12
1

European Design Guide for Surface Tensile Structures...+ Design of membrane and lightweight structures Symposium (2000) 150 European Design Guide + Proceedings of the TensiNet Symposium

  • Upload
    others

  • View
    14

  • Download
    0

Embed Size (px)

Citation preview

Page 1: European Design Guide for Surface Tensile Structures...+ Design of membrane and lightweight structures Symposium (2000) 150 European Design Guide + Proceedings of the TensiNet Symposium

1

Page 2: European Design Guide for Surface Tensile Structures...+ Design of membrane and lightweight structures Symposium (2000) 150 European Design Guide + Proceedings of the TensiNet Symposium

European Design Guide for Surface Tensile Structures

2

IASS 2004 Conference

Montpellier (France) 20/09/2004 > 24/09/2004

http://www.iass2004.org/

41st Annual SES Technical Meeting Symposium

Lincoln, Nebraska 10/10/2004 > 13/10/2004

http://www.nuengr.unl.edu/ses2004/symposia/fibrous.html

IFAI Expo 2004 Exhibition

Pittsburgh 27/10/2004 > 29/10/2004

http://www.ifaiexpo.info/

2nd Latin American Symposium Symposium

Caracas (Venezuela) 04/05/2005 > 06/05/2005

http://www.arq.ucv.ve/idec/simposio/

Techtextil Frankfurt Trade Fair

Frankfurt (Germany) 07/06/2005 > 09/06/2005

http://techtextil.messefrankfurt.com/frankfurt/en/home.html

F o r t h c o m i n g E v e n t s

The European Design Guide for Surface Tensile Structures has been publishedin August 2004. The design guide contains the following chapters:

Introduction John Chilton, Brian ForsterEngineered fabric architecture Brain Forster, Marijke MollaertForm Jürgen Bradatsch, Peter Pätzold, Cristiana Saboia de

Freitas, Rudi Scheuermann, Juan Monjo, Marijke Mollaert

Internal Environment John Chilton, Rainer Blum, Thibaut Devulder, Peter Rutherford

Detailing and Connections Rogier Houtmann, Harmen WerkmanStructural design basis and safety criteria Mike Barnes, Brian Forster,

Mike DencherDesign loading conditions Markus Balz, Mike DencherForm-finding, load analysis and patterning Mike Barnes, Lothar Gründig,

Erik MoncrieffMaterial properties and testing Rainer Blum, Heidrun Bögner, Guy NémozFabrication, installation and maintenance Klaus Gipperich, Roberto

Canobbio, Stefania Lombardi, Marc Malinowsky

The design guide contains the following appendices:

Cp Values for simple tensile structure shapes, Mike Dencher, Markus BalzCp values for open roof stadiums, Markus Balz, Mike BarnesTesting methods and standards, Rainer Blum, Heidrun Bögner, Guy NémozAn Example of the application of the testing procedure described in Appendix A3 on a PTFE coated glass fabric, Rainer Blum,

Heidrun Bögner, Klaus Gipperich, Sean Seery

The European Design Guide for Surface Tensile Structures (2004), the Proceedings of the TensiNet Symposium (2003) and of the Design of membrane and lightweight structures Symposium (2000)can be ordered on line http://www.tensinet.com/order_designguide.php :

Cost (Euro)

European Design Guide for Surface Tensile Structures (2004) 100Proceedings of the TensiNet Symposium (2003) 60Design of membrane and lightweight structures Symposium (2000) 40

The following packages can be ordered at reduced prices:

European Design Guide + Proceedings of the TensiNet Symposium (2003) + Design of membrane and lightweight structures Symposium (2000) 150European Design Guide + Proceedings of the TensiNet Symposium (2003) 130

If you order any of these publications at the same time as registering as a TensiNet member the cost of the older publications is reduced by 50% and the cost of the Design Guide is reduced by 20%:

European Design Guide + Proceedings of the TensiNet Symposium (2003) + Design of membrane and lightweight structures Symposium (2000) 130European Design Guide + Proceedings of the TensiNet Symposium (2003) 110European Design Guide for Surface Tensile Structures (2004) 80

Vrije Universiteit Brusselhttp://www.vub.ac.be/studioZ/reZearch/lightweight.htm

partnersBuro Happold Engineerswww.burohappold.com

Canobbio S.p.A.www.canobbio.com

Ceno Tecwww.ceno-tec.de

Club de la Structure Textilesyndicatbaches.free.fr

European Council for ConstructionResearch, Development and Innova-tion www.eccredi.org

Engineering SystemsInternational S.A.www.esi.fr

Newcastle Universitywww.staff.ncl.ac.uk/p.d.goslingInstitut Français du Textileet de l'Habillementwww.ifth.org

Laboratorium Blum

Messe Frankfurt/Techtextilwww.techtextil.de

Hopkins Architectswww.hopkins.co.uk

The Arup Groupwww.arup.com

Universidad Poletécnica deMadrid www.aq.upm.es

SL-Rasch GmbHwww.sl-rasch.de

Taconic Internationalwww.taconic-afd.com

technet GmbHwww.technet-gmbh.com

Technical University of Berlinwww.survey.tu-berlin.de

Tensotech Consultingwww.tensotech.com

Tentechwww.tentech.nl

University of Bathwww.bath.ac.uk/departments/arch/csemwebpage/light.htm

University of Nottinghamwww.nottingham.ac.uk/sbe

With its different activities (website, database, Design Guide, annual workshop Textile Roofs and TensiNews) TensiNet has an impact at both the educational and professional level. Initially, specific information was scattered and retained by experts. However, the networking that has been initiated reachesbeyond the partners and has an impact on knowledge and procedures in institutions as well as professional organisations and businesses. TensiNet creates a forum, an association and a reference point.

Marijke Mollaert

Page 3: European Design Guide for Surface Tensile Structures...+ Design of membrane and lightweight structures Symposium (2000) 150 European Design Guide + Proceedings of the TensiNet Symposium

Umbrellas for the Chamber of Commerce,

Würzburg In the inner courtyard of the Chamber of Commerce at Würzburgthree extraordinary umbrellas were installed, offering an impressivesight. Each umbrella has a height of approximately 13 m and the totalcovered area is approximately 475 m2. The biggest umbrella has anedge length of 14 m x 14 m. The funnel shape, which often is used indesert areas to collect rain, also has the advantage that it can drainthe surface rain via the posts, thus avoiding costly drainage systems.

