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Tensi ewsNEWSLETTER OF THE EUROPEAN BASED NETWORK FOR THE DESIGN
AND REALISATION OF TENSILE STRUCTURESw 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 0 - A P R I L 2 0 0 6 - P U B L I S H
E D T W I C E A Y E A R
Editorial Board: Mike Barnes, John Chilton, Brian Forster, Peter
Gosling, Marc Malinowsky, Marijke Mollaert, Peter Pätzold, Rudi
Scheuermann, Javier Tejera, Thomas Van der Velde
Coordination: Marijke Mollaert, phone: +32 2 629 28 45,
[email protected] Address: Vrije Universiteit Brussel
(VUB), Fac. of Engineering, Dept. of Architecture, Pleinlaan 2,
1050 Brussels, fax: +32 2 629 28 41
Tensi ews info
Editorial
This is the fourth issue of TensiNews since EU funding for the
establishment of TensiNet ceased and the organisation became self
funded – principally through industrial sponsorship by the major
partners, although supplemented by a significant number of
individual, company and university membership fees. TensiNet is now
on a sound financial footing to cover its publication, symposia and
web support costs (which to some extent have previously been
supplemented by staffing provided at the VUB in Brussels). An
expansion of the support has come about through the former Working
Group for Tensile Architecturewho have now joined TensiNet as full
partners. One effect of this is that TensiNet will in future be
sponsoring theinternational student design competition (see article
in the current issue of TensiNews). Other wider considerations,
which are raised in the short article about the working group
meeting (page 2) are:• the possibilities for further collaborations
or amalgamations with other groups• a possible reconsideration of
the aims of TensiNet, or revision of emphasis• a possible review of
the constitution or management of TensiNet
In relation to the latter two aspects it seems appropriate to
emphasise that TensiNet was set up with EU funding to be a Europe
wide network for the dissemination of information relating to
Tensile structures(particularly prestressed membranes) and to
become an industry sponsored trade, professional and
educationalorganisation managed, according to its constitution, by
its founding and subsequent industrial partners. That is a
verybroad aim and it allows plenty of scope for the organisation to
develop however it may wish, and there will be a naturaleffect for
the principal partners who provide most funding to shape future
policy, including of course the question offurther collaborations.
In that context there are three levels of collaboration:• the first
is National – there may be good organisational and perhaps
commercial reasons for the formation of
local (or national) branches of TensiNet – see for example the
article on page 2 concerning the meeting in Madrid• the second is
Europe wide – in other words increasing the emphasis on the
original aims of TensiNet which, in
addition to the exchange of information at the professional and
educational levels, also had the intention ofproviding a forum for
potential collaborations in research and development, and the
development of design guidesand eventually codes of practice
• The third is International – for example, in a worldwide
context there are four Lightweight Structures associations– LSA in
the US, LSAA in Australia, TensiNet in Europe and MSAJ (membrane
structures association of Japan).Most of these have already agreed
in principle to collaborate in the setting up of International
Symposia
TensiNews is really an industry news forum, especially relating
to new projects. It is not intended to be a magazine forresearch
and the articles are not refereed (or particularly vetted and
edited), but it might be appropriate to have aletters section and
perhaps some of the issues raised above could be discussed more
widely.
Marijke MollaertMike Barnes
2Forthcoming Events
Meeting Working Group for Textile Architecture
Regional TensiNet Meeting
3Cooltrax®
Intelligent shading material
4Desert Seal
A Tent with active Cooling
5New tensioning system
for textile façades
6Chemically Rigidized
Expandable Structures (CRES)for Space Application
8Mechanical behaviour
of coated fabrics and films usedin prestressed textile
engineering
10Literature
International workshop‘Textile Roofs 2006’
11International Students Seminar
‘de-light and air’
12Student Competition
'Textile Structures for New Building 2007'
Fabric Boat
13Multi-event area
“Los Teros de Melilla”
14Buitink Technology
entrance of Dolfinarium
15Roof Tent Structure
Khoraisch Road Retail CenterUnobtrusive Canopy 2The “Lleida”
prototype
16“The Oyster”
Casino del Aljarafe, Sevilla Textile roof for a stand
at TSV Gersthofen
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2
Tensi et partners
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 Frankfurt/Techtextilwww.techtextil.de
SL-Rasch GmbHwww.sl-rasch.de
Schlaich Bergermannund Partnerwww.sbp.de
Vrije Universiteit Brusselwww.vub.ac.be
Universidad Poletécnicade 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
form TL
Ferrari sawww.ferrari-textiles.com
Canobbio S.p.A.www.canobbio.com
Architen Landrellwww.architen.com
Group ALTO
The following members of the Working Groupfor Textile
Architecture did attend the meetingin Frankfurt: Mr. Driesch,
Verseidag; Mr. Frisch, Dyneon; Mr. Kleibel, Taiyo Europe;Mr.
Jännecke, Messe Frankfurt; Mr. Hohlstein,Messe Frankfurt; Mrs.
Heidrun Bögner,TensiNet.
As mentioned in previous meeting reports theWorking Group for
Textile Architecture willjoin the TensiNet Association and will
nolonger continue its activities as anindependent Working Group.The
three companies Verseidag, Dyneon andTaiyo expressed their
intention to join theTensiNet Association as a partner.The
following main points we discussed: The new partners paying 2400
euro expect toget more power in the management boardthan the
founding partners paying much less!
Is it possible that a whole association joinsthe TensiNet
Association so that theirengineers get total access? What would be
the fee? Is the TensiNetAssociation interested in working
togetherwith other associations like the BKTex or IVK(engineering
association for synthetics)?On the webpage the information should
besubdivided more clearly into working areas sothat potential
clients can find the requesteddata more easily: specific data for
coaters,fabricators, engineering offices etc. should beclustered.
In Mr. Driesch’s opinion the TensiNet Association should
formulatenew goals to develop appropriate solutionslike for
recycling PES/PVC-fabrics.
Heidrun Bögner-Balz
[email protected]
www.labor-blum.de
The regional TensiNetMeeting organized onMarch 2nd 2006 was a
success. About 30 experts representingaround 20 organismsand firms
attended themeeting. Prof. Llorensgave a lecture aboutthe evolution
of tensilearchitecture in Spainand Portugal in the lastfew decades,
and Juan
Monjo Carrió explainedthat TensiNet wasfunded to be
acollaborative Europeanventure. The interest ofthe current
TensiNetAssociation wasclarified. Other topicsof discussion were
theorganization of the“Iberica branch”, anIberian section on
theTensiNet website, the
organization ofseminars andworkshops to be heldin 2007, and
thetranslation of theDesign Guide.There was a goodfeeling and
nextmeetings areprogrammed to takeplace in Barcelona inApril and in
Madrid inJune to take final
decisions aboutentering the TensiNetAssociation andorganizing
the “Ibericabranch”. Even an“Ibero-americanbranch”
wasconsidered.
Juan Monjo Carrió
[email protected] Llorens
[email protected]
Working Group for Textile Architecture: Meeting Frankfurt 19th
October 2005
Regional TensiNet Meeting in Madrid, Spain
ForthcomingEvents
ROOF & CLADDINGMIDDLE EAST 2006
International symposium
Expo Centre, Sharjah,United Arab Emirates
02/05/2006> 04/05/2006
www.roofmiddleeast.com
TEXTILE ROOFS 2006Workshop
Berlin, Germany
25/05/2006> 27/05/2006
www.textile-roofs.de
ADAPTABLES 2006International Symposium
Eindhoven, The Netherlands
02/07/2006 > 05/07/2006
www.supertuesday.tue.nl/adaptables2006.htm
IASS / APCS 2006International Symposium
Beijing, China
16/10/2006 > 19/10/2006
www.iass2006.cn
TENSINET-SYMPOSIUM 2007
International Symposium
Milan, Italy
16/04/2007 > 18/04/2007
www.tensinet.com
TECHTEXTILFRANKFURT 2007
Trade FairFrankfurt, Germany
12/06/2007 > 14/06/2007
www.techtextil.messefrankfurt.com/frankfurt/en/home.html
STRUCTURALMEMBRANES 2007
International Symposium
Barcelona, Spain
17/09/2007 > 19/09/2007
http://congress.cimne.upc.es/membranes07
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The functioncooltrax® is a high-tenacity netfabric with a unique
triangulargeometry. When the sun shinesthis structure creates light
andshadow fields on the groundthat move constantly due toearth
rotation. So heataccumulation on the ground isprevented. The
specialtriangular geometry is the onlypattern ensuring that
eachpoint is evenly shaded. Thussun or shadow stripes arecompletely
avoided withoutregard to the material’s angleto the sun. This means
aperfect half shadow.
The advantagescooltrax® withstands high windloads and only
requires light constructions. It offers a maximumcooling effect due
to the material structure which has 32% of opensurface. This
prevents heat accumulation underneath. cooltrax®
reduces rain noise on dormer windows and sky lights and protects
thewindow material against e.g. hail. When used indoors cooltrax®
issuitable for sprinkler systems.
