area respectively. From tests, the structure needed larger residual pressures during deflation tests to balance with larger external load, which were around 32Pa, 68Pa, and 120Pa respectively. In addition, in tests, it was observed that the wrinkles would occur and develop in forms of horizontal wrinkles and local wrinkles resulted by sandbag loading. A model based on the vector form intrinsic finite element (VFIFE) method has been developed for corresponding loading deflation simulations. Simulated results agree with experimental tests with minor differences in predicting residual pressure. As a result of research, general guidelines are proposed in improving anti-deflation performance in engineering applications.

CS6E-5, ID 1298 (Time: 17:50 - 18:10)
TitleTARSO: A Design Framework for the Tensile Membrane Corner Condition
Author*Simon K. Chiu, Eve S. Lin (Tensile Evolution North America, Inc., U.S.A.)
KeywordTarso, corner detail, design framework, design guideline
AbstractThis paper proposes a conceptual tarso design framework based on the synthesized results from these interviews and case studies. The framework is built on rules and steps paired with recommended media for delivery all while considering functionality, constructability, and aesthetics. A pedagogical curriculum example is utilized to demonstrate the application of the framework with the focus on a mast top tarso design. This paper concludes with observed current challenges and plans for the framework’s validation while serving as the foundation for further developing tarso guidelines and computer-aided tools.

Session CS5F  Computational Methods-1
Time: 14:00 - 16:00 Thursday, September 29, 2016
Location: Room 202

CS5F-1, ID 1013 (Time: 14:00 - 14:20)
TitleFatigue Damage Analysis of Semi-submersible Platform under Combined Wind &Wave Loads
AuthorJin Ma, *Dai Zhou, Xifeng Pan, Hongbo Zhu (Shanghai Jiao Tong University, China)
Keywordsemi-submersible platform, the improved mixture simulation method, fatigue damage, formex algebra
AbstractSemi-submersible platforms operate under the combined actions of wind and wave loads with complex and changeable characteristics. This work is addressed to analyze fatigue damage of an integrated structure model, in which several methods are developed. An mixture simulation as well as a wind and wave coupling model are constructed to simulate combined wind and wave field accurately and efficiently. Formex algebra and the automatic replication technique are used to establish the parametric integrated model. The relationship between wind/wave and fatigue stress is presented to obtain the time histories of the hotspots’ stresses. The fatigue damage of the hotspot is determined in different incident angles using the rain flow counting method and Miner criterion. Some simulation results are expected to provide important reference for the wind and wave resistant designs for offshore platform design.

CS5F-2, ID 1029 (Time: 14:20 - 14:40)
TitleFree vibration analysis of a circular cylindrical shell comprised of axially functionally graded material
Author*Hiroshi Sakurai (National Institute of Technology, Sendai College, Japan)
KeywordFunctionally graded materials, Circular cylindrical shell, Free vibration, Differential quadrature method
AbstractFunctionally graded materials (FGMs) were initially developed as highly heat resistant materials and are suitable for various applications, including aerospace, biomaterials, and many others. The objective of this paper is to study free vibrations of an FGM circular cylindrical shell that has Young’s modulus and mass density varying in the axial direction by the differential quadrature method. Love’s thin shell theory is employed. The material properties are graded in the axial direction according to a volume fraction power-law distribution. First, analysis of isotropic cylindrical shell are carried out and the validity of the present method is shown. Next, an FGM shell having constituent materials of alumina and steel is studied. Comparing the behaviours of the free vibration of the isotropic shell and the FGM shell, it was found that gradient of the material properties affects the natural frequencies. However, remarkable differences in the mode shapes are not observed.

CS5F-3, ID 1149 (Time: 14:40 - 15:00)
TitleIntegrating User-Defined Elements for Topologically Interlocking Joinery and Application in Large Scale Structural Analysis
Author*Amir Hosein Sakhaei, Sawako Kaijima, Zack Xuereb Conti, Martin L Dunn (Singapore University of Technology and Design, Singapore)
KeywordTopological Interlocking Joinery, User-defined Element, Finite Element Analysis, Reduce order modelling
AbstractTopologically interlocking joineries (TIJs) are structures that connect different parts by using only the geometry and topology of the contact area. Owing to new manufacturing facilities such as 3D printers, new attention toward TIJs increased in recent years. However, there is a lack of structural analysis and application of joints in large-scale structures for current designs. In this study, to reduce the complexity of three-dimensional analysis of large-scale structural simulations, TIJs are replaced with proposed new user-defined elements developed and implemented to be used with finite element software, ABAQUS. Furthermore, the accuracy of this method is discussed by comparing the results of the proposed model and full-solid elements model. Finally, case studies are presented to illustrate the application of this method in the large-scale structural analysis.

CS5F-4, ID 1156 (Time: 15:00 - 15:20)
TitleData management and modelling of complex interfaces in imperfect discrete-element assemblies
AuthorUrsula Frick, *Tom Van Mele, Philippe Block (Block Research Group, Institute of Technology in Architecture, ETH Zurich, Switzerland)
KeywordDiscrete-element modelling, Data management, Compound blocks, Non-planar interfaces, Computational limit equilibrium analysis
AbstractRecent advances in digital fabrication and on-site construction have created new possibilities for the (pre-) fabrication of highly customised building components and the realisation of complex, assembled architectural geometries. However, currently there are no structural design methods or tools available that address the specific challenges related to the design and analysis of discrete assemblies. This paper describes an approach for the identification of contact interfaces between the elements of discrete assemblies and presents a data structure for these interactions. Furthermore, the paper presents a method for handling misaligned (e.g. intersecting), and non-coplanar interfaces. The proposed approaches are suitable as computational back-end for equilibrium analysis of discrete-element assemblies, such as the Rigid Block Limit Equilibrium method.

CS5F-5, ID 1224 (Time: 15:20 - 15:40)
TitleCloud Based Design Option Control Systems a Discussion and Implementation
Author*Sam Joyce, Andre Chaszar, Nazim Ibrahim, Verina Cristie (Singapore University of Technology and Design, Singapore)
Keywordconceptual design, version control, exploration, design exploration, dashboard
AbstractThe paper describes a cloud based design-model version control system for supporting manual and semi-automated generative design via a web-based platform which enables exploration and retrieval of designs and also the solicitation of users’ evaluations of them to enable interactive genetic algorithms to produce preference optimised design options.The current commercial building design context and supporting CAD software state-of-the-art is considered, the review also covers software development based version control systems, identifying unmet needs in the former which could be solved by the latter which is the motivation for this work. An example structural frame design problem is explored, discussing how the system functions to support performance based creative design via exploration, including visualisation and data dashboard of a design session. We conclude that such systems addresses pressing software infrastructure requirements for the AEC industry especially for expanding the range of design options managed particularly for early-stage design activities.

CS5F-6, ID 1252 (Time: 15:40 - 16:00)
TitleA Design Oriented Workflow to Prototype Functionally Graded Designs based on Solid Finite Element Analysis
Author*Sawako Kaijima, Zack Conti, Martin L. Dunn (Singapore University of Technology and Design, Singapore)
KeywordMulti-material 3D printing, Functionally Graded Design, volumetric data
AbstractMulti-material additive manufacturing processes enable the fabrication of 3D objects composed of varying material properties at microscopic scale (Doubrovski et al. [7]). Selective material deposition offers opportunities to design and fabricate objects with heterogonous properties potentially exhibiting superior functional performance characteristics compared to objects comprised of homogenous material distributions (Wu, et al. [23]). Despite the availability of 3D printing hardware capable of producing such objects, access to this new technology is encumbered by the way in which the current modelling and simulation tools represent, exchange, and process information required for multi-material additive manufacturing. We present a computation-based approach for fabricating Functionally Graded Designs (FGD) based on solid Finite Element (FE) analysis results using Multi-Material Voxel Printing technology.

Session CS6F  Computational Methods -2
Time: 16:20 - 18:20 Thursday, September 29, 2016
Location: Room 202

CS6F-1, ID 1280 (Time: 16:20 - 16:40)
TitleFinite particle method - a new approach to refined analysis of structures
Author*Yanfeng Zheng, Chao Yang, Pengfei Zhang, Yaozhi Luo (Space Structure Research Center of Zhejiang University, China)
Keywordfinite particle method, refined analysis, consistent element coupling, parallel acceleration, software design
AbstractFinite particle method (FPM) is introduced as a new approach to refined analysis of structures. Some efforts have been taken to extend the ability of FPM in refined analysis. The primary concepts and basic principles of FPM are briefly introduced. In spatial domain, consistent element coupling is implemented in FPM to balance the efficiency and accuracy, and a multi-scale planar truss is analyzed to demonstrate the robustness of the algorithm. In time domain, parallel acceleration for FPM on GPU is achieved based on the independence of solution process for each particle or element. The speedup ratio can reach up to 40~50x. A computer-aided design system for refined analysis of structures (RASCAD) is developed, which integrates a pre-processor, a post-processor and a numerical analysis module.

CS6F-2, ID 1317 (Time: 16:40 - 17:00)
TitleComputational strategy for automated symmetry detection of engineering structures
Author*Yao Chen, Jian Feng (Southeast University, China)
Keywordsymmetric structure, numerical algorithm, automated recognition, group-theoretic approach, symmetry group
AbstractSymmetry of a complex structure is not obvious to human recognition. Even though someone succeeds in recognizing certain symmetry properties of the structure, these might be the partial ones, and the others will be possibly unnoticed. To overcome this difficulty and enable the integration of symmetry analysis, we propose an automated symmetry detection algorithm for 2D and 3D engineering structures. Only the nodes and the connectivity patterns of the members are needed in advance. Using group theory, we describe different symmetry groups and symmetry operations. Then, through matrix representations of symmetry operations, the equivalence of geometric configuration of a structure is evaluated. Hence, the inherent symmetry operations of the structure are identified one by one. Examples show that the proposed symmetry detection algorithm is feasible and robust. Highly symmetric structures are recognized accurately and effectively. In addition, those non-symmetric structures can be recognized in a small number of iterations.

CS6F-3, ID 1331 (Time: 17:00 - 17:20)
TitleDynamic analysis method for cable rupture in consideration of frictional sliding at cable joint
Author*Yujie Yu, Xiaoxiang Wang, Zhihua Chen (Department of Civil Engineering, Tianjin University, China)
KeywordSliding cable, explicit solving framework, cable-supported structure, gradual sliding, cable break
AbstractThe cable system in cable supported structures usually bears high tension forces that the clip joints may unable to resist joint slip when experiencing sudden cable breaks. An advanced finite element analyzing method with considering the dynamic cable sliding effect is proposed and presented. The method supposes that the structure is a system constructed by a group of mass particles that are formed by mass lumping and connected by intermediate elements. The method mainly focuses on the force equilibrium of each particle, which is especially suitable for dynamic sliding or failure problems that involves a time-varying structural stiffness matrix. By using different changing pattern of active loads, the method can be used to simulate both strong dynamic responses and gradually changing process. This advanced analyzing method is realized in MATLAB, and used to simulate the dynamic response under gradual sliding process and sudden cable break for a cable supported truss.

CS6F-4, ID 1354 (Time: 17:20 - 17:40)
TitleNumerical analytical method of progressive-collapse resistance of large-span spatial structures based on alternate path method
AuthorJiachun Cui, *Dongya An, Chengming Li, Ziran Xu (East China Architectural Design & Research Institute Co., Ltd., China)
Keywordlarge-span spatial structure, progressive collapse, alternate path method, dynamic magnification factor
AbstractIn order to get accurate analysis of progressive-collapse resistance of large-span spatial structures, calculate the value of dynamic increase factors (DIFs) when important components failures and study influence of failure positions on DIFs, based on ABAQUS/Explicit dynamic Explicit finite element analysis software and the user material subroutine, a numerical analytical method was suggested to analyze the progressive-collapse resistance of large-span spatial structures. The method was used in analysis of progressive-collapse resistance of Ningbo Lishe international airport T2 terminal, DIFs on condition of 35 different column failure positions were calculated and influence of failure positions on DIFs was studied. In conclusion, numerical analytical method of progressive-collapse resistance of large-span spatial structures based on alternate path method and DIF value suggested in this paper could provide reference for similar projects.

CS6F-5, ID 1484 (Time: 17:40 - 18:00)
TitleImmersive Interfacing in Large-Scale Design
Author*Robert Patz, Jörg Brinkmann, Saqib Aziz, Max Marschall, Christoph Gengnagel (Berlin University of the Arts, Germany)
KeywordVirtual Reality, Virtual Reality Aided Architectural Design, Immersive Virtual Environments, Generative Design, morphology
AbstractVirtual Reality (VR) could potentially revolutionize the representation of digital design models. Immersive VR exploration is a powerful tool to facilitate decision-making, especially when architecture deviates from typical forms. This is the case in stadium design, where complex geometric interdependencies complicate the grasp of design parameters. The use of parametrically scripted models enables fast explorative investigations of multiple design variations. However, only few variations out of a digital model’s vast parameter space can be represented by common visualization tools. Since this presents a current bottleneck, we developed an algorithmic stadium design tool and combined it with an immersive spatial evaluation method through VR. This "Immersed Design Solution" enabled a critical review of common stadium design guidelines and suggested that VR outperforms conventional visualization methods by providing comprehensive and continuous perceptual feedback on various critical design aspects. This proof-of-principle demonstrates the applicability of the method and identifies areas of future refinement.

CS6F-6, ID 1510 (Time: 18:00 - 18:20)
TitleAlternative means of navigating parameter spaces
Author*Max Marschall, Saqib Aziz, Christoph Gengnagel (Berlin University of the Arts, Germany)
Keywordparameter space, optimization, interactive evolutionary computation, artificial neural network, computational design modelling
AbstractGenerative design processes are characterized by modifications of a design model's parameters with the aim of improving its quality. The entirety of possible parameter combinations in a given design scenario is referred to as parameter space, in which each parameter represents a dimension. The efficacy of a design process could be measured by the quality of the final design found in the vastness of a multidimensional parameter space, as well as by the time needed to arrive at this solution. In this paper we propose a novel method aimed at increasing this efficacy. Our approach of self-organized fitness landscapes (SOFL) facilitates the convergence towards optimized design trade-offs between numeric and subjective criteria. This is achieved by visualizing subdomains of the parameter space comprehensibly, while still leaving architectural quality assessment to the designer. This paper describes our method's applicability in architecture based on a case study in stadium design.

Session CS5G  Deployable Structures-2
Time: 14:00 - 16:00 Thursday, September 29, 2016
Location: Room 203

CS5G-1, ID 1296 (Time: 14:00 - 14:20)
TitleGeneralized geometry of foldable scissor grids based on polar units
Author*Kelvin Roovers, Niels De Temmerman (Vrije Universiteit Brussel, Belgium)
Keyworddeployable scissor grid, geometric design, generalization, innovative structure, polar scissor unit
AbstractDeployable scissor structures are hinged-bar mechanisms that can rapidly transform between different configurations. The past decades many different types of scissor structures have been developed for various applications. Double curvature is often desired to obtain functional and appealing shapes with good structural performance. Consequently polar scissor units have been extensively studied for their ability to generate doubly curved scissor structures that can undergo large volume expansions. Unfortunately this double curvature could only be spherical. We propose a generalization of the polar unit that can be used to translate the existing spherical scissor grids into non-spherical ones while maintaining their kinematic behaviour. Therefore it uncovers a large unexplored potential and broadens the applicability of this scissor grid type. This paper presents this innovative method together with a new joint model that preserves the geometric compatibility. Scale models are used to verify and illustrate the concepts presented in this paper.

