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Forthcoming Events
Contributions
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On The Design of umbrella structures
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Making wind … Eberhard Haug
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Innovative Sheltering
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Modern Teahouse 2007
for MAK Frankfurt/Main
CENO TEC in Abu Dhabi
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Architen Landrell Associates
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Aquarium Textile Roof
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Two low-cost barrel vaults
with a membrane cover
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APPP church with double layer
insulated membrane covering
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Basic Philosophy And Calling Notice
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Experimental building “paul”
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Innovationspreis Industrie 2007
Flower in Venezuela
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Cemco TensiNet Seminar
Interview with the founder
of the Membrane Structures
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Literature: Tension structures
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Literature: Solutions
Ephemeral Architecture
Saie Spring
Roof & Cladding India 2008
N E W S L E T T E R O F T H E E U R O P E A N B A S E D N E T W O R K F O R T H E D E S I G N A N D R E A L I S AT I O N O F T E N S I L E S T R U C T U R E S
w w w . t e n s i n e t . c o m N E W S L E T T E R N R . 1 3 - D E C E M B E R 2 0 0 7 - P U B L I S H E D T W I C E A Y E A R
Dear reader,
After some delay, TensiNews nr.13 has arrived. As you will notice, this issue counts more pages than before,because of a newly added feature. From now on, a more elaborate research report will be presented in each issue,focusing on a specific subject related to tensile surface structures. Apart from editing the newsletter, a lot of workhas been done to the TensiNet website, which has been given a complete overhaul. We hope you will appreciatethe clear, user-friendly interface and the much improved graphics. (For more information concerning theimproved website, please refer to the separate textbox below). To mark the arrival of the new website, both theTensiNet and TensiNews logos have been given an update as well.
Starting this year, several TensiNet Working Groups will be established. Subscription to one of these groups is opento all TensiNet members who are willing to contribute. At the moment four working groups are being installed andare inviting members to join. Other WGs are due to follow shortly and we will keep you informed as this processevolves. (Please refer to the textbox below for more information on Working Groups)
We hope you will find this issue of great interest. If you would like to contribute an article, a project description, a research report, an event or another announcement, do not hesitate to contact the editorial board. As of now, we are accepting contributions for TensiNews 14, which will be published in May 2008.
Looking forward to meeting you at one of the upcoming TensiNet events, we remain
Yours sincerely, Marijke Mollaert & Niels De Temmerman
- a new layout with an updated colour scheme improves navigation and readability- the database structure and input forms have been updated- an RSS newsfeed has been added, to keep subscribers informed
on the latest database entries- an event calendar can be browsed through to keep you informed
on upcoming events- random projects from the database are highlighted in a central banner- all TensiNet publications are grouped in one page to make ordering straightforward- News items are visible on the homepage and an RSS newsfeed feature
has also been added
New and improved
website We invite you to visit the
new website. The functionality has
been expanded and the user interface greatly
improved:
www.tensinet.com
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Editorial Board Mike Barnes, John Chilton, Niels De Temmerman, Brian Forster, Peter Gosling, Marc Malinowsky, Marijke Mollaert, Peter Pätzold, Rudi Scheuermann, Javier Tejera.
Coordination Marijke Mollaert, phone: +32 2 629 28 45, [email protected] Address Vrije Uni ver siteit Brussel (VUB), Dept. of Architectural Engineering, Pleinlaan 2, 1050 Brus sels, fax: +32 2 629 28 41ISSN 1784-5688
Ceno Tecwww.ceno-tec.de
Dyneonwww.dyneon.com
Form TLwww.Form-TL.de
IMSwww.ims-institute.org
Laboratorium Blumwww.labor-blum.de
Kurvenbauwww.kurvenbau.com
Messe FrankfurtTechtextilwww.techtextil.de
Taiyo Europewww.taiyo-europe.com
Schlaich Bergermann und Partnerwww.sbp.de
Saint-Gobain www.saint-gobain .com
Vrije Universiteit Brusselwww.vub.ac.be
Universidad Poletécnica de Madrid www.aq.upm.es
Technical University of Berlin www.survey.tu-berlin.de
technet GmbHwww.technet-gmbh.com
Tensotech Consultingwww.tensotech.com
Tentechwww.tentech.nl
Verseidagwww.verseidag.de
University of Bathwww.bath.ac.uk/Departments/Arch
University of Lincolnwww.lincoln.ac.uk/architecture/arc/
University of Newcastlewww.staff.ncl.ac.uk/p.d.gosling/pdg/
W.L. Gore & Associateswww.gore.com/tenara
Buro Happoldwww.burohappold.com
form TL
Ferrari sawww.ferrari-textiles.com
Canobbio S.p.A.www.canobbio.com
Architen Landrellwww.architen.com
Group ALTO
partners2007
INFO
TensiNews ContributionsWould you like to contribute to the TensiNet newsletter? We invite you to submit an article, project description, upcoming event, book review, etc…to the editors: [email protected], [email protected] follow these simple rules:- the text should be written in English, submitted in Word-format (.doc)- Images are to be sent separately, with a resolution of 300dpi in .jpg-format. (For easy reference during the layout process, it can be useful to include a copy of the pictures in the text file as well).For research articles the maximum word amount is set to 5000 words (equivalent of four pages in TensiNews layout).Project descriptions need to be accompanied by full contact details of the author, and other information such as architect,contractor, approx. span, height, membrane material, etc. This facilitates the inclusion of the project in the online database.
SAIESPRINGBologna, Italy Fair12/03/2008>15/03/2008 www.saiespring.bolognafiere.it
3D Modelling Symposium Berlin, Germany International Symposium07/04/2008>09/04/2008www.3d-msb.de
Roof & Cladding India 2008 Chennai, India International Symposium25/04/2008 > 27/04/2008www.roofindia.com
Fabric Formwork Conference Winnipeg, Canada International Conference16/05/2008 > 18/05/2008www.umanitoba.ca/architecture/ffc/
Textile Roofs2008Berlin, Germany Workshop 22/05/2008 > 24/05/2008www.textile-roofs.com
IASS 2008 Acapulco, Mexico International Symposium27/10/2008 > 31/10/2008www.iass-structures.org
Forthcoming Events
As of now, several TensiNet Working Groups will be installed. These Working Groups act under the wings of the TensiNet Association and will each deal with a specific subject, related to tensile surfacestructures. Their goal is to exchange knowledge on this subject by focusingand discussing in small, effective groups and to publish state-of-the-artdocuments. All TensiNet members interested in contributing to a Working Group are invited to contact the convenor. The following Working Groups have been initiated, others will follow in due course.
TensiNet Working Groups: accepting members now…Working Group convenors:- Analysis and Materials:
Peter [email protected]
- Website & Database: Marijke [email protected],
- Specifications: Klaus Gipperich
- ETFE: Rogier Houtman
SAIESPRINGBologna, Italy, 03/03/2008 www.tensinet.com
Partner Meeting
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This paper presents principles of architectural and structural design ofumbrella structures and the design methodology applied in several realizedprojects. It outlines the current application of the numerical Fluid StructureInteraction simulation for the investigation of wind loaded membranestructures and the work on generating atmospheric wind inflow conditionsfor numerical simulations.
1 - MOTIVATIONThe Architectural Office Rasch + Bradatsch is specialized in thearchitectural and structural design of lightweight structures. One of themajor tasks during the last years was the design of convertible funnelumbrella structures made of textile membranes and high strength steel.The funnel umbrellas built in the recent years have covered a range of 3.5 m to 29 m in span. Their unique design invented by Frei Otto in the late1960’s stands for itself and can at the same time be harmoniouslyintegrated into different surroundings.
2 - DESIGN PROCESSThe iterative design process is dominated by the difficulty of connecting aminimal surface prestressed membrane to elastic arms. The process beginswith the definition of the outer geometry and the formfinding of themembrane as well as the first design of an arm kinematics that meets bothboundary conditions of the open and closed arm position. In the followingiterative process the superelevations of the arm ends have to bedetermined. Redesign of the arm geometry based on the previouslycalculated deflections under membrane prestress has to take place untilthe deflected arm end is in equilibrium with the prestressed membrane atthe defined eave height. With the first system in equilibrium, based onguessed dimensions, the structural calculation under wind load can takeplace. Thereafter the geometry has to be redefined with the newlycalculated arm dimensions and their new deflections. In order to optimizethis process parameterized umbrella models where made that include thecalculation of the arm kinematics as well as the output of a detailed Finite-Element model of the structure.
3 - WIND LOAD ANALYSISThe sensitivity of membrane structures to wind loads due to their flexibilityand the reduction of inertial masses raises the question of their behaviorunder natural wind conditions. At stationary wind loads, the elasticbehavior of the flexible membrane leads to deformations with anassociated change of the flow conditions and wind pressure distributions.This effect can be enhanced by time dependent fluid fluctuations such asatmospheric or building induced turbulences. Both cases could result inaero-elastic instabilities. In contrast, most common structures aresufficiently rigid, so that interactions of wind loads with the structuraldeformation can be neglected. In boundary layer wind tunnels, the effectsof wind loads on rigid structures, typically scaled to 1:200 or 1:500, couldbe investigated. A problem occurs, when large deformation of the thinmembrane interacts with the fluid flow, because in the small model scale,similarity conditions of both, the flow and the structural vibrations, aredifficult to match.The coupled calculation of the structural deformation as well as of the flowpatterns and pressure distribution on the structure (Fluid StructureInteraction simulation) provides a design methodology for the evaluationof the behavior of light, flexible membrane structures under turbulent windconditions.The FSI methodology is based on a separate computing of the structuraland fluid domain and a periodical transfer of pressure/friction anddeformation information at the FSI interface. The standard softwarepackages used are the Computational Fluid Dynamics (CSD) code PAM
Flow and the Computational Structural Dynamics (CSD) code PAM Solidfrom ESI Group, Paris. This methodology allows using different time stepsin the fluid and structural parts for a given simulated physical duration,using sub-cycling. Information is updated at each time step for each solver(by interpolation) so that transient simulations are easily achieved. One major challenge of the numerical wind simulation on buildings is thecorrect reproduction of the natural wind conditions in the up-streamdirection of the flow. In other words, the inflow conditions of the fluid flowdomain must be defined according to the required conditions of the task.This problem was covered in outline in previous numerical simulations ofwind loaded structures. Mostly, only simplified wind profiles, which do nottake into account natural atmospheric turbulences, are used. In contrast,experimental wind tunnel investigations include these natural atmosphericturbulences. A specific wind module has been built and integrated to theESI PAM Flow software, which contains the generation of multi-correlatedwind velocity time series and specific interpolation routines.
4 - REALIZED PROJECTSSince the 1980’s the Architectural Office Rasch + Bradatsch has beeninvolved with the design of large convertible funnel umbrellas. The twoumbrella projects which are currently under construction (see below) arethe result of the experiences gained in several prototypes and otherrealized projects. Their Architectural and structural design was based on theprocedures mentioned above, including coupled FEM calculation and FSIsimulations.• 182 convertible umbrellas with a span of 26 m for the shading for the
Piazza of the Holy Mosque in Medina, Saudi Arabia• 6 convertible umbrellas with a span of 29 m in the height of 100 m on
the King Abdul Aziz Endowment Project tower in Mekka, Saudi Arabia
The objective of the FSI Methodology at these projects was to investigatethe dynamic behavior of umbrellas under turbulent wind loads to detectaerodynamic instabilities, assess dynamic safety factors and thedeformation of overlapping umbrella arrangements. The results of thenumerical simulations are used for the structural analysis and for thedevelopment of the folding kinematics in order to avoid critical contactbetween the steel arms of the lower umbrella and the membrane of theupper umbrella.
29 m Umbrella for King Abdul Aziz Endowment Project tower in Mekka, Saudi Arabia
26m Umbrellas for the
shading for the Piazza of
the Holy Mosque in
Medina, Saudi Arabia
A. Michalski, PhD candidate Technical University of MunichJ. Lienhard, University Stuttgart, Diploma work
[email protected]://www.sl-rasch.de
ON THE DESIGN OF UMBRELLA STRUCTURES
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Dynamic wind load simulationrequires a numerical quantificationof the properties of the naturalphenomenon called “wind”.
WindWind is motion of air. Air moves ona global scale because of differentialheating over the equator and overthe poles. At a fixed height aboveground, the pressure of warmer airnear the equator is greater than thepressure of colder air near the poles.This global air pressure gradienttends to move air towards thepoles. Coriolis forces tend to deviatethe pole-ward air streams to theright on the northern hemisphereand to the left on the southernhemisphere (going with the air).Beside global wind patterns weexperience regional winds such asFöhn, Mistral, Schirocco, hurricanes,typhoons, sea-land, mountain-valley wind systems and more. High altitude winds becometurbulent near the ground, wheremotion of air is perturbed bysurface roughness features anddifferential heating. Wind loads onstructures can fluctuate due tonatural turbulence of the wind, dueto turbulence created by nearbyobjects, and due to turbulenceinduced by the consideredstructure itself. The numericalsimulations employ computationalfluid dynamics (CFD) codes toevaluate the dynamic wind loads.Computational structural dynamics(CSD) codes calculate the effectsof these loads on structures.Coupled fluid-structure interaction(FSI) analysis can detect aero-elastic instabilities when thestructural deformations from windloads interfere with the flowpattern. This article outlines thevirtual design of structures underfluctuating wind loads.