The application areasAt home the shading materiallets the light
in, but keeps theheat outside. Hence it can beused for sun
parlours/wintergardens, dormer windows/attic
windows,terraces/patios and balconiesas well as for
carports.Shading can also be neededin business buildings in
open-plan offices, conferencerooms, vestibules, light streetsor
glassy airport halls.The shading material is alsoappropriate for
leisure timecanopies over sandpits in thedomestic garden, places
atthe beach, sun lounges by thepool, children’s paddlingpools,
camping sites, etc.
The coated mesh can be used for sun shields on a bigger scale
like formarket places, street cafes, school yards, kinder gardens
andplaygrounds as well as for fields for tennis, football/soccer,
golf andathletics.
heytex® cooltrax® this name stands for a whole new way to enjoy
the sun in the shade and for shading places
3
Close-up of the cooltrax® shading material
Booth in cooltrax® material, Gartenlust & Landvergnügen,
Ippenburg
Test results (temperatures in function of the time of the day)
for testing boxes placed on pavement with closed sides in the
climatic zone of Casablanca
Katrin von Dreele: [email protected] • www.heytex.com
THE INTELLIGENT SHADING MATERIAL
Base fabric W/F (DIN ISO 2076) trade mark polyesterYarn W/F (DIN
53830) meshwork 550 dtex,
triangular fields 167 dtexBase cloth weight (g/m2) (DIN 53854)
ca. 150 g/m2
Coating material PVCTotal weight (g/m2) (DIN 53352) ~480
g/m2
Tensile strength (N/5 cm) (DIN 53354) 850/550Elongation at break
W/F ~22%/21%Thickness ~0.9-0.95 mmWelding adhesion at least 100 N/5
cmLight fastness grade 7Flame retardancy (DIN 4102 Teil 1) B1
burning dropletsAir resistance coefficientCw (DIN 1955) 1.054Total
strength coefficient Cg 0.818
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The Munich and London based design firm ‘Architecture and
Vision’presents a new design and prototype for a one-person tent to
be usedin the extreme temperatures of the desert. The inflatable
tent is theresult of a study performed for the European Space
AgencyTechnology Transfer Programme and employs several
conceptsdiscussed in Space Exploration. The prototype has
beenmanufactured by Italian aerospace company Aero Sekur S.p.A.
The structure is making use ofthe specific temperature curve
inhot arid regions, where the air isgetting considerably cooler
themore distant it is from theearth’s surface. This effect isused
by many desert animals likethe camel.
The tent has recently been in the exhibition “SAFE: Design Takes
OnRisk” from October 2005 until January 2006 at The Museum ofModern
Art (MoMA) in New York. It will be shown this summer in theMuseum
of Science & Industry in Chicago in the special
exhibition“Leonardo da Vinci: Man, Inventor, Genius”.
Model at the exhibition “SAFE: Design Takes
On Risk” at The Museum of Modern Art
Desert Seal is an inflatableone-person tent for hotextreme
environments. Theintroduction of a verticalelement allows a high
air-intake for cooling the tentinside. In addition it
allowsentering the tent upright andtaking the cloth of
inside,protected from wind. Theentrance can be opened andclosed by
a zipper.
To create the vertical element an air beam construction has
beenchosen to allow a dense packaging and lightweight construction.
Theair beams form a vertical A-frame, which ends in an aluminium
plate,which allows a stand-off for the air-intake. Between these
air beams asilver-coated awning is spanned to form an anti-clastic
shape. Thisprovides an elegant transition fromvertical to
horizontal as well as aflutter-free spanned textilesurface, which
offers goodaerodynamics with a low wind-resistance.
The first prototype has beenmanufactured by the Italianaerospace
company Aero SekurS.p.A. (www.aerosekur.com),specialised in
parachutes and life-saver inflatables. The tent consists of an air
beam structure made ofyellow PU-coated polyethylene fibre. The two
V-shaped air beams arekept on distance by another air beam at the
widest part of the tent. Atthe top and bottom end they are held by
an aluminium plate, whichdefines an end and allow the openings for
the airflow.
The awning is a silver-coated high-strength textile to reflect
heat andprotect from direct sunshine. The awning is seamed together
out offour pre-cut pieces and glued directly onto the air beam to
allow aneasy set-up also in strong winds. In its longitudinal axis
the tent isfixed to the ground from both ends by ropes and two
large plastictent pegs, which allow fixation in the sand, but also
in other grounds.The A-frame provides lateral stability.
The tent design follows twobaseline strategies to protectagainst
the excessive heat in thedesert. First, it is providing apassive
sun protection by heatreflective shading material andsecond, it is
making use of in-
situ resources. In the desert, where the balancing plant cover
ismissing, the ground heats up very quickly by the radiation of the
sun.The fact that air is actually a good insulator, prevents it
from heatingup as much and as fast as the ground. In fact, the air
becomesconsiderably cooler the more distant it is from the Earth’s
surface.During the day, the temperature can easily reach 60°C and
beyond atground level, while just 2-3 meters above, it can be up to
40°C lower.This characteristic is used to cool the tent. Water
based coolingtechnologies would have a high weight penalty, whereas
others wouldrequire a lot of energy.During the day, an electric fan
in the top of the tent, 2.26 m above theground, constantly blows
cooler air into the tent, thus reducing theinterior temperature.
The fan is powered by batteries charged by aflexible solar panel
mounted outside the tent. This rollable solar panelis a development
by the Swiss company VHF-Technologies. Batteriesare standard AA
rechargeable batteries.During the night, the desert ground radiates
heat off to space and isquickly reaching temperatures below zero
°C. Since air is acting againas a good insulator, it stays
considerably warmer on higher levels. Thistemperature inversion now
allows to collect warmer air, using thesame principle. The fan on
top is now running on batteries andblowing warmer air into the
tent, protecting from the cold air atground level. This
environmental condition in the desert is not only used by animalsto
fulfil their cooling requirements, but is also employed
sincecenturies by traditional building know-how. In Iran, for
example, manyold buildings have so called ‘wind-towers’, where the
cool air isscooped and led down a chimney into the building.
Recent and near-futuredevelopments in battery andsolar-panel
technologyincreasingly allow new conceptsalso in mobile structures,
which
Diagram showing the temperature curve inrelation to the distance
of the ground in the desert
Picture from inside the tent, showing the airoutlet at the
bottom end
Picture from inside the tent showing the electricfan on top of
the tent and the two air beamsforming the vertical A-frame
structure
Front and side elevations of the Desert Seal tent
DESERT SEALA Tent with active Cooling
Andreas Vogler and Arturo Vittori •
http://www.architectureandvision.com
The Desert Seal tent set up with the flexiblesolar panel
installed. The silver metal coatedawning is reflecting the heat
from the sun
View of Desert Seal with the flexible solar panelinstalled
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New tensioning system for textile façadesBuitink Technology has
developed and patented an innovative system
to tension textile façades and membranes: an inflatable
tensioning tube
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even a few years earlier wouldhave been easily dismissed,since
the technology wouldnot have met therequirements. The tent
packstightly into a backpack andweighs less than sixkilograms. The
beauty of thisstructure derives from itsfunctionality and
efficiency,particularly dealing with suchnatural energies as sun
andwind. The aerospacearchitecture background ofthe designers is
visible in theconception, construction andmaterialisation of the
project,using natural resources andminimum weight
fortransportability. Desert Seal’s‘down-to-earth’ conceptderives
from currentlydiscussed Space Explorationconcepts. A
smalltransportation volume, largedeployment volume and
alight-weight construction arecrucial for all
spacecraft.Inflatables have beenanticipated from the verybeginning
of space flight andare considered for HumanHabitats on Moon and
Mars.The temperature extremes ofSpace are also found onEarth and
the use of localenergies (In-situ ResourceUtilisation) for
coolingand/or heating is reducingtransportation mass.
HumanSpaceflight is relying onactively controlledenvironmental
systems. The energy needed to drivethe small electric fan isgained
by a light-weightflexible Solar Panel, atechnology also tested
forspaceflight. Thermal controlis one of the key points indesigning
space structures.Desert Seal exploits severalconcepts used in the
spacethermal control systems. Thealuminised fabric used for thetent
cover is very similar tothe Multi Layer Insulation(MLI) used for
spacecraft.
The Desert Seal tent can be packed denslyand is quickly deployed
by a pump
All pictures: © Architecture+Vision
Visualisation of textile façade
Examples of detail
Working principle of tensioning system
Working principle of tensioningsystem
Test set-up
Textile façade When a fabric is used to create a textile façade
at the exterior of a building, onehas to take into account (large)
wind forces. Especially above 10-20m and incase the textile façade
is installed at more than 15cm away from the building(which means
no or less pressure compensation), the forces on the fabric will
belarge. In these cases a once-only pre-tensioning of the membranes
might not besufficient, especially when façades for the long term
(permanent) are installed.