CS5G-2, ID 1305 (Time: 14:20 - 14:40)
TitleModel analysis and test for deployable platform of microsatellite
AuthorHe Huang, *Fuling Guan (Zhejiang University, China), Shuhua Zhu (East China Architectural Design & Research Institute Co., Ltd. Anhui Branch, China)
Keyworddeployable platform, dynamic analysis and test, Microsatellites
AbstractIn recent decades, the deployable platform structure for more payloads is usable and attracts the view of researchers and engineers to improve and expand the functions of microsatellites. Generally, torsion springs on hinges are the common driving style on the deployable structure since there is little power supplied on the microsatellite and self-unfolded spring potential energy can be the feasible way. It is uneasy to accurately make the dynamic simulation due to these hinges on the deployed platform structure. In this paper, a kind of triangle-grid deployable platform structure was designed and fabricated. An assumption was made to simplify the nonlinear of the contact elements and gaps on the hinges. A kind of tension rope equivalent was employed to simulate the contact between the end of the bar and the pack plate of the node. The relative dynamic tests were processed and analyzed with the numerical results. In the conclusions, it was verified that this method was practicable and convenient.

CS5G-3, ID 1330 (Time: 14:40 - 15:00)
TitleSeries expansion method for determination of order of mechanism with partially rigid joints
Author*Ryo Watada (Takenaka Corporation, Japan), Makoto Ohsaki (Kyoto University, Japan)
Keywordmechanism, partially rigid joints, singular value decomposition, series expansion
AbstractA method for evaluating the order of mechanisms of partially rigid frames is presented. The frames are defined as assemblies of rigid beams and springs at their ends. Nonlinear compatibility conditions of translations and rotations are derived at member ends with respect to the nodal displacements and generalized strains representing rotations around arbitrarily inclined directions. The degree of kinematic indeterminacy is computed using singular value decomposition of the linear compatibility matrix. The order of mechanism is determined by the existence condition of higher-order coefficients of nodal displacements and generalized coordinates. The detailed procedure of the analysis is shown through the numerical examples of a two-bar and a four-bar linkages.

CS5G-4, ID 1384 (Time: 15:00 - 15:20)
TitleTwo Novel Geometrical Solutions to Fold the Continuous Textile Membrane to the Outer Perimeter of a Spoked-wheel Roof
Author*Motoi Masubuchi (freelance, Germany)
Keywordmembrane structures, retractable roof, spoked-wheel structure, adaptive structure, web-database
AbstractMost of the membrane retractable roofs with spoked-wheel structure store the folded membrane in the center, when the roof is open. A bundle of folded membrane remains in the center of the roof, which is not favorable, for instance, for broadcasting; the bundle casts a shadow in the playing field. However, if the textile membrane can be folded to the perimeter of the roof, the problem would be solved. There will be no shadows on the field. Moreover, this creates a free opening. Any proposed solution has to deal with a geometrical issue, as well as, a structural question concerning prestressing of the membrane. Amongst several approaches to overcome these problems, two novel practical geometrical solutions will be introduced. Furthermore, the possibility of non-circular form in plan, which is demanded in real projects such as a football stadium, will be discussed. Finally one design proposal will be presented.

CS5G-5, ID 1479 (Time: 15:20 - 15:40)
TitleFreeform developable spatial structures
AuthorDavid Reeves, Vishu Bhooshan, *Shajay Bhooshan (Zaha Hadid Architects, U.K.)
Keywordfabrication, developable, reciprocal, graphic statics, Varignon
AbstractMany of the challenges faced in the design and production of spatial structures arise from geometric complexities at structural nodes. These components are often time consuming to resolve and expensive to fabricate (Pottmann et. al [1]), motivating the need for repetition which significantly limits design freedom. We present a method for modelling a class of freeform spatial structures whose inherent geometric properties allow for fabrication via relatively inexpensive 2-axis CNC cutting technology. Building upon principles of graphic statics (Rankine [2]) the method represents a structural network via its dual - a volumetric mesh composed of polyhedra with shared faces. While the structural significance of such an approach has already been detailed in (Akbarzadeh et.al [3]), we demonstrate its advantages as they relate to fabrication through the design and construction of a full-scale prototype - a self-supporting structural network with high nodal variance composed of modest sheet materials.

Session CS6G  Deployable Structures -3
Time: 16:20 - 18:20 Thursday, September 29, 2016
Location: Room 203

CS6G-1, ID 1265 (Time: 16:20 - 16:50)
Title[Keynote] Structural design of balloon-borne VLBI reflector considering sub-reflector adjustment mechanism failure using multiobjective optimization
Author*Nozomu Kogiso, Ryo Kodama, Kimihiro Kimura (Osaka Prefecture University, Japan), Yasutaka Satou, Akihiro Doi (Japan Aerospace Exploration Agency, Japan), Hiroaki Tanaka (National Defense Academy of Japan, Japan)
Keywordmultiobjective optimization, trade-off analysis, reflector, isogrid structure, Balloon-borne VLBI
AbstractThis study evaluates the optimum configurations of the primary reflector of 3 m aperture for the balloon-borne VLBI (very long baseline Interferometry) that is a radio telescope for space observation from the stratosphere in the submillimeter wave band. The reflector composed of an iso-grid structure is required high aperture efficiency under the deformation due to variations of elevation angle and temperature during observation. In order to alleviate the deterioration of the aperture efficiency, the sub-reflector is equipped with a focal position adjustment mechanism. However, the adjustment mechanism may fail during observation. The effect of the adjustment mechanism failure on the aperture efficiency is investigated through multiobjective optimization approach. The design problem is solved using the STOM (satisficing trade-off method). As STOM can obtain the single Pareto solution corresponding to the user's preference for each objective function by introducing an aspiration level, the trade-off analysis is easily performed.

CS6G-2, ID 1418 (Time: 16:50 - 17:10)
TitleThe Bio-Inspired Node for Variable Stable and Kinetic Structures
Author*Melodi Simay Acar (Harekethane, Turkey)
Keywordbio-inspired design, kinetic node, Flower of Life, optimization, transformation
AbstractStructure is the way of arranging the parts or forming a whole in a particular way by putting the parts together by a specific order. The structural orders in natural structures dynamically change and gain stability in respect of the function for the whole system to obtain maximum efficiency with minimum material usage. Therefore, unfolding of space, minimum energy shapes - Platonic Solids, systematics in the components of cell are examined for analyzing structural efficiency in nature since the understanding of biological models can lead to more ecologic and new efficient adaptable structural systems. An adaptable structure or its component, which has capabilities of portability, reusability, easy to construct, minimizing the cost and material usage and reducing application time is crucial for the life-cycle of the built environment. The novel bio-inspired kinetic node provides capability to transform two-dimensional structural order into three-dimensional adaptable structures as static and dynamic by optimization.

CS6G-3, ID 1450 (Time: 17:10 - 17:30)
TitleFlexible polyhedra with two degrees of freedom
Author*Iila Lijingjiao (University of Cambridge, U.K.), Tomohiro Tachi (Tokyo University, Japan), Simon D. Guest (University of Cambridge, U.K.)
Keywordflexible, polyhedron, rigidity, finite mechanism, flexibility
AbstractPolyhedra were long considered rigid, but following Connelly, flexible examples with one degree-of-freedom have been known. Here we show a flexible polyhedron with two degrees-of-freedom, generated using a scheme that could be extended to multiple degrees-of-freedom. A polyhedron that has two degrees of freedom is generated based on a set of three tetrahedral joined along edges. Crinkles are added to turn this underlying object into a polyhedron without removing the flexibility. The parameters defining the polyhedron are adjusted to remove clashes and extend the range of motion. We examine whether the two degrees-of-freedom are linked, to determine whether the range of motion of one hinge limits the range of motion of the other, but for a particular example we find that this is not the case.

CS6G-4, ID 1490 (Time: 17:30 - 17:50)
TitleMiura-ori based folding cell structure
Author*Anastasia Ioannidi, Katherine Liapi (Department of Architecture, University of Patras, Greece)
Keywordcell structure, Miura pattern, folding, flexural-hinge joint, material thickness accomodation
AbstractThis paper presents a novel concept of a 3D cell structure that can be easily deployed, collapsed and transported, and can be utilized for habitation and other purposes in emergency or temporary situations. In its initial stage, the structure consists of two identical parallel surfaces connected to each other with transverse linear members. Each surface is divided into slightly slanted square shaped surface elements connected to each other that fold according to the Miura crease pattern. As the structure deploys, an array of 3D cells are created between the two surfaces. The structure is a one-DOF mechanism, and it presents a compact configuration in its collapsed state. Although small scale physical and digital models have proven the validity of the concept, in the full scale application of the concept, several constrains related to the material thickness emerge. Such issues have been successfully addressed and are discussed in the paper.

CS6G-5, ID 1281 (Time: 17:50 - 18:10)
TitleFeasibility of multi-layer freeform deployable structures
Author*Mehdi Babaei (Department of Civil Engineering, Faculty of Engineering, University of Zanjan, Iran)
KeywordMulti/Single-layer, Scissor-like, Foldable/Deployable Structures, Freeform, Weight
AbstractIntroduced centuries ago, deployable/foldable structures have been more thoroughly investigated during the recent decades. One of the famous types of these structures is the scissor-link configuration, which contains duplets. Most of the studies, however, have been focused on geometric and structural design of single layer forms, formulation for configuration, nonlinear analysis and optimal form findings. From the structural and architectural points of view, however, multi-layer deployable free forms have many advantages. In this work, formulation for multi-layer forms is developed more accurately by satisfying foldability conditions. Feasibility of these types is discussed by proposing simple connections and evaluating different design parameters. Flat multi-layer forms of 6m to 15m span are designed and compared by weight and maximum deflection as objective functions, to select the optimal form. Results show that some geometric parameters have to be defined and then feasibility of the required geometry should be tested numerically.

Friday, September 30, 2016

Session CS7M  Form Finding & Optimization -3
Time: 9:00 - 11:00 Friday, September 30, 2016
Location: Ito Hall

CS7M-1, ID 1277 (Time: 9:00 - 9:30)
TitleStep-by-step stability analysis of shallow grid shells: Buckling versus snap-through
Author*Amedeo Manuello, Fabio Bazzucchi, Alberto Carpinteri (Politecnico di Torino, Italy)
Keywordform finding, grid shell, interaction, snap-through, buckling
AbstractDifferent methods, physical and mathematical, were used to find the shape minimizing the internal stresses of shallow grid shells. Because of their original organic shape, the design of grid shell structures challenges architects and structural engineers in more than one way. The form-finding generally adopted (optimization techniques, genetic algorithms etc.) leads to the definition of a particular shape in which the stresses are minimized for a certain loading configuration. In this way, the same structural scheme may be affected by instability problems, even up to the collapse. In the present paper, the grid shells, obtained by the form-finding of suspended 3D models, are analyzed according to snap-through instability and to the Eulerian buckling effect. In this way, the interaction phenomena between the two local and non local equilibrium paths of the structures are analyzed according to particular slenderness and shallowness ratios showing a snap-back instability of the grids.

CS7M-2, ID 1358 (Time: 9:30 - 9:50)
TitleTopology optimisation of a concrete floor slab guided by manufacturability constraints from a vacuumatic formwork
Author*Christopher Magan (Delft University of Technology, Netherlands), Jeroen Coenders (White Lioness technologies & Delft University of Technology, Netherlands), Frank Huijben (ABT consulting engineers, Netherlands), Rob Nijsse, Aad van der Horst (Delft University of Technology, Netherlands)
Keywordtopology optimisation, vacuumatic formwork, concrete, floor slab, manufacturability
AbstractThis paper presents a design for a topology-optimised concrete floor slab, of which the structural optimisation process is guided by manufacturability constraints from a vacuumatic formwork. The design has been obtained using an open-source, three-dimensional topology optimisation algorithm. Traditional floor systems are cost-optimised but can have the disadvantage of being structurally inefficient. Topology optimisation allows for efficient material distribution, and thus a reduction in weight. Topology-optimised floors are typically regarded as being difficult to produce, however, and cost too much to be considered in building designs. In order to reach a compromise between a low self-weight and low production costs, two features are included in the optimisation process. First, manufacturability is directly incorporated in the optimisation, rather than afterwards. Secondly, the highly malleable vacuumatic formwork system by Huijben has been used as a premise. Its advantages may cause the formwork costs to be reduced considerably when producing floor slabs.

CS7M-3, ID 1382 (Time: 9:50 - 10:10)
TitleDiscrete Optimum Structural Design of Sinusoidal Corrugated Web Beam using DE
Author*Donwoo Lee, Sudeok Shon, Seungjae Lee (Korea University of Technology and Education, Republic of Korea)
KeywordCorrugated plate, Optimization, Differential evolution, Discrete variable
AbstractThis present paper studied the weight optimum design processor for sinusoidal corrugated web beam using the differential evolution algorithm and investigated the effects of parameters. Global search algorithm and discrete variables are used to developed program and the convergence of the result was compared with the optimal solution convergence of the weight optimum design. The shape parameters for the design of sinusoidal corrugated web can be defined by the depth of corrugation wave, weigh length and web thickness. The corrugation function of sinusoidal shape, half-wave length and inertia moment of corrugated web can be defined, respectively. We consider objective function as minimum weight of the girder, and use slenderness ratio, stress of flanges and corrugated web, and the girder deflection as the constraint functions. And also the DE (Differential Evolution) algorithm is adopted to search the global minimum point by using the production list as a discrete design variable.

CS7M-4, ID 1457 (Time: 10:10 - 10:30)
TitleApplication of the Load Path Network Method in the design of prestressed shell structures
Author*Lluis Enrique, Joseph Schwartz (Swiss Federal Institute of Technology of Zürich, Switzerland)
KeywordShell structures, Prestressing, Equilibrium, Strut-and-Tie, Graph theory
AbstractLoad Path Network Method (LPNM) [1] is an equilibrium-based method for the design of three-dimensional structures based on the lower bound theorem of the theory of plasticity. The goal of this method is to stimulate the exploration of possible three-dimensional flows of internal forces in equilibrium in a structure in order to help the integration of structural concerns in the design process of a building project. This paper shows the application of LPNM for the design of prestressed shell structures. The goal of this application is to allow the designer to find the right layout of prestressing cables and the necessary amount of prestressing force in such cables in order to keep the mass of concrete of a given shell structure only or mainly under compressive forces.

Session CS8M  Form Finding & Optimization -4
Time: 11:20 - 13:20 Friday, September 30, 2016
Location: Ito Hall

CS8M-1, ID 1461 (Time: 11:20 - 11:40)
TitleGeodesic Search on Triangle Mesh for Frame Structures
Author*Yohei Yokosuka, Toshio Honma (Kagoshima University, Japan)
KeywordGeodesic Search, Triangle Mesh, Halfedge data structure, geodesic frame structures
AbstractFinding lines of minimal length between arbitrary two points on a three dimensional surface is an important problem in various fields. The geodesic search has been developed as procedures to search on the discretized surface because it should be available to execute on the arbitrary curved surface. Conventionally, discretized surfaces are interpolated by using higher-order functions to solve the geodesic equation. However, the planer unfolding of a curved surface cannot be uniquely determined. In this paper, we present the procedure of a search for the geodesic line on a triangle mesh. This procedure is useful to apply searching geodesic line for an arbitrary surface, and the surface can be uniquely unfolded in a plane. To execute numerical computation, we use the finite element technique as interpolation of coordinate values, and the Halfedge data structure. We indicate numerical results and validate that our approach is useful for the geodesic search.