Aero-elastic instabilityWind norms were developed whichprescribe the static wind loads forthe design of structures. Thefamous Tacoma Narrows Bridgeexperienced aero-elastic resonanceunder sustained winds, which madeit fail spectacularly in 1940 a few
months after its construction. Thisencouraged engineers to verifydesigns for aero-elastic instability.
Failure of the Tacoma bridge (Wikipedia)
While atmospheric wind tunnelscan easily apply turbulent winds toreduced-scale rigid objects, theycannot be used easily when thebuilding deformations interact withthe aero-dynamic wind loads. This is because of conflicts ofsimultaneously modeling the aero-elastic similitude of both, the flow pattern and the structuralvibrations at reduced scales. Fluid-structure interactionsimulation, however, can overcomethis handicap.
Atmospheric wind tunnelsIn so-called “atmospheric windtunnels” natural wind conditionsare synthesized by manipulatinginflow obstructions in the shape of“spires” and by adjusting the“roughness elements” of aroughness stretch ahead of theanalyzed object.
Atmospheric wind tunnel
Atmospheric wind tunnel experiment (Courtesy IfH University of Karlsruhe, Prof. Ruck)
In a dynamic CFD or FSI simulation,synthetic wind fields must begenerated from known statisticalwind data, such as local mean windprofiles, turbulence intensity
profiles, covariance functions, windpower spectra and spatial flowcoherence functions. These datacan be derived from the individuallocal wind records supplied bymeteorological stations.
Wind recordsWind velocity records, ui(t), can betransformed into a time-constantwind “mean” velocity, ūi , and atime-variable “fluctuation” gustwind velocity record ui’(t)
ui(t)=ūi+ui’(t)
Typical wind record with mean and standarddeviation
The duration for measuring thetime-constant mean wind is oftentaken as 10 minutes. Thefluctuations measure wind gusts of3 - 5 second duration. Turbulenceintensity is defined as the standarddeviation divided by the mean.
Wind norm data include windprofiles and turbulence intensityprofiles. These data are available atdifferent sites from long standingseries of wind recordings.
Mean wind (10 min), gust wind (3-5 sec) andturbulence intensity profiles
The vertical mean wind profiles, forexample, are specified for differentregions: urban, woodlands,seascapes. As indicated in thefollowing figure, the uniform windvelocity is reached fastest oversmooth seascapes.
Different mean wind profiles
Synthetic wind fieldgenerationBased on statistical windquantities, two methods for thenumerical generation of syntheticwind fields, or input time series ofthe wind fluctuations, have beenimplemented for PAM-Flow.
They approximate best the knownstatistical wind data of naturallyturbulent wind processes, asdefined for various regions andlocations: (1) “Auto-regressive processes of
order p” (AR(p)), where a windfield depends on p past windfields based on purely recursiveand statistical considerations.
(2) “Wave superpositiontechniques”, (using inverse FFT)where the atmospheric surface-layer turbulence is based on 3Dspectral tensors.
Once the turbulent fluctuationshave been synthesized at thechosen inflow boundary gridpoints, the mean velocities must beadded to obtain the total syntheticwind records, which can now beinterpolated to the fluid meshpoints at the inflow boundary:
Synthetic wind field from known meanprofiles and calculated fluctuations
Results. The mean wind velocity profile andsnapshots of fluctuations obtainedfrom a synthesized wind field usingthe AR(p) method is shown in thefollowing figure.
Generated numerical wind profiles
The expected spatial and temporalcorrelations of the generated flowpattern are recognized in the darkercurves to the right, while randomwind velocity fluctuations (lightercurves) lack this correlationinherent to the wind.
Applications.The AR(p) scheme is applied toflexible umbrella structures. Owingto the AR(p) scheme, thefluctuating mean wind profile canbe applied instead of theconservative gust wind profile.A free-standing single umbrellathat covers an area ofapproximately 29x29 m (a) ismodeled in PAM-Solid (b) and inPAM-Flow (c) and it is subjected toa synthetic wind field. The umbrellais made of a very high strength
MAKING WIND …
From Botticelli’s Birth of Venus
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INNOVATIVE SHELTERINGPRESENTATION OF WORLD STANDARD FOR SHELTERS AND TOPICS
FOR THE INNOVATION OF EMERGENCY SHELTERS
It is one of the main responsibilities of the Dutch Red Cross to stimulateinnovation of emergency sheltering throughout the world. Therefore, fromNovember 21st to November 23rd 2007, the Dutch Red Cross in cooperationwith the Eindhoven University of Technology held the three-day internationalconference and workshop “Innovative Sheltering”. The aim of the conferenceand workshop was to challenge researchers, companies and NGOs to developbetter solutions to sheltering problems of people hit by disasters. In suchcases it is important to react fast and provide aid in an effective manner withattention for the long-term redevelopment of the area. This task calls forinnovative solutions and products. Approximately one hundred participantsfrom various companies, universities and NGOs attended InnovativeSheltering. The event was supported by TensiNet and the Shelter Centre.More information can be found on
www.innovativeshelter.com
The Shelter Centre, an NGO supporting communities impacted by conflictsand natural disasters, presented an objective world standard for sheltering ofthe Red Cross on which innovation and improvement of sheltering will bebased. The standard can be found on
www.sheltercentre.org/sheltercentre/attached/SM07b-Standards.pdf
Based on the ideas of the participants of Innovative Sheltering five topics wereformulated, around which participants were gathered. The five topics were asfollows:
1. Mapping Universities will develop a global emergency aid system containinginformation. The goal is to make a tool that will provide every Red Crossorganization in case of emergency with the correct data and local contacts andorganizations. Moreover the databank can be used for developing location-tiedsheltering concepts. Universities have been invited to join this group.
2. High-tech innovations for low-tech solutionsThe participants will study membranes, photovoltaic cells, heating systems,heat insulation and lighting. They will focus on feasibility of new innovationsfor emergency sheltering.
3. Cardboard shelteringThe participants will study the benefits of cardboard sheltering and improveexisting concepts.
4. Teaching and information for local innovationsThe participants will supply information by writing a book and setting up awebsite. With this information and by settingup training programmes this groupwill teachpeople to help victims of disasters with localmaterial and “simple” techniques.
5. Transitional shelteringThe whole group of participants is divided intoseveral subgroups which will focus onsheltering for the period up to 10 years afterthe calamity.
The Eindhoven University of Technology, theDutch Red Cross and the Shelter Centre haveformed a response commission for every topic.The response commissions in cooperation withthe participants will start fundraising in order torealize the ideas that will improve emergencysheltering.With an increasing number of disasters andpeople affected by these disasters, the need foradequate sheltering is more urgent than ever.Innovative Sheltering has been a starting pointto a process of innovation by bringing togethervarious disciplines and expertise. Within thenear future we hope to present the results.
Arno Pronk, [email protected]
steel frame, which deploys a high-tech, UV-resistant, synthetic fabric(Teflon).
(Courtesy Liebherr Werke Ehingen)
Umbrella structure: (a) in reality; (b) structural model; (c) CFD model
Synthetic wind field A time snapshot of the velocitycontours from the generated windfield is shown on different sectionsand at the flow domainboundaries, (d).
Umbrella structure: generated wind velocityfield (time snapshot)
The overturning moment at themast foot of the umbrella is aprincipal design factor. Thismoment is plotted over time (e)and surface velocity and windpressure loads on the umbrella areplotted at times of large (f) andsmall (g) moments.
Note that the turbulence seen overthe umbrella surface stems fromthe umbrella itself, but also fromthe turbulent nature of the wind.The natural wind turbulence is nowavailable in the CFD and FSIsimulation packages.
Flexible structures. Flexible structures are sensitive towind loads, with possible aero-elastic instabilities, such assustained edge flutter shownbelow.
If folded away, gusty winds maydamage the flexible fabric, whichcalls for rigorous wind load design.
The methodology can be appliedto the design of wind turbines:
Compiled by : Eberhard Haug
Wind implementation : Alexander Michalski
Simulations : Pierre de Kermel
Permissions : SL Rasch GmbH / Liebherr Werke Ehingen / University Karlsruhe
Source: ESI GroupPAM-TALK Issue 34 – Spring 2007
“Adaptable and polyvalent shelter kit”presented by C. Henrotay
Shelter by R. Giesbers photo C. Henrotay
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The inflatable Tea Pavilion of the„Museum für angewandte Kunst(MAK)“ was as a kind of jointbetween sculpture and temporaryroom for ceremonies an unusualjob for us. It is a gift by Japanesecompanies to the city of Frankfurtand especially to the MAK whichhas very tight connections to Japanbecause of its far easterncollection.
An extract from Wikipediadescribes the tea ceremony: (Japanese ... cha-no-yu, engl. hotwater for tea), also known as tearitual is related to the philosophy ofZen. All the schools, and most of thevariations, however, have facets incommon: at its most basic, the teaceremony involves the preparationand serving of tea to a guest orguests. (…)Both tea houses and tea rooms areusually small, a typical floor sizebeing 4 1/2 tatami, the traditionalJapanese floor covering. The smallesttea room can be as little as one-and-a-half mats, and the size of thelargest is determined only by thelimits of its owner's resources.Building materials and decorationsare deliberately simple and rustic. (...)
Conversation is kept to a minimumthroughout. Guests relax and enjoythe atmosphere created by thesounds of the water and fire, thesmell of the incense and tea, andthe beauty and simplicity of the teahouse and its seasonallyappropriate decorations.
It is unusual that from thebeginning Kengo Kuma has chosenmodern material. While wood andsliding walls were left out, a hint ofdiminutive bamboo is found at thebase of the pavilion. Tatamis,although made of easy-to-cleansynthetic material, the low ceilings
and the even lower doors as well asthe zoning and the counter-sunkfire-place have been kept by KengoKuma during the whole designprocess.Even on his first drawings heshowed a smoothly shapeddouble-bowl structure which we
modified and specified duringmonthly meetings. At the end theorganic shaped structure withmembrane cover became a self-carrying double-wall pneu withminimized assembly anddismantling times – and it fits intothe budget of Japanese sponsorsand the museum. After several very positive pressreactions in db, Baumeister and theMAK-publications Prof. Schneiderinformed us that the magazin„Architectural Digest“ selected theModern TeaHouse as one of the„110 Highlights des guten Stils inDeutschland (110 highlights ofgood style in Germany) “. We were aware that the ModernTeahouse was very conciselydesigned and that the sculpturalapproach seemed appropriate. We knew as well that form,material and structural analysis areone and that we were not allowedto take any compromises. It wasimportant that Canobbio testedour details and optimized untileven Signor Bargelli, technician ofthe production, was content. Hereespecially the now conic pattern ofthe welding points is in my mindwhich avoids any wrinkles at theoutside cover although folds werepredictable because of the localload concentration of the ropes.
Because of its shape the Teahousegot the working title „Peanut“: acover of 80 m² encloses with adistance of 40-100 cm an about 60 m² cover.
KKAA Sept. 2005 KKAA Febr. 2006 formTL March 2006 formTL March 2006
KKAA Febr.2007
View in the evening with LED light (Uwe Dettmar, Frankfurt)
MODERN TEAHOUSE 2007FOR MAK FRANKFURT/MAIN
Tent construction has always been deeply embedded in the Arabianmentality. Therefore it is no great surprise that in particular textile projectsin Arabic-speaking countries such as the King-Faisal-Stadium in Riad, haveset important milestones in the development of modern membranestructures. CENO TEC has also developed a key market in the Near Eastsince the 1970s. With a widerange of projects from a car parkto stadium roofing, the teamfrom Greven has alwaysdelivered convincing referencesand created long-term trustfrom their Arabic clientele.
The client for one of CENOTEC's latest projects was noneother than Sheikh Sultan, amember of Abu Dhabi's royalfamily, who gave CENO TEC thetask of completing variousmembrane constructions for hisprivate residential grounds.
A total of 6 single-point funnel canopies for the swimming pool installationand 3 membrane sails for the adjacent private beach were assembled inMay 2007 – but not only as protection against the intense sun, as the readermay think. Above all they are designed as optical highlights to enhance theentire pool and beach area.
CENO TEC BUILDS HIGH-QUALITY SUN-PROTECTION SYSTEMS IN ABU DHABI
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At the footprint the two covers areair-tightly welded together and 3-4 times per m² joined togetherwith thin synthetic ropes betweenwhich the air is blown in, similar toa dinghy or water wings. But insteadof membrane stripes - such as theones used for inflatable matrasses -the two covers are only pointwiselyjoined which leads to a golf ballshape and defines the texture of theinner and outer surface.
The stability of this flexible bowl isformed by the size of the footprint,the internal pressure and thenumber of joints. From 1.000 Pascal internal pressure the„Peanut“ stands up and with 1.500 Pascal the flexible bowl isstable enough to face a storm. The blower is dimensioned for 2.200 Pascal so that there isenough capacity for the air. We had to take into account thatafter several times of assemblyand dismantling the leakage of thecover will increase. Therefore theblower got a variable regulation so that the leaked supporting aircan always be added. Another big advantage is the soft blower noise
which allows a use inside theentrance hall.
Although the Modern Teahouseseems to be thin-skinned andsensitive, it is not because of theTeflon fabric which is inured tokink. It survived the run ofthousands of visitors at the day ofthe inauguration and as wellseveral times of assembly anddismantling.