Existing tensioning systems By tensioning the panels with a
spring system, larger forces can be taken by thefabric, to provide
tension and to give the fabric the possibility to deform to
acertain extent. This can be done by fixing the panels to a
(aluminium)tensioning tube or by providing the fabric with springs
or elastic rope. Thesesystems have some disadvantages. Springs and
elastic rope will wear in timeand will have to be replaced. A
tensioning tube needs periodic maintenanceand lubrication. Besides,
it needs a very precise and controllable measuring andtensioning
(also in the long term) of the tubes and fabric. Maintenance
andreplacement of parts will often have to take place in areas that
are difficult toreach. Further, when using springs or elastic rope,
space will remain betweenthe fixation points to the façade and the
fabric panels. Also the fixation partswill remain visible. Finally,
an aluminium tensioning tube is rigid and notflexible, which can
make it difficult to introduce forces into the fabric evenly.When
e.g. one fabric panel covers the complete width of a façade and is
fixedto aluminium tensioning tubes, the wind forces on the panel
will vary ondifferent locations of the fabric panel (at the corners
there will be probablymore force than in the middle).
New: Buitink inflatable tensioning tube In addition to existing
tension systems and to take away some majordisadvantages, Buitink
Technology developed a new tensioning system: theflexible,
inflatable tensioning tube. The system consists of an inflatable
tube towhich the fabric panels are connected, by means of e.g. a
weld or connectionprofile. By inflating the tube, the fabric is
tensioned like a spring system. In caseof external forces, the
fabric will tend to deform and will therefore need extralength.
This length is obtained by deformation of the round tube into a
moreoval shape. Depending on the diameter of the inflatable tube
and the innerpressure, this will result in an opposite resulting
pulling force from the tube,which keeps the fabric tensioned and
will bring it back to the original state. A simple and central air
unit maintains the system of inflatable tubes.
Advantages of the inflatable tensioning tube The inflatable
tensioning tube has a number of major advantages. First of all,the
tubes need no or hardly any maintenance. The only maintenance will
haveto take place at the central air unit (e.g. a yearly
inspection), which basically isthe complete tensioning system.
Besides, architects have more freedom indesign, since the tube can
be installed out of sight and the fabric can beconnected directly
on the façade (without having space between the fabricpanels and
the fixations for the springs or elastic rope). Further,
differentcombinations of diameter, inner pressure and maximum
deformation can bechosen. Moreover, the inflatable tubes will
provide for stiffness perpendicularto the tensioning direction but
at the same time they will remain flexible andbendable. This way,
external forces can be introduced into the fabric panels ina more
evenly way than in case of a rigid tensioning tube. Finally, it is
easy togive the tubes on a higher level on the façade more inner
pressure, to takelarger wind loads (the tensioning properties can
be adapted to localcircumstances). A short summary of the
advantages: freedom of design anddetailing, tensioning of flat
fabric panels possible, maintenance only at the airsystem, many
possibilities of application, and evenly introduction of
forces.
A large number of applications….. The system with inflatable
tensioning tubes can be used for a lot moreapplications, like
tensioned ceilings, banners, tents and even trampolines!
Rienk de Vries: [email protected] •
www.buitink-technology.com
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Chemically Rigidized Expandable Structures (CRES) for Space
Application
BackgroundBetween 1979 and 1992, underEuropean Space Agency
(ESA)contracts, Contraves AG (Zurich,Switzerland) undertook
todevelop a technology forinflatable space rigidizedstructures
(ISRS) — intended toserve a wide range of spaceapplications — that
raised interestbeyond the original sponsor, e.g.of researchers in
the US and inJapan. Unfortunately, thissomewhat
unconventionaltechnology could not obtain theflight opportunity
that it neededto prove itself in a real testenvironment, leading
the Swisscompany to abandon activedevelopment early in the
1990sthen, ten years later, to whollywithdraw from the field. In
themeantime, ESA has restarted aneffort in this
technologicaldomain. Dr. Bernasconi had the privilegeto become
involved with thiswork at its very onset (when hewas massively
involved both inthe technology definition and inthe design of the
first reflectors)and to accompany it through itsexpansion phase.
Because of hiscompetence, in the 1990s hebecame the sole point of
contactfor the ISRS field, and performeda number of studies and
assessments for interested thirdparties. Since
Contravesdisclaimed any further interest, hehas continued to offer
hisengineering services and hisexpertise about inflatableexpandable
structures, doingbusiness under the firm of «MCBernasconi
Consultants» (MCBC,for short) since January 2003.Below, we
summarize some of thepast activities related to the threeclasses of
applications: precisionstructures, backbones, and heavy-duty
items.
Precision StructuresFor historical reasons, work atContraves
centered on microwaveantenna reflectors, whosedifferent forms find
numeroususes in communications,astrophysical research, andremote
sensing.
Reflectors for CommunicationsAntennae & Radio TelescopesThe
experimental activities atContraves led to the manufactureof some
eight complete parabolicreflectors, with apertures rangingfrom 1 to
10 m. Three early scalemodels of a symmetric (center-fed) reflector
were used toappraise issues such as foldingand deployment,
manufactureprocesses, and achievableaccuracy. In successive
phases,
the first-ever "inflatable" offsetreflector was built, with
three 3 mobjects used for extensive tests,collecting data on
accuracy (0.7 mm root-mean-square (rms)for the last object
manufactured)and electrical performance --measured at frequencies
up to 22 GHz on an object (Figure 2)folded, re-deployed, and
cured.Also tested were the concept'shigh packaging efficiency
(Figure1), its controlled deployment invacuum, and the
chemicalrigidization under simulatedspace conditions. Successively,
a10 m aperture, offset-fedreflector designed for
multi-beamoperation at 1.6 GHz wasmanufactured and tested
(underclean-room conditions -- Figure 3):while the initial 2.2 mm
rmssurface error grew to 2.7 mm rmsafter folding and deployment,
thereflector still kept a side lobe levelof -33.8 dB.Most
communications antennaeadopt offset-fed configurations,to minimize
interferences: inradio astronomy, where issues ofgain and
resolution predominate,symmetric (on-axis) designs aremore common.
Investigating theQUASAT orbital radio telescope, a European
scientific groupsuggested to base it on CREStechnology. Supporting
activities
at Contraves culminated in themanufacture and test of a 6
mdiameter Test Article (Figure 4)(1.2 mm rms). Further, weprovided
assessments andsupport for scientific projects(e.g. Radioastron,
the MODESTconcept) and, following upvarious external queries,
weevolved a self-contained,compactly stowed, reflectorconcept, to
create relatively largeapertures (up to 6 m) to small-satellite
missions.
Solar ConcentratorsHigh-concentration-ratio solarcollectors
represented a pre-eminent application forflexible wall structures.
A study ofa Solar-Thermal Upper Stage (Figure 5), led by EADS
SpaceTransportation, offered theopportunity to assess the
interestof continuously inflated reflectorsfor such an application,
as thelimited life time (up to a month)of such a system makes the
use ofthis technology possible.
Backbone StructuresTo satisfy their functions,precision
structures demandextended design, analysis, and in-process control
measures, butthey do build on a technologybase that allows
realization ofbearing elements without
Figure 1: A typical deployment sequence of an inflatable offset
reflector demonstrated with “LOAD-3-1” - the first ever rigidizable
offset reflector (on the floor ofContraves’ 10000-class clean
room). ©Contraves AG (1984)
Figure 3: LOAD-10 offset reflector at the end of manufacture
©Contraves AG (1990)
Figure 4: 6 m Test Article for the QUASAT radio telescope
reflector (nominally at 1/3 scale) within Contraves Space
100000-class clean room.
©Contraves AG (1988)
Figure 5: LH2 solar-thermal stage featuring apair of solar
concentrators relying on inflatablecollectors for the first stage,
with CPC elementsas second stage.
©EADS-ST (2001)
Figure 2: The 3 m ISRSoffset antenna asused for far-field
RFmeasurements,with feedsand support
structure byCSELT, Turin
©CSELT (1986)
6
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7
inherent accuracy requirements.Thus, lightweight backbonesseem
the logical objects to beginimplementing a CRES capability,as ESA
and industry areattempting today. Analysesshowed that -- even with
simplemorphologies -- the technology'sversatility in complying
withvarious needs, still reachesnumerous prospective users.
Planar Instrument Carriers &Solar SailingAny CRES item has
an overhead(container, pressure-controlitems, etc) that may become
tooimportant when used on a "toosmall" object with "too simple"
afunction. As a torus replacesseveral linear elements, suchframes
return a better value forthe investment overhead. Anddesigns where
a toroidalstructure deploys and supports aflat membrane can suit to
a widerange of tasks. In particular, solarsails have been assessed
in anumber of studies (Figure 6): thetorus design remains
attractivefor such uses up to some 100 min diameter. Toroidal
supportstructures received attention for apower transmission
rectenna, aswell as for thin-film photovoltaicsolar arrays (TFPV --
Figure 7). To date, no such object has beenbuilt in Europe, but
experienceexists both with more complexitems (as used within the
FIRSTshield model, mentioned belowand including rings of 3.5-4
m,each incorporating 12 nodes),and with purely inflatable,
butlarger (6-15 m), stabilization toriwithin antenna
reflectors.