CS8M-2, ID 1471 (Time: 11:40 - 12:00)
TitleAn Application to Generate Frame Structure Based on Plane Tessellations and Irregularities
Author*Toshifumi Mae (National Institute of Technology, Oita College, Japan)
Keywordhoneycomb, nodal displacement, irregularity, complexity, conceptual design
AbstractThis paper describes generation of a spatial frame structure from 2dimensional frame that is spread by irregular hexagons. The method to generate the frame structure is shown by operation of nodal point in the frame. First, when vertical load is imposed to the frame in plane, displacements occur in every nodal point. The node where max displacement occurred is raised in the upward direction by a unit length. Thereby the shape will have a convex out of the plane, and displacement will be reduced. Repeatedly, the shape will have an irregularity and complexity, and will be deformed hardly gradually. Finally, although the volume of members increased, the displacement of nodal point is reduced very much. It seems a new structure that has an irregularity and complexity that can be seen in nature.

CS8M-3, ID 1493 (Time: 12:00 - 12:20)
TitleOptymization of surface dividing using energetic potential method
Author*Kajetan Sadowski (Faculty of Architecture Wroclaw University of Technology, Poland)
Keywordconceptual design, morphology, form finding, optimization
AbstractSpatial structures are one of the most popular structural systems used to cover large spaces. Arrangement of the bars and nodes has a big influence on the distribution of forces inside the structure. Author was developing the method of dividing a surface which was called the energetic potential method. It is based on a natural process we know as the Coulomb Law. Using it we can create a self-optimizing structure where all of its nodes, mutually repulsing, are finally located in a similar distance to one another. Thanks to special computer program written by Author it was possible to generate a lot of structures with unique topology and after that could do a static analysis of them. After those it was found that some structures have a better ratio than popular structures so Author suppose that the method can have practical application in future.

CS8M-4, ID 1497 (Time: 12:20 - 12:40)
TitleForm finding and structural analysis of a freeform stone vault
Author*Tom Van Mele (ETH Zurich, Switzerland), Anjali Mehrorta (University of Cambridge, U.K.), Tomás Mendez Echenagucia, Ursula Frick (ETH Zurich, Switzerland), John Ochsendorf (Massachusetts Institute of Technology, U.S.A.), Matthew DeJong (University of Cambridge, U.K.), Philippe Block (ETH Zurich, Switzerland)
Keywordfunicular, freeform, masonry vault, thrust network analysis, discrete element modeling
AbstractThis paper provides an overview of the form finding and analysis of a freeform, unreinforced, cut-stone, dry-set vault with 399 voussoirs. The vault covers an area of 75 m2 and spans more than 15 m in multiple directions. The thickness of the discrete, stone shell varies from 12 cm at the supports to 5 cm at the highest points. The paper describes the TNA-based funicular form-finding process starting from a geometrically defined target surface and a layout of the horizontal thrust in the system, and resulting in a three-dimensional network of forces in compression for the given loading and boundary conditions. Furthermore, the paper discusses the discretisation of the funicular geometry into voussoirs, and describes the conversion of the complex voussoir geometry into tetrahedralised compound blocks for analysis in 3DEC. Finally, the results of the structural analysis addressing both static and dynamic loading conditions are discussed.

CS8M-5, ID 1512 (Time: 12:40 - 13:00)
TitleIsogeometric Eigenshells: shape and topology finding design approach
Author*Jelena Milošević (Faculty of Architecture, University of Belgrade, Serbia), Saša Kovačević (School of Mechanical and Materials Engineering, Washington State University, U.S.A.), Miodrag Nestorović (Faculty of Architecture, University of Belgrade, Serbia)
Keywordform finding, topology finding, shell structures, eigenshells, isogeometric analysis
AbstractThis paper describes an approach that addresses shape finding and pattern generation in design of shell structures. Eigenshells represent structures which have modal form tessellated by structural pattern. The subject design approach is based on the deformation modeling and isogeometric concept, and realized through two sequence processes. In the first sequence shape optimization is conducted by application of standard optimization algorithm. Starting from the defined search space, optimal shape - modal form, is emerge in the process of deformation of the initial NURBS geometry. In the second sequence obtained shape is tessellated in the network which geometry represents principal stress directions. Different from proposed similar methods, in this approach NURBS based Isogeometric analysis is used for description of structural behavior. Isogeometric concept facilitates conservation of the geometric representation, enabling integration of design and analysis. Effectiveness and creative potentials of this approach were confirmed by the example.

CS8M-6, ID 1547 (Time: 13:00 - 13:20)
TitleStructural optimization of a shell bridge built with the Pneumatic Forming of Hardened Concrete construction method
Author*Thomas Pachner (Waagner Biro Stahlbau AG, Austria), Benjamin Kromoser, Johann Kollegger (TU Vienna, Austria)
Keywordstructural optimization, concrete shell, pneumatic formwork, flexible formwork, membrane
AbstractConcrete shells designed according to the flow of forces are very efficient structures. The basic problem is that the costs for formwork and falsework have made these fascinating structures less and less economical to build. A new construction technology called Pneumatic Forming of Hardened Concrete (PFHC) was invented at the TU Vienna managing the construction process completely without formwork and falsework. A pneumatic formwork lifts a flat hardened concrete plate and at the same time additional post-tensioning cables are tightened to support the bending process of the flat plate into a semi-discrete surface resembling a double curved shell. A very challenging task is to design a concrete shell according to the impacting forces and to the boundary conditions needed for PFHC. In the present paper the geometry optimization for the construction of a deer pass over a two-track rail will be explained.

CS8M-7, ID 1356 (Time: 13:20 - 13:40)
TitleShape Optimization by Presence of Antiplane Shear Deformation in Free-Form Shell Structure
Author*Tetsuro Nishida (Graduate Student, Graduate School of Science and Engineering, Kagoshima University, Japan), Toshio Honma (School of Science and Engineering, Kagoshima University, Japan), Yohei Yokosuka (Graduate School of Science and Engineering, Kagoshima University, Japan)
KeywordShape Optimization, Antiplane Shear Deformation, Free-Form Shell Structure, Shell Element
AbstractFree-form shell structures that can be constructed with long span are designed in a lot of projects recently. These structural systems need to satisfy both designability and mechanical rationality. However, it is difficult to decide a curved shape by designer’s experience and intuition. In this study, shape optimization for free-form shell structures using Bézier curved surface is described. Moreover, the curved surface coordinates and the shell thickness are adopted by implementing the parametric surface as design variables. In shape optimization, the shell thickness around the support tends to become thick by stress concentration occurring. Therefore, the antiplane shear deformation cannot be ignored in thick shell element. In this paper, we investigate the difference of the form obtained by the shape optimization by using shell element with/without the effect of the antiplane shear deformation for free-form shell structures and indicate the knowledge of the shell element with the antiplane shear deformation.

Session CS7Y  WG17: Historical Structures
Time: 9:00 - 11:00 Friday, September 30, 2016
Location: Gallery-1

CS7Y-1, ID 1433 (Time: 9:00 - 9:20)
TitleSeismic Behavior of Historical Domes
Author*Satwant Rihal, John Edmisten (Cal Poly State University, San Luis Obispo, California, U.S.A.), Sinhui Chang (Nabbih Youssef Associates, Los Angeles, California, U.S.A.)
KeywordDomes, Unreinforced Masonry Thin Shells, Historical Structures, Seismic Behavior, Finite Element Analysis
AbstractThis paper presents the results of a study to investigate the behavior of thin masonry domes under the action of gravity and lateral seismic loads. The finite element method of analysis is used to determine the reaction components for the support conditions specified, amd maximum stresses and deformations are presented. An analogous hemispherical concrete dome was selected for this initial study because its stress conditions were known for gravity loads. This was necessary for the development of a finite element model for use in a dome analysis. For our study, we chose the hemispherical dome and the shallow dome for comparison. Both domes have a span radius of 11.43 meters and a thickness of 127 millimeters. This compares with the classification of the masonry domes. It is the authors’ hope that this study will help enhance the understanding of seismic behavior and the conservation of historical thin masonry domes.

CS7Y-2, ID 1077 (Time: 9:20 - 9:40)
Title“The Key to the Problem is the Section:” Pier Luigi Nervi’s Proposed Copertura for Reynolds Aluminum
Author*Thomas Leslie, Benjamin Kruse, Kyle Vansice (Iowa State University, U.S.A.)
KeywordAluminum, Nervi, Fabrication, Construction
AbstractIn 1960, Pier Luigi Nervi was approached by the Reynolds Aluminium Company to re-imagine a defunct project for an indoor stadium in New York City. Reynolds had been interested in the publicity from the original project, and they sought Nervi’s help in re-designing it as a demonstration project. Reynolds’ engineers met with Nervi to develop a scheme for 100,000 spectators that, had it been built, would have been the largest aluminium structure ever. Its 1200 foot span would have been the largest indoor space in the world. Nervi re-imagined the processes his firm had used to build other large span roofs in his trademark ferrocemento. But with aluminium Nervi faced new problems of deflection, creep, and connectivity. Using digital reconstructions this paper examines whether the Reynolds project could have been built, and how it would have performed structurally, using unpublished drawings and correspondence in the Nervi archives.

CS7Y-3, ID 1314 (Time: 9:40 - 10:00)
TitleSeismic behaviour of modern heritage spatial structures: the Hall B of Turin Exhibition Centre by Pier Luigi Nervi
Author*Erica Lenticchia, Rosario Ceravolo (Politecnico di Torino, Italy), Cristiana Chiorino (Pier Luigi Nervi Project Association, Italy)
Keywordmodern architectural heritage, seismic assessment, Pier Luigi Nervi, historical spatial structures.
AbstractTurin Exhibition Centre consists of the main Hall B and the smaller adjacent Hall C, both designed and constructed by Pier Luigi Nervi (1947-1948, and 1950). In this work, Nervi combined for the first time his personal technique of ferrocement in a large-scale project with an extensive use of prefabrication. This paper, in particular, reports on the on the seismic behaviour of the Hall B. In fact, both halls were realized without accounting for seismic actions, but only for static configurations, in accordance with the technical standards of the time. To this aim, several Finite Element analyses of Hall B were performed in order: i) to assess the vulnerability of historical spatial structures to seismic actions, with special attention to Nervi’s structures; ii) to investigate the possible influence of non structural elements on the global dynamic response; iii) to contribute to increase existing knowledge about Nervi’s great legacy.

CS7Y-4, ID 1245 (Time: 10:00 - 10:20)
TitleForensic investigation upon the local collapse of an empire style building
AuthorAndreea-Terezia Mircea, *Cornel Muntea, Ludovic Kopenetz (Technical University of Cluj-Napoca, Romania)
Keywordhistoric building, masonry vault, collapse
AbstractIn July 2015, suddenly a part of the first floor external deck, the masonry vault and a ground floor masonry wall of an historic building collapsed. The building is situated on the southern part of Cluj medieval fortification, and at the basement of the south fronton it is still preserved an ogival vault made of medieval stones. The architecture of the building belongs to the empire style with decorations, it covers a built area of more then 2600 m2, and is developed on partial basement, ground floor and one storey. The technical inspection revealed degradation of the finishing, as well as of the bearing structure. The paper presents the progress and results of the investigation upon the local collapse, which emphasize a chain of causes in a biographical approach.

CS7Y-5, ID 1294 (Time: 10:20 - 10:40)
TitleTesting Models in selected prestressed concrete structures between 1945 and 1960
Author*Horst Peseke, Manfred Grohmann, Klaus Bollinger (B+G Ingenieure Bollinger und Grohmann, Germany)
Keywordhistory, prestressed concrete, methods

Session CS8Y  Historical Structures
Time: 11:20 - 13:20 Friday, September 30, 2016
Location: Gallery-1

CS8Y-1, ID 1327 (Time: 11:20 - 11:40)
TitleScale models for spatial structures from the 19th to the 21st century
Author*Eberhard Moeller (Karlsruhe University of Applied Sciences, Germany)
Keywordscale models, testing models, measurement models, physical models
AbstractSeveral structural designers and engineers of the 19th and 20th century like Antoni Gaudí, Pier Luigi Nervi, Eduardo Torroja, Fritz Leonhardt, Félix Candela, Frei Otto or Heinz Isler used physical models up to scale 1:1 for designing as well as for structural analyzing some of their well-known spatial structures. Physical models make structural behavior obvious and comprehensible not only for experts, whereas mathematical or numerical models often are considered to represent a black box system. One main intention of this paper is to spread but even more to collect scattered and perhaps nearly forgotten information about still existing as well as about unfortunately lost physical and measurement models for spatial structures from all over the world in order to found and fill an international database about such models. The database will be useful for organizing exhibitions or even museums about the works of civil engineering.

CS8Y-2, ID 1315 (Time: 11:40 - 12:00)
TitleParallel universe - Evolution of Hungarian shell architecture
Author*Orsolya Gaspar, Istvan Sajtos (BME- Budapest University of Technology and Economics, Hungary)
Keywordconcrete shell, historical structures, Hungarian School, structural analysis, knowledge transfer
AbstractThe present paper describes the evolution of Hungarian shell architecture in the 20th century, with special emphasis on how it has been linked to the mainstream shell architecture of the Western world. The main contribution of the ‘Hungarian School’ to the international community was a refined theoretical methodology for some unique problems of shell construction. The actual built examples, the daring structural solutions of the era have never received much publicity. During the Golden Age of reinforced concrete shells from the end of WWII to the 1970s, Hungary, then belonging to the Soviet sphere of interest, was seemingly isolated from the mainstream development of Western shell architecture. Case studies are shown revealing the possible influences an internationally well-known archetype might have had on a particular design. The case studies also highlight the Hungarian characteristics of the era’s shell building.

CS8Y-3, ID 1387 (Time: 12:00 - 12:20)
TitleRegional character in international construction: A case study for Olympic architecture and engineering
Author*Laura Alexandra Brown, Manuel Cresciani (Northumbria University, U.K.)
KeywordSummer Olympic Games, Regional Character, Globalisation, Nervi, Calatrava
AbstractAs the size and scale of the summer Olympic Games proliferated over the 20th Century, there has arisen a dilemma, in representing regionalism, nationalism and globalism in Olympic architecture. This paper examines, how regional and international characteristics of design impact upon the resultant architectural legacies of the Games, scrutinizing how the language of design is conceptualized with global or local properties; to act as an iconic monument to the event, whilst contributing to the local community and connecting with the historic evolution of the city. Whilst it seems that some of the works examined in this article, in spite of their international success, managed to keep what can be defined as a ‘Regional character’, distinctive of a particular culture in terms of architectonic language and technological resources; this quality seems to be lost in recent editions of the Games and represents one of the challenges to the next Olympic Cities.

CS8Y-4, ID 1108 (Time: 12:20 - 12:40)
TitleReconstruction of the roof structures the Krásna Hôrka castle
Author*Miloš Slivanský, Jaroslav Sandanus (Slovak University of Technology in Bratislava, Slovakia)
Keywordreconstruction, strengthening, roof structure, timber, historical
AbstractKrásna Hôrka castle was originated in the 14th century. The castle is situated in the eastern part of Slovakia, in the village Krásnohorské Podhradie. In 2012 the fire disaster totally damaged all of roof structures, including wooden ceilings. Restoration works at the castle started immediately. Most of structures was realised as a copy of the original roof structures. Later, the control static calculations of the renewed roof structures, have been executed. Obtained results have indicated that the renewed roof structures do not fulfil the requirements for the reliability according the Eurocode 5. Strengthening of the roof structures the Krásna Hôrka castle was proposed by the combination of 2 different means:- adding a steel rods to increase the horizontal stiffness of the base structure,- adding a steel plates to the specific members to strengthen the points, where the joints are constructed by the half dove-tail joint.