You will find the Teahouse in theentrance hall of the museum or ona little hill in the museum’s park –or it is waiting for the next teaceremony packed on a trolley. If you like you even can hire theTeahouse because also the bloweris movable.
[email protected]@form-tl.de
www.form-TL.de
Owner City of Frankfurt Architect KKAA Kengo Kuma & Associates, Tokyo, Japan Structural design formTL ingenieure für tragwerk und leichtbauand Membrane patterning gmbH RadolfzellManufacturing and assembly Canobbio S.p.A., Castelnuovo Scrivia, ItalySize covered area 32 m²Perimeter length: 20 m
9 m x 4,6 m x 3,4 m (length x width x height) weight: 150 kg
Surfaces: 80 + 60 m² (outside, inside) 306 synthetic parts with screwable snap hooks
Membrane HF weldable Gore Tenara Type 1 3T40 (630 gr/m² PTFE-fabric coated
with fluor foil and with 38% translucency) Pattern 116 patterns with 30-80 cm width and 40 to 400 cm lengthAnchorage The Peanut is fixed with 40 m heavy duty-zips
on a LED lightened boxgirder, which is plugged on a foundation plate
Blower S+H Nolting GmbH, maximum +⁄- 1.000 m3/h, Radial-blower with dryer and pressure control
Design March 2006 - June 2007Manufacturing and assembly July 2007Inauguration August 2007Published Baumeister 9-2007, db 10-2007Awards Architectural Digest 10-2007: Highlights in Deutschland
”Straplinks” between inner and outer cover(formTL)
Close view (Prof. Schneider) Supporting air supply und air pressurecontrol with standard elements from foodindustry (formTL)
Extra-valve for the active ventilation of theair chambers during summer time also ascooling system (formTL)
formTL March 2007 formTL June 2007
Connection point and “Straplink” (formTL) Welding of “Straplink”-connection points atCanobbio’s (formTL)
The umbrella constructions are mobile and have various heights from 4.60 to 7.40 m and differing diameters, ranging from 8.10 to 12.60 m. As some of the umbrella surfaces overlap, they are opened and closed fullyautomatically in sequence in order to avert possible collisions.
The 3 membrane sails for the beach were arranged around a central mast asa so-called "tri-sail" structure and anchored at the sides. They roof in a totalof 320 m2.Just as the location itself – the palace and the entire grounds of theresidence –, the materials used for the membrane structures are also onlythe "crème de la crème": All steel and rope constructions aremade using stainless steel with athree-layer white coating. Themembranes are made of PTFE tissue,specially created for this task. Theadvantages of this high-qualitymaterial:- Absolute buckling resistance
(important for the folding process)- Extreme UV and weather
resistance- Not prone to soiling
All umbrella membrane surfaces were sewn using 100% PTFE thread andnot tacked. By using various material layers at the bottom of the membraneand at the pinnacles, the fabrication accentuated the design, which is stillfurther underlined by the use of green PTFE ties. The green colour of the tiesharmonises with the turquoise blue tone of the pool and sea water. Furthervisual refinement was provided on the umbrella stands with ceramics, someof which were decorated with gold-plated tips. The support pedestals werealso enhanced with ceramic elements.
Client Al Nasr Irrigation & Contracting.Co.LLC Abu Dhabi in the name of Sheikh Sultan
Planning Büro für LeichtbauJ.Tritthardt with Textil-Bau-Konstruktion
J.Schilling Membrane CENO TEC GmbH Textile Constructions Covered Area Foldable Umbrellas: 4x ø12,60 m / 2x ø8,10 mTri-sails: ~318 m²Year of Construction 2007
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SPECIAL PROJECTS ARCHITEN LANDRELL ASSOCIATESO2 SHOP LONDON-UKDesigned as a tactile and friendly space, Architen Landrell was commissionedto add a fabric and lighting feature to the O2 store inside the O2! Once theMillennium Dome, one of London’s most famous iconic structures, AEG andO2 have transformed the space into a brand new entertainment centreincorporating shops, restaurants, music and sporting venues. In theentranceway lies a concept store and interactive lounge space for thecommunications giants to market their services.Large, inflated PVC coated polyester pillows were installed over two entirewalls and formed the basis of the installation. The O2 shop was an entirely innovative design. Without being able to fixdirectly to the floor, the whole installation – fabric, lights, steelwork andcontrol systems - had to be suspended from the existing wall. Unlike any ofour other projects, the pillows were welded in a particular way to produce thedesired wrinkles! A welding tool had to be specially created to ensure thiswould consistently occur.Architen’s lighting department designed the lighting of the pillows with LEDcolour changers mounted on the frame behind. Proximity sensors located ateach column interact with customers and change the effect of the lighting aspeople draw near or step away. The funky colour changing pillows helprealise the designers desire to create a laboratory space which encouragespeople to interact with the phones and their environment.
As part of the new £25 millionAirSpace development project,Architen Landrell won the contractto install an impressive 225 metrelong fabric ribbon structure at theImperial War Museum in Duxford. Known as The Flight Path, thisstructure not only provides adramatic visual cue to lead visitorsthrough the exhibition, but is usedin a number of ways to enhance thedisplays themselves. Presentinglarge bold printed graphics, itssurface forms a projection screenfor audio visual presentations and aback drop for effects lighting, whichhelps to identify distinct areas ofthe exhibition, giving different areasa sense of enclosure and a surfaceon which to present various
materials or aircraft components. Created from a stretch materialmade from Lycra, and then dyedand printed with the aeroplanesilhouettes, the fabric was chosento be as malleable and flexible aspossible. ‘Socks’ of the fabric weremade and then stretched over asteel frame to create a perfectlysmooth and continuous ribbon.The Flight Path was conceived as a1.8 metre wide undulating, twistingribbon that passes in three-dimensional form down the lengthof the first floor gallery. Starting atthe main entrance on the groundfloor, the structure rises up thestairway to the main exhibitionspace, and performs a number ofaerobatic manoeuvres as it flowsthroughout the hanger.
Location: Manchester, UKClient: Manchester International Fesitval Year of Completion: 2007 Architect/Designer: Stephenson Bell Architects Main Contractor/Customer: ISG Totty Category: Exterior, Special ProjectsMarket Sector: Entertainment, Events Fabric Type: PVC - coated polyester fabricDesign Style: ConicFunction: Weather Protection, Sculptural/Decorative Dimensions: 21m high and 21m in diameter
Client: Trustees of the Imperial War Museum
Year of Completion: 2007 Main Contractor/Customer:
Fraser RandallLocation: Duxford, UKCategory: InteriorMarket Sector: ExhibitionFabric Type: Stretch FabricDesign Style: BannerFunction: Sculptural/Decorative
Located atthe heart ofManchester,the FestivalPavilion
manufactured and installed byArchiten Landrell is a beautifullydynamic space specially designed forthe Festival in conjunction withaward-winning architectsStephenson Bell.The pavilion was manufactured inPVC coated polyester fabric in orderto achieve maximum strength anddurability but also to enable a quick
and easy installation and removal.The temporary structure wasinstalled on site ready for the openingof the festival on 28th June 2007 andremained in place for a number ofweeks before being taken down atthe end of the festival period. Its unusual form made it a strikingcentre piece for the newlyestablished festival. While thepavilion stood, it formed the focalpoint for the entire festival andserved as the place to meet, talk,eat, drink and soak up the atmosphere.
INTERNATIONAL FESITVALPAVILION MANCHESTER-UK
IMPERIAL WAR MUSEUM DUXFORD-UK
O2 RIVERWALK LONDON-UKStretching around 150 m, and leading from the bank sideto the entrance of the entertainment centre, the walkwaywas designed to provide complete weather protection forthe VIP guests. Encased in a beautiful willow wall, designersBarr Gazetas intended the walkway to have as muchprivacy as possible to create an exclusive entrance. Thesymmetry and curvature of the fabric has elegance in itsdesign and juxtaposes effectively with the more industrialdesign of the Dome. A wow factor was also important to the client and thoughthe walkway provided an impressive entrance, the additionof interactive lighting ensures a stunning arrival. Architen’slighting division was tasked with the design and supply of
an interactive lighting system that lights the walkway in an array of vibrantcolours as the VIP visitor’s progress to their destination. Also included inArchiten’s project was the refurbishment of the existing lighting whichincluded the replacement of over a thousand light bulbs and extensiveservicing control equipment. Two additional inverted umbrella canopieslocated on the pontoon were also thrown into the Architen brief, as was theinstallation of a further three inverted cone canopies on the bank side on thecanting bridge. Fabric was an obvious choice for the designers. Not only doesit provide a lightweight structure with graceful form, translucency and anaesthetically seamless interface between the existing listed fabric structure ofthe O2 dome and the inverted cone and umbrellas on the canting brow, it alsoties in well with the natural surroundings and promotes the ethos of theGreenwich Peninsula which dates from the original days of the MillenniumDome. The large spans at each end of the walkway were challenging butnecessary in order to enable emergency access for vehicles. Integration with
existing structures alsomade it an unusualproject for our designteam. As the pontoonmoves up and downwith the movement ofthe tide, the canopy hadto be designed to movewith it.
Location: Greenwich, London, UKClient: AEG Year of Completion: 2007 Architect/Designer: Barr Gazetas Main Contractor/Customer: Skanska McNicholasFabric Type: PVC - coated polyester fabricDesign Style: Conic, Ridge and ValleyFunction: Weather Protection, Sculptural/
Decorative, Walkway Canopy, Feature Lighting
Location: London, UKClient: O2 Year of Completion: 2007 Architect/Designer: JPDA Main Contractor/ Bedford &Customer: HavenhandCategory: Interior, LightingFabric Type: PVC - coated polyester fabricDesign Style: InflatableFunction: Sculptural/Decorative,
Feature Lighting
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IntroductionThe Almuñécar Aquarium is a 3000 m2 underground installationwhich shows Mediterranean faunaon two levels below the KuwaitSquare next to the market andnear the City Hall of theandalusian town of Almuñécar(Spain). The Aquarium emerges tothe surface by means of its controlbuilding, staircase and lift, allarranged around an opencourtyard. We designed a textileroof in order to protect thiscourtyard from direct sunshine andrain. As the only part of thebuilding that shows above is themembrane, it has also beenenvisaged as an eye catcher inorder to attract visitor’s attention.Two water ponds reflect the whiteand lofty membrane set in front ofthe backdrop of white apartmentbuildings.The Almuñécar Aquarium Textile Roof
The textile roof protects the outdoorentrance to the Aquarium
StructureThe design of the structure isbased, on one hand, on the existingsupport structure of the aquariumand on the other, on a form thatallows tying up a free flowingborder without the use of anycables fixed to the ground. Thesolution consists of three archeswith different heights and spans(22, 24 and 22 m) which achieve adune-like image.
Trussed beams provide stability and take theprestress of the fabric
The branchesreduce drasticallythe span of thearches
The arches sit on top of six tree-like structures held in place by twoperpendicular trussed beams. Thesix masts beneath the tree-likestructure are anchored to the topslab of the aquarium andcorrespond in position to thereinforced concrete columnsunderneath. The structure provides10 peripheral anchor points for theedge cables and the membrane.The arches consist only in a pair ofCHS because the spans arereduced drastically by means ofbranching the masts as trees intheir upper parts. The porticos areset 9 and 10 m apart from eachother because of the irregularposition of the concrete columnsunderneath. Therefore we find only onesymmetry plane in the longitudinaldirection. In the same directiontwo trussed beams between theseporticos provide stability and takethe pre-stress out of the fabric.They project 5 meters behind the entrancebuilding and 6 metres over theopen square.
MembraneThe analysis was performed withan integrated model of the beams,arches and membrane.The membrane was manufacturedin a single piece to avoid joining onsite. It is fixed to 10 peripheralpoints and simply leans on thearches without any device to fix iton them. All the cables passunderneath the fabric in order toavoid any perforation. There aretwo different corner details
Statical analysis with EASY-Beam
according to whether they aresubjected to the arches or to thebeams. At the end of the arches, acircular bended plate allows fordifferent directions of edge cablesand corner plates. At the end ofthe beams, a plate is weldedperpendicularly to the direction ofthe corner plate and extra holesare provided for ease ofinstallation and pre-stress.
At the end of the arches, a circular bended
plate allows for different directions of edge
cables and corner plates.
At the end of the beams, a plate is weldedperpendicularly to the direction of thecorner plate.
RedundancyTies of the arches and cablesbracing the whole structure wererelaxed after pre-tension of themembrane. It means that theywere replaced functionally.Nevertheless, it is advisable tomaintain them in place preventinga general distortion or collapsefrom local failures.
Ch.García-Diego &H.Pöppinghaus:
[email protected]: [email protected]
www.arqintegral.com
THE ALMUÑÉCAR AQUARIUM TEXTILE ROOF
Client: AQUASCENIC,S.L.Location: Kuwait Square, Almuñécar, SpainGeneral Architect for the Aquarium: Carlos Javier Jiménez GonzálezArchitects and Structural Engineers for the steel structure and textileroof: Arqintegral: Ch.Garcia-Diego, J.Llorens & H.PöppinghausMembrane: PVC coated polyester FERRARI
Précontraint 1202 with FLUOTOP surface treatmentRoofed area: 700 m2
Steelwork: Metalisteria Anaya S.L. Vilasart de Dalt, SpainManufacturing and installation: T&P Construcció Tèxtil s.c.p.