Single-Tier Structures: Aero brakes and moreAs the flexible
parts grow to asignificant size, it appearsindicated to position
thespacecraft body in the frame by atripod connection (or one with
4,5, or 6 legs). Single-tier elementscan deploy lightweight
aerobrakes (e.g. to lower a piggybacksatellite's orbit, or to
accelerate aspacecraft's end-of-life decayfrom orbit), to support
shadow
shields or «instrumented»membranes (microstrip, lens or
reflectarray antenna elements;sensors or multifunctionaldevices,
etc). Our studies have shown the attractiveness of such anoption
for (slow) aero braking,both in terms of mass and costs (Figure
8).
Two-tier Structures: Telescopes'Tubes and Thermal
ShieldsMastering the creation of nodesconnecting out-of-plane tubes
toa flat frame enables the creationof 3-dimensional
assemblies,complex truss works andpolyhedral skeletons. The
initialscientific proposal for a FarInfrared Space Telescope
(FIRST)foresaw an 8 m mirror, radiativelycooled to 150 K, thus
requiringan expandable thermal shield inthe 10 m size range, for
which itsuggested a CRES object. Wedefined this shield as a
two-tierassembly, with 48 cylindrical strutelements joined at 24
nodes, eachinterfacing with either four orthree struts. Several
ESTECcontracts supported the work atContraves, including the
manu-facture of a complete 3.5 mskeleton (Figure 9), used
forpackaging, deployment, cure, andgeometric check activities.
Expandable space structures nomore complex than this can
covermany applications – includinghangars and other
unpressurizedenclosures. In their basic form,orbital hangars build
anenclosure for shielding astronautsand hardware duringmaintenance
and repair activities,adding services like controlledlighting, some
thermalconditioning, work stations andmore. Shielding cryogenic
upperstages appears an engineeringapplication viable for a
FIRST-shield level technology. Also, theuse of inflatable
structures forrealizing greenhouses, particularlyoperating on
planetary surfaces,has been discussed and currentlyreceives an
increasing amount ofattention.
Heavy-duty Structuresfor HabitationExpandable, habitable
volumesembody an ambitious use ofmembrane structures technology.In
2001, the Italian Space Agency(ASI) sponsored the firstEuropean
study in this direction,in which Dr. Bernasconiconsulted for
Oerlikon-ContravesItaliana (Rome). In analyzing thepackaging of
flexible-wallhabitats of different basicgeometries, he showed that
botha full torus and its C-annulusderivative (Figure 11) are
mostconvenient in terms of theachievable expansion ratio -- i.e.
the ratio of the volume of thestructure expanded to its
volumestowed. A recommendedmodification of theconfiguration "A"
habitat (Figure10), complying with a 4.7 mhigh, 4 m diameter
stowagevolume, would increase theexpansion ratio (from 4.5 to
5.9)and thus the habitat's volume(225 m3 vs 135 m3).If expandable
habitats offer acapacity well beyond thatotherwise compatible with
atransportation systems, they raisethe problem of furnishing
them.To create secondary internalstructures, one can use
eitherconventional, rigid, equipment --that has to pass through
airlocksand hatches connecting withdistinct carriers in a
timeconsuming way -- or foldingelements. MCBC, as part of theHTS
(Zurich) team, hasaddressed the type and layout ofauxiliary
structures that the«Space Haven» module (understudy at Alenia
Spazio) wouldneed. But this remains an areafor much future
work.
http://esprist.bathome.org • Dr Bernasconi,
[email protected]
MCB Consultants bring the accumulated expertise of the
pioneering work at Contraves AG into current and future
developments
Figure 6: Frames andPICs (Planar InstrumentCarriers): the
concept ofa solar sailing spacecraftfor asteroid exploration,with
four 2500 m2
saillets. ©MCBC (1995)
Figure 7: Concept for a toroidal support frame(PIC) for a
thin-film photovoltaic array.
©MCBC (2004)
Figure 9: The 1/3-scale model of the ISRSskeleton for the
FIRST’s thermal shield.
©Contraves AG (1990)
Figure 8: Single-tierskeletons, such as could be used e.g. on
smallsatellites to form a light-weight aerobrake, or tosupport a
reflectarrayantenna or a lenscollector.©Contraves AG (1990)
Client European Space Agency (ESA), ESTEC, The Netherlands
Original contractor Contraves AG, Zurich, SwitzerlandEngineer
MCBCMaterials Textile composite of Kevlar with a modified
cycloaliphatic epoxy resinExecution 1980 - 1991
Figure 10: An inflatableorbital habitatinvestigated during the
SpeS Study
©IACSA/Ing. Speranza (2001)
Figure 11: AC-annulus shell in cross section.©MCBC (2004)
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In the beam theory one finds theexpression E J as the
bendingstiffness in the differentialequation for the displacement
w:
M is the bending moment, E isthe E-modulus of the materialand J
is the axial momentum ofinertia of the cross section.Analogue
equations are valid forthe displacement of plates. In thetheory of
membranes such anexpression for the stiffness is notyet known. The
question rises: canone define an analogue expres-sion for the
membrane stiffness?
Approximate theory of membrane deformationand stress
distributionTo get an expression for themembrane stiffness one
startswith the equilibrium conditionsfor a prestressed
membrane.Assuming a covariantformulation, these conditionshave the
form:
Here N is the stress tensor withthe contravariant componentsNαβ.
Bαβ are the covariantcomponents of the curvaturetensor. In the
pre-stress state oneassumes the load p to zero, andobtains an
anticlastic surfacewith a negative Gaussiancurvature. The stresses
here maybe nαβ and the curvature bαβ inthe homogeneous
equilibriumconditions
Under a loading p perpendicularto the membrane surface thestress
will change from the pre-stress nαβ to the Nαβ and thecurvature
will change from bαβ toBαβ :
Setting these expressions into theequation above and
neglectingexpressions of order two one gets:
For the change of curvature ∆bαβone gets a linear
approximationin function of the displacementsu in perpendicular
direction:
Here the suffixes indicate thesecond covariant derivative of u.
For the changes ∆nαβ one canwrite a linear
elasticapproximation:
The Εαβγδ are the components ofthe tensor of rank four
ofelasticity and the εγδ are thecomponents of the tensor
ofdeformations. For a two-dimensional orthotropic materialΕαβγδ has
the following form:
Ε1111 is the stiffness in the warpdirection. Ε2222 is the
stiffness inthe weft direction. Ε1122describes the influence
ofPoisson ratio. Ε1212 is the shearmodulus. For the deformation εγδ
one canassume when neglecting the non-linear terms and theinfluence
of the tangentialdisplacements:
Thus one gets the following ex-pression for the displacement
u
where D is called the membranestiffness:
Partial solutionIf the load does not change overthe surface and
if the initialcurvature is almost constant, a particular solution
of thisequation may be written as
Interpreting this, one mayunderstand that D is themembrane
stiffness. Thisstiffness has the form:
One can easily prove that D ispositive if the determinant of
thestiffness tensor is positive. The physical dimension of D is
force/length3.Using this expression for u, one gets for the change
of thestresses under a load p in thisapproximation:
Now one may use the possibilityof scaling the tensor of
thematerial stiffness by dividing it bythe highest stiffness, say
E1111 =E, further called the scalingfactor or magnitude of
theelastic moduli. Then one gets:
with the abbreviations:
Using this one gets
D can be composed as a productout of two parts: one part E,which
indicates the magnitude ofthe elastic moduli, and one part ∆, which
describes theinfluences of curvature andanisotropy. The part ∆ is
oforder two in curvature. The deflection u now may be written
as:
The deflection is indirectproportional to ∆ and E, and thus
indirect proportional to the square of the curvature.The increment
of stress results in:
The increment of stress isindependent of the magnitude of the
elastic moduli E, butindirect proportional to thecurvature. These
conclusions arevalid for the case that the valueof D is high
enough. If u is aparticular solution of the
equilibrium conditions it is tostate that u does not fulfil
anyboundary condition. But then ageneral solution can be writtenas
the sum of this particularsolution and a solution of thehomogeneous
equation:
When neglecting the tangentialdisplacements and assuming
theboundary of the problem to beparallel to the x2-coordinate andx1
orthogonal to this boundary,the solution for the homo-geneous part
along thisboundary is:
The total solution will be:
The condition u = 0 for x1 = 0leads to:
Thus the solution will be
along the boundary x2 = 0.
To clarify these results, D and thestatic properties under
pressureload will be calculated for twocases with finite element
models.Here, the approximationsmentioned above are notapplied; the
deflections in thetangential direction are takeninto account.
Case study 1Assume a hyperboloid of thefollowing form:
The covariant components of thetensor of curvature can
becalculated to be:
The size of the surface is 20m x 20m projected on the
x1-x2-plane. Assume first that warp and weftare approximately in
thedirections of the generating
8
The mechanical behaviour of coated fabrics and films used in
prestressed textile engineering: Its importance in the analysis and
how to derive membranestiffness by simple theoretic
considerations
áâ 0//
-
straight lines. Then themembrane stiffness D results in:
where C is the elevation and G isthe determinant of the
metrictensor:
The term E1212 is approximately300 kN/m. Thus D will
berelatively small and the stressesdependent of the magnitude ofthe
elastic moduli E.The values for the physicalcomponents are assumed
to be:
The load p is considered to be250 N/m2. (figure 1)
In figure 2 the maximaldisplacement u in normaldirection is
shown as a functionof the magnitude of the elasticmoduli E.