CS8Y-5, ID 1337 (Time: 12:40 - 13:00)
TitleThe Approach of Sergio Musmeci to Structural Folding
AuthorPierluigi D'Acunto, *Lukas Ingold (ETH Zuerich, Switzerland)
KeywordSergio Musmeci, folded plate structures, reinforced concrete, parametric design, postwar Italy
AbstractThanks to the experimental nature of his work, Sergio Musmeci (1981-1926) holds an exceptional position within the Italian School of Engineering of the postwar period. Musmeci’s peculiar view on structural design is supported by the search for new structural forms, which is initiated by his exploration on structural folding. In particular, during the 1950s, folded plates are applied by the engineer in place of the conventional beam and slab typology for the design of various roofs in reinforced concrete. In this paper, the approach of Musmeci to structural folding is discussed. The investigation is focused on the folded plate roof of Stabilimento Raffo in Pietrasanta, which is here regarded as a fundamental moment in the research of the engineer in the field of structural folding. The design method used by Musmeci for the development of the project is examined in details.

CS8Y-6, ID 1145 (Time: 13:00 - 13:20)
TitleStructural analysis and CG expression for ENGAKUJI SHARIDEN as a historic timber structure in Japan
Author*Hideyuki Takashima (Kanto Gakuin University, Japan)
Keywordanalysis, historic structure, 3D CG
AbstractBy the present author, the structural both modelling and analyses for ENGAKUJI SHARIDEN have been conducted through the fundamental case studies under FEM simulations. ENGAKUJI Temple has been built at Kamakura City nearby Yokohama in 1285. The SHARIDEN is a timber structure and has been selected as Japanese national treasure. In the present study, the further refinement for the FEM model and its validity will be discussed. Also, by utilizing AVS which is one of the powerful 3D CG modelling software, the relative precise 3D CG expression with “fly through” animation will be demonstrated.

Session CS7A  WG13: Bio-inspired Control of Structures
Time: 9:00 - 11:00 Friday, September 30, 2016
Location: Sanjo Main

CS7A-1, ID 1055 (Time: 9:00 - 9:20)
TitleStructures that learn, self-diagnose and adapt
Author*Ian Smith (EPFL, Switzerland)
Keywordactive structures, Shape control, Self-diagnosis, Learning
AbstractModern sensing, computing and control technologies are creating opportunities for innovations in structural engineering. This paper describes how bio-inspired ideas have been implemented on two adaptable structures over several years. It is shown how the following three ideas are implemented: previous control experience is reused to improve future control performance (learning); small movements are used to identify damage (self-diagnosis); and damaged structures are adapted so that their performance is improved (damage tolerance). Computing algorithms include stochastic search (sometimes called evolutionary algorithms), case-based reasoning and reinforcement learning. While the first structure has been actuated to maintain form, the second structure has been actuated to deploy, thereby demonstrating how large shape changes over several degrees of freedom can be controlled. These two structures have provided useful platforms to develop, test and evaluate solutions for adaptive structures.

CS7A-2, ID 1171 (Time: 9:20 - 9:40)
TitleDeployable tensegrity using shape memory alloy springs
Author*Xian Xu, Huiying Cai, Yaozhi Luo (Zhejiang University, China)
Keyworddeployable tensegrity, SMA springs, folded state, deployment path
AbstractTensgrity systems composed of tension elements and compression elements have potential to be used as deployable structures due to the unilateral stiffness of tension elements. In this paper, a new concept of deployable tensegrity using shape memory alloy (SMA) springs is proposed. Two different deployment schemes are considered according to the tension/slack state of tension elements during deployment. In the first scheme, tension elements are allowed to be slack, leading to quite flexible fold. The deployment path considering dynamic effect or not is analyzed via ADAMS and dynamic relaxation method respectively. In the second scheme, tension elements are required to be in tension and the deployment path is determined on the equilibrium manifold. A proof-of-concept model is manufactured to verify the feasibility of the proposed new concept of deployable tensegrities using SMA springs.

CS7A-3, ID 1322 (Time: 9:40 - 10:00)
TitleTowards biomimetic actuation for a deployable structure
Author*Ann C. Sychterz, Ian F.C. Smith (École polytechnique fédérale de Lausanne, Switzerland)
Keywordbiomimetic, deployable structures, motion tracking
AbstractDeployment along multiple degrees of freedom structure is challenging. Analogies to biological systems have potential to enhance performance. For experimental work, a tensegrity structure is employed. In previous work, the last stage of deployment of a tensegrity structure, connecting at mid-span, was enhanced using case-based reasoning. This study includes an evaluation of control commands of a near-full-scale deployable tensegrity footbridge. Bio-inspired control algorithms are found to reduce deployment time. Using a feedback-based sensitivity analysis as a means of selecting which cables to activate at what time increases the speed of deployment when compared with commands that have been determined through a simpler algorithm. Control through real-time sensitivity analyses is adaptable to other control tasks and other structural systems. This work provides an example of how biologically-inspired algorithms can improve methods of movement for complex structures.

CS7A-4, ID 1375 (Time: 10:00 - 10:20)
TitlePassive control of structures using kinematic base-isolators inspired by human spine
Author*Mohammad Reza Chenaghlou, Aydin Fathpour, Mahmood Reza Azghani (Sahand University of Technology, Iran), Yaser Shahbazi (Tabriz Islamic Art University, Iran)
Keywordkinematic base isolator, passive control, human spine
AbstractBase isolators are used as passive control devices for a structure during an earthquake. There are different types of base isolators which are used in a building. In this paper, a modified kinematic base-isolator is proposed based on human spine structure. The human spine works like a multilink inverted pendulum and uses different method to establish its equilibrium and stability. By using circumferential cables similar to ligaments and muscles and appropriate materials between two surfaces similar to intervertebral disk, it is possible to provide desired function for a base isolator. After modeling of the isolator, its behavior is derived and used for investigation of its effects on the structural behavior.

CS7A-5, ID 1499 (Time: 10:20 - 10:40)
TitleShape Control of Smart Orthotropic Cross-ply Cylindrical Membrane Shell Panel
Author*Yaser Shahbazi (Tabriz Islamic Art University, Iran), Mohammad Reza Chenaghlou (Sahand University of Technology, Iran)
KeywordSmart Structures, Membrane, Active Control
AbstractIn this paper, application of polyvinylidene fluoride (PVDF) actuator for shape control of cylindrical membrane shells is addressed. At First, the equation of motion of a smart cylindrical membrane shell panel (SCMSP) with classical simply supported boundary conditions are reviewed. The SCMSP is made of an orthotropic elastic core covered by outer PVDF layers. The polarization vector is parallel to the applied electric field intensity vector both parallel to the diagonal direction. SCMSP displacement fields are also expanded using of double Fourier series satisfying simply supported boundary conditions and the discretized systems of linear ODEs of motion are obtained using Galerkin method. The space state equation corresponding to lateral displacement and its derivation are obtained. Then, the SCMSP is excited by harmonic load and its shape is controlled using Pole-Placement approach. The results show that the proposed active control strategy can present each desired shape of SCMSP after excitation.

CS7A-6, ID 1513 (Time: 10:40 - 11:00)
TitleLinear algebra-based matrix structural analysis of two-dimensional reciprocal structures
Author*Dario Parigi (Aalborg University, Denmark)
Keywordmatrix analysis, reciprocal structures, kinetic structures
AbstractReciprocal structures are formed by mutually supported elements joined together according to the principle of reciprocity. The principle of reciprocity is based on the use of load-bearing elements which, supporting one another along their spans and never at the ends, compose a spatial configuration with no clear structural hierarchy. According to this definition, reciprocal structures cannot be modelled with the theory of pin-jointed frameworks, composed by bar elements connecting only at their ends with pin (hinge) joints. The following paper proposes a formulation for the extension of linear algebra-based matrix structural analysis to assemblies in which elements join also in intermediate points. Such a formulation in particular must include now the possibility to describe an expanded set of joints as prismatic joint, slider and half slider. The goal is the possibility to evaluate all the static and kinematic details of a more general set of assemblies, including reciprocal assemblies.

Session CS8A  WG13: Computational Methods
Time: 11:20 - 13:20 Friday, September 30, 2016
Location: Sanjo Main

CS8A-1, ID 1038 (Time: 11:20 - 11:40)
TitleAccelerated proximal gradient method for equilibrium analysis of elastoplastic spatial truss structures
Author*Yoshihiro Kanno (Tokyo Institute of Technology, Japan)
Keywordelastoplastic problem, incremental analysis, accelerated gradient scheme
AbstractThis paper presents an accelerated proximal gradient method for elastoplastic analysis of large-scale trusses. The method can be extended to cable.truss structures. When we assume small deformation of the structure and a nonnegative hardening modulus of each structural component, it is well known that the incremental problem can be recast as (convex) quadratic programming (QP). In this paper, we present an equivalent unconstrained optimization problem. Efficiency of an accelerated first-order optimization method is compared with a standard QP solver that implements an interior-point method.

CS8A-2, ID 1435 (Time: 11:40 - 12:00)
TitleForm finding of cable nets for retractable membrane roofs
Author*Hiroki Tamai (Schlaich Bergerman Partner, Germany)
Keywordform finding, cable net, openable roof, membrane folding, optimization
AbstractWhen a retractable membrane system is incorporated with a cable structure, and the cables are used as the tracks along which the membrane is pulled and folded, the form finding of the cable structure needs to satisfy not only equilibrium but also a number of geometric constraints that allow the fold of the membrane. This paper discusses a sufficient condition for the structural membrane to fold and unfold without tearing between the track cables, and demonstrates cable net form finding under this condition. The cable forces are also determined to reduce the variation of cable force while maintaining a doubly curved surface. The numeric examples, including the canceled roof design for New National Stadium Japan for Tokyo Olympic 2020, demonstrate that the equilibrium configuration of a cable net can be used to visualize the membrane’s foldability; new equilibrium structural forms with new architectural values can be generated.

CS8A-3, ID 1093 (Time: 12:00 - 12:20)
TitleShape optimization of gridshells by bending moment minimization
Author*Giovanni Della Puppa, Martin Trautz (RWTH Aachen University, Germany), Stefano Lenci (Polytechnic University of Marche, Italy)
KeywordOptimization, Form-finding, Gridshell, direct differentiation, Differential Evolution
AbstractDue to the enhanced efficiency of structures subjected to normal stresses rather than bending, the optimization of a gridshell should seek for an almost moment-free design, whereas the design variables are represented by the nodal elevations. The new approach proposed in this paper is based on a discretization of the structure with 3D Beam elements. The objective function is defined as a scalar indicator of the bending moment, which affects the entire structure. First order sensitivities are achieved by direct differentiation of the objective function with respect to nodal elevations. Both gradient-based and evolutionary algorithms are applied in order to search for an optimal design. Results are compared with benchmarks found in the references.

CS8A-4, ID 1274 (Time: 12:20 - 12:40)
TitleMinimization of sound radiation in doubly curved shallow shells by means of structural stiffness
Author*Tomas Mendez Echenagucia (Block Research Group, Institute of Technology in Architecture, ETH Zurich, Switzerland), Bert Roozen (Department of Physics and Astronomy, KU Leuven, Belgium), Philippe Block (Block Research Group, Institute of Technology in Architecture, ETH Zurich, Switzerland)
KeywordSound radiation, Rayleigh Integral, Genetic Algorithms, Finite Element Analysis
AbstractA large amount of the embedded energy of buildings is due to their structures. Consequently, designers have been developing lighter and material efficient structures. However, lightweight structures are vulnerable to aerial and structure-borne noise transmission, especially for the lower frequencies. Sound insulation from environmental noise or footfall is commonly addressed by increasing the mass of the structure, resulting in inefficient constructions. In the lower frequency range, structural stiffness plays a significant role in preventing sound transmission. This paper studies the relationship between stiffness and the acoustical insulation properties of shallow structural shells. The sound radiation of doubly curved shells, under point loads, is estimated by computing the surface normal velocity using Finite Element Method and the radiated sound power using the Rayleigh Integral. The paper shows the potential of optimizing shallow shells for sound transmission by means of their shape, the distribution of mass, and the topology of stiffening ribs.

CS8A-5, ID 1475 (Time: 12:40 - 13:00)
TitleComputational morphogenesis and construction of an acoustic shell for outdoor chamber music
Author*Gabriele Mirra, Eduardo Pignatelli (inlogicdesign, Italy), Sergio Pone (University of Naples Federico II, Italy)
KeywordComputational morphogenesis, Acoustics, Acoustic optimisation, genetic algorithms, Timber structures
AbstractThis paper presents a deterministic method to design acoustic chambers for outdoor performances, and emphasises the benefits of a computational morphogenetic approach to the problem. It represents the newest outcome of a research program, conducted by ReS-Team and sponsored by VPM, on the development of the acoustic chamber ReS. The research work is based on the interaction between two different topics – Computational Morphogenesis and Acoustics - which proceed on independent but parallel paths. As a computational tool for any Python®-based environment, it aims to fill the gap between the architectural and acoustic design. By means of geometrical acoustics theory, descriptive geometry and genetic algorithms, the acoustic performance of a given topology is optimised according to defined acoustical parameters. The awareness of possible variations in the acoustic configuration is also increased. Applications are meant to predict the acoustic behaviour within any semi-reverberant field of an acoustic environment.

CS8A-6, ID 1275 (Time: 13:00 - 13:20)
TitleInteraction between different instability phenomena in shallow roofing structures affected by geometrical imperfections
Author*Fabio Bazzucchi, Amedeo Manuello, Alberto Carpinteri (Politecnico di Torino, Italy)
Keywordstability domain, coupled instability, nap-through, imperfections sensitivity, reticulated roof
AbstractInstability of equilibrium represents the major issue for the design and the safety of lightweight long-span roofs. Geometrical imperfections may affect the global and local stability of spatial structures. Furthermore, geometric nonlinearity requires different analytical and numerical approaches. The present paper investigates on the interaction between two different instabilities when a structure is affected by a random pattern of geometrical imperfections. To this purpose, the snap-through phenomenon of several shallow latticed roofs was analyzed by a displacement nonlinear analysis. The effect of following parameters was analyzed: internal and the external constraints, slenderness and shallowness ratios. Interaction domains of snap-through vs. Eulerian buckling were obtained. These original domains indicate the prevailing instability collapse mechanism with regards to the structure geometry. The proposed approach provides indications about the maximum tolerable imperfections and actual limit buckling loads of long-span reticulated roofs, according to the interaction between different instability phenomena induced by geometrical imperfections.