Cornellà de Terri, SpainYear of construction: 2007
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Background Information:Before, there was an open parkingwithout a roof. A specialcommission of the city asked for anarchitectonic proposal, maintainingthe use of the parking.
Objectives of the roof:- A special design to
provide adistinctive designquality and goodinsertion in thecity
- Rain and sunprotection, so thespace can be usedas a comfortableparking all year
- Allowing entranceof natural light, at least 7%, so thearea is notdarkened
- Eliminating directsolar radiation, topreventoverheating
- Easy installation
Description:The covering is made of a PVC-coated polyester membrane,tensioned on a supporting steelstructure. The tri-articulated framesin reticulated steel round pipe aremade with different radius of
curvature. They are placed every4.62 m and span 20 m.With the generation of high andlow points in the perimeter, it waspossible to direct and concentraterainwater to eight points thusavoiding the use of gutters andsolving the water drainage bymeans of small buckets that arethen connected to the maindrainage system. It is a low-costsolution, of quick assembly. The objectives of the project werefulfilled: obtaining a very pleasantspace for parking.
Reasons for choosing a prestressedPVC-coated polyester membrane: It complies with all the objectives,and when compared to othertraditional systems such as glass,plastic, metal or concreteconstruction, these traditionalsystems do not meet all the
TWO LOW-COST BARREL VAULTS WITH A MEMBRANE COVER
PARKING JUNCAL
Background information:Initially the swimming pool wasonly used for summer. Theobjective was to use it also inwinter, taking advantage of thesolar energy to heat a smallcovered part.
Objectives of the roof:- Design with minimum air volume
for heating- Allowing entrance of natural light
and solar radiation- Rain protection- Easy installation of the membrane
Description:The cover is made of translucentPVC-polyester membrane,tightened on the supportingstructure. The main structure consists of tri-articulated arches, made of laminated wood. The arches have a span of 12 m andare placed at a distance of 4.5 m.With this solution, the use of a
detachable cover was possible on awooden frame. The wood was agood choice within the naturallandscape.
Reasons for choosing aprestressed pvc membrane: It complies with all the objectives,specially the fact that themembrane can be removed insummer.
Project: Parking Juncal Location: Montevideo, URUGUAY Construction date: June 2003Covered surface: 800 m2
Roof design and project: arch. Roberto Santomauro & arch.Patricia PintoRoof structural engineers: Marella & Pedoja.Roof fabrication and installation: www.sobresaliente.comGeneral project: archs. Anderson & Varela
DON JOAQUIN SWIMMING POOL
Project: Don Joaquin Swimming-PoolLocation: San Jose, URUGUAYConstruction date: June 2005Covered surface: 150 m2
Roof design and project: arch. Roberto Santomauro & arch. Patricia PintoRoof structural engineers: Marella & PedojaRoof fabrication and installation: www.sobresaliente.comGeneral project: arch. Miguel Cecilio
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For the Andreas-Paulus-Petrus Parish at Maassluis in The Netherlands,architects Mari Baauw and René Olivier of Royal Haskoning made a designfor a new church. In the past, different layouts of a church have beendeveloped, each layout having its own effect on the liturgical process in thechurch. It is restrictive to choose one layout as a basis for the design. Here,the design is based on an innovative functional layout. The architects havechosen to introduce the concept of segmentation: the segments should acthorizontally and vertically, wide, deep and high and should be large andsmall at the same time. Moreover, it should feel comfortable for groups aswell as individuals and it should become a space that breathes.These conceptual ideas were transformed into a physical model based onfive different shells grouped together, partially overlapping each other. Bydoing so, the aforementioned segmentation was possible. The daylightenters the building between the overlaps of the different shells.
The design by the architects was merely based on the functionalrequirements of the spaces, meaning that there was no materialization ofthe design. So the starting point for the structural design was the physicalmodel of the architect. The structural concept of the church consists of fiveshells that are structurally independent. Each shell consists of three steelarches which are mutually connected by girders. At the top and the bottomside of each shell a membrane is positioned. Onto the lower membraneplaceholders are welded in crucifix shape, which hold an insulation layer. Atthe inside of the church the stamp of the crucifix weld is slightly visible,effectively bringing a smooth appearance to the inner fabric. The lowermembranes of the two main shells have a valley cable which creates astrong curvature in the lower fabric, resulting in a strong visual impact atthe inside. The outer fabric of the two main shells also has a valley cable butit does not influence the shape of the fabric, leading to a normal saddleshape form. This creates a large space between the outer and inner fabric,giving room to the internal steel structure and even allowing for the use ofstraight girders instead of curved ones.
The outer and inner layers of fabric are mutually connected by a closing slabwrapped around the steel arches. Because this is a doubly curved membranecomponent, it is also treated as a membrane. To be able to formfind thefabric slab, a contact surface analysis is conducted. As the fabric continuesall around the shells, it proved cumbersome to attach the façade, which isplaced between the overlap of the different shells, to the supporting steelstructure. This was solved by creating holes in the fabric at a certaindistance from each other. This enabled a vertical placeholder to go troughthe fabric to connect the secondary steel structure of the façade with themain bearing structure. The gap between the secondary steel structure andthe fabric is closed by a slab that enables movement of the fabric.
Rogier Houtman, Harmen Werkman, [email protected]
Project name: APPP church, Maassluis (NL)Client: Andreas Paulus Petrus ParishArchitect: Mari Baauw, René Olivier of Royal Haskoning Material: outer fabric 1400 m2 Ferrari Fluotop T2 1202
inner fabric 1000 m2 Ferrari Fluotop T2 702 opaqueStructural Engineer: Royal Haskoning, Rotterdam (NL)Membrane Engineer; Tentech Utrecht (NL)Steel&Concrete contractor: De Klerk Werkendam (NL)Membrane contractor: Buitink Technology, Duiven (NL)Façade Contractor: Rodeca Alphen ad Rijn (NL)Building service Contractor: Stewitech Duurzaam (NL)
Plan view of church
Principle of insulation
Segmentation of shells also outside clearly visible
Isometric view of steel structure
Isometric view of steel structure and innerand outer fabric
View inside the space between upper and lowerfabric
Both inside views show the strong impact of the curved lower membrane and the colored façade.
Front view of church
APPP CHURCH WITH DOUBLE LAYERINSULATED MEMBRANE COVERING
requirements. Furthermore, someof them add new problems, suchas increasing internal heat andblocking the light completely.
Design:The roof shape is obtained byalternating two families of frames,which generate high and lowpositions. These allow to obtainthe curvature in the membrane,and also the pluvial water isdrained to a very few welldetermined points.
Prestressing:The tension in the membranes isobtained by a cord, which tensionsthe canvas to the structure.
Building process:After installing and anchoring thestructure, the membranes wereassembled in two days.
Materials:The structure is made of 9 framesof reticulated 2,5” and 2” steeltubes. The membranes are madeof threaded polyester PES HT1100dtex, 5x5 threads per cm (12 threads per inch) with PVCcoating, UV protection on theoutside, a weight of 800gr/m2
(230oz/sqyd) and a breaking loadlimit of 30daN/cm (167lbs/inch).
Design:The roof is generated withelliptical arches to obtain theminimum air volume to be heated.
Prestressing:The tension in the membranes isobtained by a cord, which tensionsthe canvas to the structure.
Building process:After installing and anchoring thestructure, the membranes wereassembled in one day.
Materials:The structure is made of laminatedwood arches. The membranes aremade of threaded polyester PESHT 1100dtex, 5x5 threads per cm(12 threads per inch) withtransparent PVC coating, a weightof 800gr/m2 (230oz/sqyd) and abreaking load limit of 30daN/cm(167lbs/inch).
Roberto Santomauro,[email protected]
www.sobresaliente.com
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This article proposes an initial basic philosophyfor the new TensiNet Analysis and MaterialsWorking Group and in so doing, calls forinterested parties to become involved. The working group offers the opportunities to discuss existing and to propose newperspectives on the analysis of fabricstructures. It especially encourages theconsideration of the concept that materialstesting and computational mechanics aremutually dependent and, by implication, not to be considered as independent.Current representations of fabric stress-strainbehaviour are based on plane-stressassumptions, and tend to simplify the availabledata (e.g. use of secant elastic moduli). Young’smoduli and Poisson’s ratios are typicallydetermined for each test so as to provide thebest fit plane to limited scattered data points.These planar representations provided limitedcorrelation with test data. The elastic constantsdo not comply with plane stress theory sincecoated woven fabrics are not homogeneousmaterials: they are composites with theinteraction of orthogonal yarns making them act as a constrained mechanism.As an initial basis of a forum for discussion, a new approach to incorporating fabric testdata in structural analysis was proposed at theTensiNet symposium in Milan (2007): use of direct correlation between pairs ofstresses and strains. This avoids the inherentapproximation in defining elastic constants orother parameters to quantify the fabricbehaviour, requiring a fundamental change inthe integration of material information intocomputational analysis.
Representation & use of testresults – plane stressUse of biaxial fabric test data in structuralanalysis is typically set within a plane stressframework using elastic moduli and interactionterms. The suitably of this approach forrepresenting non-linear fabric behaviour has
been assessed by comparing test data with a‘best fit’ plane stress model. Residual strain hasbeen removed from the test results and themean value of the loading and unloadingcurves have been calculated. This simplificationapproximates the inelastic hysteretic fabricbehaviour with an elastic response and isnecessary before trying to represent the fabricbehaviour with a plane stress model.Plane stress theory defines a relationshipbetween stresses and strains in thin continuausing Young’s moduli and Poisson’s ratios.Applying plane stress theory to the principalwarp and fill fabric axes gives:
σw σf νfwεw = ——— - ————— , (1)Εw Εf
σf σw νwfεf = ——— - ————— , (2)Εf Εw
where ε = strain, σ = stress, Ε = Young’smodulus, subscripts w and f denote warp andfill directions respectively, and ν = Poisson’sratio, defined as:νwf = fill direction strain caused by unit strain
in the warp direction,νfw= warp direction strain caused by unit
strain in the fill direction.The results for each pair of tests on one type offabric have been combined into one data-set,and values of Young’s modulus and Poisson’sratio have been determined to minimise theroot-mean-square deviation of the plane stressvalues from the test results (Table 1). No constraints were imposed on the values ofYoung’s modulus and Poisson’s ratio. For eachstress state tested the strains predicted by (1)and (2) have been compared with the testresults (Table 1). The plane stress equationsdefine planes in the stress-stress-strain spacewhich can be used to visualise therepresentation of the test data (Figure 1 & 2).
The overall correlation between the test dataand plane stress representation is good. ForPVC-polyester fabrics the variation between
the test data and plane stress model is onlytwice as much as the variation between thetwo repeat tests (Table1). The plane stressrepresentation is only slightly less accurate forthe PTFE-glass fabrics, but the fabric responseis more consistent between tests making themean 6 to 7.5% discrepancy between the testdata and plane stress model more significant.The good fit of the plane stress model to thePVC-polyester test data can be attributed tothe low level of crimp in the fabric, and the lowtensile modulus of the polyester yarns. The lowlevel of crimp (compared to PTFE-glass fabrics)results in less marked non-linearity. The lowtensile modulus reduces the effect of thetransition between crimp interchange at lowload and yarn extension at higher loads. Whilstthe mean deviation of the plane stress
TENSINET ANALYSIS & MATERIALS WORKING GROUPBASIC PHILOSOPHY AND CALLING NOTICE
RMS strain difference RMS Fabric Material Young’s modulus Poisson’s ratio‡ for all test data points strain difference
(Type†) (kN/m width) (percentage strain, (percentage sd = standard deviation) of test strain range)
Warp Fill νfw νwf Warp Fill Warp FillTaconic Solus 1120 PTFE-glass (G5) 960.7 371.7 1.87 0.57 0.53, sd = 0.50 0.96, sd = 0.91 7.21 6.41Taconic Solus 1300 PTFE-glass (G6) 1229.3 416.7 2.02 0.50 0.41, sd = 0.37 0.88, sd = 0.81 6.82 5.99Taconic Solus 1410 PTFE-glass (G7 ) 2246.9 1161.7 1.36 0.60 0.49, sd = 0.45 0.34, sd = 0.33 9.72 4.93Verseidag B18059 PTFE-glass (G6) 755.5 356.2 1.78 0.58 0.64, sd = 0.58 1.38, sd = 1.27 6.29 6.49Verseidag B18089 PTFE-glass (G6/G7) 852.2 341.5 1.91 0.54 0.75, sd = 0.70 1.29, sd = 1.23 7.93 6.61Ferrari 702T PVC-polyester (I) 592.0 342.9 1.01 0.35 0.20, sd = 0.18 0.33, sd = 0.30 5.35 4.47Ferrari 1002T PVC-polyester (II) 772.8 463.0 0.98 0.37 0.34, sd = 0.32 0.46, sd = 0.45 7.95 5.71Ferrari 1202T PVC-polyester (III) 877.9 506.0 0.79 0.42 0.51, sd = 0.47 0.46, sd = 0.42 8.08 5.23Ferrari 1502T PVC-polyester (IV/V) 1192.2 536.1 1.59 0.37 0.45, sd = 0.41 1.02, sd = 0.94 6.33 6.58Verseidag B6853 PVC-polyester (III) 825.7 341.6 1.20 0.38 0.50, sd = 0.45 0.66, sd = 0.60 7.54 5.18
All values are determined from adjusted test data, i.e. with residual strain removed.‡ According to plane stress theory Poisson’s ratio cannot exceed 0.5. However, higher values are required to model the high level of warp-fill interactionand large negative strains which occur in woven fabrics under biaxial load,νfw= fill direction strain caused by unit strain in the warp direction, νwf = warp direction strain caused by unit strain in the fill direction.