The main sub-structure of the roof consists of clamped steel postsand a fine frame fixed on the posts by horizontal and sloped struts.The extremely demanding tensioning process of the posts was carriedout via the top plate into the ceiling of the underground parking spacedirectly beneath.

Due to the use of ETFE-foil for these umbrellas their appearance isvery filigree and light. A cable-net integrated in the ETFE-foilstransmits the external loading to the frame and post.

3

Membrane structure: Three transparent funnel-shaped umbrellas,

consisting of ETFE-foils

Primary structure: Steel columns

Location: Inner courtyard of the Chamber of Commerce, Würzburg

End of project: October 2003

Client: Chamber of Commerce, Würzburg-Schweinfurt

Architects: Architekten BDA, Prof. Franz Göger/Georg Redelbach

Realization of membrane Structure: covertex GmbH, Obing

Technical data membrane Roof area: approx. 475 m2

Number of layers: 1

Thickness of foil: ETFE 200 µm printed with dots

Tensile strength: 52 N/mm2

Fire class: DIN 4102 - B1

Architect: Peter Pätzold

Manufacturer: Peter Pätzold together with Jakob Frick Baumodelle

Dimensions: Height: 2.6 m, Diameter 2.3 m, Covered area 4.2 m2

Material: Aluminium mast, galvanized steel foot, plywood,

PU coated PES fabric (light spinnaker fabric)

Ventilator: 12 V, 125 m3/h, solar module and battery, 5W

www.covertex.de [email protected]

For an election campaign aninnovative, expressive andmobile booth was needed for aparty as an alternative for thenormally used umbrellas andtables. The pneumatic boothfulfils all the requirements: it ismobile and light, expressive andconvertible. On the top of analuminium mast with anintegrated round table themembrane is connected over akind of hub. At the top of thishub the ventilator is located.Inside the mast are the electricalcables and the rainwaterdrainage. The foot of the boothis a standard footing for marketumbrellas. The whole boothcan be demounted within

5 minutes into manageablepieces, transportable in a smallcar or by hand.This inflating pneumatic‘bubble’ is an eye-catcher andan attraction. In less than 2 minutes the pneumaticstructure is totally inflated by asolar powered ventilator. The ventilator is regulated by atwo-step switch, which reducedthe air volume after the bubbleis totally inflated. The high translucency of themembrane material allows thepneumatic balloon to glowunder the influence of brightsunlight. For use during thenight appropriate lighting canbe installed inside.

Mobile andconvertible booth for

election campaign

Page 4: European Design Guide for Surface Tensile Structures...+ Design of membrane and lightweight structures Symposium (2000) 150 European Design Guide + Proceedings of the TensiNet Symposium

4

A mobile tent structure forms anelegant and charming cover forthe existing grandstand of theScherenburgfestspiele inGmünden above the River Main.A light translucent membraneroof provides shelter from windand rain for the spectatorsduring the theatre summerfestival without destroying theopen air athmosphere that thisplace is well known for. Andbeing well integrated with thehistorical red sandstone ruins ofthe old castle this white strechedtextile roof creates anarchitecturally unique situationfor the theatre play. Also, itsattractive silhouette forms thenew symbol for thesummerfestival, that can be seenfrom far out in the valley.

One interesting aspect of thisproject is the first officialapplication of the TensinetDesign Guide as a technicalreference for the engineering andthe approval procedure of thistent structure with the TÜV,which is the authorizedassociation for technicalsupervision in Germany.

The membrane roof issupported by two internallylocated lattice masts (10.5mheight), which were positionedwithin the existing grandstand atthe edge of the upper stairways.The position and the form ofthe lattice mast provide acomfortable and safe situationfor the movement of the publicand also create the minimumdisturbance for the visibility ofthe spectators. Each one ofthese main masts supports twolattice outrigger beams. Thisoutrigger system provides theroof with structuralindependence regarding theadjacent historical building andallows the great span towardsthe stage. The lattice steelstructures also provide new well-positioned supports fortechnical illuminationequipment.

For the membrane itself aTenera 3T20 fabric is used. Thisis a 100% Fluorpolymer fabricwhich has high tensile strength,is highly translucent (20%), dirtrepellant and wheather - andUV- resistant. It was chosen forits main charactersitics and forthe architectural quality of thewhite light that is shiningthrough the Teflon fiber and forits high flexibility and friction

free surface, which is a primaryrequirement for keeping a goodaesthetic appearance of themembrane through thesuccesive erection processes overthe years. Along its edges andridges the fabric is reinforcedwith high tensile Polyester belts.At the membrane edge corners,the belts are attached to thesteel frame and the peripheralsuspension cables by means ofdemountable steel plates. Afterthe disconnection of all steel

attachments, the pure textilemembrane structure allowssimple flexible handling andcleaning. The fabric is stretchedby peripheral tubular masts andsuspension cables, which areanchored to permanentinjection anchors in the groundor in the solid stone walls.

The fabric qualities and thespecial structural detailing of themembrane as well as the steelstructure detailing facilitate the

handling and the mobility of thecomplete tent structure withoutlarge cranage equipment. Thiswas an important aspect for thedemountable tent roof that shallbe installed every year at thebeginning of the theatre seasonand shall be removed afterwardsby the team of the theatretechnicians. The precisegeometry and prestress of thetensile structure is guaranteedduring the erection by thepermanent anchorage pointsand by the adjusted and fixedsystem length of the tentstructure single members.

A great challenge of this projectwas to develop the design, tomanufacture and to finish theerection of the tent structurewithin 12 weeks. Also, this tightschedule had to include anofficial approval procedure bythe TÜV, which is theauthorized association fortechnical supervision inGermany. So there was no timefor any major changes of thearchitectural and structuraldesign concept and the TÜVhad to agree from the firstdesign stage with the loadassumptions and with the safetyconcept for this project. But neither the German DINcodes include standards for thewindload distribution on typicaltent shapes, nor was the time orthe budget available to evaluatethe windpressure distribution forthis particular tent shape by aphysical wind tunnel testing. In this critical situation the TÜVaccepted the PreliminaryTensiNet Design Guide fortensioned membrane structuresas a reference. This state-of-the-art compendium for tensionedstructures that is written by thewell recommended Europeendesigners and manufacturers oftensioned structures alsoincludes in Chapter A1 arecommendation for thewindpressure cp valuedistribution of free-standing tentroofs and the TÜV agreed toapply this reference as basis forthe structural calculation of theScherenburg tent structure.