CS8A-7, ID 1248 (Time: 13:20 - 13:40)
TitleAn automated approach to the generation of structured building information models from unstructured 3d point cloud scans
Author*Martin Tamke, Henrik Leander Evers, Mateusz Zwierzycki (CITA - The Royal Danish Academy of Fine Arts, Schools of Architecture, Design and Conservation, Denmark), Raoul Wessel, Sebastian Ochmann, Richard Vock, Reinhard Klein (Computer Science, University of Bonn, Germany)
KeywordMetrology, BIM, Point Clouds, Automation in AEC
AbstractIn this paper we present and evaluate an approach for the automatic generation of building models in IFC BIM format from unstructured Point Cloud scans, as they result from 3d-laser scans of buildings. While the actual measurement process is relatively fast, 85% of the overall time are spend on the interpretation and transformation of the resulting Point Cloud data into information, which can be used in architectural and engineering design workflows. Our approach to tackle this problem, is in contrast to existing ones which work on the levels of points, based on the detection of building elements, such as walls, ceilings, doors, windows, and spaces and the relation between these.We present use cases with our software prototype, evaluate the results, and discuss future work, that will bring the research further towards the aim to create automatically semantic links between the conception of building design in BIM and simulations with the build environment.

Session CS7C  WG20: Teaching Shell & Spatial Structures
Time: 9:00 - 11:00 Friday, September 30, 2016
Location: Room 001

CS7C-1, ID 1270 (Time: 9:00 - 9:40)
Title[Keynote] How well do we appreciate the structural legacies?
Author*Mamoru Kawaguchi (KAWAGUCHI & ENGINEERS, Japan)
Keywordappreciation, evaluation, legacy, trusses
AbstractA good structural designer should have an ability of properly appreciating structures designed by others, especially those structures which are called legacies. This is not always easy, however, mainly perhaps due to poor education of structures at school today. The present paper deals with this issue.

CS7C-2, ID 1329 (Time: 9:40 - 10:00)
TitleDesign and Fabrication of Modern Ger utilizing Pantadome System in Architectural Design Class
Author*Hiroyuki Tagawa, Yusei Tazaki, Kazuhiko Yanagisawa, Shigeyuki Okazaki (Department of Architecture, Mukogawa Women's University, Japan), Mamoru Kawaguchi (KAWAGUCHI & ENGINEERS, Japan)
KeywordPantadome, Self-ascending, design and fabrication, architectural education, full-scale model
AbstractEvery semester in the architectural design class at Mukogawa Women’s University, graduate students are assigned to design and fabricate full-scale architecture. In 2013 a modern ger utilizing Pantadome system was designed and fabricated. Roof structure was fabricated at ground level and lifted up by means of the Pantadome mechanism. In 2014 more sophisticated ger with paper-tube was designed, fabricated and constructed on the site. In 2015 more technically advanced ger utilizing self-ascending Pantadome system was designed and fabricated. As several students outside the ger pulled the strings up or down, a roof ascended or descended. Through these hands-on experiences, students learned the mechanism of spatial structures, particularly the principle of Pantadome system and its application to spatial structures, as well as architectural design. This paper describes the whole process of design and fabrication of these ger structures utilizing Pantadome systems conducted in architectural design class.

CS7C-3, ID 1036 (Time: 10:00 - 10:20)
TitleModeling and Load Testing of Cable Net Structures
Author*Ivan Markov (Rensselaer Polytechnic Institute, U.S.A.)
Keywordcable net, conceptual design, hands on, load testing, measurements
AbstractThe recently developed course at the Department of Civil and Environmental Engineering at Rensselaer Polytechnic Institute covers topics and approaches that are usually not covered in a CEE curricula. The primary goal is to stimulate students’ intuition and heuristic understanding of structural systems. The final project offers hands-on experience where the students are challenged to develop methods to build, support, load test, measure, record and analyze behavior of various unconventional structural systems. Recent project involved cable net modeling where the students teamed up in groups of two each having specific task. The groups’ work had to be highly iterative and interactive to successfully blend the work of all in one successful laboratory experiment. This paper presents how the students resolved the challenges, and learned by solving issues, making decisions, testing models and visually observing model failures.

CS7C-4, ID 1097 (Time: 10:20 - 10:40)
TitleTeaching spatial structures through interdisciplinary projects
AuthorRomuald Tarczewski, *Joanna Jablonska, Elzbieta Trocka-Leszczynska (Wroclaw University of Technology, Poland)
Keywordteaching of spatial structures, interdisciplinary student projects, interaction of architectural and structural approach
AbstractDeveloping the students' understanding of the interactive relationship between architecture and structural systems is a complex and multistage process. At the Faculty of Architecture University of Technology classes are held, during which students gain a solid understanding of the structural systems and learn how to design them. In the later stages of education there are projects developed of various architectural forms in which students must demonstrate the ability to practical application of the knowledge gained. The final step is the work on a master's degree diploma, in which the student must demonstrate the ability of a comprehensive understanding of the design process as an interactive operation, involving many specialties.

CS7C-5, ID 1131 (Time: 10:40 - 11:00)
TitleThe Architect-Engineer Dichotomy
Author*Bharath Gowda (Independent Consultant, India)
Keywordartist-scientist dichotomy, Architect-Engineer Dichotom
AbstractIn the past a master builder used to be educated in Architecture, Engineering, Mathematics, Philosophy. Currently Architecture has become a specialization in its own right, but without core knowledge of its own and leaning on others fields of knowledge for its existence. This has led to a dichotomy between architecture and the rest of field of knowledge. In particular, the dichotomy between Architecture and Engineering. The artist-scientist dichotomy is applicable to all human endeavors; the Architecture- Engineering dichotomy is a subset of the artist-scientist dichotomy that deals with the built environment. This paper gives a perspective of the Architect-Engineer dichotomy with solution. This paper outlines the dichotomy between Architecture and Engineering in four main categories of 1) Knowledge & Thinking 2) Innovation 3) Art & Technology, Sense & high-tech sensibility and 4) Education. It also discusses the ethical issues pertain to this dichotomy.

Session CS8C  Teaching of Shell and Spatial Structures
Time: 11:20 - 13:20 Friday, September 30, 2016
Location: Room 001

CS8C-1, ID 1011 (Time: 11:20 - 11:40)
TitleUnderstanding the Critical Role of Materiality in Academia through Design-Build Projects
Author*Mauricio Soto-Rubio (University of Calgary, Canada), Cornelia Turney (University of calgary, Canada)
KeywordPlywood, Active Bending, Education, Design-Build, Wood
AbstractThis paper examines the importance of considering the behavioural properties of construction materials in the process of developing architecture projects in academia and it interrogates the pedagogic effectiveness of design-build projects in architecture schools. To illustrate this idea, the paper showcases the active-bending plywood research pavilion developed at the University of Calgary during the fall semester of 2015.

CS8C-2, ID 1199 (Time: 11:40 - 12:00)
TitleStructural Intuition and Creative Play: An Architectural Perspective to Shell Pedagogies
Author*Gabriel Tang (Sheffield Hallam University, U.K.)
KeywordPedagogy, Workshop, Construction, Design, University
AbstractThe notions of structural intuition and creative play had been raised by particular structural artists. Professor Pier Luigi Nervi expressed the importance of Structural Intuition in his 1965 Elliot Norton Lectures at Harvard University whilst Professor Heinz Isler described and drew attention to the idea of creative play in his shell practice through a child-like and non-preconceived observations of nature. Illustrated by past experience of working with architecture students in hands-on design/ construction workshops, as well as from explorations in a design studio environment, this paper presents and shares learning and teaching practices by the author, with a specificity to architectural education, in hope of opening up discussions on the pedagogies of shell teaching with creative experimental research.

CS8C-3, ID 1350 (Time: 12:00 - 12:20)
TitleReciprocal frame structures, a first academic approach to sustainable structures
Author*Nayar Gutiérrez, America Flores, Adolfo Preciado (Instituto Tecnológico y de Estudios Superiores de Occidente, Mexico)
KeywordReciprocal, nexorades, timber, sustainable
AbstractHerein we introduce an academic approach to teach students spatial structure from a sustainable perspective to give them tools to generate appropriate technology in the building environment. The students explore sustainable and structural properties of construction materials and systems. The base approach for sustainability rely on the biomimetic principles. They use reciprocal frame structures, without any tool and with local materials, to build structural systems for canopies and bridges. These structures give significance to a high performance structural system made of tree branches or other local materials that are built for temporal or permanent use, in small or big scales, with minimum impact to its surroundings. They give special emphasis to generating a reciprocal frame culture in which there is the need to change pragmatical approaches to develop a structure from geometric and material perspective.

CS8C-4, ID 1485 (Time: 12:20 - 12:40)
TitleSupporting research projects via student workshops
Author*Max Marschall, Michel Schmeck, Christoph Gengnagel (Berlin University of the Arts, Germany), Mette Ramsgaard Thomsen, Martin Tamke (Centre for Information Technology and Architecture, Royal Danish Academy of Fine Arts, Denmark)
Keywordworkshop, student, hybrid structures, form-finding, bending active
AbstractAs part of a joint research project between the Centre for Information Technology and Architecture (CITA) and te Department for Structural Design and Technology (KET), a one week student workshop was organised at the Royal Danish Academy of Fine Arts (KADK) in Copenhagen. This paper outlines the teaching methods applied to reach maximum insight from student interaction, despite the unfamiliarity the students had with the research matter: physical and numeric form-finding for light-weight hybrid structures. Hybrid structures are defined here as combining different components of low stiffness together to create an enhanced system of high stiffness.

CS8C-5, ID 1488 (Time: 12:40 - 13:00)
TitleCasting thin-shell structures with experimental materials and fabrication methods: an architectural design pedagogy
Author*Georg Rafailidis, Stephanie Davidson (State University of New York at Buffalo (UB), U.S.A.)
Keywordmonocoque, casting, paper, fibers, thin shell pedagogy
AbstractThis paper documents the results of two syllabi, both innovative pedagogy for undergraduate architecture students which involved experimenting with unconventional materials toward the fabrication of thin-shell structures. Students were asked to construct a large span with found forms and a weak material in a short time. Materials included cotton linters, waste fibers, twine pulp, paper, and concrete, among others. Both courses were hands-on, allowing students to draw constant empirical observations about the physical behaviors and potentials of their materials through intensive experimentation and testing. Both courses incorporated ideas about “found” or incidental formwork, and addressed issues of temporality and eventual decay. The objective of the courses was to cultivate structural intuition in the students through a making-intensive task at full scale using materials that offered no predetermined construction or fabrication orthodoxies. Both courses introduced a novel teaching method for architecture students, integrating fundamental structural lessons with design and material experimentation.

CS8C-6, ID 1201 (Time: 13:00 - 13:20)
TitleMaking CORDIN User friendly
Author*Pascal Huybers (private, Netherlands)
Keywordalgorithm, 3d-animation, rotation, polyhedra, web based
AbstractThe program CORDIN has been set up and extended over many years of development. Initially it was ment to create all polyhedra and their derivates. Later on, all types of superellipses have been implemented. Cordin has been of great value for illustrations in many articles and presentations over the years. Cordin has been written in GFA-basic which is no longer supported on new computers, besides it needs to be more user friendly.It would take too long to refactor Cordin completely from scratch right now. There has been chosen to start with extending only the graphical presentation of shapes from Cordin’s library. Cordin’s creations are shown in 3D-animated rotation. Also, the program is web-based now and freely accessible for everyone at http://www.huybers.net/polyeder/polyhedron.html.

Session CS7D  Metal Roofs -3
Time: 9:00 - 11:00 Friday, September 30, 2016
Location: Room 002

CS7D-1, ID 1247 (Time: 9:00 - 9:20)
TitleStructural stability analysis of reticulated dome
Author*Jan Sviben, Mario Uros, Damir Lazarevic (Faculty of Civil Engineering, University of Zagreb, Croatia (Hrvatska))
Keywordreticulated single layer dome, buckling, nonlinear analyses, imperfection, plastic hinge
AbstractThis paper deals with stability analysis of a single layer reticulated ultralight dome and the influence of various geometrical imperfections on the load capacity of the structure. Amplitude and the shapes of imperfections are not initially known, therefore, properly scaled critical buckling modes are used as initial imperfections (Lazarevic, Andelic and Uros [3]). Except geometric nonlinearity, material nonlinearity is also used because of the high element stresses. A single layer aluminium dome with triangular pattern is studied. The numerical simulations are performed on the spatial model using geometrical and material nonlinear dynamic analyses with large displacements and small strains. Two types of imperfections are used, which correspond to the first positive eigenvector and the deformed shape from the dead weight. There are two sets of amplitudes defined for each type of imperfection (5 and 10 cm). As a result, the equilibrium curves with precritical and postcritical regions are obtained.

CS7D-2, ID 1366 (Time: 9:20 - 9:40)
TitleNumerical study on floor truss pinned connection in long-span steel structure under heavy load
Author*Dayi Ding, Junzhu Linghu (Wuzhou Engineering Design and Research Institute, China), Yuanqing Wang (Key Laboratory of Civil Engineering Safety and Durability of China Education Ministry, Department of Civil Engineering, Tsinghua University, China)
KeywordPinned joints, Steel structure, Numerical study
AbstractPin joints were adopted to connect the steel column and steel trusses of the second floor in long-span steel structure under heavy load in order to meet the requirement of ideal pin connection. The bar of steel truss is made of steel I-beam, which transitionally connect to the steel column by pin joints. But there is a problem that Design code for the steel structures (GB50017-2003) involves no design formula for pin joints, professional designers could only use foreign codes for reference which will lead to unsafe factors and waste of material. Therefore it is meaningful for us to do research on pin joints. In this case, Pin joint finite element model is built up by ABAQUS software ,and the process of tension, compression and cyclic loading are simulated to analysis the influence of load on bearing capacity. In conclusion, Pinned nodes are still in theirs flexibility under the design load and have good ductility under the failure load. The bearing performance of pinned joint meet the design requirements.

CS7D-3, ID 1367 (Time: 9:40 - 10:00)
TitleStability Analysis of Cable-Stiffened Aluminum Alloy Single-layer Reticulated Shells Considering Shear Performance of Joints
Author*Mingzhe Shi, Minger Wu, Ping Xiang (Tongji University, China)
KeywordAluminum Alloy, Reticulated Shells, Shear Performance, Bolt-connected joints, Cable-stiffened
AbstractThe combination of cable-stiffened two-way reticulated shell and aluminum alloy single-layer reticulated shell forms a new kind of shell structure which combines their advantages. The joint system using in this shell structure is aluminum alloy gusset (AAG) joint. Consider the construction of AAG joint, the effect of shear performance cannot be ignored. In order to study the mechanical performance of AAG joint, FE models considering contact between components were established. The results of analyzing bending and shear properties of the joint were imported into a global model (with the span of 60m and the rise of 10m) via a new joint model with the capacity of producing bending and shear deformation. Global stability analysis of the shell under symmetrical and unsymmetrical loads were carried out. The results indicated that the load distribution had little influence, but the effect of joint rigidity is relatively greater.

CS7D-4, ID 1391 (Time: 10:00 - 10:20)
TitleInfluence of spatial autocorrelation length of corroded thin-walled member thickness on ultimate compressive strength
Author*Naohiko Watanabe (National Institute of Technology, Gifu College, Japan), Masato Suzaki (Nagoya University, Japan), Masafumi Tanaka (Musashino University, Japan)
Keywordcorrosion, buckling, plate, autocorrelation, FEA
AbstractThis study investigated the relationship between the characteristics of the thickness distribution of a corroded plate and the ultimate compressive strength using an elastic-plastic finite element analysis. In this analysis, we used a simulation model following a Gaussian random field with a specific autocorrelation length for each case. Parametric analyses showed that the ultimate strength of the plate had a linear declining trend with increase in the autocorrelation length in such a way that the length was less than the specific value. Next, the effects of the initial deflection and the eccentricity on ultimate strength of corroded plate were investigated. A method for estimating the ultimate compressive strength using the concept of “observed area” with a specific width was considered. We found that almost all the local plastic deformations occurred in the region having this specific length.