Table 1. Plane stress representation of fabric test data
Figure 1. Test data for two test and best fit plane, Ferrari1202T PVC-polyester
Figure 2. Test data for two test and best fit plane, TaconicSolus 1410 PTFE-glass
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representation from the test data is good, thestandard deviation is large (similar to thedifference, Table 1). For some stress ratios andload levels the correlation is not so good, ascan be seen in Figure 1 & 2.
Even when mechanically conditioned, theresponse of PTFE-glass fabrics is highly non-linear due to significant crimp interchange at lowload and tensile extension of the stiff glass yarnsat high loads. The repeat tests on PTFE-glass givemuch closer results than for PVC-polyesterbecause the tensile properties of glass fibres areessentially linear elastic, unlike the non-linear,time dependent polyester yarn behaviour. For the PTFE-glass fabrics, in the fill direction the RMS difference between the plane stressmodel and test data is 3.5 times greater than the difference between repeat tests.The relatively close correlation between theplane stress model and test data seems to be instark contrast with previous work on the non-linear nature of coated woven fabrics.However, previous research used stress-straindata for initial fabric behaviour (Clulow & Taylor,1963; Day, 1986), which exhibits greater non-linearities than the mechanically conditionedresponse. For structural analysis it is theconditioned behaviour which is appropriate inwhich medium to long term material propertiesare required. Furthermore, conventional stress-strain plots at a single warp to fill stress ratiomay show significant non-linearities whilstcomprehensive data giving an overview of thefabric behaviour for all stress states may obscurethese important features. However, a planestress representation leads to a number ofinconsistencies from a computational mechanics(viz. analysis) perspective. For example, a linearelastic orthotropic material subjected to biaxialstress, the Young’s moduli and Poisson’s ratio arerelated by:
νwf νfw——— = ——— , (3)Εw Εf
where:Εw is the warp direction Young’s modulus,Εf is the fill direction Young’s modulus,νwf is the fill direction strain caused by unit
strain in the warp direction andνfw is the warp direction strain caused by unit
strain in the fill direction.The values of Young’s modulus and Poisson’sratio determined above (Table 1) do not fit thisrelationship. Consider the mean values for eachfabric material from Table 1:PTFE-glass fibre:
Εw / νwf = 1209 / 0.56 = 2157,Εf / νfw = 530 / 1.79 = 296,→ Εw / νwf ≠ Εf / νfw
PVC-polyester:Εw / νwf = 852 / 0.38 = 2242,Εf / νfw 438 / 1.11 = 395,→ Εw / νwf ≠ Εf / νfw
It is proposed here from inspection of thevalues of Young’s modulus and Poisson’s ratioin Table 1 that these values adhere more closelyto an inverse of the plane stress relationship foran orthotropic material. However, a constant(C) also needs to be introduced for therelationship to hold:
νwf νfw——— = C ( ——— ) (4)Εf Εw
Values of C are reasonably consistent for eachfabric material:PTFE-glass: Mean value of C = 1.40
(standard deviation = 0.11),PVC-polyester: Mean value of C = 1.51
(standard deviation = 0.33).For comparison, if a similar constant is intro -duced in (3) the values are much more variable:PTFE-glass: Mean value of C = 7.32
(standard deviation = 2.82),PVC-polyester: Mean value of C = 5.70
(standard deviation = 2.54).The inverse relationship introduced in (4) ismore apposite for coated woven fabrics than theplane stress relationship (3). Whilst having littleassociation with plane stress theory, (4) providesa simple relationship between the Young’smodulus and Poisson’s ratios which bestrepresent the biaxial response of architecturalfabrics. Informal peer review of this researchquestioned the validity of the values in Table andthe relationship defined by (4):
“This material would violate the reciprocaltheorem and the conservation of energy.Consider a unit square of material. I will use sfor stress and e for strain. If we consider twoload conditions1. sa and sb in the x and y directions
respectively 2. sc and sd in the x and y directions
respectivelyIf we apply 1 followed by 2 the strain energy isW = ½ ( sa.ea + sb.eb ) + ½ ( sc.ec + sd.ed )
+ ( sa.ec + sb.ed )If we apply 2 followed by 1 the strain energy isW = ½ ( sa.ea + sb.eb ) + ½ ( sc.ec + sd.ed )
+ ( sc.ea + sd.eb )Now the strain energy should be independentof how we get there for conservation of energyso that implies that
½ ( sa.ea + sb.eb ) + ½ ( sc.ec + sd.ed ) + ( sa.ec + sb.ed )½ ( sa.ea + sb.eb ) + ½ ( sc.ec + sd.ed )+ ( sc.ea + sd.eb )
or ( sa.ec + sb.ed ) = ( sc.ea + sd.eb )Using a strain-stress relationship
ex = A.sx + B.syey = C.sx + D.sy
we get that( sa.sc.A + sa.sd.B + sb.sc.C + sb.sd.D ) =
( sa.sc.A + sb.sc.B + sa.sd.C + sb.sd.D ) or ( sa.sd.B + sb.sc.C ) = ( sb.sc.B + sa.sd.C ) Which is only satisfied if B = C. Or the standardrelationship between E and nu for anorthotropic material; i.e. the nu values are notindependent.” Hendry, 2005
This query is correct in the context of ahomogeneous material. Fundamental is thefact that coated woven fabrics are nothomogeneous materials: the interaction ofwarp and fill yarns and the behaviour of thetwisted yarn structure mean that they arebetter described as a mechanism. It is thismechanical interaction which causes the elasticmoduli and Poisson’s ratios not to fit therelationship for a homogeneous material (3).This effect is augmented by the fact that thefabric is composed of two different materials.The mechanical properties of the fibres and the coating dominate the fabric response atdifferent load levels (essentially coating at low load, fibre/yarn at high load).
Any lack of conservation of energy is due tofrictional effects at crossovers, inelastic yarncrushing and inelastic coating extension. Thevalues of elastic modulus and Poisson’s ratioprovide a useful tool for approximating thenon-linear fabric response surface with a bestfit plane. It may be more appropriate to referto these as arbitrary parameters which define abest fit plane, as opposed to than mechanicalparameters or elastic constants. They enablethe test data to be used in existing analysiscapabilities with little or no modification. The values provide convenient notation todefine the extension and lateral contraction ofthe fabric for a given load state. Definition ofelastic moduli and Poisson’s ratios should notbe taken to mean to suggest that the fabricbehaves as a typical homogeneous material. It has already been established that fabricshear and bending do not correspond to theconventional definitions used for engineeringmaterials. For example, simple shear is definedas a constant area deformation, whereas shearof woven fabrics results in a reduction in area.The biaxial tensile behaviour is alsofundamentally different to other materials. Whilst Young’s moduli and Poisson’s ratios canbe used to approximate this behaviour, it is clearthat plane stress theory is inappropriate foraccurately describing the non-linear biaxialbehaviour of architectural fabrics. This adopteddefinition is fundamentally linked to thedevelopment of computationally-based analysistools, and particularly finite element typetechnologies. Historically these have been verymuch formulated from within a computationalmechanics framework. The definition ofconstitutive models continues to lag behindother algorithm-based activities to the extentthat often the material description is almostseen as secondary, with little or no opportunityto change or influence the fundamentalassumptions. This has also been in part due tothe almost independent development ofcomputational mechanics and materials science.There exists a lack of understanding of materialbehaviour within a computational mechanicscontext, and at the same time, an equal lack ofunderstanding of computational mechanicswithin a materials science context. The unifyingenvironment within which to develop thesesciences is simulation.Arguably, the purpose of simulation is toenable the prediction of events andphenomena leading to the quantification and minimisation of risk and uncertainty. It comprises a number of mutually dependentcomponents as depicted in Figure 3, rangingfrom numerical models, through to materialdescription, and finally to laboratory and fieldtesting. The purpose of the working group is toadvance the capabilities of simulating thebehaviour of fabric structures.
Figure 3. Defining simulation
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A possible new approach forcomputational mechanics &textile materials scienceTo successfully represent complex non-linearfabric test data for a wide range of fabrics(including as yet untested fabrics) requires amethod with no a priori assumptions about theform of the response, the level of warp-fillinteraction or the distribution of the datapoints. Development of the planar responsesurface given by plane-stress theory leads tosurface fitting methods such as bi-linear orpolynomial representations. Any such methodwill result in some simplification of the originaldata, and may need to be modified for differenttypes of fabric. For example, Testa, Stubbs andSpillers’ bi-linear representation of fabricstress-strain behaviour requires the ‘changepoint’ to be modified for each test. It hasalready been established that fabric shear andbending do not correspond to the conventionaldefinitions used for engineering materials. It is proposed that response surfaces are used,but without the constraining assumptions ofplane-stress which are not appropriate fordescribing architectural fabric behaviour.Previous researchers have used fabric testscarried out at a limited number of stress ratios(Day, 1986; MSAJ/M-02-1995; Minami et al,1997; Blum, 2002). Using a new test protocolthat explores numerous stress states a muchwider population of the data space can bedetermined. The test regime is stresscontrolled, which is appropriate as the range ofexpected stresses is known and the strains arerequired. However, during finite-elementstructural analysis, displacements arecalculated from which warp and fill strains aredetermined and the corresponding stresses arerequired. Hence strain-strain-stress responsesurfaces are required to visualise the materialresponse as it will be used in finite elementanalysis (Figures 4 & 5). It is proposed thatdirect correlation between pairs of strains andcorresponding pairs of stresses can be used forstructural analysis. This avoids the inherent
approximations and inaccuracy incurred whennon-linear fabric behaviour is represented usinga plane stress model.The strain-strain-stress surfaces are very steepcompared with the corresponding stress-stress-strain surfaces. Small changes in displacement(strain) give large changes in stress. The opposite is also true – small changes instress generating large strains, especially duringcrimp interchange. This will potentially makeanalysis using this data unstable. However, thisis not a problem caused by this method; it is aninherent characteristic of the fabric response.For accurate representation of fabric behaviourthis highly sensitive response must be includedin the analysis. Numerical stabilisationtechniques such as arc length control found inelasto-plastic analysis may be effective inmaintaining the non-linear solution stability. Thesteep gradient of the strain-strain-stress surfacesincreases the importance of including thevariability of the test results. When directcorrelation between strains and stresses is usedin a finite element analysis, surface gradients are not required. Consequently, a differentiablesurface function does not need to be defined,unlike when Young’s modulus is required as partof a plane stress framework. The test data isincluded in the analysis with little modification,and no prior assumption about the form of theresponse. However, for an elastic analysisresidual strain will need to be removed.Various interpolation schemes exist to fit localsurface patches on to a specified number of‘nearest neighbours’ to the point of interest(Chivate & Jablokow, 1995; Jüttler & Felis,2002; Weiss et al, 2002). For simplicity, use of a triangular interpolationscheme is proposed to provide reliable, linearinterpolation. Three pairs of strains (datapoints) are chosen which form a triangleenclosing the pair of strains for which stressesare required (Figure 6). The position of thestrain data point within the triangle is used to
interpolate between the three pairs of stressesat the apexes of the triangle. Interpolationwithin the triangle can be carried using areacoordinates (Cook et al, 1989).This interpolation scheme provides a simple,workable solution. Alternative approachesinclude a local polynomial ‘patch’ surface fittedto a given number of neighbouring points andits use to determine stresses at the point ofinterest, genetic algorithms (GA) or geneticprogramming (GP) to generate two functionsfor the warp and fill strain-strain-stressresponse surfaces. GAs and GPs would avoidthe need for a database of test values andinterpolation during the analysis. However,a function which correlates perfectly with thetest data (i.e. passes through all data points)may not provide sensible results between datapoints (similar to the poor interpolationprovided by mean and difference functions). Even if testing is carried out to failure, extra -polation beyond the tested stress states maybe required in the following potential scenarios:1. A structure with higher stresses which will
need some modifications to reduce the fabricstress. Whilst the accuracy of the predictedstresses is not critical because the structurewill not be built in this form, an indication ofthe stress distribution would aid the designprocess,
2. Small areas of high stress are common, forexample at the top of conics and aroundclamp plates. These increased stresses may be allowable in areas of double-thicknessreinforcement. Alternatively, some stressconcentrations may be deemed to be due tolimitations of the FE model (for example, dueto an overly course mesh or unrealisticallyrigid edge constraints) and so may be ignored,
3. Higher stresses may occur during the geo -metrically non-linear iterative analysis beforethe model converges on the final solution.
In each of these situations it is important thatthe analysis is able to continue for stress statesbeyond the extremes of the data set and returnfeasible values. Extrapolation beyond the dataset is therefore required. For the triangularinterpolation method, the three points nearestthe stress-state of interest will define a plane(in the strain-strain-stress space) which givesthe level of strain at the point of interest. The two-dimensional analogue of this is linearextrapolation from the last segment of a multi-linear fit. This provides a robust solution whichwill give reasonable values. Alternatively,nominal values can be used beyond the edgesof the data set (for both high and negativestresses) to maintain numerical stability.