This application of the TensinetDesign Guide that is developedwith the support of theEuropean Community and aimsat defining European BuildingStandards for tensile membranestructures was in fact a furtherstep towards this common goal.

Client: Theaterverein Scherenburg, Gemünden/ Main, Germany

Architect, Engineer: Architekturbüro Rasch + Bradatsch

Contractor: SL-Rasch GmbH

Dimensions: Covered area 380m2 (max. width ±27m, max. depth ±17m)

Height of main masts 10.5m; height of external masts from 5 to 6m

Weight: 25kN (6.5kg/m2 covered)

Material: Steel works - mild steel, hot dip galvanized

Cables - galvanized steel cables with swaged sockets

Membrane - Tenara 3T20 (630g/m2); rainwater tight fabric

from 100% Fluorpolymers

Execution: April 2004 - June 2004 (approx. 3 months)

[email protected] • http://www.sl-rasch.de/

Grandstand Tent Cover for the open-air theatre

in Scherenburg, Gemünden/Main,

Germany

Page 5: European Design Guide for Surface Tensile Structures...+ Design of membrane and lightweight structures Symposium (2000) 150 European Design Guide + Proceedings of the TensiNet Symposium

5

Lightweight with large span: Tensairity®

The Swiss company Airlight has developed, with the Tensairity®

concept, a new pneumatic beam which enables spectacularapplications especially in civil engineering. The synergetic combinationof an air filled flexible tube, cables and rods gives with low pressure avery light but strong structure element.

What is the difference between Tensairity® and existing pneumaticstructures? The innovative Tensairity® concept is based on the factthat air pressure is totally independent of the span and slenderness ofthe constituting elements. In other words: Tensairity® allows theconstruction of very light roof structures with extremely large span.The load bearing capacity of Tensairity® is so high that with a pressureof 200 mbar it is already possible to build temporary bridges evensuitable for heavy transports. Compared to traditional airbeams,Tensairity® needs just 1% of air pressure. With such low pressure, airlosses are easily compensated.Apart from civil engineering many other fields of application arepossible: floating structures, sport equipment, airships and evenaerospace applications.

Figure 1. FEM Analysis of Tensairity® beams

Basic principles

The basic idea of Tensairity® is to use low pressure air to stabilizecompression elements against buckling. The basic Tensairity®

structure consists of a cylindrical airbeam (a low pressure fabrictube), a compression strut tightly connected to the membrane alongthe whole length of the airbeam and at least one pair of cables

spiraled around the airbeam thatare firmly connected to thecompression element at both endsof the beam.

Figure 2. The Tensairity® girder: compression element on top, airbeam and cables

The compression element is connected to the membrane and thuscan be consideredas a beam on anelastic foundation.The buckling loadof such a beam isthen independent ofthe span.

Figure 3. Temporary bridgespanning 8 m

(First prototype)

Airlight Ltd.

The Tensairity® technology has been developed and patentedworldwide by Airlight Ltd. Switzerland. The company markets thistechnology and offers with licensing many other services such astraining and support by direct applications. The main mission is tohelp engineers in applying the technology and to further develop theTensairity® concept.

The main target of Airlight are civil engineers who, in a four-dayintroductory course, learn the theory behind the design and numericalsimulation of Tensairity® structures. The access to a vast amount ofrelated information and details speeds up the task of the engineer inthe proposal and design phase.

TENSAIRITY® PROJECT: Breitling, Baselworld jewellery exhibition

The Tensairity® beam elements with 10 m span having a diameter ofjust 30 cm (resulting in a slenderness ratio of 33) and an internalpressure of only 0.50 bar have a load bearing capacity of more than25kN. Four Tensairity® beam elements can carry the BentleyContinental GT sports car and more than 20 people.

Figure 4. a, b, c Breitling, Baselworld jewelley exhibition.

The beams, made of asilicon coated fiberglassfabric, are alsoilluminated through aglass window at one endgiving a particularlighting effect.

Compression

CableAirbeam

Building owner/customer: Breitling SA, Grenchen, Switzerland

Engineering: Airlight Ltd., Biasca, Switzerland

Architect: Alain Porta, Lausanne, Switzerland

Manufacturer: Canobbio SpA, Castelnuovo Scrivia (Al), Italy

Completion: april, 2004

Fabric: Silicone coated Fiberglas, Atex 5000, Interglas Technologies

[email protected]

http://www.canobbio.com • http://www.airlight.biz

Page 6: European Design Guide for Surface Tensile Structures...+ Design of membrane and lightweight structures Symposium (2000) 150 European Design Guide + Proceedings of the TensiNet Symposium

In northern Finland we usuallyhave a lot of snow. Not in anexcessive way that we are forcedto use it for our buildings likeInuits make their igloos, butmore in a playful way that wecan have fun with it. In the earlydays of the air halls some peoplewere testing pneumaticstructures as a mould forconcrete and different resin-based materials.In Finland, in a northern citycalled Kemi (www.snow-castle.net), some people got theidea to build the biggest snowcastle in the world.

In Sweden they already had builtstructures from ice but not fromsnow.

The first moulds were made bycombining plywood with timberor steel, but off course doublecurved forms were difficult toaccomplish.

Our long-time client(www.mailari.fi), renting bigtents for all kind of summerfestivals, asked us to buildmoulds for making small igloos.The biggest problem withmoulds using air pressure hasalways been how to fix them to

the ground, because of the sizethe inner pressure has to be upto 4-5 kPa to resist the weight ofthe packed snow against thewalls. On the other hand themoulds should be easy to moveand handle to meet commercialdemands. Some experimentsseemed promising, showing thatthe structure could be built in10 minutes and was a closedvolume with a demountablebottom. The smallest ones canbe carried by two men havingthe full pressure inside. Thepressure stiffens the wholestructure with its bottom.

The first prototype measured6m x 4m (diameter x height),later adding 8 smaller ones ofsize 3.5m x 2.3m. The biggestone we made was 12m x 8.5mand next winter we have plannedto build one of size 16m x 11m.The most difficult thing is howto make snow that is structurallystable enough, not how to makethe mould itself.