CS7D-5, ID 1467 (Time: 10:20 - 10:40)
TitleFE modelling and static performance analysis of space trusses with the consideration of purlin and roof panel systems
Author*Jinzhi Wu, Jiulong Wang, Guojun Sun, Yigang Zhang (Beijing University of Technology, China), Jihui Xing (Beijing Jiaotong University, China)
Keywordspace truss, multi-scale modeling, secondary structure, non-structural component, static behavior
AbstractThe stiffness of the secondary structures will contribute to the main structures. To study the influence of them, the Multi-scale FE modelling method for the whole space truss structure with bolted spherical nodes is introduced, including the bolted ball joints, the purlins and roof panels. And a simplified FE modelling method is given afterwards. The static behavior of some numerical 30m×30m space trusses with different supporting conditions and different loads are analyzed. The results indicate that the non-structural components, such as purlins and roof panels can improve the vertical stiffness of the space trusses and reduce the internal forces of the chords significantly. The stiffness of the secondary structure can be used to improve the load bearing capacity of the main structure. Based on the equivalent moment of inertia, a simplified method is introduced to estimate the influence of the roof system on the main structure.

CS7D-6, ID 1472 (Time: 10:40 - 11:00)
TitleHyperboloid structure for monumental buildings – minimum consumption of material and maximum stability and unity with nature
Author*Hanna Kovalchuk (Kyiv National University of Construction and Architecture, Ukraine)
Keywordhyperboloid, metal spatial structures, twice ruled surface, green building, seismic resistance
AbstractThe main idea of this project is using a hyperboloid structure for the National Stadium in Japan. This structure performs the next functions: outer shell, holding the cover over the tribunes, holding a round console construction for walking and entertainment (shops, cafes, etc.), which encircles the stadium, aesthetic function, protecting the stadium from the wind. The main point of this structure is its little weight, consumption of material and high rigidity and seismic resistance at the same time. The second dignity is unity with nature. Hyperboloid structure is a grid structure, so it lets the trees grow right through it. I propose to make the stadium something like extension of the parks by which it is surrounded.

Session CS8D  Presevation & Temporary Structures
Time: 11:20 - 13:20 Friday, September 30, 2016
Location: Room 002

CS8D-1, ID 1423 (Time: 11:20 - 11:40)
TitleSeismic retrofit design for a building of cylindrical shell structure of the Osaka Expo ‘70, the Tower of the Sun
Author*Hiroshi Kunitomo (Showa Sekkei, Inc., Japan)
KeywordRetrofit design, cylindrical shell
AbstractThe building called the Tower of the Sun was completed in 1969 for Osaka Expo ’70 for a temporary facility as exhibition inside and outside. Afterwards, the building was going to be demolished, however, a preservation movement made the building preserved in 1972 as structure whose interior was not open to public. To the contrary in the 2011 a plan of the refurbishment was raised to be open to public. This paper explains the analysis of structural safety mainly. The safety was confirmed by a governmental structural appraisal as a building higher than 60m called Koso Hyotei and the other building disaster prevention appraisal called Bosai Hyotei. The summary of the reinforcement is that steel braced frames of inscribed horizontal quadrangle at the upper part and additional 200mm thick reinforced concrete wall along the existing wall at the lower part were adopted.

CS8D-2, ID 1227 (Time: 11:40 - 12:00)
TitleAnalysis of bamboo truss structure with hand-made rope joint
Author*Takuo Nagai (The University of Shiga Prefecture, Japan)
KeywordBamboo structure, Temporary building, Manual work, Hand-made joint, Full-scale test
AbstractIn our previous study, we proposed the joint-making method for constructing temporary emergency buildings in large areas affected by hazards using cloth tape and rope to construct bamboo structure and discussed the allowable strength of joints. However, we have not examined the precise restoring force properties of joints. In this study, we first construct a restoring force model for a single joint based on experimental results. Next, we apply the model to a simple full-scale truss and conduct numerical analysis. Finally, we discuss the validity of the model by comparing the numerical results with the loading test results on the actual truss.

CS8D-3, ID 1495 (Time: 12:00 - 12:20)
TitleFabrigami: Design and fabrication of an origami-inspired ice and fabric shell
Author*Lancelot Coar (University of Manitoba, Canada), Caitlin Mueller (Massachusetts Institute of Technology, U.S.A.), Lars De Laet (Vrije Universiteit Brussel, Belgium), Jason Hare, Kim Wiese, Stephen Oberlin (University of Manitoba, Canada)
KeywordFabric, Ice shell, origami, cable net, parametric
AbstractFabric and ice shells, first pioneered by Heinz Isler (Chilton [2]), are lightweight structural systems that allow for inexpensive and reversible construction of free-standing stiffened shell structures. They are of interest for exploring new structural forms and construction methods and are analogs for shells built with more permanent materials. This paper reflects on the design and construction of a fabric and ice shell (6.6mx11.5mx3.6m), called Fabrigami, built in Winnipeg, Canada in January 2016. The project introduces a new formal and structural typology for fabric-based shell structures, taking inspiration from origami and folded plate structures but also utilizing the curved geometry of stretched fabric for added structural stiffness. The paper includes a detailed discussion of the design process, structural behaviour, fabrication, construction, and the resulting performance of the completed shell structure, and concludes with an assessment of how this temporary structure’s innovations could be used for permanent buildings in the future.

CS8D-4, ID 1530 (Time: 12:20 - 12:40)
TitleMobility Analysis of Multi-loop Deployable Structures Based on Screw Theory
Author*Dong Lu, Jianguo Cai, Jian Feng (Southeast University, China)
Keyworddeployable structure, mobility, screw theory
AbstractRecently, deployable structures have become a hot topic for research, especially with the development of aviation and aerospace technology. However, the mobility analysis of the multi-loop deployable structures is made more difficult by the traditional mobility formula. Therefore, on the basis of screw theory, the calculation method of mobility of deployable structures is thoroughly discussed. In this paper, the foldable bar structures are briefly introduced and the mobility of foldable bar structures can be solved by both the methods of screw theory and topological constraint graphs. By calculation, we find that the analysis method can solve the mobility analysis of the multi-loop deployable structures which is difficult by the traditional method, and plays an important role in further research about the mobility of other complex deployable structures.

Session CS7E  Membrane Structures -3
Time: 9:00 - 11:00 Friday, September 30, 2016
Location: Room 201

CS7E-1, ID 1300 (Time: 9:00 - 9:20)
TitleBIM Application to the Membrane Roof – A Practical Case Study of the Anaheim Regional Transportation Intermodel Center (ARTIC)
Author*Eve S. Lin, Simon K. Chiu (Tensile Evolution North America, Inc., U.S.A.)
Keywordmembrane structures, ethylene tetrafluoroethylene (ETFT), BIM, case study, design process
AbstractAs the largest ETFE installation in North America and the first awarded LEED-Platinum transit center, the success of the Anaheim Regional Transportation Intermodel Center (ARTIC) is attributed to their applications of Building Information Modeling (BIM) and seamless team collaboration. Therefore, ARTIC’s BIM applications can be viewed as exemplifying the current status of BIM technologies and can serve as a benchmark for future development, especially with reference to membrane structure design. With this intent, this paper presents a case study detailing ARTIC’s BIM applications and design process of its ETFE roofing design. This paper then concludes with a discussion on the novel approaches and subsequent limitations of ARTIC’s BIM applications, as well as the direction for future building technology development for membrane design.

CS7E-2, ID 1324 (Time: 9:20 - 9:40)
TitleViscous characteristics of ETFE film sheet under bi-axial tensions with unequal stress ratios
Author*Tatsuya Yoshino (Taiyo Kogyo, Japan), Shiro Kato (Toyohashi University of Technology, Japan)
Keywordmembrane structures, ETFE films, Visco-elastic, constitutive equations, FEM
AbstractThis study aims at clarifying the behavior of ETFE film sheet under unequal bi-axial stresses based on both FEM analysis and experiment. The study [1-3] discussed both tensile and visco-elastic deformation under equal biaxial tensions, and the first author proposed the nonlinear incremental visco-elastic constitutive equations.The present paper focuses on the experimental and numerical studies for creep tests. First, the creep tests under unequal biaxial tensions are performed for several stress ratios: (1:0), (5:1) and (2:1). With emphasis on equal stress ratio, comparison is performed for the maximum stresses of 6 and 9MPa, followed by identification of Poisson’s ratio for stress ratio (1:0). Secondly, the numerical simulations for the creep tests are performed, where the nonlinear incremental visco-elastic constitutive equations [3] are applied. Comparing the experimental results with the simulated results, the validity of the proposed constitutive equations is finally confirmed.

CS7E-3, ID 1326 (Time: 9:40 - 10:00)
TitleLarge deformation analysis of wrinkled and slack membranes via a vector-form finite particle method
AuthorYaozhi Luo, *Chao Yang (Zhejiang University, China)
Keywordwrinkled and slack membrane, membrane structures, vector form finite particle method (V-FPM), tension field model, wrinkling model
AbstractThe nonlinear analysis of wrinkled/slack membrane structures remains a challenge in research work and engineering practice. Using a general structural analysis framework of the vector-form finite particle method (V-FPM), this paper explores the possibility of a newly developed membrane model being applied for this subject. The fundamental variables are discrete point values, rather than functions. The prominent advantage is that nonlinear iterations and special modifications can be avoided, and thus it is well-suited for treating with the numerical difficulties associated with wrinkles. In addition, in analogy to the basic ideas of plastic modification, a wrinkling algorithm based on Raddeman's model is developed, which conforms with the explicit incremental formulations of V-FPM. Finally two classical examples are presented to demonstrate the feasibility and accuracy of the proposed approach for wrinkling analysis. It reveals that V-FPM could stimulate the wrinkled and slack regions of membranes effectively and give stable results.

CS7E-4, ID 1346 (Time: 10:00 - 10:20)
TitleExperimental validation of a foldable kinematic fabric structure
Author*Maarten Van Craenenbroeck, Silke Puystiens, Lars De Laet, Danny Van Hemelrijck (Vrije Universiteit Brussel, Belgium), Wim Van Paepegem (Ghent University, Belgium), Marijke Mollaert (Vrije Universiteit Brussel, Belgium)
KeywordFabric structures, Kinematic structures, Experimental validation, Digital Image Correlation, Adaptable structures
AbstractThe inherent flexibility of fabrics makes them a very suitable construction for lightweight adaptable structures.This paper focuses on the experimental verification of a kinematic fabric prototype by comparing the experimental force and strain results to the predictions made by numerical model utilizing a linear elastic orthotropic material model.The conducted comparison showed large differences in absolute values for both forces and strains. However, the general behaviour of the prototype was approximated quite well and most deviations could be attributed to the numerical model not taking into account the compensation applied to the fabric nor the permanent deformation of the boundary belts.Further research on this topic will focus on modelling the prototype using more advanced material models attempting to increase the accuracy of the numerical predictions. However, the research presented in this paper already shows that even simple analysis methods can be used to design kinematic fabric structures to some extent.

CS7E-5, ID 1351 (Time: 10:20 - 10:40)
TitleReview of membrane tension maintenance system through membrane tension measurement
Author*Sang-Wook Jin, Don-Woo Lee, Seung-Jae Lee (Korea Univ. of Tech. & Education, Republic of Korea)
Keywordmembrane structure, membrane tension, tension measurement, measurement equipment, tension maintenance
AbstractMembrane structure is a system that is stabilized by maintaining a tensile state of the membrane material that originally cannot resist the bending or pressure. Tension relaxation can transpire to the tension that is introduced to the fabric over time, due to the innate characteristics of the membrane material. Thus, it is important to accurately understand the size of the membrane tension after the completion of the structure. Jin and Ohmori have proposed the principle of theoretically and indirectly measuring the tension by vibrating the membrane surface with sound waves exposures against the surface. The authors of this paper measured the tension of pre-existing membrane structure for its maintenance by using the developed portable measurement equipment. Through analyzing the measurement data, we propose the points that should be improved and the technical method for the new maintenance system of membrane tension.

Session CS8E  Membrane Structures -4
Time: 11:20 - 13:20 Friday, September 30, 2016
Location: Room 201

CS8E-1, ID 1357 (Time: 11:20 - 11:40)
TitleRecent development of bi-axial shearing test method for fabrics
Author*Wujun Chen, Chengjun Gao, Zhenyu Qiu, Taibai Shi (Shanghai Jiao Tong University, China)
Keywordarchitectural fabric, mechanical property, bi-axial shear test, shear modulus, shear behaviour
AbstractAccurate mechanical parameters and good understanding of mechanical behaviors of architectural fabrics are important to structural analysis, design and safety. Biaxial tensile test, as an effective means of measuring elastic modulus, has been acknowledged and applied in engineering over the decade. In case of biaxial shearing test, the cruciform specimen is used, the loading arm is 45°with respect to warp and weft direction, the loading protocol cold be defined routinely according to plain stress theory of orthogonal composites materials. A series biaxial shearing tests of PVDF-coated fabrics are performed to investigate the shear behavior. The characteristics of the shear strain, shear stress-strain curve are analyzed comprehensively. The shear behavior of PVDF-coated polyester plain-woven fabrics shows remarkable viscous-elastic-plasticity.

CS8E-2, ID 1388 (Time: 11:40 - 12:00)
TitleResearch on structural behavior of Tensairity dome
Author*Zhenggang Cao, Zongshuai Wan (Harbin Institute of Technology, China)
KeywordTensairity, membrane, stability, space structure
AbstractTensairity dome is a lightweight space structure composed of struts, cables and airbags inflated by low pressurized air. In this paper, two forms of Tensairity dome, two-way and spoke form, were designed and analysed. The zero-stress state, the inflated state and the load state were successively simulated. External loads obviously changes the air pressure inside the gasbag, and the effect of temperature on this structure is particularly intense. The static behavior of the structure was investigated for distributed load, asymmetric distributed load and wind load on the upper membrane. The results show that both two forms of structure have good static performance, and gasbag and cables can greatly improve the stability of the structure. On the basis of the spoke form, another type of Tensairity dome with two gasbags was designed and analysed. The results show that it has good mechanical properties, and the stability could meet code requirements.

CS8E-3, ID 1449 (Time: 12:00 - 12:20)
TitleStructural design of membrane structure using plastic stretch and heat shrink of ETFE film
Author*Masaya Kawabata (Yokohama National University, Japan), Toshinobu Takemura (NTT Facilities, Japan), Soichiro Furutani (Taiyo Kogyo, Japan)
Keywordtrue stress, true strain, equivalent strain, relaxation, yield stress
AbstractIn order to establish three dimensional curved surface fabrication technique by stretching plane film, this paper discusses the elastic-plastic characteristic of ETFE film and its evaluation method, and considers the example and effect of the curved surface fabrication by stretching. Around 10% stretch is the optimal since yield strength per unit width serves as an extreme. It is checked that smooth curved surface has been formed with target rise near 10% as a result of three dimensional elongations, and that the stable rigidity had been acquired.