Figure 4. Strain-strain-stress representation of test data,Ferrari 1202T PVC-polyester, two views
Figure 5. Strain-strain-stress mean surfaces, Ferrari 1202TPVC-polyester, two views
Figure 6. Interpolation between pairs of strains
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Feasible fabric strain statesThe population of the strain-strain space can beexamined by plotting the data points on thestrain-strain axes (Figure 7); effectively lookingdown the z-axis in Figure 4. The strain-strainspace is unevenly populated; particularly forPTFE-glass there is a concentration of datapoints around the origin. With the highlysensitive strain-stress response it may bebeneficial to use knowledge of the fabric
response to modify the test protocol to furtherpopulate the sparse areas in Figure 7b. However,a strain controlled system is not recommended:it would be easy to specify strains which requirestresses beyond the design stress, potentiallyresulting in fabric failure. The data points inFigure 7 are from multiple tests on a range offabrics at stresses from zero through prestress to25% UTS. Hence the population of the strainspace indicates the bounds of the feasible fabricresponse for that material type. The PTFE-glassfabric has a very discrete response envelope; thebehaviour is dominated by crimp interchangewith little extension of the stiff glass fibre yarns.In contrast the polyester yarns are more easilyextensible giving a greater range of possiblestrain states. This type of diagram provides anew tool for quantifying and understanding thebiaxial behaviour of different fabric types. Testdata for individual fabrics can be plotted in thesame way to characterise the feasible fabricstrains. This could be used as a tool for choosingfabrics depending on the required strainbehaviour. For example, a barrel vault roof maybe installed by tensioning in the fill direction toinduce prestress in the warp by crimpinterchange. These strain-strain plots show whatlevel of negative strain is available in each fabric.A similar plot on three axes showing feasiblewarp, fill and shear strains is also proposed.
Developing the Scope for the Analysisand Materials Working GroupCurrent representations of fabric stress-strainbehaviour are based on plane-stressassumptions, and tend to simplify the availabledata (e.g. use of secant elastic moduli). These planar representations can bemanipulated to establish locally good
correlations with test data. However, thecorresponding elastic constants do not complywith plane stress theory assumed in theassociated computational mechanics foranalysis. Coated woven fabrics are nothomogeneous materials: they are compositeswith the interaction of orthogonal yarnsmaking them act as a constrained mechanismwith relatively high levels of variability.In developing the scope of the working group, a number of questions can be considered, asmall selection of which are listed as follows:1.Is it necessary to complement the existing
plane stress theory and develop a newmethod for describing architectural fabricbehaviour?
2. Should alternative constitutive models /formulations be explored?
3. Are current analysis tools adequate?4. The computational mechanics community is
moving towards stochastic-based analyses. Isthis something that should be explored tocircumvent the issue of factors-of-safety andenable the specific inclusion of materialcharacteristics, structure life, environmentalconditions, etc, to be considered explicitly?
5. …?
It is hoped that this article will encourage thestart of the activities of the Analysis andMaterials Working Group in 2008. Everyone is invited to join!
Peter Gosling, Convenor of the Analysis andMaterials Working GroupProfessor of Computational StructuralMechanics,School of Civil Engineering &Geosciences, Newcastle University, Newcastle-upon-Tyne, NE1 7RU, UK
[email protected] 7. Population of strain space; multiple tests on (a)PVC-polyester, (b) PTFE-glass fibre
References & BibliographyAnsell, M., Barnes, W. & Williams, C. (1984) Structural
properties tests for coated fabrics, Proceedings of aConference on the Design of Air Supported structures,Institute of Structural Engineers, Bristol, 35-45.
ASTM D 4851-97, Standard Test Methods for Coated andLaminated Fabrics for Architectural Use, AmericanSociety for Testing and Materials.
Barnes, M. (1999) Form finding and analysis of tensionstructures by dynamic relaxation, Inter national Journal ofSpace structures, 14, n. 2, pp 89-104
Bassett, R., Postle, R. & Pan N. (1999a) ExperimentalMethods for Measuring Fabric Mechanical Properties: AReview and Analysis, Textile Research Journal, 69 (11) 866-875.
Blum, R. (1980), Mechanics of fabrics in tension structures,pp 495-512, Mechanics of flexible fibre assemblies, edited by JohnW.S. Hearle, John J. Thwaites, Jafargholi Amirbayat, Alphen aan denRijn, Netherlands Germantown, Md.: Sijthoff & Noordhoff
Blum, R. & Bidmon, W. (1987) Spannungs-Dehnungs-Verhalten von Bautextilien, SFB 64, Mitteilung 74.
Blum, R. & Bögner, H. (2002) Evaluation Method for theElastic Moduli, Tensinews Newsletter 3, Internet Publication2002 (www.tensinet.com), p.3.
Boisse, P.; Borr, M.; Buet, K.; Cherouat, A. (1997) Finiteelement simulations of textile composite formingincluding the biaxial fabric behaviour, Composites Part B:Engineering, v 28B, n 4, p 453-464
Boisse, P.; Borr, M.; Buet, K.; Cherouat, A. (1997) Finiteelement simulations of textile composite formingincluding the biaxial fabric behaviour, Composites Part B:Engineering, v 28B, n 4, p 453-464
Boisse, P.; Gasser, A.; Hivet, G. (2001) Analyses of fabrictensile behaviour: Determination of the biaxialtension-strain surfaces and their use in formingsimulations, Composites - Part A: Applied Science andManufacturing, 32 (10) 1395-1414
Brunetti, A. (2000) Fast and precise genetic algorithm fora non-linear fitting problem, Computer Physics Com -munications, 124 (2-3) 204-211
BS 3424-21 (1993) Testing coated fabrics. Method 24.Method for determination of elongation and tensionset, British Standards Institution
Chen, Y.; Lloyd, D. W.; Harlock, S. C. (1995) Mechanicalcharacteristics of coated fabrics, Journal of the TextileInstitute, 86 (4) 690-700
Chivate, P. & Jablokow, A. (1995) Review of surfacerepresentations and fitting for reverse engineering,Computer Integrated Manufacturing Systems, 8 (3) 193-204
Clulow, E.E. and Taylor, H.M. (1963) An experimental andtheoretical investigation of biaxial stress-strainrelations in a plain-weave cloth, Journal of the TextileInstitute, 54, T323-T347.
Cook, R., Malkus, D. & Plesha, M. (1989) Concepts andapplications of finite element analysis, 3rd edition, JohnWiley & Sons, 149-152
Day, A.S. (1972) Dilating clay equations, Arup Journal, 7 (4)20-23
Day, A.S. (1986) Stress strain equations fornon-linear behaviour of coated woven fabrics, IASS symposium proceedings: shells, membranes and spaceframes, Osaka, 1986, vol. 2, Elsevier, Amsterdam
Grosberg, P. and Park, B.J. (1966) The mechanicalproperties of woven fabrics, part V: the initial modulusand the frictional restraint in shearing of plain weavefabrics, Textile Research Journal, 66, 420-431
Hendry, S. (2005) Arup Research and Development.Personal correspondence.
Jong, S. de, Postle, R. (1978) A general analysis of fabricmechanics using optimal control theory, Textile ResearchJournal, 48, 127-135
Jüttler, B. & Felis, A. (2002) Least-squares fitting ofalgebraic surfaces, Advances in ComputationalMathematics, 17, 135-152
Kageyama, M., Kawabata, S., Niwa, M. (1988) Thevalidity of a “linearizing method” for predicting thebiaxial-extension properties of fabrics, Journal of theTextile Institute, 79, 543-565
Klein, W. (1959) Stress-strain response of fabrics undertwo-dimensional loading, part I, The biaxial tester,Textile Research Journal, 29, 816-821.
Menges, G., Meffert, B., (1976) Mechanical behaviourof PVC coated polyester fabrics under biaxial stress,J. Kunststoffe German Plastics, 66 (11) 12-14
Minami, H., Yamamoto, C., Segawa, S., Kono, Y. (1997)A method for membrane material nonlinear stressanalysis using a multi-step linear approximation,IASS Inter national Symposium on Shell and SpatialStructures, Singapore
Mollaert & Forster (2004) European Design Guide forTensile Surface Structures, TensiNet
Reinhardt, H. (1976) On the biaxial testing andstrength of coated fabrics, Experimental Mechanics, 16(2) 71-74.
Sasai, T.; Kawabata, S. (1985) Biaxial tensile propertiesof textured yarn fabrics, Journal of the Textile MachinerySociety of Japan, 31 (2) 29-34
Schock, H.J. (1991) On the structural behaviour andmaterial characteristics of PTFE-coated glass-fibrefabric, Journal of Coated Fabrics, 20, 277-288
Shanahan, W.J.; Lloyd, D.W.; Hearle, J.W.S. (1978)Characterising the Elastic Behaviour of TextileFabrics in Complex deformations, Textile ResearchJournal, 48 (9) 495-505
Skelton J. & Freeston, W.D. (1971) Mechanics of elasticperformance of textile materials: Part XIX. The shearbehaviour of fabric under biaxial loads, TextileResearch Journal, 41, 871-880
Tan, K.Y., Barnes, M.R. (1980) Numerical re pre sen ta -tion of stress-strain relations for coated fab rics,IstructE symposium on design of air supported struct., Bristol
Testa, R.B.; Yu, L.M. (1989) Stress-strain relation forcoated fabrics, Journal of engineering mechanics, 113 (11)1361-1646
Wang, F. (2002) Prediction method for tensile propertyof woven fabrics in lower loads, Journal of Dong HuaUniversity (English edition), 19 (2) 6-14
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Cocoon “paul” has been developed in the context of a PhD-thesis about“adaptive textile building envelopes”. The work has been carried out at theInstitute for Lightweight Structures and Conceptual Design (ILEK) at theUniversity of Stuttgart in co-operation with Professor Werner Sobek. “Paul” isplaced next to the former Institute for Lightweight Structures by Frei Otto,which is under the direction of Werner Sobek since 1995.The study of adaptive building envelopes belongs to the forward-lookingdevelopments in the building industry. The goal is to develop aesthetic andphysically variable building envelopes. The work covers substantial aspectswithin the range of architecture and material science. Hereby the firstapplication potentials of the latest technologies and materials intextile membranes are pointed out regarding biomorphic architecture. High-tech and simple, direct accessibility and serviceability were combined. Aspecial role plays the picture, which determined the formfinding procedureas a premise. “paul” points out analogies from built architecture to livingorganisms - it is less an organic architecture - rather a built organism - alivearchitecture. The experimental building represents a symbiosis from “moreorganic“ architecture and High-Tech. The built metamorphosis is able to bereacting automatically to changes of the environment. The possibility for theadjustment to changed environmental condition is obvious in nature and isdesignated as adaptation. The colour change of the chameleons and thetropism of plants are mentioned on behalf. Architectural constructions andarchitectures behave so far to a large extent statically, they do not react oronly with large energy expenditure to the changes of their environment. Theexperimental building “paul” has aesthetic and physical not-constantcharacteristics, and has the ability for automatic adjustment to outsideenvironmental condition. With organic and adaptive structures the proximityto nature becomes visible again. The alleged artefact approaches nature again- on functional and also formal level - and becomes part of it. Altogether thewall built-up is similar to a living skin - it works, as often used in nature, as amulti-layer-system, which is arranged cellularly. The multi-layer-system isdoped with different high functional materials. The top layer of the skin has avery small degree of pre-manufacturing - the skin is not load-carrying - itserves only as weather protection - the folding follows the bimorph entireappearance. The different layers possess individual functions - a multi-layersystem from different membranes and function layers. Below the top skin thelight layer appears to a form vein or nervoussystem. This system has an overall length of 8 kmand consists of optical glass fibres, which makes apermanent colour change possible using 1200 lightspots. The different light conditions are controlledvia colour wheels. During the day “paul” appears in monochrome white - at the night the conversiontakes place. This variability leads to most differentlighting effects - warm and cold tones — themulticoloured butterfly wing with innumerablecoloured light spots or mystic conditions with avague, non-directional light skin, which dips thewhole architecture into a mysterious light:sometimes cheerfully, sometimes darkly andmysteriously - and this in innumerable variants.
Below the light layer one can find the insulation layer - a diaphragm, which isendowed with high-isolating ceramics. Beneath them lies - as internal storagelayer - another diaphragm, which is implemented by phase change materials.These can improve sustainable the storage capabilities of lightweightstructures by the change of the state of aggregation and the associatedreversible absorption and delivery of heat. Insulation and storage layercompose of more than 60,000 cells. At high temperatures the diaphragm issofter than at low temperatures. The acoustic characteristics are improved inrelation to conventional fabric structures. The total thickness of the multi-layer-skin is about 1.4 cm. Storage and insulation values are comparable tothose of a conventional solid wall of approximately 15 cm thickness. Theclassical architectural elements such as roof and wall are waived - thediaphragm skin is integrative. The lower part of the butterfly group consists ofa shape of approximately 8 m length - it is a glass-carbon-fibre-hybrid, thatwas laid down on the ground – no establishment of a foundation took place.High-grade steel ribs are put into the lower bowl, which are coupled by glass-fibre-rods in transverse direction. The steel ribs describe the generated form ofthe cocoons and were bent with a program written for it. The largest roomheight of the accessible cocoons amounts to 3.0 m. Formally the experimentalbuilding reminds of a pupated butterfly, which is located on the site.