The curves plotted differ inelevation of the hyperboloid, or, in
other words, with thecurvature: the higher thecurvature, the lower
thedisplacement. The dependenceon the modulus resembles a
hyperbola as predicted by the theory, although the stiffness D
is very low. There is no difference betweenthe principal behaviour
for high and low curvature,respectively C.
In figure 3 the maximal stress inwarp direction is presented
infunction of the magnitude of theelastic moduli E. Once more
thecurves differ in the curvature Cof the hyperboloid: the
lowestone belongs to the largestcurvature.
Here the conclusion derivedabove does not work: one sees
aremarkable increment of themaximal stress with the scalingfactor
E.
Case study 2The same shape is used but themain axes of
anisotropy areoriented along the diagonal ofthe surface. The
covariantcomponents of the tensor ofcurvature along these axes
are:(figure 4)
Here the membrane stiffness Dresults in:
This value of D is higher because the stiffness in warp and weft
direction is in the orderof MN/m.
Figure 5 represents the maximaldeflection as a function of the
magnitude of the elasticmoduli E. The single curvesdiffer in
curvature C: the uppercurve belongs quite clear to the lowest C,
the lower one to the largest C. The hyperbolicbehaviour is quite
evident.
Figure 6 presents the maximalstress in the warp direction as a
function of the magnitudeof the elastic moduli E for different
curvatures C.
For C = 0.1 the stresses dependon E but form C = 0.3
thisdependence disappears with increasing C. For higher curvatures,
the maximal stress does notdepend on the scaling factor E,or, in
other words, on the magnitude of the elasticmoduli E. That is why
the E-moduli are asked only veryroughly from the design people.But
since lately, the preferreddesign of the structures becomesmore and
more flat, the precisevalue of the E-moduli willbecome
necessary.
Conclusion
1. It is possible to define amembrane stiffness D whichreflects
the materialtangential stiffness tensorand the influence
ofcurvature.
2. If D is large enough theincrease of stress undernormal loads
does notdepend on the stiffness itself. One has not to knowthe
stiffness matrix veryexactly.
3. Under constant normal load one can find analgebraic
particular solutionof the equilibrium conditionswhich do not fulfil
theboundary conditions.
4. The deflection under normalloads depends from
thestiffness.
5. If D is low the stress increaseunder normal loads dependson
the stiffness. One has toknow the stiffness matrixexactly.
AcknowledgementsThe numeric analysis for theexamples of this
paper was doneby K. Reimann and M. Jentschusing the programming
system/7/, /8/, /9/
Rainer Blum
[email protected]
Heidrun Bögner-Balz
[email protected]
www.labor-blum.de
REFERENCES[1] Bidmon, W. und Blum, R., Spannungs-
Dehnungs-Verhalten von BautextilienSFB 64 Mitteilung 74,
1987
[2] Blum, R., Beitrag zur nichtlinearen Mem-brantheorie, SFB 64
Mitteilungen 73,1985
[3] Bögner, H., Vorgespannte Konstruktionenaus beschichteten
Geweben und Rolle desSchubverhaltens bei der Bildung von
zweifachgekrümmten Flächen aus ebenen Streifen,Dissertation
Stuttgart, 2004
[4] Meffert, B., Mechanische EigenschaftenPVC-beschichteter
Polyestergewebe,Dissertation Aachen, 1978
[5] Blum, R.; Bögner, H.: Evaluation method for the Elastic
Moduli,Tensinews Newsletter 3, Internet-publication 2002
[6] Blum, R.; Bögner, H.; Némoz, G.:Material properties and
testing, in European Design Guide for TensileSurface Structures,
Brussels 2004
[7] K. Reimann and M. Jentsch:
“Numerische Berechnung und Visualisierungdes
Spannungs-Dehnungs-Verhaltens vonGeweben mit SCOOP-BB”,
FemScopeGmbH, 2005.
[8] K. Reimann and M. Jentsch: “Object-oriented Analysis of
Textile Structures usingthe SCOOP Framework”. ECCOMASStructural
Membranes 2005.
[9] M. Jentsch, K. Reimann, R.Wagner andS. Rudolph: “Innovative
Design ofMembrane Structures”. ECCOMASStructural Membranes
2005.
9
αβγδ
Figure 1. Saddle shaped surface with orientation of the main
axesof anisotropy parallel to the boundaries
Figure 4. Saddle shaped surface with orientation of the main
axesof anisotropy rotated 45°
Figure 2: Maximal deflection u as a function of E for
increasingcurvature C
Figure 5: Maximal deflection u as a function of E for
increasingcurvature C
Figure 3: Maximal stress as function of E for increasing
curvature C
Stre
sses
s in
kN
/m
Figure 6: Maximal stresses as a function of the scaling factor E
forincreasing curvature C
CASE STUDY 1CASE STUDY 1
CASE STUDY 2
Def
lect
ion
in m
Scaling Factor E in MN/m
Increasing curvature C
Max
imal
str
esse
ss in
kN
/m
Scaling Factor E in MN/m
Increasing curvature
Def
lect
ion
in m
Scaling Factor E in MN/m
Increasing C
Scaling Factor E in MN/m
Increasing C
-
TEXTILE ROOFS 200611TH INTERNATIONAL WORKSHOP ON THE DESIGN AND
PRACTICAL REALISATION OFARCHITECTURAL MEMBRANE STRUCTURES TU BERLIN
MAY 25TH – 27TH 2006
ObjectivesThe workshop’s objectives are toprovide fundamental
practicalinformation, as well aspresenting the state-of-the-art
intextile roof engineering know-how. In addition to acomprehensive
programme ofpresentations in English by keyfigures from the
membranestructure industry, a uniqueopportunity for the study
andhands-on development ofpractical case-studies in aninformal
tutorial environmentwill be provided. Above all, theworkshop aims
to providepractical answers to real-worldquestions.
IntroductionIn the last eleven years, tenworkshops on the Design
andRealisation of Textile Roofs wereheld in Berlin. Due to
thepractical emphasis and uniqueformat, these events have provento
be increasingly popular.Textile Roofs is now anestablished annual
event. The 2005 workshop (reportsavailable at
http://www.tensinet.com, in the librarysection) attracted around
eightyparticipants from twentycountries. The series willcontinue in
2006 with furtherdevelopments and enhance-ments to the
programme.The workshops are concernedwith the design of
architecturalmembrane roof structures. Formost people such roofs
aretypified by world famous sportsstadia and temporary
expositionstructures. Although prestigiousbuildings of this type
continueto utilize tensile roofing systems,the scope of application
has
widened considerably over thepast decade. Today, tensile
roofsare routinely used in shoppingcentres, corporate
headquarters,leisure centres, zoos, schools,and even factories.
With acombination of visuallydramatic curvilinear forms,
andeconomic efficiency, sucharchitectural solutions representan
attractive option for manysituations.The participants to the
previousevents have come from a widerange of backgrounds,
rangingfrom established experts tocomplete novice students.
Thisrich mix appears to explain partof the popularity of
theworkshops.
Programme and LecturersThe detailed programme may befound at the
workshop’swebsite.In addition to a comprehensiveseries of lectures
presented inEnglish by key figures from themembrane structure
industryand academia, opportunity forthe hands-on development
ofpractical case-studies in aninformal tutorial environmentwill be
provided. The followingkey subjects will be addressedduring
extended morninglectures:· Introducing Lightweight
Structures· Computational and Physical
Modelling · Project Management and the
Design Process· Detailing, Connection Design
and Fabrication · Project Case Studies · Materials for Textile
Structures · Environmental Aspects
During each afternoon, thehands-on workshop will runwith
opportunities for bothcomputational and physicalmodelling. In
parallel to thispractical activity, specializedlectures will be
presented onstate-of-the-art topics for themore advanced
participants.
Students SeminarThis year, an InternationalStudents Seminar held
fromMay 23th – 27th is part ofTextile Roofs 2006. Selectedstudents
with different fields ofstudy and great interest intensioned
structures, have thechance to develop a sense forthese structures
by practicalexperience. Finally, they will havethe possibility to
discuss theirwork with the participants andprofessionals of the
workshop.
SponsorsIn addition to the TechnicalUniversity Berlin, Textile
Roofs 2006 is supportedby technet
GmbH(www.technet-gmbh.com),Ferrari (www.ferrari-textiles.com) and
TensiNet(www.tensinet.com).
Prof Dr. Ing. Lothar Gründig,
[email protected]
www.textile-roofs.de
Model built by Elisa Gutierrez Pneumatic construction by Matti
Orpana, Tensotech
10
Architextiles explores thecontemporary intersectionsbetween
architectural and textiledesign. Focusing on thepossibilities for
architectural andurban design, this issue examinesthe most
generative set ofconcepts, forms, patterns,materials,
processes,technologies, and practices thatare driving the
proliferation ofthis multi-disciplinary designhybrid.