Anyway, those are small in sizecompared to the sport halls wehave made in Finland: there aretwo halls for football training,size 120m x 68m x 21m and forthe next winter we have plannedone of size 180m x 72m x 22m.Because of the Finnish weatherconditions these membranes are

6

Bubbles in the snow

Textile Grandstand Roofing for the New “Estádio Intermunicipal Faro-Loulé” on the Algarve Coast

Figure 1 A two-storey snow hotel covered withthe sow (reception in the centre, 8 roomsaround)

Figure 2a, 2b Internal views of the snow hotel Figure 3 Airhall of 100m x 60m x 18m

One of the most interestingapplications for TextileArchitecture is the field ofstadium roof construction.Generous, airy, and translucentroof designs which can also beshaped in varied form can beseen worldwide in many stadiumsin the meantime. The operatorsof smaller stadiums also make

more and more use of thebenefits of this design. The new“Estádio Intermunicipal Faro-Loulé” which was openedofficially in a ceremonial openingon 23rd November 2003 is oneof these examples.In accordance with a layoutdesigned by the architects HOKSportsevent and the AARQ,Atelier de Arquitectura in Lisbon,the south and east tribunes wereeach arched over by a roof designsuspended from rope binders,using an additional steel archconcept to support thisconstruction.A total of 32 membrane fieldseach with a width of 14.40metres and lengths varying from31.00 to 45.00 metres is roofed.The covered base surface is atotal of 10168m2 in size.Highly-resistant polyester fabricwith double-sided PVC coatingwas selected as membranematerial. Due to the use of a finalpaint coat with fluorine polymerpaint, the material additionallyfeatures a dirt-resistant surfacefinish.

The membrane building specialistCENO TEC GmbH carried outthe work with the engineeringspecialist office IPL-Ingenieurplanung LeichtbauGmbH who were already involvedin the project implementation ata very early stage to make thearchitects´ design feasible for theconstruction of the membrane,i.e. to harmonise the material-specific and design-construction-type requirements whichcharacterise the construction ofthe membrane such as sufficientcurvature in opposite directionsto avoid water or snow pockets,suitable steel elongations andfixing details appropriate formembranes.In particular, it was important todissolve the relatively flatdiscontinuous course of themembrane and to transform itinto a stable structure.

Practicable details conformingwith the supporting frameworkstructure to be providedexternally had to be developedfor production and mountingwhich made it possible to deviateloads burdening the membranestructure in a clean and, as far aspossible, linear manner to thesupporting framework. Themembrane surfaces and theindividual cutting strips weredetermined based on theexternally specified geometry.Here the exact material behaviourunder load had to be determinedby a load-controlled biaxial testwhich in the end served todetermine the compensationvalues for the cut. The individualfields - approx. 550 m2 in sizeincluding the edge designs - weremanufactured completely at theCENO TEC plant and shipped tothe building site. There, the elements weremounted to the supportingframework within a short period.In this respect, Textile Design canbe compared with “PrefabricatedHouse Operations“, meaning

Page 7: European Design Guide for Surface Tensile Structures...+ Design of membrane and lightweight structures Symposium (2000) 150 European Design Guide + Proceedings of the TensiNet Symposium

that the mounting timecompared to the project term isrelatively short. The mountingwork was implemented within aperiod of 5-6 weeks.

always manufactured in onesingle piece: this is thetraditional Finnish way notfound in any other country.

The Finnish climate has alwaysbeen suitable for air halls andthe number of built structureshas risen to more than 500 infourty years which is a lot for asmall country.

Finland is also exporting a lot ofsteel framed PVC-coveredstructures all around the world.(www.besthall.com).

7

The original Maritime Station was built in the sixties with a veryimpressive structure made of concrete shells. In 2003 it wascompletely renovated, and as part of this renovation, a new entrancebuilding was planned. Finally, the option of a light structure as a hallfor a heavy building was decided.

The situation of the roof, on a breakwater, almost surrounded by thesea as part of the harbour, conditioned it in two different ways:

On one side, the design should simulate the masts and yards of a TallShip. In order to get this, the whole structure is hanged on amainmast (35m height, ∅ 619mm) in the middle and small masts(∅ 219mm) on the border. The geometry of the tent, one half-cone asa mainsail and one irregular paraboloid as a gaff-topsail, and thedetails of the structure are constant references to ships (top basket inthe mainmast, six small masts: some of them as a kind of jib-boom,stainless clews of the sails, and so).

On the other side, the structural analysis should face expected windloads of almost 180 km/h, making the structure to be light but muchmore resistant than others. For this reason, the membrane used wasFerrari 1302 Fluotop T2, strong enough for this load and good fordirt-resistance and saline environment. The steel used for masts andarches is high resistant A52b/S355 JR.

The half-cone is attached under the top basket to the main mast, andit has two fixed borders –curved steel tubes - and three more fixedpoints on masts with four free borders - cables or bolt-ropes. The paraboloid is anchored to the mainmast in a fixed border withplates, and five more points to each mast with bolt-ropes betweenthem.

The mainmast is stabilised by cables in order to reduce flexion due toeccentric forces transmitted from the membranes. These cables(grouped in two families, one on top of the mainmast and he otheron the second membrane fixation) are fixed to the masts and finallyto foundations (which were designed for seismic loads).

The bottom of the mainmast is a spherical articulation designed tofix the position of the mast with the upper family of cables. On a lower position the mast is fixed to the concrete slab with a steelcrown: where the mast passes through the concrete slab. This way, it does not work as an articulated mast.

The finishing of the main floor is a wooden deck, being an otherreference to the nautical origin of this Tall ship anchored on land.

ANCHORED ON LANDMaritime Station entrance building

in Alicante harbour

Client: Alicante harbour authority

Location: Alicante harbour(Spain)

Main contractor: VIAS y

CONSTRUCCIONES

(Javier Vidal)

Contractor: COMERCIAL

MARÍTIMA L&Z, S.L.