Although the picture of the cocoons exists, traditional boundaries and formaldevelopments are being questioned - its outlines are vague, which is stillsuperelevated by the variable light arrangement - firm conditions andgeometries are being dissolved - boundaries and form smear and are in apermanent state of change. “paul” represents its most characteristiccharacteristics - its change and adaptability - “paul” is a picture of itself. “paul”reacts to changing external climatic conditions. Beside the builtmetamorphosis “paul” shows its possible conversion properties by thereversible characteristics of the skin and by the picture of the pupatedbutterfly group. The pupated group is as metaphor of the change in status andgenesis, which happens in the building envelope physically and aesthetically -the non-constant characteristics. By metamorphosis one understands, besidesthe conversion process, in addition, the existence of variations - in such a waythe experimental building exists in this tradition also in “next to each other”different and contrary conditions and attitudes - for instance hard and softly,custom-made and non-confect, smoothly and folded, monochrome andcoloured, Low-Tech and High-Tech. This dualism is clarified by the completelycontrary day and night conditions. The simple details of the prototype and thetreatment of the top weathered layer as “non-confect” represent a strongcontrast to the doping of the complex building skin using high-efficientfunctional materials - from air and space industry, and/or automobile industry.The adding of the membrane among themselves, and/or with the sub-elements, is based on simple mechanism from the clothing technology, itconcerns velcro and zippers - they possess models in nature. Contrary to solidconstruction types the multi-layer-skin - despite its conditioning properties - ischaracterised by a high degree of the translucency. On sunny days it ispossible to notice the branches and leaves of the adjacent trees blowing in thewind. The building envelope conditions and is nevertheless able tocommunicate with the environment - one can look through and notice vague
outlines. During the night the artificial light ofthe second layer shines through the insulationand the cell structure appears as a poeticstarlit sky. Buildings of the future andpossibly all components will be similar to thecharacteristics of an organism - they possessnon-constant properties - building skins withits translucent structure show that futurearchitectures can be airy and light-flooded -skins and cladding structures, whichtransform architecture into amorphous anddiaphane light bodies.
In the context of the work, components and systems are used, which adaptautomatically or control the building envelope by chemical and/or physicalmodifications to changing outside climatic conditions. The possibleadaptations serve to optimize the energy and emission balance and to improvethe user comfort as well. Technically and aesthetically new possibilities of
buildings are shown and fundamentalrequirements of an “adaptive textile buildingenvelopes” and the possibilities of the shapefinding of the overall architecture, resulting fromit, are pointed out. Building skins and beyondthat architecture, which possess non-constantcharacteristics, are developed - they are able tochange both physically and aesthetically andadapt. The goal is “intelligent” building skins andbuildings, which do adapt independently and notcomputer-controlled or electronically inspired totheir environment. With the employment ofhigh-efficient materials - and dealing with light -a sensual architecture can result - anarchitecture, which lives not only of the mind,but also on moods.
Buildings of the future - and possibly all components - can change and adaptautomatically. They behave like an organism - this entails a new style -flexible and alive architectures, which - despite or straight because of the useof high technologies - embody a maximum of sensuality and poetry.
Pictures: Gabriela Metzger; ILEK; University of Stuttgart
Markus Holzbach, [email protected] www.formorf.com
EXPERIMENTAL BUILDING “PAUL” - ADAPTIVE TEXTILE BUILDING ENVELOPES
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At the Expo 2000 in Hannover the“Flor de Venezuela” was one of thebig attractions. The Architect Fruto
Vivas was inspired by a flower andaccordingly the roof, which consistsof 16 petals made of tensioned
membrane on a slender steel truss,could open and close depending onthe weather conditions like a flower.After years of political decision-making the pavilion is now beingrebuilt in Barquisimeto/Venezuela.
The detailed planning for the roofstructure in 2000 was done by SL-Rasch GmbH and the newinstallation of the membranes wasdone by Dangel u. BringmannArchitekten GbR. The successful installation shows
once again that textile structurescan be reused even after a longerstorage of the membrane and thatthis construction method is highlysuitable for temporary andadaptable structures.
INNOVATIONSPREIS INDUSTRIE 2007 - INITIATIVE MITTELSTAND
NEW GENERATION OF AQUEOUS PTFE DISPERSIONS FOR TEXTILE ARCHITECTURE APPLICATIONS
FLOWERFROMHANNOVER NOW INVENEZUELA
Stev Bringmann - [email protected] www.Bringmann-Architekten.de
Introduction Fluoropolymers are high-performance plastics that are used in harshchemical and high-temperature environment, primarily in performancecritical applications in the automotive, aerospace, electronics,telecommunications and chemical industries. Aqueous fluoropolymer dispersions, particularly, have successfully beenused for a variety of coating applications such as metal coating of bake andcookware, fabric coating of glass cloth for textile architectural membranes,used e.g. in stadiums, airports, railway stations and many other buildings.Further applications include impregnation of felts, yarns and many othertextile substrates. Perfluorooctanoic Acid (PFOA), in the form of its ammonium salt APFO, isbeing used by Dyneon and other fluoropolymer producers as an essentialpolymerization aid in the manufacture of certain fluoropolymers, includingaqueous dispersions. In general, the PFOA used to helpmaking fluoropolymers is largelyremoved during the final steps ofpolymer production, and furtherremoved by the hightemperatures applied when therespective fluoropolymers areprocessed into finished articles.The interest in the persistentchemical PFOA stems from thefinding of its widespread presenceat very low levels in theenvironment and in people. Asignificant amount of researchhas been conducted on this substance, with several hundred laboratorystudies performed by 3M and independent researchers regarding PFOA. Based on the extensive scientific research conducted to date, the overallweight of evidence indicates that no adverse human health orenvironmental effects would be expected from the low levels found. Due inpart to the finding of the widespread presence of PFOA, 3M announced thephase-out of its production of PFOA in 2000. 3M did not want to add to thepresence of PFOA in the environment and the company wanted to focus onmore sustainable technologies.
Project Description Dyneon - as said above - has been using PFOA, precisely its ammonium saltAPFO, for the manufacture of a variety of fluoropolymers including aqueousfluoropolymer dispersions. Being dedicated to environmental care and sustainability, already in 1993,Dyneon started process improvements and developments on technologies,enabling the company to reduce APFO emissions from its Gendorffluoropolymer manufacturing plant. Since then, significant investments intorecycling technologies helped reducing the residual APFO contents in wastewater and air.
Moreover, not only plant emissions have been reduced, but also the residualAPFO content in fluoropolymer dispersions has been lowered significantlyby state-of-the art containment and recycling methods. The patented capture and recycle technology used by Dyneon has been alsooffered to other companies to help them reduce their own PFOA releasesinto the environment. Further advancements in all of these technologies willcontinue to be pursued. The above described technology advancements - in particular - allowedDyneon in 2004 to introduce and commercialize first PTFE dispersion gradesfor textile applications with a residual APFO content of below 20 ppmversus 2000 ppm in formerly existing dispersion grades. This achievementrepresents an APFO reduction rate of more than 99 %. Consequently, in 2006, the complete PTFE dispersion portfolio wascommercially converted to such "APFO-reduced" product grades.
In addition to those achievementsin PTFE dispersions, in 2006 alsothe complete fluorothermoplasticdispersion portfolio, which isimportant for welding of textilemembranes, had been convertedto solely "APFO-reduced" productgrades. Also here, a reduction ofresidual APFO product content ofsome 98 % had been realizedwithout losses in productperformance and no negativeimpact on the textile processingindustry. Since end of 2006, Dyneon, thus
offers its complete fluoropolymer dispersion portfolio exclusively andcommercially with reduced APFO content. Hereby, coating customers are able to use fluoropolymer dispersions withan environmentally more favourable profile, thus contributing to responsiblecare. This conversion had been conducted in close contact to Dyneon'scustomers, supporting them in all testing, processing and requalificationquestions. Dyneon is going to achieve the EPA (US Environmental Protection Agency)targets as part of the EPA's PFOA Stewardship Program. Those targetsinclude a 95 % PFOA reduction of emissions and product contents by theyear 2010 as well as an elimination of PFOA emissions and product contentsby the year 2015. Due to its APFO containment technology achievements, resulting in thereduction of both, APFO plant emissions, as well as residual APFO productcontents in fluoropolymer dispersions, Dyneon obtained thelnnovationspreis lndustrie 2007. As part of Dyneon's containment strategy and commitment to responsibleenvironmental management, technology efforts on further reducing PFOArespective APFO emissions and product contents will be continuouslypursued.
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BÖGNER-BALZ: How was the initial ideaof the membrane master courseborn?OFF: The initial idea was not a singleidea. There were two thingsprobably coming together: First wewere starting teaching aboutmembrane structures at theAugsburg University of AppliedSciences and just out of acoincidence I was, for the thirdtime, at Textile Roofs in Berlin.Everybody there, especially Marijke[Mollaert], was complaining that:we actually need a university basedcourse to study - the workshop isjust too short; and you only stay atthe surface… So we just needed tohave such a course and then Isimply said: okay, let’s try. That’s it. The whole course and how ithappened to be was not plannedmerely like this. The main reasonwhy it became this kind ofinternational course with one bigpermanent resident time in Dessauand then tutored through theinternet was that there is nouniversity which has the peoplewho can teach all these subjects.So we had to collect themindividually from other universities.And the only way you can do thatis when they are not teaching attheir home university. So we havechosen the semester-(holiday)breaks. But then they have only ashort period. And how can youmaintain the course? Actually thestudents come from all over theworld; the teachers come from allover Europe for the moment. Andthen they spread again, go homeand then the only way tocommunicate is the internet. Andthat was the idea. It was bornwithin the discussion with Prof.Alex Furche. […] But what happensnow is boosting the whole thing.
The second course is incredible. Wehave a lot of requests forworkshops from other universitiesfrom almost all over the worldfrom these participants. What willhappen is that ideas will spread andwe will have a teaching network allover the world.BÖGNER-BALZ: And then you came toDessau and found there the rightplace to start the course?OFF: Yes and no. I became Professorfor project development at thisuniversity. I was not at thearchitectural faculty first. But I said:fine, let’s simply try it – it’s worth atry. And then I had to push andtwist a few people - from thepresident who was enlightened bythe idea to some people from theministry. There is also anotheraspect to it. This school is in thenew country of Germany, inSachsen-Anhalt which was part ofthe former east. They now put a lotof energy in their universities… justthinking of the facilities, we’ve goteverything here. They know theyhave to move into the future anddon’t protect the past. That’sprobably why it was possible fromthe beginning, with the presidentand the ministry, to find open ears.If I would have tried this at more
established universities, theyprobably wouldn’t let me do it;they don’t have the need to move.[…] That’s one of the reasons plusthe historical coincidence of theplace – the Bauhaus. […] I think it’sa fantastic coincidence: the nameof the Bauhaus, the place, and thisisolated situation for the moment.This is all coming together - a lot ofcoincidence happening.We didn’t know that when westarted, and what we can learnfrom this is probably – you juststart and if you keep on tryingthings will come up, somethingdifferent may come out at the endbut you’ll get somewhere. […] BÖGNER-BALZ: What are the contentsof the course?OFF: The course is intended to get aperson being able to design,calculate, compensate and erectmembrane structures - a sort of“Leonardo DaVinci” of membranestructures. He should be able toget into any field connected withmembrane structures, tounderstand the limits of what weknow, as well as all the possibilitiesof what we can do. That’s actuallythe idea.BÖGNER-BALZ: You started about a yearago. How many students have yougot and how successful has thecourse been so far?OFF: The actual first course startedeighteen months ago. Thepreparation for it also took twoyears. The first course started with21 participants and 20 are stillthere. We have already changedthe second course a bit. We had tocome down from 90 to 60 creditsfor the whole course. We learned alot altogether from the first course.Still most of them are with us andalready for the second course nowwe are fully booked. Actually weonly offer 25 seats, that’s theabsolute maximum. We don’t havemore capacity.BÖGNER-BALZ: And you have alreadygot some students registered for thefollowing courses as far as I know?OFF: Yes, that makes me happy. Wehave eight students already whosent some files.
C E M C OT E N S I N E TS E M I N A RLIGHTWEIGHTR O O F S T E X T I L ESOLUTIONSOn the 21st of June 2007, a seminar titled “Lightweight roofs.Textile solutions” was held inMadrid as part of the CEMCO2007 course organized by theEduardo Torroja Institute forConstruction Science. The eventwas attended by professionalsfrom the textile industry,government officials and individualarchitects and engineers.
The seminar addressed three mainareas, with presentations by thefollowing authors:
1. Structural solutions- Ramón Sastre (UPC)- José Ignacio Lloréns (UPC)- Juan Murcia (IETcc)
2. Functionality and materials- Paulo Mendoça (UMinho)- Joan Nos (FERRARI)- Feike Reitsma (IASO)- Jorge Neves (UMinho)
3. Projects- Patrick Vaillant (IASO)- Javier Tejera (BAT)- Joan Nos (FERRARI)
The seminar concluded with around table moderated by JuanMonjo (IETcc), with the followingspeakers:- José Ignacio Lloréns (UPC)- Juan Murcia (IETcc)- Paulo Mendoça (UM)- Jorge Neves (UM)- Javier Tejera (BAT)
The Iberian Section of TENSINETwas publicly presented on theoccasion of the seminar, and thetranslation into Spanish of theassociation’s Design Guide forTensile Surface Structures wasannounced.