CS8E-4, ID 1453 (Time: 12:20 - 12:40)
TitleIn-situ determination of stress and strain distributions of inflatable membrane structure based on photogrammetry
Author*Bing Zhao, Wujun Chen, Jianhui Hu, Chengjun Gao (Shanghai Jiao Tong University, China)
Keywordinflatable membrane structure, in-situ determination, strain and stress distributions, photogrammetry
AbstractThis paper presents an in-situ method to determine strain and stress distributions of inflatable membrane structure using photogrammetry. Firstly, dynamic shape of the target inflatable membrane structure can be obtained following photogrammetric procedure. Secondly, based on 3D coordinates of measured points before and after deformations, strain distribution can be calculated from the deformations of triangular elements. Thirdly, based on the measured geometrical shape and internal pressure, stress distribution can be determined on the equilibrium of inflated pressure and film internal force using force finding method, after simplifying it to a membrane link structure with external forces on connection nodes. To validate the proposed method, the strain and stress distributions of an ETFE (ethylene–tetrafluoroethylene) cushion model are evaluated. The acceptable agreement between experimental and numerical results demonstrates that the proposed method is suitable for determining strain and stress distributions of inflatable membrane structure under service condition.

CS8E-5, ID 1486 (Time: 12:40 - 13:00)
TitleMaintaining the Tension of Adaptable Membrane Structures
Author*Kai Schramme, Annette Bögle (HafenCity Universität Hamburg, Germany)
KeywordMembrane Structures, Architectural Textile, Biaxial Testing, Adaptive Façade, Movable Structure
AbstractThis paper introduces new possibilities in the design of adaptable membrane structures. Traditionally, these structures have two states: Either the fabric is folded together in parking position or deployed in serving position. However, loads can only be carried in deployed state when the membrane is pretensioned. As a consequence, the membrane structure can only be moved when the load application is negligibly small. Textiles that are part of the building envelope and serve as sun shading do not need to fold together if they are adaptable and can be adjusted to the amount of sun transmittance. To adjust the membrane’s shape during all weather conditions, the tension must be maintained during motion of the adaptable membrane structure. The aim of this paper is to highlight the most important material properties that are inevitable in the design of adaptivity and illustrate various setups given by the example of a four-point-sail.

CS8E-6, ID 1507 (Time: 13:00 - 13:20)
TitleAnalysis of the interaction between integrated linear compression elements in membranes
Author*Nils Ratschke, Annette Bögle (HafenCity University Hamburg, Germany)
KeywordTensegrity principle, textile membrane, Tensegrity-Membrane-Structures
AbstractThis research project deals with the analysis of the interaction of integrated linear compression elements into architectural membranes. The advantages and disadvantages of Tensegrity structures and textile membranes are analyzed in the first part of this work. With the knowledge of the single systems a hybrid Tensegrity-Membrane-Structure could be described, influenced by few realized projects like “Textegrity I”, “Underwood Pavilion” and “Pavilion Noda”. To verify these considerations of a combined hybrid system using textile membranes, based on the Tensegrity principle, a numerical analyzation was implemented. The results of these numerical studies are several positively influences of the single structures to the hybrid system like e.g. less deformations, higher stability and a larger variety of forms.

Session CS7F  Snow, Wind & Disarster
Time: 9:00 - 11:00 Friday, September 30, 2016
Location: Room 202

CS7F-1, ID 1123 (Time: 9:00 - 9:30)
Title[Keynote] Report of snow damage of Kumagaya Dome
Author*Ryozo Umezawa, Takuya Agari (Umezawa Structural Engineers Inc., Japan)
KeywordSnow damage, Membrane sheet, Against global buckling, EM sensor, single layer dome
AbstractRecently worldwide anomaly of the natural phenomenon is happened frequently. Particularly an estimation of the heavy snow load, acts on a light-weight dome is urgent issue of Japanese architecture. That is a like issue such as the long- period earthquake ground motion problem for high-rise buildings and base-isolated buildings. This is a report concerning snow damage of Kumagaya Dome by the heavy snow covered the Kanto area, occurred on February 15, 2014. That was the first record of a heavy snow in history.

CS7F-2, ID 1272 (Time: 9:30 - 9:50)
TitleNumerical simulation of snowdrift on a membrane roof
Author*Xiaoying Sun, Rijing He, Yue Wu (Key Lab of Structure Dynamic Behaviors and Control of the Ministry of Education, Harbin Institute of Technology, China)
Keywordsnowdrift, Numerical simulation
AbstractLong-span structures are quite sensitive to uneven distributed snow loads, therefore it is vital to estimate the wind-induced redistribution snow loads accurately. This paper presents the results of numerical simulation of snowdrift on a long-span membrane roof at first. Based on Euler-Euler method in multi-phase flow theory, the numerical simulation adopt Mixture model by employing commercial CFD software FLUENT. Assuming the snow is evenly distributed at the initial time in simulation, combined with the snow deposition and erosion model, the result is given as the contour map of snow distribution coefficient under different wind velocities and directions, and we give the most unfavorable form of snow distribution. Next, under the condition of laying air-jet pipelines on the roof, the snow sweeping process is simulated by employing transient solver in FLUENT, the result is given as the time dependent residual snow mass fraction and snow mass flux which provide some useful suggestions on practical application.

CS7F-3, ID 1440 (Time: 9:50 - 10:10)
TitleEffect of partial unbalanced snow load distributions of double layer truss domes on the load carrying capacity
Author*Koichiro Ishikawa, Shohei Fujita (University of Fukui, Japan)
Keyworddouble layer truss dome, snow load, partial undistribution, buckling, load carrying capacity
AbstractThe study deals with the static elasto-plastic analysis considering a member buckling of double layer truss domes subjected to uniform and partial unbalanced distribution snow loads. The load carrying capacity of the truss dome is investigated by means of the analysis using a model of a pin connected truss model. The maximum snow load and the reaction at the support are investigated by the analysis of the truss dome subjected to the various snow loads. A distribution of the snow load is taken to be three distribution forms such as a uniform, a central portion and a one half side portion forms. The collapse mechanism of the dome has the member buckling chain due to a compression stress. The effect of the unbalanced snow load distribution to the load carrying capacity is compared with the load carrying capacity of the dome subjected to uniform distribution snow load.

CS7F-4, ID 1072 (Time: 10:10 - 10:30)
TitleEquivalent Static Wind Load for Large-span Spherical Domes
Author*Ying Sun, Ning Su, Yue Wu, Shizhao Shen (Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education, Harbin Institute of Technology, China)
KeywordESWL, spherical dome, wind-induced response, wind tunnel tests
AbstractSpherical dome is one of the most typical forms of large-span buildings, especially applied in landmarks such as exhibition halls, sports centres. Wind loads and wind-induced responses on such roof structures are necessary in the design process. Based on wind tunnel measurements on a series of rigid dome model with different rise-span ratios, height-span ratios and approaching flows, the wind load models including statistical model and spectral model are summarised. Using the wind load model the wind-induced responses are calculated in frequency domain. By defining the basic wind-induced response as static response under completely correlated RMS wind load, considering the background and resonant effects, the equivalent static wind load model for spherical domes based on mean wind load and RMS wind load is provided. The parameters in the model was discussed and recommended for engineering reference.

CS7F-5, ID 1308 (Time: 10:30 - 10:50)
TitleWind-induced vibration response of flat membrane
Author*Yuan Cao, You Lu, Yingying Zhang (China University of Mining and Technology, China)
Keywordadded mass, fluid-structure coupling, wind-induced response, numerical simulation, modal properties
AbstractThe membrane structure is light and thin, widely used in large span spatial structure. However, the membrane structure wind-induced response mechanism is not clear, and the wind disaster occurred frequently. This is due to the complex vibration characteristics of the membrane structure, and the significant fluid-structure interaction between the structure and the wind field. Numerical simulation was used to analysis the circular membrane vibration test and wind tunnel investigation on 45 degree tension membrane. Results show that the large eddy turbulence model can be used to simulate the transient response of 45 degree flat membrane structure considering the effect of fluid-structure coupling. It is necessary to consider the relaxation and creep effect of the membrane material in the further study of wind induced vibration.

Session CS8F  Disaster & Applications
Time: 11:20 - 13:20 Friday, September 30, 2016
Location: Room 202

CS8F-1, ID 1309 (Time: 11:20 - 11:40)
TitleAero-elastic Wind Tunnel Test of a High Lighting Pole
AuthorYaozhi Luo, *Yucheng Wang, Jiming Xie (College of Civil Engineering and Architecture, Zhejiang University, China)
Keywordhigh lighting pole, aero-elastic model, wind tunnel experiment, high-rise structure, aerodynamic damping ratios
AbstractThe vortex excited resonance and wind-induced dynamic instability phenomenon of high lighting pole under strong wind is very concerned during structure design. A 1:25 multi-freedom aero-elastic model was designed for a high lighting pole in Zhoushan. In order to validate the similarity characteristic of the model, free vibration test was proceeded and the results were further processed. “Beat” phenomenon was eliminated and damp ratio of the model is 0.0032. According to the formal experiment result, the major along-wind fluctuation respond was 1st vibration component under designed wind speed. By analyzing the power spectrum of the base shear response, it was found that 2nd vortex-excited resonance exists under some wind directions. The aerodynamic damping ratio was calculated by random decrement technique and vibration test and the result showed that aerodynamic damping ratios are all positive under different wind speed, which demonstrated that the wind-induced instability will not occur.

CS8F-2, ID 1189 (Time: 11:40 - 12:00)
TitleCollapse analysis of cable nets under strong wind based on Finite Particle Method
Author*Ying Yu, Ping Xia (Shantou University, China)
KeywordFinite Particle Method, vector mechanics, cable net, strong wind, collapse
AbstractThe finite particle method (FPM) is a new structural analysis method which is based on the Vector Mechanics. This paper presents collapse analysis of cable-net structure under strong wind using the FPM. The theoretical fundamentals of the FPM are given in this paper. Methods to handle geometric and material nonlinearities of cable element are proposed. The fracture criterion and model for cable element are built to simulate the failure of cable nets. The form-finding and load analysis of a hyperbolic parabolic cable net are then performed in order to initialize the successive of nonlinear analysis. The collapse progress of the saddle cable net under strong wind is simulated by the FPM. Analysis of the energy variations during the collapse process show the failure mechanisms of the cable net. The numerical applications highlight the capability of the proposed procedure to solve complicate collapse problems with the FPM.

CS8F-3, ID 1526 (Time: 12:00 - 12:20)
TitleDynamic response analysis of new steel shed-tunnel structure under rock fall impact
Author*Chang Wu, Bao-long Gou, Xiu-li Wang, Ya-xiong Liang (School of Civil Engineering, Lanzhou University of Technology, China)
Keywordsteel shed-tunnel structure, dynamic response, rock fall impact, numerical models
AbstractThe conventional concrete rock-shed has some disadvantage, such as massive foundation and high weight, so constructing such a structure is usually very difficult and expensive. To overcome the construction difficulty and reduce costs, a new type of steel shed-tunnel structure was proposed. It has good economic benefit and social benefit. In order to analyze the dynamic response of this structure under rock fall impact, the model is established by using the ANSYS / LS-DYNA program. The dynamic stress, dynamic displacement and acceleration were analyzed. The results show that the flexible steel shed structure can generate large deformation to absorb impact energy. As the main body in the force, the steel arch beam mainly bear bending moment. The steel shed-tunnel structure has remarkable superiority in stress, construction, environmental, and economy etc. and hence is suitable for the rock-fall protection.

CS8F-4, ID 1534 (Time: 12:20 - 12:40)
TitleAnalysis and application of space truss combined by concrete-filled steel piles and pipes under debris flow
Author*Xiuli Wang, Yonghong Ran, Yanpeng Zhu (Lanzhou University of Technology, China)
Keyworddebris flow, impact, impact load, concrete-filled steel tubular piles, numerical simulation and experiment
AbstractSpace structure have wildly used on many field because the good performance. Debris flow is a common natural disaster in mountain area. China is one of the countries with the most serious geological disasters in the world. The loss caused by landslides is very serious in recent years. Based on thorough investigation and study on the protection structure of debris flow in domestic and foreign, the innovation space structure has been proposed. As a new protect structure, the concrete-filled steel tubular piles can intercept stone effectively so as to reduce the impact damage of debris flow. Based on the finite element program ANSYS/LS-DYNA, the model of the concrete-filled steel tubular piles is established, and the dynamic response of its two positions is simulated and analyzed under the impact force. Besides, the experiment study of full-size model has been carried out.

CS8F-5, ID 1166 (Time: 12:40 - 13:00)
TitleDamage to suspended ceilings attached on large-span spatial structures and improvement measures
Author*Yan Lu, Yifeng Zhao, Qinghua Han, Jie Xu (Tianjin University, China)
Keywordlarge-span spatial structures, suspended ceilings, improvement measure
AbstractThe failure of suspended ceiling systems is one of the most widely reported types of non-structural damage in large-span spatial structures after an earthquake. This paper mainly summarizes damages to suspended ceilings attached on the large-span spatial structures by 2005 Miyagi-ken oki earthquake, 2010 Chile Earthquake, 2011 Great East Japan Earthquake, and 2013 Lushan Earthquake in China. Then a 4.0m×4.0m elevated test frame constructed was used to test the suspended ceiling by the shaking table test. The well-shaped structure is designed to model the flexible supporting spatial structures. The damage and fragility evaluation of the regular suspended ceilings and improved suspended ceilings was summarized based on the shaking table tests. And the failure of the grid result from the failure of the connection of the main runner and cross runner, the cross runner and the brace runner. Several measures should be taken to protect the connection of the grid.

Session CS7G  Towers & Coolings
Time: 9:00 - 11:00 Friday, September 30, 2016
Location: Room 203

CS7G-1, ID 1321 (Time: 9:00 - 9:20)
TitleA design method for the large-diameter steel tube in high rising structures
Author*Zhaohua Lu (Tongji Architectural design(group) Co.,Ltd, China), Renle Ma, Xue Bai (Department of Structural Engineering, Tongji University, China)
Keywordlarge-diameter steel tube, high rising structures, local stability, reverse balance flange, longitudinal flange
AbstractDue to the demand of the architecture, function and appearance, a kind of large-diameter steel tube has been gradually used in the high rising structures. Unlike the lattice tower, the design of large-diameter steel tube requires real concern to ensure the local stability. According to Chinese code [1], the diameter-thickness ratio of steel tube should be lower than 100 , thereby resulting in wasting a large scale of materials. Moreover, the steel tubes are bulky and hard to transport. This paper proposed a novel design method of large-diameter steel tube. In order to improve the local stability, flanges, stiffened plates and steel frames were used to ensure the local stability of steel tubes. In addition, a numerical analysis was performed. Considering the transportation, the large-diameter tube should be divided into pieces by the circumferential and the longitudinal flanges. In this way, the lifting weight can also be reduced.

CS7G-2, ID 1371 (Time: 9:20 - 9:40)
TitleNumerical and experimental analysis of structural details of electrical transmission line towers
AuthorMichal Botló, Martin Magura, Ján Brodniansky, *Ján Brodniansky (Faculty of Civil Engineering, Slovak University of Technology in Bratislava, Slovakia)
Keywordtowers, transmission lines, Conical cross sections, slip-joint connection, shell structures
AbstractThe presented paper deals with the design and examination of steel towers of electrical transmission lines with circular or polygonal cross section. Structures of this kind are a safe and reliable option when selecting the appropriate structural solution, but nevertheless often remain omitted due to difficulties with design methodology. Conical towers` cross sections are in most cases categorised as class 4 sections and therefore act as shell structures when subjected to the action of load, being prone to buckling and web deformation. The article provides the results of FEM analysis of multiple connection details of conical steel towers, highlighting the key aspects of design, the crucial points for consideration, and the resultant stresses and deformations invoked by load these towers withstand. Furthermore, it provides a simplified methodology of calculating the stress in the most vulnerable structural detail, i.e. the slip-joint connection of tower segments. The method is also compared with the FEM software analysis and its weaknesses are identified.