(José M. Lastra, Javier Tejera)

Engineering: COMERCIAL MARÍTIMA

L&Z (José M. Lastra, Javier Tejera),

THEMA

(Guillermo Capellán)

Fabric/Structure material suppliers:

FERRARI / FAMECA, COTNSA

Year of construction: 2003

Covered surface: 600 m2

[email protected]

http://www.arquitextil.net

[email protected]

Figure 4 Airhall of 95m x 55m x 16m

http://www.tensotech.com

[email protected]

[email protected]

www.ceno-tec.de

Architect AARQ Atelier de

Arquitectura, Lissabon +

W.S. Atkins, UK

Engineering IPL - Ingenieur-

planung Leichtbau GmbH (D)

Contractor CENO TEC GmbH

Fabric PVC/PES fabric with a

dirt-repelling final PVDF coating

Covered Area 10168 m2

Year of Construction 2003

Page 8: European Design Guide for Surface Tensile Structures...+ Design of membrane and lightweight structures Symposium (2000) 150 European Design Guide + Proceedings of the TensiNet Symposium

8

Last June the Ninth InternationalWorkshop on the Design andPractical Realisation of Archi-tectural Membrane Structures was held at the Technical University Berlinand was co-financed by Ferrari, technet Gmbh and TensiNet. The mainobjectives of this workshop were to provide fundamental information, aswell as presenting the state-of-the-art in textile roof engineering. Ever sinceits conception nine years ago, the event has been growing in number ofparticipants, bringing together the expertise of successful engineers andarchitects as well as the enthusiasm of newcomers to the topic. This year’sevent brought together about 90 people from over 25 countries worldwide.In addition to a comprehensive programme of lectures presented in Englishby key figures from the membrane structure industry and academia,opportunities for the study and hands-on development of practical case-studies in an informal tutorial environment were provided, touchingsubjects such as computational modelling, design process, detailing,environmental and economical factors, physical modelling and materials.

The general structure of the Workshop and the ‘key-note’ topics andlectures were the same as last year, but new for this year’s event was thatsome presentations focussed on the Project Studies.

Ms. Stefania Lombardi (Canobbio Spa) gave a general introductory lectureon tensile structures and how an idea can be transformed into a real-lifemembrane structure, providing us with an insight on the process involved.

Dr. Dieter Ströbel of technet Gmbh explained the working of EASY softwarefor the computational modelling of lightweight structures, dealing withformfinding, load analysis and cutting pattern generation.

The Vrije Universiteit Brussel(VUB) was representedby newcomers Tom Van Mele, Niels De Temmermanand Caroline Henrotay, all architectural engineers,two of which gave their first ever presentation for an

internationalaudience. Theypresented theirresearch topic‘InteractiveKineticArchitecture’and ‘4-dimensional Design’, both dealingwith adaptability, but within adifferent timeframe.

Mr. Hubert Reiter from CovertexGmbh gave a presentation on theuse of ETFE foil, which can mainly

be used in architecture in two ways: mechanically prestressed forms andpneumatic cushion structures. He described the design and erectionprocess of The football Globe, a 670 m2 transportable structure, made outof inflatable ETFE hexagons and pentagons, patched together to form agiant football.

Textile manufacturer Ferrari S.A. was represented by Mr. P. Burnat, Mr. F.Reitsma and Mr. J. Tejera who gave a lecture on SKY®300, a newlydeveloped silicone coated fabric material for interior applications which hashigh flame retardency. The benefits of silicone are a good resistance to UV.,humidity and chemical aggressions.

Mr. Ingo Lishke from Textil Bau Gmbh consideredthe impact of climbing for textile projects. As anillustration, the cladding of the TUB’s mainbuilding was climbed with the help ofGewerbeklettern Erfurt.

Prof. Josep Llorens stated that detailing for fabricstructures is not yet thoroughly documented orwidespread practice, even though designing andevaluating connections and joints is critical to the

overall concept and the resulting structure.

Ms. Prof. Dr.-Ing. Rosemarie Wagner shared some ideas on a recentdevelopment in tension structures concerning a system for modelling andsimulation of membrane structures. It allows describing the design processin all its aspects and allows interfering of the user at each step. A non-linearoptimization algorithm is used, based on a FEM-formulation.

In sessions, parallel to the lectures, a Computational Modelling Workshopwas led by Dieter Ströbel and in an exhibition on Temporary Architecturesome projects by students from the Technical University Berlin werepresented.

The event was concluded by an interactive discussion, led by JürgenHennicke and Josep Llorens, on the physical aspects and constructiondetails of membrane structures.

We’re looking forward to the ‘10th anniversary’ edition of this event nextyear which will be held from 26th till the 28th of May 2005.

Textile Roofs 2004

www.textile-roofs.com • [email protected]

New coatings and multi filamentsMaterial compounds have a long tradition in the textile technology and a growing perspective.

The company Polymade ITT has made new products on the base of innovative textile components.

SOLAFLON coatings

With the SOLAFLON a newcoating system for innovativetechnical textiles has beendeveloped which leads to a wholeproduct family for textilestructures. SOLAFLON is a PTFEbased coating system with allwell-known f

eatures of

fluorpolymers in

the field of

constructional physics. Thenovelty consists in the fact that aglass clear PTFE derivate can beused in any thickness of coating.Because the coating appears as atransparent and flexible film onboth sides of the glass fabric, thecoating is even not visible at thefirst glance.

The developed

technology allows coatings from

some µm's up to some 100µm,whereas the polymer shows a highflexibility even at bigger layers.

Solaflon is nearly 100%transparent from 200nm up to2500nm. This means that it isnot only UVC stable but it alsoshows no optical change afterstrong radiation with high energyquanta like gamma radiation,where normal PTFE disintegrates.Within the range of the solarradiation from 300nm up to

2500nm Solaflon shows noabsorption. This means that alsothe UVB and UVA are passingSolaflon. If glass fabrics arecoated with Solaflon withoutadditives and such a materialwould be chosen for a football /soccer stadium the growth of thegrass would not be hindered.

That all together allows productsin a very big range oftransmission, which generally isonly limited by the glass fabric. Inthis respect a transparency of50% is nothing special.With the variable thickness of thecoating light and flexible textilescan be created. Even with theworst cross creases the Solaflonfilm on the glass fabric remainsunaffected. Because the bonding

between the polymer and theglass fibres is just a physical oneas mechanical anchor into themiddle of the multifilaments ofthe glass, this connection can bedisturbed when sharp creasesoccur. Due to this effect a darkerline could be observed, butdespite this visual effect thesurface remains absolutely tight.That concerns also only trans-parent Solaflon coatings whichdon't contain any additive. Thatcan be made invisible by heatingup the coating with a hot airstream, when the fabric isinstalled and is under tension.