Architextiles represents atransition stage in spatialdesign's
re-orientation towards amore networked, dynamic,interactive,
multi-functional, andcommunicative state. Theparadigms of fashion
and textiledesign, with their unique,accelerated aesthetics,
andability to embody a burgeoning,composite, and complex rangeof
properties such as lightness,flow, flexibility, surfacecomplexity,
and movement, havea natural affinity witharchitecture's shifts
towards amore liquid state. Theemergence of Architextiles
toarchitectural prominencechallenges traditionalperceptions and
practices ofinteriors, architectural, urban,landscape, and fashion
andtextiles. Interweaving newdesigns and speculative projectson the
future, Architextilesbrings together architects,designers,
engineers,technologists, theorists, andmaterial researchers to
unravelthese new methodologies offabricating space.
Each of the contributors offers aunique insight into
thedimensions of Architextiles. Thistitle includes the work of
NigelCoates, Dagmar Richter, LarsSpuybroek, Frederic Migayrou,Peter
Testa, Dominique Perrault,Kennedy & Violich, DavidWakefield,
Bradley Quinn,Robert Kronenburg, Will Alsop,Matilda McQuaid,
UshidaFindlay, Marie O'Mahoney,SHoP, Arup, Tensys,Massimiliano
Fuksas, and newprojects and writings fromyoung and emerging
designersand theorists.
LITERATUREby M.G. Garcia
Architextiles
Paperback: 128 pages Publisher: Wiley-Academy , Nov 2006
ISBN: 0470026340
-
D E - L I G H T A N D A I RTOPIC
Even today, tensioned andinflated membranes are
stillfascinating. This fascination isbased on the relation of the
freeshaped tensioned structures tonature, and depends on theorganic
shapes, the lightness andtransparency of textile buildings.Like in
nature, the shapes ofmembrane structures are lessdetermined by the
designpurpose, and are quite a bitmore influenced by the processof
development.Non-tensioned membranes andcables are slack, and can
berolled, or folded up, and onlytensioned or inflated membranesget
their stiffness and stability.The kinematics and the
nearlynon-existent bending stiffness ofmembranes and cables
areleading consequently to thetensioned shapes. The shapes
aredefined by the equilibrium ofinternal stresses and
forces,obeying mechanical principles,and they are not free in
theirdesign. Developing tensionedand inflated structures requiresan
attitude towards designingstructures that is not justdetermined by
the will of thedesigner, but also affected by theprocess of finding
the right shapeunder given circumstances, andthe search for the
right solutiondefined by the structure itself.The main emphasis of
theInternational Students Seminarlies in developing and
manufacturing building modelsfor tensioned and
inflatedstructures, including allexperiences during the process
ofdevelopment and manufacturing,up to the final and real model.The
design of membranestructures is closely related to aninterest in
new fields of research,and triggered by some form ofcuriosity while
developing, andfun during manufacturing.Interests in new ways of
thinkingand unusual approaches areaffecting the appearance of
thebuildings.
TARGETThe major aims of the Inter-national Student Seminar are
inthe design and manufacturingprocess of tensioned and
inflatedstructures. The building processis influenced by an
interest ofgetting into new fields, thegathering of experience, and
thestepwise success. The design ofmembrane structures is
deeplyrelated with the behaviour of thefabric and the possibility
totension, join, and fix thematerials. Therefore, one of thetargets
of the seminar is to pointout the relation between form,material
behaviour, andstructural behaviour which canbe realized during
manufacturingand construction. Another aim isto get practical
experience indesigning and manufacturingtensioned and inflated
membrane structures. Thepractical experience can hardlybe
teached using computermodelling, neither for the 3D-shapes and
animations, norfor the numerical simulation ofstructural behaviour.
The gapbetween virtual designedstructures and real building
isgetting wider and wider, and oneof the aims of the
internationalseminar is to show thepossibilities and
differencesbetween physical modelling andcomputational
design.Participants of the Seminar areteachers of invited
EuropeanUniversities, and they arebringing eager students
along.These students come fromdifferent fields of study, but
theyshare an interest in and anenthusiasm for tensionedstructures.
Students have thechance to develop a sense forthese structures by
practicalexperience, and have thepossibility to discuss their
workwith the participants andprofessionals of the Workshop.Being
open minded and free inthinking are the inhibitions ofdesigning
tensioned and inflatedstructures, and this will enable anew type of
internationalworkshop, combining practicalexperience and
theoreticalbackground, while working in thefield of tensioned
structures.Main importance is attached tothe interplay between
massiveand light structural elements.The light structural
elementshave to serve moveability,mobility, sustainability
andinnovation, challenging theimagination.
ORGANISATIONThe International StudentsSeminar is part of the
TextileRoofs Workshop 2006. Textile Roofs workshops areannually
organized by TU Berlin(www.textile-roofs.de) and technet GmbH,
Berlin(www.technet-gmbh. com).The participants of the
StudentsSeminar have the chance tolisten to the lectures of
theworkshop for free. The Inter-national Students Seminar is
co-organized by the TechnicalUniversity of Berlin, the Univer-sity
of Applied Science Bielefeld/Minden, the University ofApplied
Science Munich and theTechnical University of Vienna.Responsible
persons for therealisation and organisation ofthe Seminar are P.
MichaelSchultes (Vienna) and RosemarieWagner (Munich). P.
MichaelSchultes studied architecture atthe TU Vienna and sports at
theUniversity of Vienna. He washead of the family companyfrom 1982
to 2000 (www. schulteswien.com).Within the module
ExperimentalBuildings at the TU Vienna manyinteresting and
non-conventionalproblems have been approached,founding unusual
solutions(www.h1arch.tuwien.ac.at/hb1/documents/43/
aufgeblasene_arch_folder.pdf).
Prof. Dr.-Ing. Rosemarie Wagner
[email protected]
Prof. Dr.-Ing. Lothar Gründig
[email protected]
Peter Michael Schultes
DESIGN TASK: MOBILE TEA HOUSE“A motorcycle with sidecar stopped
in front of the hotel. A manremoved his helmet and started to work.
Within a few minutes thesidecar was changed into a small restaurant
with two gas cooker anda nice looking table being piled with small
tablets full of goodies. Bynow people stopped and picked spits with
minced meat, calamaripieces, sausages and chicken wings. They
dipped the pieces intoboiling water then into yellow, red or orange
dressing, which is addedon small plates, eat while standing and
paid afterwards the numberof empty spits they hold in their hand.
Everything was clean,appetisingly and was organised at best.The man
was Chinese. The poor Malayan had the impression neverbe successful
surrounded by such competitor.”from: Tiziano Terzani, A
Fortune-Teller Told Me: Earthbound Travelsin the Far East, Three
Rivers Press, 2002.
WORK PACKAGEThe project of the seminar is to design and to build
on the scale of M 1:5 or M 1:10 a tent which can be stored in the
trailer of a bicycletogether with all equipment such as cooker,
dishes, silverware, tea,milk, cakes etc.. The tent has to serve
space for onetable with 2 guests. The structure ofthe tent can be
inflated or tensioned.The best designs will be built in scaleM 1:1
and presented on theconference in Eindhoven, Adaptables ’06,
www.adaples2006.nl
INTERNATIONAL STUDENT S SEMINAR ‘DE-LIGHT AND AIR’ TU BERLIN MAI
24 TH – 28 TH 2005
11
-
A client wantedto build atraditionaltypical ofBahrain old
boatout of fabric.The concept wasto make theboat and displayit for
theIndependenceDay celebrationin Manama.
The idea sounded dull in thebeginning. But few sketches andquite
some moments of thoughtshad formalized the idea of howto do it.
Once we knew how totackle the problem, all aspects ofwork came to
view so clearly.
The first step was to get theshape of the boat hull to matchthat
of the traditional BahrainiBoat. This was done by takendigital
photos of boats lying onthe shores of the city ofManama. Ratios
representingwidth and heights, andmeasurements of curvatures ofthe
boat hull were taken fromthese digital photos. The measurements
were redrawnwith AutoCAD. The hull is
6 meter long and the mast is 10 meter high.Once the shape was
complete3D Studio MAX was used to givethe boat a more realistic
look.The work was presented to thecustomer and we got animmediate
approval, as the 3Dpresentation did its magic.From a fabrication
point of view,the biggest hurdle in this project
was the forming of the steelmasts to mimic that of
thetraditional Bahrain Boat. Weneeded to bend steel, CHS of 8inches
with a wall thickness ofabout 15mm, for the support ofthe sail. We
needed to get the rightradius of curvature to match thatof the
fabric.
That took a lot of ingenuity onbehalf of our fabrication
team.