CS7G-3, ID 1183 (Time: 9:40 - 10:00)
TitleNumerical study for the wind load effects on four-cylinder structures
AuthorRenle Ma, *Xu Qiu, Yuan Sun (Tongji University, China)
Keywordfour-cylinder structures, force characteristics, yaw angle, flow pattern, numerical simulation
AbstractSuccessful numerical simulations can reveal important flow characteristics and information which are extremely difficult to obtain experimentally. Two- and three-dimensional (3-D) numerical simulations of flow past four-cylinder structures were conducted at named Reynolds number of 2.07×105. The yaw angles (β) in the range of -30° to 30° were considered. The governing equations are the incompressible unsteady Reynolds-Averaged Navier–Stokes equations and RNG k-ε turbulence equations, which are solved using a finite-volume method. The effects of the yaw angles on wake structures, pressure distribution and hydrodynamic forces of each cylinder were investigated. The drag coefficient of each cylinder agrees well with the independence principle. The total drag coefficient slightly increases with the increase of β. The 2-D numerical results overestimated the drag coefficient of the four-cylinder structures.

CS7G-4, ID 1184 (Time: 10:00 - 10:20)
TitleNumerical simulation of drag coefficient for guyed mast with and without ancillaries
AuthorRenle Ma, *Yuan Sun, Xu Qiu (Department of Building Engineering, Tongji University, China)
Keywordguyed mast, ancillaries, drag coefficient, computational fluid dynamics
AbstractGuyed masts are exceptionally tall and slender structures widely used for wireless broadcasting and communication industries. Wind load is the main load affecting the stability of the structure. Numerical method using Computational Fluid Dynamics (CFD) to determine drag coefficients is presented in this study. Two section models of guyed masts with and without ancillaries are developed. The three-dimensional steady Reynolds-averaged Navier-Stokes (RANS) equations are solved by employing the RNG turbulence model. Drag coefficients obtained by numerical simulations are compared with the wind tunnel test data and those predicted by the existing codes and standards. The numerical results are generally in good agreement with the experimental measurements. CFD is found to be a valuable tool to evaluate the drag coefficient of guyed mast as a supplement or even alternative to wind tunnel test with sufficient accuracy.

CS7G-5, ID 1128 (Time: 10:20 - 10:40)
TitleOn the hyperbolic shell geometry of natural draught cooling towers for effective structural design
Author*Sang-Yun Lee, Sam-Young Noh (Department of Architectural Engineering, Hanyang University, Republic of Korea)
Keywordnatural draught cooling tower, hyperbolic shell geometry, natural frequency analysis, nonlinear FE analysis, global damage indicator
AbstractThe form-finding of a hyperbolic shell is the most important process in the natural draught cooling tower design. The result of the previous work leads to the idea that the inner area of the hyperbolic shell generator should be minimized for the cooling tower with higher first natural frequency. In this study, the inner area of the 1-shell or 2-shell hyperbolic generator was determined graphically under varying height of the throat and the angle of the base lintel. From the graph, several shell geometries were selected and analyzed based on natural frequency. Three representative cooling towers were selected for the analysis of the structural behavior by means of nonlinear finite element (FE) method and evaluated using a damage indicator based on the change of natural frequencies. The results show that the damage behaviour of the cooling tower reinforced heavily due to a lower first natural frequency is not necessarily advantageous than the other two.

CS7G-6, ID 1362 (Time: 10:40 - 11:00)
TitleComparison of Wind-induced Interference Criteria and Effects under Typical Towers-Group Arrangements
Author*L. Zhao, Y.Y. Zhan, Y.W. Liang, J.X. Cao, Y.J. Ge (Tongji University, China)
KeywordCooling tower, Wind-induced interference, Wind tunnel test
AbstractInterference factors (IFs) are commonly used to envelope various dynamic loading distributions due to wind-induced interference effects. However, those parameters are discrete in values for different evaluation criteria. Aiming at unifying cognitive distinction for series equivalent criteria about IFs, cooling tower groups with typical 6-towers arrangement were selected to conduct case studies by wind tunnel tests and numerical calculation, investigating interference effects among classical rectangular and rhombic arrangement. 25 kinds of IFs' definitions were totally compared basing on three index levels, namely loading, internal force and reinforcement ratio. Wind pressure measurements about 1:200 reduced-scale model were carried out in TJ-3 wind tunnel, corresponding 3D dynamic or static calculation were finished to analyse IFs. Main conclusions can be summarized, such as there are great distinctions about IFs’ value for different criteria, whose maximum may reach 42%, IFs’ variance coefficients in loading level would be the largest, and those in reinforcement level are the smallest, etc.

Session CS8G  New Approaches
Time: 11:20 - 13:20 Friday, September 30, 2016
Location: Room 203

CS8G-1, ID 1087 (Time: 11:20 - 11:40)
TitleNumerical Study of Vortex Induced Vibration of a Cylinder with Span-wise Waviness
Author*Kai Zhang, Dai Zhou (Shanghai Jiao Tong University, China), Hiroshi Katsuchi, Hitoshi Yamada (Yokohama National University, Japan)
Keywordwavy cylinder, flow control, vortex induced vibration
AbstractThe current paper aims at clarifying whether the circular cylinder with span-wise waviness, which has been proven to be effective in mitigating the aerodynamic forces, could suppress the vortex induced vibrations. The numerical results show that with zero or small structural damping, the response of the wavy cylinder is almost the same with the normal cylinder, i.e., large amplitude vibrations occur, together with frequency coalesce and amplification of the aerodynamic forces. However, as the structural damping increases to a threshold value, this particular geometry outperforms the normal cylinder. The current paper provides some guidelines for the potential use of the wavy cylinder in spatial structures as a low drag, low VIV-response device.

CS8G-2, ID 1289 (Time: 11:40 - 12:00)
TitleDesign of two guadua bamboo hyperbolic paraboloid grid shell roofs: structural analysis and physical joint testing
AuthorTim Michiels, Lu Lu, Russell Archer, *Sigrid Adriaenssens (Princeton University, U.S.A.), Greta Tresserra (Sustainable architecture for development, Colombia)
KeywordBamboo, Gridshell, Hypar, Parametric design
AbstractIn this study we examine the relationship between the structural behavior of a bamboo grid shell and its most critical bamboo joint. A finite element analysis is performed in order to determine how the overall hypar form influences the internal loads in the bamboo poles under loading combinations of self-weight, wind and earthquake loading according to the Colombian Building Code. The most critical joint (“fish mouth”) that interconnect the bamboo poles are analyzed through laboratory testing. A better understanding of the flow of forces in the hypar grid shells combined with a detailed quantification of the behavior of this “fish-mouth” joint, allows for a more informed and efficient use of the bamboo material used in Colombia. This study thus seeks to demonstrate how an eco-friendly, widespread and inexpensive material such as bamboo can be used at its full structural capacity in the design and construction of large span spatial roofs.

CS8G-3, ID 1292 (Time: 12:00 - 12:20)
TitleFabrication of Concrete Parts using a Frozen Sand Formwork
Author*Oliver Gericke, Daria Kovaleva, Walter Haase, Werner Sobek (Institute for Lightweight Structures and Conceptual Design (ILEK), University of Stuttgart, Germany)
Keywordfrozen sand formwork, waste-free formwork, concrete structures, new fabrication method
AbstractThe present paper concerns the newly developed formwork method for fabrication of concrete parts which combines high precision of CNC processing technologies with potentials of frozen sand as formwork material. Sand has been identified as beneficial material for production of complex concrete structures due to its good formability in combination with its full reusability. For the production of formwork elements using CNC milling, the sand is mixed with water and frozen into a solid state to ensure precise processing and a long-lasting stability of formwork geometry. In addition to the description of production method, the production of two specimen of thin-walled spatial concrete parts is demonstrated and discussed.

CS8G-4, ID 1310 (Time: 12:20 - 12:40)
TitleTransformable and foldable plate structures
Author*Valentina Beatini (Abdullah Gul University, Turkey)
Keywordorigami, transformable-foldable plate structure, multi-stable mechanism, assembly of spherical linkages, variable topology
AbstractThis is a study on a novel family of modular foldable plate mechanisms, characterized by being not only foldable but also transformable. The term transformable is used here to describe a mechanism that during motion, traces curvatures which differ not only in magnitude, but also in sign. Such behavior is obtained by integrating into a novel, symmetrical arrangement three 4R-linkages, composed by equal quadrangular and equal triangular plates. The mechanism moves with one degree of freedom from a fully flat –folded configuration through unfolded ones, finally reaching a partially flat-folded state. The ability to invert curvature is a new achievement in the field of foldable plate structure, which extends their applicability from simply larger-smaller configurations to substantially different configurations and usages therefor.

CS8G-5, ID 1325 (Time: 12:40 - 13:00)
TitleStress Monitoring of Steel Structure of Hangzhou Olympic Sports Center Stadium
Author*Zeyu Zhang, Yaozhi Luo (College of Civil Engineering and Architecture of Zhejiang University, China)
Keywordstress monitoring, remote monitoring system, wireless sensor, unloading, temperature effect
AbstractAiming at the difficulties in the field measurement of the large span spatial structure, we used self-developed wireless sensor remote monitoring system to collect and transmit the strain data of the steel structure of Hangzhou Olympic Sports Center Stadium during construction and service process. Based on load sensitivity analysis and component importance analysis, 828 strain sensors were arranged in different parts of the structure. And there were a total of four parallel chain-type networks for wireless transmission of data. Analyzing the monitoring data, the real stress change of the unloading process and the influence of the temperature effect on structure are studied in the paper.

CS8G-6, ID 1349 (Time: 13:00 - 13:20)
TitleDesign protocol for bamboo structures based on the principles of Building Information Modeling
Author*Juan Gerardo Oliva, Agustín Hernández (Universidad Nacional Autónoma de México, Mexico), Chu-Hee Lee, Rodolfo Lorenzo (University College London, U.K.), Marcos Ontiveros, Alejandra Palma, Magdalena Trujillo (Universidad Nacional Autónoma de México, Mexico)
KeywordBamboo, BIM, Design
AbstractBamboo has been used worldwide long before the discovery of modern construction techniques and materials. Nevertheless, its use has remained as a handcrafted practice, with regionalized methodologies and construction techniques. The research group at the Universidad Nacional Autónoma de México-UNAM has successfully characterized the mechanical properties of three different species of Mexican-grown bamboo: Oldhami, Guadua Angustifolia and Phyllostachys bambusoides, as well as started the development of research projects for the analysis and design of lightweight structures with bamboo [1, 2]. Translating the results into practice, UNAM and University College London-UCL are working on a joint research project with the goal of developing an international design protocol for bamboo (whole culms) structures based on the principles of Building Information Modeling-BIM; expecting to develop the relevant scripts for geometric 3D modeling, structural analysis and robotic fabrication. The project’s preliminary results are presented in this paper.

Session CS9M  Hangai Prize Presentation
Time: 14:40 - 16:20 Friday, September 30, 2016
Location: Ito Hall

CS9M-1, ID 1269 (Time: 14:40 - 15:00)
TitleForm evaluation of free-form shells by using bending strain energy ratio
Author*Hayato Utebi, Kenji Yamamoto (Tokai University, Japan)
KeywordBending strain energy, Free form shell, Shape evaluation, Finite-element analysis, Algorithmic design
AbstractRecently, due to the development of structural materials and structural analysis technology, various large span structures with complex forms have been built. There might be a structure with a structurally irrational shape among them. For that reason, this study aims to make an index that can evaluate the mechanical performance of shell shape at an early design stage. In this paper, the rate of the bending strain energy in the strain energy caused by external forces, which is called the bending strain energy ratio, is proposed as the index. The bending strain energy ratios are calculated for various shells which have classic shapes such as sphere or cylinder, and complex free shapes. The relations between the index and the maximum responses and the charact

CS9M-2, ID 1025 (Time: 15:00 - 15:20)
TitleAssessing the necessity to account for geometric nonlinearity in von Mises trusses representing simple shallow roofs
AuthorMaria Livanou, *Charis Gantes (National Technical University of Athens, Greece)
Keywordgeometric nonlinearity, material nonlinearity, von Mises truss, snap-through buckling, Euler member buckling
AbstractOverall objective of this research is to evaluate the importance of geometric nonlinearity in the structural behaviour and design of shallow truss roofs, depending on their geometric configuration and on their material as well as cross-sectional properties, and eventually to propose simple analytical criteria for assessing whether linear analysis can be safely adopted for design purposes. For that purpose, the simple von Mises truss model is analytically and numerically investigated, with emphasis on the interaction between geometric nonlinearity at the system level and buckling, material nonlinearity and imperfections at the member level. The obtained results are compared to the criterion proposed in Eurocode 3 for adopting first order analysis for the design of steel structures. Interesting findings are reported that can then be extended to more complex reticulated shells.

CS9M-3, ID 1242 (Time: 15:20 - 15:40)
TitleDeployment Study on a Single-Layer Deployable Truss Structure Driven by Elastic Components
Author*Tianhao Zhang (Tongji University, the University of Tokyo, China), Minger Wu (Tongji University, China), Fuling Guan (Zhejiang University, China)
KeywordDeployable Structure, Deployment Procedure, Numerical Analysis, Measurement of Deployment
AbstractThe deployment analysis and test for a single-layer deployable truss structure driven by elastic component is conducted, aiming to design a flat deployable structure suit for small satellites. The numerical model of components is built and assembled utilizing ADAMS, the software specialized for dynamics of multi-body system. The deployment of the deployable structure is simulated by means of numerical analysis. The dynamic performance of the deployment is investigated through the movement of joints of the structure. The 1.6 meter model was assembled and the deployment test is executed by means of method of non-contact measurement with high-speed cameras. The coordinates of the key joints during deployment are measured. The results of the measurement are compared with the results of numerical analysis.

CS9M-4, ID 1005 (Time: 15:40 - 16:00)
TitleLow carbon vaulted masonry structures
Author*Catherine De Wolf (MIT, U.S.A.), Michael Ramage (University of Cambridge, U.K.), John Ochsendorf (MIT, U.S.A.)
Keywordembodied carbon, vaulted structures, material efficiency, natural materials, optimization
AbstractTo reduce embodied carbon in buildings, two strategies are available. First, material efficiency is improved. Second, the materials are chosen for their low carbon content. The operational carbon of buildings has lowered recently, but for immediate emissions savings innovations in embodied carbon are needed. This research demonstrates that most material mass lies in roofs and floor slabs, rather than in walls and columns. Therefore, the first strategy to reduce impacts would be to lower their material quantities in floor and roof design. For the second strategy, alternative materials are studied. Vaulted masonry structures combine both strategies: vaults span spaces efficiently and masonry has a lower embodied impact than steel and concrete. Results demonstrate that a combination of both strategies effectively lowers the embodied carbon of buildings: typical floor and roof structures range around 440 kgCO2e/m2 whereas vaulted tile masonry can be as low as 60 kgCO2e/m2.

Session CC  Closing Session
Time: 16:40 - 17:30 Friday, September 30, 2016

CC-1, ID 1556 (Time: 16:40 - 17:10)
TitleFuture Events
AuthorOrganizing Committee of IASS2017

CC-2, ID 1557 (Time: 17:10 - 17:30)
TitleClosing Address
AuthorKen'ichi Kawaguchi (University of Tokyo)