Juan Monjo Carrió[email protected]
Interview with the founder of the Membrane Structuresmaster course in Dessau, Prof. Robert Off and students of the first semester, Dessau, April 2007 The first international master course on textile architecture worldwide(www.membranestructures.de) started in March 2006 at the AnhaltUniversity of Applied Sciences, instigated by Prof. Robert Off. The coursewhich is addressed to engineers and architects aims to offer participationsimultaneously with involvement in professional life by having one activeweek per semester while all other support and practice is communicated viathe internet. The teaching staff consists of international academics andprofessionals in the field of textile architecture. After the first 3 semesters have passed the students of the first study courseare starting their master thesis – time to consider progress. For this occasionDr. Heidrun Bögner-Balz has met Prof. Robert Off and some students of thefirst course (Paolo Barroso (Brazil), Shehzad Irani (India), Alex Schön (SouthAfrica), Sergio Leiva (Chile) and Xenia Diente (USA)) to talk about theirimpressions.
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BÖGNER-BALZ: Who are the studentsparticipating in the master courseand where are they coming from?OFF: The students are coming fromall over the world except we don’thave anybody from Australia yet.The first course cohort were mainlyprofessionals already working in thefield of membrane structures,having companies dealing withmembrane structures, who had themain idea to really increase theirknowledge; because although theyare safe within a certain project sizethey know if they go to biggerprojects, stadium roofs or anythinglike this, they should really knowwhat they are doing. They areprofessionals trying to get the realuniversity educational backgroundto be confident in building thosestructures. In the second course wealso have those types ofprofessionals, the course is anywaymade for professionals, but thereare more civil engineers andarchitects now who are not yet inheavy contact with buildingmembrane structures. So now this isbecoming more of a starting coursefrom a really zero starting basis… BÖGNER-BALZ: How is the mastercourse financed?OFF: We finance the course byourselves. The university providesus with the necessary facilities;anything else has to be paid by thecourse itself.Actually we could call it a sort ofpublic-private partnership. It issomething which is totally unusualfor German universities and I thinkthat’s a very good aspect to it. Wecan move much faster and quickerthan universities generally, butcombined with the guarantee, youdon’t have to pay the bill for theheating and those things. It could work for many morecourses like that!
BÖGNER-BALZ: Now I would like tohear something about thestudent’s expectations. Have theybeen met so far? How does theinternet-teaching work? Does theexchange work? Please tell me abit about your impressions!PAOLO, ENGINEER, BRAZIL: The first thingis: membrane structures were themost important thing thathappened to my life during the lastthree or four years. I learned abouttensile structures in 2000. Therewas an international seminar. I hadthe opportunity to talk to Frei Otto
and Majowiecki - the biggest guyson these designs. […] I decidedthat this is the future forarchitecture and engineering. Weare now coming back to ourposition […] where we were onlyone people, one science. And thenthey divided. Now we are comingback together. We are creating astructure and we’re creatingbeauty….together…this isamazing! […] Here I learned somuch. I already did some mistakes.I already did some structures in thepast without any technicalknowledge. But now I can comeback to Brazil again and […] I canbe more confident because now Iknow what I’m doing. And this isthe tool for us. This university is thetool for us to develop our futureprojects. So 100% approved - and Ihope this goes on forever and ever!ANDREAS, ARCHITECT, GUATEMALA: I think oneof the interesting side-effects aboutthis course is the networking. Wemanage to get together across, andyou get enriched by the experiencesof other people. It’s not only thecourses you take here and the tasksyou do but also the exchange withother people, other countries andtheir experience especially from thefirst course which had a lot ofpeople with a lot of experience fromall different fields and differentlevels. We have people who work onthe engineering side; we havepeople working in the manu -facturing. You can really gather a lotof information through this contextwe’re able to establish here.BÖGNER-BALZ : Do you think theexchange will go on after thecourse? ALL: ….HOPEFULLY!!!
SHEHZAD, ENGINEER, INDIA: One morebrilliant thing that I feel is the timeand space this is happening. If youtake out another time this synergywouldn’t have happened. And secondly it’s also aboutDessau: being at the Bauhaus. In away it was the starting point formany architectural developments.When we come back to membranestructures […] you do not knowcompletely when you are anengineer or a designer, what theproblems are, what the plus-pointsand the negative points are whendoing a membrane. That’s why wehave such a lot of problems […],which we can solve workingtogether. […] I feel that […]
because this place is so isolated,that we can spend such a long timetogether. If this is happening in abig city like Berlin or Stuttgart theneverybody would have been on acity-tour rather then sittingtogether and discussing.ALEX, MANUFACTURING ENGINEER, SOUTH
AFRICA:
From my point of view that I amliving in a third world country and I am sure to say I am also speakingfor others I talked to: We reallydon’t get kept up-to-date withwhat happens in the world thatmuch because we really stay faraway. And the whole mentality canbe quite repressive at timesbecause people just accept lesserquality. When I started I alwayswanted to be in a position where Iproduce top quality. I think thiscourse is really opening your eyesso that you actually learn it and getin contact with people on aworldwide basis in that sort ofnetwork where we can get all theinformation and at the end it willwork better than for mainstructures.BÖGNER-BALZ : Thank you very much.Anyone else who would like to addsomething? SERGIO, ENGINEER, CHILE: My experiencehere is a little different to the oneof the others guys. Because it wasthe first time that I didn’t’ have tothink about whether to join thecourse. And I made the decisionright away: okay I just go. And I took the chance to stay herein Germany for learning moreabout membranes. I come fromChile. There is nothing aboutmembranes so I thought to do thecourse one week there and then goback to my normal job. I thought itwould be a little bit difficult. So I took the chance to stay here.And at the moment everything isgoing “super” like the Germans say.And I learn a lot about membranes. XENIA, ARTIST, USA: I was impressed bythe prompt critique, the review ofthe Gozo presentations the othernight. Because usually when I seeprofessors criticizing student’s workit’s usually from a designperspective. But the requirementswere both design and details andsome of the engineering. You had three differentprofessionals criticizing from thisdifferent point of views. It wasfascinating to see arguing fordesign, arguing for cost or theengineering or the actualisation.That’s really good because where I work it’s usually just the architector the designer criticizing […] they don’t think about the practical things too… It’s very well-rounded.
L I T E R A T U R E
Tension structures, Form and behaviour
W. J. Lewis
The tension structures discussed inthis book are predominantlyroofing forms created from pre-stressed cable nets, cable trusses,and continuous membranes (fabricstructures). A unique feature oftheir design process, whichprovides a focus for the book, is'form-finding' - an iterative processof defining the shape of a structureunder tension. The book discussesthe role of stable minimal surfaces(minimum energy forms occurringin natural objects, such as soap-films) in finding optimal shapes ofmembrane and cable structures.The discussion of form-finding isextended to structural forms theshapes of which are supposedlyknown, such as suspension bridgecables.
The book presents numericalmodelling of the structural formand behaviour of tensionstructures, but also addressescertain misconceptions related totheir design. It provides uniqueinsights into the most commonlyused computational methods,emphasising their main strengthsand limitations. Mathematicalexpositions do not go beyond thelevel of undergraduate engineeringmathematics and, whereverpossible, non-mathematicallanguage is used to aidunderstanding of the fundamentalconcepts. The intention of thebook is to provide a balancebetween analytical and pictorialaspects of the subject. Examplespresented demonstrate thepotential of tension structures asan art form.
ISBN: 0 7277 3236 6 price: £30
pages 201 hardcover
Thomas Telford published 2003
Proceedings of the TENSINET SYMPOSIUM 2007
Ephemeral Architecture,Time And TextilesPolitecnico di Milano - 16th - 18th April 2007Heidrun Bögner-Balz, Alessandra Zanelli
The main theme of the TensiNet Symposium 2007 was EphemeralArchitecture and in particular, the relationship between membranearchitecture and the concept of time. Ephemeral Architecture describestensile structures built with lightweight membranes, which respond tothe principles of firmness, commodity and delight, distancing themfrom the classical interpretation embodied by everlasting, monumentalarchitecture.The objective of the Symposium is to emphasise how therelationship between membrane architecture and the concept of time isconstantly evolving, giving new life to all ephemeral architecturalexpressions.Ephemeral Textile Architecture not only responds to the needs ofcontemporary society for flexible and lightweight building, but is also the result of an ecological design strategy, where temporaryconstructions can be disassembled after use, leaving future generationsfree to decide how to use those spaces again.
Keynote LecturesFlexible Architecture and Tensile Membranes,
Robert KronenburgEphemeral Architecture, Werner Sobek
Table of ContentsLightweight Structures and Architecture of
LightNew Interests in Textile ArchitectureMembrane Architecture and Thermal BehaviourAnalysis and Formfinding Studies
for Lightweight StructuresTextiles and Time: Towards a New Temporary
Architecture?Designing for Lightweight StructuresLearning from FailuresTextiles for Flexible StructuresInnovation in Translucent and Transparent
MaterialsTextiles and New Applications Textiles and Life Cycle Assessment Approach
L I T E R A T U R E
ISBN: 9 788870 909326pages 419 – DIGITALPRINTpublished 2007 Full Price: 24 € Price for TensiNet members: 20 €
ROOF & CLADDING INDIA 2008EXHIBITION & CONFERENCE
25 – 27 April 2008 at Chennai Trade Centre, Chennai, India.The event is endorsed by TensiNet.
In its 7th edition, the ROOF & CLADDING INDIA series has now become the benchmark event in Asia for Roofing, Cladding, Metal Building Systems, Spaceframes, Waterproofing, Insulation, Tensile Membranes, Roofing Machinery & Fasteners etc.
ROOF & CLADDING INDIA 2008 is also now the only event in Indian sub-continent to be - endorsed by the NRCA - National Roofing Contractors Association (USA)- supported by the CNWBMIA – China National Waterproof Building Material Industry Association
The organizers Unitech Exhibitions Pvt. Ltd. (India) are offering 10% discount on booth charges for the membersof TensiNet. For booth bookings and other information, please visit the website or contact the organizers videemail at [email protected]
www.roofindia.com
th7edition
in ROOFseries Asia’s largest show for
roofing, cladding & allied products
2 5 - 2 7 A p r i l 2 0 0 8Chennai Trade CentreC h e n n a i I n d i a
ROOFING SYSTEMS
ARCHITECTURAL CLADDING
FACADE ENGINEERING
METAL BUILDING SYSTEMS
SKYLIGHTS & SKYDOMES
WATERPROOFING
INSULATION
TENSILE MEMBRANES
ROOFING MACHINERY
and much more.....
ROOFING SYSTEMS
ARCHITECTURAL CLADDING
FACADE ENGINEERING
METAL BUILDING SYSTEMS
SKYLIGHTS & SKYDOMES
WATERPROOFING
INSULATION
TENSILE MEMBRANES
ROOFING MACHINERY
and much more.....
endorsed by
ROOF EXHIBITION & CONFERENCE ON ROOFING PRODUCTS
INDIA 25-27 April 2008 Chennai Trade Centre Chennai
EXHIBITION & CONFERENCE ON CLADDING TECHNOLOGYCLADDING INDIA 25-27 April 2008 Chennai Trade Centre Chennai
SAIE SPRING BUILDING KNOW-HOW
12th -15th March 2008, Bologna As regional representative of the TensiNet Association, Alessandra Zanelli ofthe Dipartimento BEST, Politecnico di Milano, was invited to organise aSeminar during the SAIE SPRING (the most known Fair of the Building Sectorwithin the Italian context) and also to take part in the “CuoreMostra” Exhibition, which will be the “core” of the SAIESPRING Event, dealing with the role of innovativematerials’ research and construction systems incontemporary architecture. The TensiNet seminar will takeplace on Thursday 13th of March 2008 from 14.00 h – 15.30h and bears the title ‘Designing with membranes in Europeand Italy: the role of the university research and of theTensiNet network’.
SEMINAR Programme: Introductory presentation
Prof. Andrea Campioli, researcher Dipartimento BEST, Politecnico diMilano, university representative in Italy of the European network TensiNet
Presentation of a National research on textile coveringsArch. Alessandra Zanelli, Politecnico di Milano, Dipartimento BEST
Research and development of tensile structures in Europe:Prof. Marijke Mollaert, TensiNet management boardProf. John Chilton, TensiNet management board
CUORE MOSTRA Tensinet PAVILION: the core of the exhibition is composed of 10 universities/research centers/European associations which are involved in the innovation of building coverings.
TensiNet will have an exposition booth of 16 sqm with the following objectives: - present TensiNet through the website and exhibitors brochures hanging on
internal side walls of the pavilion - present Politecnico di Milano through the recent National research on
textile architecture - present some of the universities which are TensiNet members by means of
a poster and some students models- show the different kinds of textile coverings: each technology will be
represented by a mock-up and by a reference poster with the latestarchitectural projects realized with the mock-up related technology.
www.saiespring.bolognafiere.it/
We invite you
to visit the
TensiNet booth
and attend
the seminar