The utilization of the fabric tocreate the boat in its
traditionallook was easy. Some detailswere compromised. For
example,the hull has got an opening atthe bottom. This is surely
notfound in any boat!! However, for us it was necessaryfor the
fabrication of the steeland fabric of the hull. Similarlyfor the
sail, it was manufacturedas an independent entity. The mast and the
hull are doneand manufactured and installedseparately. When all
parts wereput together, the picture wascomplete. The design
philosophy allowedthe fabrication and theinstallation to be
manageable toa very good degree.
3D-model
General view of the Bahrain boat
A traditional typical old boat of Bahrain
Location Manama
Architectural Concept Osama Thawadi
Concept Development Yousif Ahmed
Structural Design Robert Medina
Fabrication and Installation Contractor Gulf Shade - Bahrain
Year of construction 2005
Material PVC polyester fabric: Ferrari 1002, 1050g/m2
FABRICBOAT
www.gulfshade.com • [email protected]
The TensiNet Association and Techtextil - International Trade
Fair forTechnical Textiles and Nonwovens - are holding the 9th
Competition onthe subject of: 'Textile Structures for New
Building'. TensiNet andTechextil cordially invite students of
architecture and civil engineeringto enter this competition. Also
invited are all young professionals inthese fields who completed
their courses of study after January 1st
2006. The competition aims to promote innovative ideas and
problemsolutions in relation to building with textiles or
reinforced materials,which have concrete prospects of being
realised. The competition alsoaims to promote the prize winning
students and young professionals.Furthermore, it is hoped that the
competition will intensify contactsbetween the young generation,
the universities, the technical textilesindustry and broad areas of
the building industry.
Tasks: the subject of “re-usability and recyclability”The
competition covers all fields of textile building:• earthworks,
traffic-route construction, landscape engineering,
constructions for environmental protection• civil engineering
and industrial constructions,• building - from building with
textile-reinforced concrete or textile-
reinforced plastics to building with membranes for permanent
andtemporary, variable and mobile constructions
• interior fitting - including developments such as the use of
polymer optical waveguides for light transmission, textile air-duct
systems for draught-free air-conditioning of rooms, mobile
sound-insulation walls in production halls, etc.
• product design for architecture.The subject of 'Re-usability
and recyclability' has also been included asa main theme. There are
no restrictions on the project subject chosen.Both supervised and
unsupervised work will be accepted.
PrizesThe prizes will be presented within the framework of a
ceremony atTechtextil in Frankfurt in 2007. Additionally,
prize-winning projects willbe exhibited in a special show at
Techtextil 2007. The organisersreserve the right to exhibit the
projects at other Techtextil events and toinform the specialist
world and the public about the prize-winningprojects. A certificate
will confirm the prizes.
JuryThe members of the 'Textile Structures for New Building'
jury willinclude renowned academics and a number of architects and
engineerswell known in the field of textile construction. Michael
Jänecke, willparticipate on behalf of the organisers.
Composition of the workPlans, photographs or models may be
submitted. The work should beorganised in a manner suitable for
exhibition max. 2 plans in A0 or 4 plans in A1, max 12 photographs,
format min. 18 x 24 cm,1 Model in a solid transport box: surface
area max. 70 x 70 cm, 1 A4 page description integrated in the
work
Further informationmay be obtained fromMr. Michael Jänecke, from
members of theTensiNet Associationor from ILEK, Universität
Stuttgart,tel +49 711 685 3599, fax +49 711 685
3789,www.uni-stuttgart.de/ilek
9TH STUDENT COMPETITION 'TEXTILE STRUCTURES FOR NEW BUILDING
2007'
12
Exhibition at Techtextil Frankfurt 2005 ©Techtextil
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DescriptionThe project is composed of a pitched roof with a 15°
slope thatcovers an 11m (36ft) space with a repetitive 6m (20ft)
module. It ismade of hardwood trusses and conic-shaped membranes in
PVC, pre-stressed by means of central regulating masts, with
lateral scrollableclosures.The membranes are screwed to the
structure by means of wood screwswith small aluminium plates.The
formal solution resembles the existing wooden construction. Itwas
integrated on one of its sides to the main building.
Background InformationLos Teros de Melilla is an estate located
on a farm near the city ofMontevideo, dedicated to agriculture and
cattle-breeding activities,but whose premises can be engaged for
hosting parties and events ofall sorts.
DesignThe roof was generated with a lateral pitch for rain
drainage to oneside, beginning at the height of the existing
buildings. The roof iscomposed of three 11mx6m (36ftx20ft)
independent conical shapes,so as to cover the area with the least
amount of structural elements.
Design ProcessOnce the main design parameters were defined,
there was specialattention to avoid making the conical shapes too
high-rising, and that—at the minimum height— the membrane could
perform its functionscorrectly regarding tensions, as well as
properly draining rainwater toprevent unwanted ponding.
The membrane was designed with the force-density method, and
thecutting patterns defined by triangulating the surface. The
wooden elements were designed according to the tensionstransmitted
by the membrane, every detail studied in 3D solving alljunctions
with the metal fittings, which were specially designed foreach
node.
Building ProcessAll the woodwork was prepared atthe carpenter’s
workshop, and theironwork at the blacksmith’s.The parts were then
set up on site by means of a crane.Next, the membranes were fixed
tothe perimeter with plates and woodscrews, and ultimately, the
conicalshapes were pre-tensed with thespecially designed regulating
masts.
PrestressingThe pre-tensioning of the membranes was done
manually by means of three telescopic centralmasts with regulation
bolts at their base.
MaterialsThe structure is made of 4x8” Patagonian Walnut
(Lapacho), withpainted metal fittings, anchored to the ground
through concretebases.
The membranes are made of polyester fabric PES HT 1100dtex, 5x5
threads per cm (12 threads per inch) with PVC coating, UVprotection
on the outside, a weight of 800gr/m2 (230oz/sqyd) and abreaking
load limit of 30daN/cm (167lbs/inch).
ConclusionsThe objective sought after by the roof was achieved
to perfection,accomplishing an enjoyable space for holding
events.
MULTI-EVENT AREA “LOS TEROS de Melilla”
Outside views of the Los Teros de Melilla membrane roofs
Connections in the wooden supporting structure
The installation of the membrane
Pre-tensioning the membranes
Supporting construction in woodConical membrane shape
Location Montevideo, URUGUAY
Construction date September 2000
Covered surface 200sqm (2.153sqft)
Roof design and project Roberto Santomauro & arch. Patricia
Pinto
Roof structural engineer eng. Marella & Pedoja
Roof fabricator and contractor Sobresaliente ltda
General project arch. Ritorni
Objectives of the Roof1. Eliminating direct solar
radiation that can disturbongoing activities.
2. Allowing entrance of naturallight, at least 7%, so theindoor
area is not darkened.
3. Rain protection.4. Low building costs, so as to
keep investment risks low,and not generateconsiderable losses
shouldthe enterprise not prosper.
5. Easy installation.6. Special design to provide
distinctive design quality.8. Integrating with the existing
building, without distortingthe existing construction.
[email protected], Roberto Santomauro
www.sobresaliente.com
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Reasons for Choosing a Prestressed PVC
Membrane 1. It strictly complies with all
the objectives.2. When compared to other
traditional systems such asglass, plastic, metal orconcrete
construction, thesetraditional systems do notmeet all the
requirements.Furthermore, some of themadd new problems, such
asincreasing internal heat,blocking light completely,and more
importantly, notoffering the aesthetic andformal opportunities
PVCmembranes have to offer.
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1414
A combination of tensioned membranes and a laminated wood
structure
Buitink Technology recently finishedthe membrane- and wood
structure,which together form the entrance ofthe Dolfinarium in
Harderwijk (theNetherlands). Buitink Technologyengineered,
produced, and installedthe entrance canopies, as well as themasts
with printed flags asdecoration. The architect specificallychose
this combination of woodand membranes to create thedesired
atmosphere.
It was a challenge to design all the details of the wood
structure tobe able to take the large forces resulting from the
membranes. Forthis project several specific details were
developed.The layout of the bearing structure corresponds to a
spine. In thecentre there is a tower, carrying the logo of the
Dolfinarium. At bothsides a wooden laminated Larch (spine) beam is
placed. It is carriedby portal frames formed by laminated Larch
columns and purlins. Inbetween the portal frames purlins are
cantilevering from the spine-beam.The architect had designed a
rather flat membrane. To prevent largedeformations and ponding of
the fabric, the pretension is high. Thetension forces from the
fabric, combined with the relatively large
eccentricity, caused by the height andthe curvature of the
wooden beams,created large permanent bendingmoments and forces in
the wood.This required special detailing of thewood connections.
Special attention is paid to the rainflow over the fabric. Because
thestructure is an entrance covering, it isnot desirable that the
water drainsall along the boundary of the fabric.At the other hand,
the architect didnot want to see any water drainagesystem. A
compromise was found byadding rims on the fabric, andguiding the
water by means of thinchains to the ground. In thepavement drainage
systems areprovided.