Due to the high transparency ofSolaflon any colouring ispossible. Each RAL colour can beadded and the result is a brilliant,

Page 9: European Design Guide for Surface Tensile Structures...+ Design of membrane and lightweight structures Symposium (2000) 150 European Design Guide + Proceedings of the TensiNet Symposium

9

CP values for simple ridge and valley structures

www.polymade-itt.de

Michael Blum[[email protected]]

colourful and glossy material.With the incorporation of Irodinparticles the full range of metalliccolours is available, but also theshine of colourful interferencephenomena's can be realized.Due to the optical neutrality ofthe Solaflon matrix alsofunctional particles can be builtin. Out of this reason a “heatstop” effect can be generated.Special pigments which aretransparent in the visible,especially for green light andwhich are reflecting the totalinfrared allowing transparentstructures with cold light. Themembranes will remain coldbecause the IR is reflected andnot absorbed.

Another feature is the possibilityto create a low emissivity at thesurface of the membrane. Thatwill be done by aluminising theglass fabric by PVD (physicalvapour deposition) and thensheltering the metallic aluminium

coating with a thin layer ofSolaflon (about 10µm). Due tothe slight absorption of the far IRby Solaflon the effect ofaluminium remains nearly thesame, but it is secured againstcorrosion by the Solafloncoating. One of the main properties is thepolarity of Solaflon. That allowssimple seams to be made with RFwelding systems like those forwelding PVC. All membranesqualities can be treated likePolyester/PVC, what means thatmany companies are able totailor this material.

Solaflon can be used fortechnical fabrics which have tofulfil the A2 fire preventionstandards.

TECHNOFIL filaments

TECHNOFIL filaments are yarns,which consist of various technicalmulti filaments as core media like

• Glass (yarns / plied yarns /rovings)

• Polyester yarns• Aramide fibers / fibres of

high tensile strength• Other textile filamentsin

combination with coatingmaterials like• PVC• PU / PE• SOLAFLON• PVDF / FEP / PFA

The TECHNOFIL filamentscoating is performed in anextrusion process. This technologyallows the use of nearly all modernthermoplastic materials ascoating, whereas the customizedplastic can be modified in alldirections (flame retardant, UVprotection, gloss, colour, polymersoftening agents etc.)Besides the wide field of PTFEcoated glassfibers and PVC coatedPET fibres, the importance ofother coatings especially offluorpolymer coatings is growing.

TECHNOFIL filaments are usedfor various products like screens,blinds, shading fabrics, filtermaterials, insect screens,conveyor belts, belt systems andsupporting fabrics

The following paper is an extractfrom the European DesignGuide for Tensile SurfaceStructures.

Appendix A1 of the EuropeanDesign Guide for Tensile SurfaceStructures has been prepared soas to give general guidance onthe Cp factors that may beexpected for typical tensilestructure shapes. The term Cprefers to the wind pressurecoefficient that multiplies thesite wind pressure to give thewind loading pressure.

Archive wind-tunnel tests oftensile structures, as well asliterature covering both rigidand tensile structures have beeninvestigated for informationgiving typical external Cp valuesfor four types of simplemembrane structure. The typesconsidered are:a) Coneb) Ridge and Valleyc) Hypar/Saddled) Hybrid cantilevered canopy

From this investigation diagramsand tables giving average Cpvalues have been obtained. TheCp values given are on the samebasis as those given in theEurocode for conventionalstructures and are intended foruse with the Eurocode.The external Cp values can beused in the following equation:

External Wind Pressure (load)=Site Wind pressure

x External Mean Cp

The site wind pressure can befound using the Eurocodeprocedure for terms qref(reference mean wind velocitypressure) and ce(ze) (exposurecoefficient - this includes for theterrain and gust factorspertaining to the site). TheEurocode includes windspeedmaps for the whole of Europeand from which the basic sitereference mean wind velocitypressure can be determined.Internal/undersurface Cp valuesfor the ridge/valley forms should

be determined using theEurocode approach based onthe distribution and size of anyopenings in the buildingenvelope. The mean Cp valuesare given below as an averagevalue for a zone defined asshown in the diagrams. Theyare suitable for the design of themembrane and its supportingstructure but not for claddingpanels and individual purlins,which will be subject to higherlocal loading as described in theCode. The behaviour of thewind and hence the Cp valueswill not vary greatly with smallchanges in overall structure size.The Cp values given here can beassumed to be valid forstructures with bay dimensionsof 10-100m.

Shape parameters:The defining shape parametersfor this type of structure are

a) Ratio:valley width valley depth

b) Open or closed sides.

External Cp ValuesSides Open

Closed

Ratio of 2.5 4Valley Width

to Valley DepthApproximate 39 26

slope of membrane (deg)

Cp ZonesA +0.6 +0.3

-0.39B +0.23 +0.25

-0.33C -0.41 -0.2D -0.2 -0.3E -0.11 -0.45F -0.38 -0.35G -0.38 -0.8H -0.33 -0.5I -0.33 -0.9J +0.14 +0.35

-0.3 -0.3K +0.58 0.3

-0.29L +0.38 +0.3

-0.42 -0.2M -0.38 -1.2N -0.38 -0.6O +0.38 -0.4

-0.37P +0.45 +0.2

-0.46 -0.2Q +0.12 +0.3

-0.27 -0.3

Table External Cp Values for “Ridge and Valley” Type Structures

Figure 1 Typical “Ridge and Valley” Type of Membrane Structure.

Figure 2 Ridge and Valley CpZone Definition

Page 10: European Design Guide for Surface Tensile Structures...+ Design of membrane and lightweight structures Symposium (2000) 150 European Design Guide + Proceedings of the TensiNet Symposium

10

Abstract: As the New BangkokInternational Airport Projectsrequired the implementation ofa new material concept, it was avery special task to develop theinner membrane, which is alsocalled “Inner Liner”. Thefollowing article should give acomprehensive overview andalso describe some special issuesof this project.

1. General features ofthe membranematerials

The Werner Sobek Engineers,the company Transsolar and theLaboratory for Dynamics andAcoustics in Stuttgart havecommonly created the conceptof the 3–layers membranes,which should guarantee, that(besides the static requirementsof the construction) the air-traffic noise emission close totaxiways and runways should bereduced as much as possible.Additionally it was required tosupport the energetic concept ofthe construction with newcomposites and coatingtechnologies of the membranes.

Besides it was also obligatory,that the „Inner Membrane” hadto be certified in accordance tothe flame retardancy classifi-cation DIN 4102 A2. The outermembrane was chosen as theclassical and reliable Glass-PTFEcomposite with high trans-lucency, which has been proofedlong term in textile architecture.