Buitink Technology buildsentrance of Dolfinarium in
Harderwijk
General view
Frontal elevation
Side elevation
Section
Drawing of the wooden structure and membrane
Wooden spine beam and purlins at the entrance
Rather flat curvature of the membrane
Solution to direct the rain flow
The connection of the membrane to the wooden purlin and portal
frame
Location Harderwijk, The NetherlandsTotal surface covered:
Entrance 205 m2
Lockers 75 m2
Owner Dolfinarium Grévin & Cie, Paris,
FranceDesign/Architect Eremco, Paris, FranceMain contractor GMB
Infra BV, Opheusden, The NetherlandsWood- and membrane structure
Buitink Technology,
DUIVEN, The NetherlandsWood construction GLC Houtconstructies,
ARNHEM, The NetherlandsEngineering Wood construction Semplonius
Adviesbureau, Laag Soeren
and Adviesbureau Lüning, DoetinchemEngineering membranes Tentech
BV, Delft, The NetherlandsMaterial 1002 Fluotop T2 (Ferrari)Year of
construction 2005
www.buitink-technology.com
Rienk de Vries , [email protected]
Rogier Houtman , [email protected] • www.tentech.nl
Exterior view of the glass façade ©Covertex
The connection between the membrane and theglass façade
©Covertex
The membrane cantilevering over the glass façades ©SL-Rasch
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15
Furniture and equipment arefrequently difficult to integrateinto
the urban or naturallandscape. For monumental sites,historic
places, landmarks, andinteresting environments, the“Lleida”
prototype was designedin order not to interfere visually.
It is a 6m x 4m self-supportedcanopy, formed by two
frames,united by T-shaped cross beams.The beams hold a
longitudinalCHS arch that pushes down theroof made of a membrane
tiedup to the frames by means ofelastic rope.
The two surfaces includedbetween the frames anddeformed by the
arch areanticlastic, resistant to the wind,and they drain
properly.
There are no inclined planes,slopes, nor vertical faces
thatobstruct the vision, because thesurfaces are perceived as
asmoothly deformed horizontal
plane. In this way, the canopydoes not consolidate a volume, as
it used to happen to thepitched roofs of pavilions.
The steel sections are lined withrounded pieces of wood
toincrease the visual and tactilereceptiveness, thereby raising
thetemperature of the metal, andsoftening the aggressiveness
ofedges and corners, procuring tothe user the same gentleness
thatis provided to the environment.The “Lleida” prototype has
beenused in a variety of differentlocations and purposes.
Name of the project The “Lleida” Canopy
Client Lleida City Council
Location Lleida, Spain
Architects Llorens & Soldevila
Membrane structure PVC-Coated polyester
Manufacturing Toldos IASO, Lleida, Spain
Roof area 6m x 4m per module
First year of construction 1987
15
http://www.upc.ed/ca1/cat/recerca/tensilestruc/portada.html
Josep Llorens, [email protected]
UNOBSTRUSIVE CANOPY 2 THE “LLEIDA” PROTOTYPE
The longitudinal courtyard of the Shopping Mall at the
KhouraisRoad Retail Centre in Riyadh (approx. 115 m x 10-16 m) is
coveredby a Roof Tent Structure. The longitudinal layout of the
membraneroof structure is curved in plan and elevation with an axis
of symmetryin x- and y direction, and has its maximum width and
height at itscentre. The maximum dimensions of the roof in plan are
approx. 22 x 130 m with a 3D membrane area of approx. 2 350 m2 and
aglazed area of approx. 180 m2. The complete roof structure is
generated as a continuous tensionequilibrium form, and this results
in the dynamic appearance of theroof structure that is full of
suspense.
The membrane roof consists of 15 single segments that
aresupported by 14 steel archstructures. The membrane edgesare
continuously connected alongthe arched steel frames. Thecurved
membrane roof edges thatare cantilevering over the plane ofthe
façade are reinforced by steelcables that are spanning betweenthe
tips of the steel arches.
The steel arches consist of two curved steel beams with a
skylightglazing in between. This skylight glazing is made of
ornamented sunprotection glazing. The geometries of the different
sized steel framesfollow in height and width the overall curved
shape of the membraneroof that is at both short sides connected to
the concrete roof slab.The two long sides of the roof tent
structure have inclined glassfaçades with an increasing height,
approx. 9m towards its centre.These façades are made of an
insulated sun protection glazing system.The natural air ventilation
and also the emergency smoke exhaust areprovided by automated vents
that are integrated with the façade. Theroof itself does not have
any openings. There are special cut andspecial sealed glass
elements where the curved roof beams penetrate
the façade. The membrane roof and the top of the façade
areconnected by a foldable membrane strip to seal the interior air
space,and to allow for movement of the membrane under wind.
The rainwater from the tent roof is discharged over the
wholeperimeter of the roof, onto the roof deck underneath. There
are nospecial rainwater collection points.
All forces resulting from the roof are transmitted to the
buildingstructure at the footing points of the steel arch supports,
at the twoedge beams, and at the tension bar footing points. The
concretestructure of the building is designed to carry all reaction
forces from
the tent roof structure. For this,the anchor bolts to connect
thetension bars, and the edgebeams are cast with the concreteroof
structure. The footings forthe V-shaped steel columns arefixed to
the concrete structure byvertical anchors. All horizontalforces are
transferred to theconcrete structure by shear pins.
Inside views of the membrane covered Shopping Mall ©SL-Rasch
Client Al Shaya GroupLocation RiyadhArchitects, Structural
Engineers (tent roof) Architekturbüro Rasch + BradatschCompletion
June 2004Contractor (tent roof) SL- Rasch GmbH with Stahlbau Süssen
(steel works)
and Covertex GmbH (membrane works)Dimensions 130m x 22mMembrane
Glass/PTFE (2 350 m2)Steel mild steel, galvanized, coatedCables
steel cables, galvanizedFaçade insulated sun protection safety
glass with ornamented printing
[email protected]
www.sl-rasch.de
KHORAISCH ROAD RETAIL CENTER, RIYADHROOF TENT STRUCTURE
Biergarten Details
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“The Oyster” Casino del Aljarafe, Sevilla The new Casino will
beinaugurated in April 2006. As apart of the rehabilitation works
inthe existing office building, a newentrance marquee was
planned.The canopy roof was needed toprotect the entrance from
therain, as well as from the Sevillasun (more than 3000 sun
hoursper year, 19ºC year averagetemperature, 27ºC average
inJuly-August). Part of the difficulty of thisdesign was to find a
way toanchor the roof to the existingbuilding with an
“untouchable”skin of glass and precast concrete
pillars. It was decided to build avery light structure, with
specialattention to the transmission ofthe loads to the right
points.Therefore, a curved 26m longbeam was fixed to the roof
slab,and two masts placed in a V-shape were added in order
tostabilize the arch. Smaller mastssupport the high points.Client
and building typedetermined the final design. TheV-shape is in fact
a reference tothe symbol of victory in casinos. The fabric is a
Ferrari 1202 nacre-silver colour, reinforcing theluxury aspect of
the roof. Form
and colour provide the roof withits nickname: “The Oyster”.
The fabric is fixed to the arch bya keder and the back borders
arepockets with cables tightened tothe three corner plates.
Thesecorner plates are connected tothe small masts placed on
theroof slab at appropriate points
(heads of pillars, nerves ofslabs), and stabilized by means
oftwo cables per mast.These cables are anchored in thelevel +0.60
slab over the roof, inorder to minimize the impact ofthe forces on
the curtain wall.The entire structure was planned,designed,
manufactured, anderected in 19 working days.
Client: Mace Management - Casino del Aljarafe Proprietor
Engineer: BAT · Buró Arquitectura Textil, Javier Tejera,
José Javier Bataller, Ana Vispe, Rebeca Muñoz, Marian Marco
Manufacture & Installation:Servicios y Constultas, S.L.,
Antonio Lucena
Fabric material supplier: Ferrari S.A., Joan Nos
General view of the entrance marquee Supporting structure Front
view of the entrance marquee
Javier Tejera Parra, [email protected] •
http://www.buroarquitecturatextil.com
Textile roof for a stand at TSV Gersthofen
The textile roof over the standand the terrace has a width of12m
and a length of 54m. Four 13m high masts are placed at a distance
of 18m in the longitudinaldirection.
The anchorage ofthe cable, running in the longitudinaldirection
over the high points of the masts, assures thestability in
thelongitudinal direction.
Every 6m, a beam spans in thetransverse direction. The loadsare
taken by the connection atthe top and the back side of
thestand.
The high points (every 6m) of the membrane are attached to the
longitudinal cable. The anti-clastic membrane shape is tensioned
between the high points and thetransverse beams of the roof: the
snow is carried by the ‘snow bearing direction’, while the upward
wind is takenby the ‘tensioning’ direction.The used membrane is
PTFE-coated glass.
Client Stadt Gersthofen
Architect Architekten SZZ, Stich, Ziegler, Zirngiebel
Landscaping Eger & Partner, Landschaftsarchitekten
Design & engineering of the tensile roof Kiefer Textile
Architecture
Structural engineer Dipl.Ing. H. Steinherr
Material PTFE-coated glass fabric
Year of construction 2005
Michael Kiefer, [email protected]