The medial layer is fabricated ashighly transparent polycar-bonate, which is mounted in asteel-grid construction.

The third and from inside visual“Inner Liner” of this membraneconstruction was asked to fulfila composition of new require-ments of flame retardancy,acoustic and energeticproperties, light transmittanceand light reflectance and lastbut not least with the generalappearance of the material.

2. Special features of the INNER LINERThere were no materials in themarket available, which couldfulfil the complete set up of therequirements. Especially therequired low emissivity and thesound absorption establishedcreated a too high obstacle forthe conventional materials. Thecompany PD Interglas AG tookthe first task to develop the basicglass-grid – a fabric which wouldallow an aluminium-coating andcould perform a sound absorp-tion and a light transmission bythe correct grid-hole-opening-ratio. It was suggested thataluminium-coatings on glassfabrics would perform physicallysimilar effects like aluminiumfoils, the so called “LowEmissivity” or heat reflection.

Other than polyester basedfabrics, glass weaves as coatingand composite bases are able tosupport the flame retardancyrequirement A2. Althoughaluminium coatings on glassweaves seem not be too com-plicated in general, but it’s aspecial problem, to make surethat the aluminisation is embed-ded and does not lead to anoxidation, what would destroythe reflective property of the alu-minium layer in the far Infra-Red.

Because all well known coatingcomposites like PTFE, PVC orany other plastic materials arenot suitable for the task, abrand new coating polymerbecame the key element of theproduct development.

It was a high transparent, noncombustible and film-forming

polymer, which had beendeveloped out of the group offluoropolymers. This film-forming ability should allow toreopen the grid-holes of theweave after the coating of themembrane was completed, andtherewith to enable a highsound absorption.

The weave design and coatingcomposition allowed exceedingthe fulfilment of the requirednoise reduction coefficient of >0.7 to a new textile achievementvalue of 0.89.

Interglas AG asked Polymade todemonstrate the feasibility ofthe task in between 6 weeksafter November 2002, becausePolymade had developed acoating composite which hadbecome known to the marketunder the company’s brand“SOLAFLON”.After having demonstrated thegeneral feasibility and pre-serialproduct testing, the complexproduction logistics of thiscomposite had to be plannedand coordinated, especiallybecause a width of 2.20 m hadto be aluminised in an industrialavailable vapour depositionprocess. Other than inconventional slow coatingprocessing for industrial fabrics,the aluminisation is processedon a high speed level of 300 m/minute. This is a very difficultprocess to a relatively sensitiveglass-grid weave, which requiresunusual quality securing steps.Before receiving the order from

New Bangkok International Airport (NBIA)

The „Inner Liner“

Model of the New Bangkok International Airport

Micro perforations Emissivity of the aluminised membrane

Page 11: European Design Guide for Surface Tensile Structures...+ Design of membrane and lightweight structures Symposium (2000) 150 European Design Guide + Proceedings of the TensiNet Symposium

11

the general contractor of NBIACompany ITO, numerous testshad to be performed, mainlyaiming to the long termmechanical strength of thecomposite. This qualificationprogram was coordinated underthe product name A-Tex 2500Low E and was coordinatedbetween the manufacturer ofthe glass fabric, the coatingcompany, B&O Hightex and theLaboratory Dr. Blum inStuttgart. The material logisticsfor the roofing material such aspurchase, appearance control,documentation etc. is executedby OGAWATEC, Tokyo tosupport the general contractorITO, Bangkok and thefabricating company B&OHightex, Riemsting, Germany.

Pure glass based fabrics withouta sufficient polymer coatingcannot be used in tailoring andfabrication, because thematerial is too sensitive.

The process of coating shouldbe carried out asymmetrically,that no oxidation can occur onthe aluminium side, withoutoverruling the “LOW E” effectby the fluoropolymer coatingwith an absorption in the farInfra-Red. A stronger coating onthe back side should allow aneasier handling of themembrane in tailoring, weldingand assembly. The requiredsolar reflection of the white sidewith more than 60% could beguaranteed due to the trans-parent coating of SOLAFLON.

To fulfil the required opticalfeatures of the fabrication in104 “Typical Bays”, a suitabletechnical “connection” or seam,had to be qualified. Thedemand of a weld strength,which corresponds to thematerial strength with3250N/5cm, could be achievedby the availability of atransparent and compatiblewelding-aid. The coatingmaterial does not lead to lossesof the tensile strength of thefabric, but improves the glassfilament protective embedding.Consequently it was possible tokeep the tensile strength afterthe micro-perforation of themembrane. As aluminiumcoating is an energy barrier forthe economical RF welding-method -what generally ispossible with SOLAFLON- theseams had to be made with a socalled heating bar welding.

3. Fabrication processof the INNER LINERThe required glass-grid-fabricwas woven at the PD Interglasweaving factory inMalmerspach/ France. Beforethe fabric roles could be sent toget aluminised, they had to get aSOLAFLON-base coating.Without this base coating it isnot possible, to get the requiredreflection values of thealuminium. The aluminiumdeposition is processed in threesteps up to a thickness of120nm. After returning thecharges of about 20000m2 to30000m2, the furtherfluoropolymer-coating andmicro-perforation is processedin four different fabricationsteps. The appearanceinspection and role recordingtook place at the weavingfactory in Malmerspach/France. Only there, Interglas AGhad an accurate sleeveconstruction which allows a foldfree winding and inspecting ofthe approximately 600kg heavyroles. Precise protocols alloweconomical cutting patterns andthe optimisation of the tailoring.

4. Demands on theappearance of theINNER LINERAs glass weaving without anydefects is not possible, it was aspecial challenge to reduce thenumber and the allocation ofthe defects under the norm ofallowed defects for solar-protective screens, falling shortfrom a maximum of 10m per100 ongoing-meter and mostlyto offer 25m middle pieces ofthe typical Bays for zero defect“cutting patterns”. A quality improvement programimplemented by the participantscould guarantee that the defectnumber could be reduced toapproximately 30% of thespecified standard. For thisreason it was possible toassemble more than thespecified cutting patterns.Aluminium coated glass-weavesare functioning as a reflector or

a mirror and are also sensitivelike a mirror. All kind of creasesin the weaves appear as dark orbright marks. This caused aspecial demand to the fabri-cation, the transportation andthe assembly, where eachapproximately 1100m2 pre-fabricated membrane has to beinstalled at the construction sidein one piece. Furthermore glass-weaves don’t have any elasticity,therefore a highly specificcutting pattern, a faultlessfabrication and frictionlessassembly has to be secured.Each avoidable contact towardsthe optically sensible materialcould influence the appearanceof the membrane. Keeping thatin mind and observing thehandling instructions, thetechnical requirements as

mechanical strength, LOW E,transmission and soundabsorption will remainunchanged. When some yearsago the designers of themembrane constructionspecified the Inner Liner, therewas no material compositeavailable, which could fulfil thebunch of demands. Thischallenge, to introduce a soundabsorbing and open aluminisedglass fabric with LOW E andother optical properties was thetask which had to be matched. Without these nearly impossiblechallenges and the coincidenceof visionary demands on the oneside and the new SOLAFLONtechnology on the other side,the break through of thisinnovative material wouldn’thave happened.

Material inspection

The Inner Liner at the New BangkokInternational Airport

www.polymade-itt.de

Michael Blum [[email protected]]

Walter Duerbaum [[email protected]]

Prof. G.K.Brueck [[email protected]]

Page 12: European Design Guide for Surface Tensile Structures...+ Design of membrane and lightweight structures Symposium (2000) 150 European Design Guide + Proceedings of the TensiNet Symposium

TensiNet will assemble a list of universities dealing with Textile Architecture in terms of research and/or education. They will be mentioned one by one in TensiNews.

A C A D E M I C INSTITUTIONSFACULTY OF BUILDING TECHNOLOGY, UNIVERSITY OF EINDHOVENDouble curved pre-stressed net - Project Lightweight Structures 2004For many years now, the Struc-tural Design Department of theBuilding Technology Faculty atthe University Eindhoven, hasbeen active in the field of light-weight structures. Research,education and projects givestudents the opportunity to studythis subject. Each year we willorganise a project in which thestudents design, calculate,produce and assemble aparticular lightweight structure.These projects will increase theunderstanding of the structuralbehavior, the architecturalfreedom, and the importantissues of its production. This yearthe assignment was to design asculpture of a double curved, pre-stressed net with an equal mesh,to hang in the atrium of theBuilding Technology Faculty. Fourgroups of three or four studentsstarted to make several designs bysketching, using nylon stockingsand the formfinding module ofthe computer program GSA 8.0.GSA is an internal developedprogram by Arup. For theformfinding it uses Dynamic

Relaxation with the elementforces based on their forcedensity and length. The TU-Eindhoven has developed aprogram called Convers toconvert the cable layout of theGSA model into an equal meshand its cutting pattern. The meshgenerated was 110mmx110mminstead of the 100mmx100mmmesh we assembled. This wasdone to incorporate a 10%stretch due to the required pre-stress in the net. This equal meshreplaced the model in GSA, andwas used to calculate theprestress forces in the edge ropes.With the forces and the pre-stres-sed lengths of the edge ropes, theunstressed length between theconnections with the net could becalculated knowing the elasticitymodulus of the rope. For this, theproperties of the materials weretested, including their ultimateforce. The firm Huck Torimex BVin Katwijk aan Zee, producingamong other things nets of ropesand steel cables, showed interestin using their product for doublecurved pre-stressed structures,

and donated all the materials forthis project. A polypropylenemesh of 100mmx100mm ∅ 3mm,and polypropylene edge ropes∅ 5mm were used. After finishingthe calculations and producingthe working drawings, thestudents were divided into twogroups, one producing the netand the other producing the edgeropes. The edge ropes and sup-port points were given a uniquecode to co-ordinate theproduction. The connectionbetween the edge ropes and thenet was made with steel wires ofabout 70mm long, pinned threwthe ropes and twisted for fixation.To assemble the structure, weused the railing of the atrium assupport points. The structure wascalculated with a force of50N/100mm in the net (15% ofits ultimate load), which gave amaximum force of 1200N in theedge ropes (30% of its ultimateload) and 1700N on the supportpoints. During assembly thelocations of the corners of the netwhere measured to justify thelength of the span ropes and the

pre-stress in the structure. Withthe intension of developing thisyearly project into an internationalevent, we would like to welcomeall students and people interestedin participating next year.

The European Design Guide forTensile Surface Structures is aproduct of over three years workby the members of TensiNet - A Thematic Network forUpgrading the BuiltEnvironment in Europe through Tensile Structures, which was initiatedon 1 March 2001. This guide and the other activities of TensiNet werefunded by the European Commission, under theCompetitive and Sustainable Growth (Growth) Programmeof Framework Programme 5. The tensile surface structure business has grownconsiderably in the last 15 years and is predicted to growfurther. Such structures are becoming bigger and moresophisticated. More clients are interested in using them butthey are still considered to be special – a new technology. If tensile surface structures do not figure widely in thedesign vocabulary of European architects, engineers, urbanplanners, building owners and national authorities, theirapplication will continue to be constrained. Therefore,

there is a need for people to bebetter informed about thegeneral behaviour and theadvantages and disadvantages ofusing tensile surface structures inrelation to more conventional

buildings. For instance, the internal environment is seen as a key issue -how do such enclosures behave and to what functions are they suited?

There is also the question of maintenance. How do thesestructures differ from ‘normal’ buildings? These issues arecovered in the design guide. It is a generally held view thatEurope needs a code for Tensile Surface structures and thisdesign guide is a valuable and necessary step to a pan-European Normative document. Once an EN is availablethe industry becomes respectable and clients’ confidenceshould increase. In turn, that should lead to more businessfor constructors and designers. Nevertheless, this EuropeanDesign Guide for Tensile Surface Structures is not intendedto be a European standard. However, as a ‘state-of-the-art’report it is a step in that direction.

12

L I T E R A T U R E European Design Guide for Tensile Surface Structures

Brian Forster, Marijke MollaertISBN: 9 789080 868717 • Pages: 354, Soft Cover • Published: 2004 • _100.00

1 • Formfinding model in GSA2 • Net with equal mesh (blue) following the shape

of the formfinding model (brown)3 • Axial forces in the ropes4 • Connecting edge ropes and the net with knots5 • Assembled net in the atrium of the Building

Technology Faculty, TUE

1 2 3

4

http://www.tue.nl

[email protected]

5