Leo Chelsea Portfolio Checkpoint

P neumatics STRUCTURAL MATERIALS RESEARCH CATALOGUE CONTRIBUTORS

Leo Spurgin & Chelsea Serrano-Piche

STUDIO 703

ARCH 3501 - ARCHITECTURAL DESIGN STUDIO 4 COLLEGE OF ARCHITECTURE TEXAS TECH UNIVERSITY - FALL 2008

1

2

3

4

5

6

1

1.0

1.1 Pneumatics

1.2 Tensairity

1.3 Tensairity Con.

1

1.1

Pontiac Silverdome

Some commonly used fabrics used in pneumatic membranes are polyvinal chloride coated (PVC) polyester fibres, Polytetrafluoroethylene (PTFE or Teflon) coated fiber glass, or silicon coated fiber glass. These membranes are translucent but by no means transparent. On the other hand, Ethylene tetrafluoroethylene (ETFE or Tefzel) foils, nowadays commonly used as air cushions for facades and roofs in architecture, have a very high transparency.

Pneumatics

“Structural Air”

Of or pertaining to air, gases, or wind.

Air as a structural element has many uses both architectural and otherwise. Pascal’s Law is what makes pneumatic structures possible. It states that air is considered the fluid which, when put under pressure in a confined area, will instantly apply equal pressure at all points of contact. As air is pressurized within pneumatic architecture, the membrane equally expands. Cables are often installed to hold down the membrane, rather than support it. The cables are typically made of steel because of cost, availability, and life span. A compression ring is needed to hold down and stabilize these cables in pneumatic systems used as roofs often spanning sports arenas. The two basic types of air supported structures are high profile and low profile designs, which refer to the height relative to the span. Low profile designs are used to span large distances while high profile designs incorporate air in more than just the roof structure. The type of air used in low profile designs is just that, air. It is moved with fans and air ducts from the outside and circulated continuously. The same goes for high profile designs although compressors work much harder to bring the air in and keep the pressure equalized. Using gases instead of air would be costly and inefficient. Helium, for example, would not be ideal for these membranes because their molecules are smaller than those of common air making slow “leaks” constant.

Pros of Pneumatic Systems: - Membrane can be translucent, transparent, solid for shading purposes, UV resistant, non-flammable - Membrance can have acoustic to optimize interior space - Membranes are foldable, recyclable, temporary, prefabricated, cost effiecient, resistant to extreme temperatures, and fairly sturdy. (www.Intents.be)

Cons of Pneumatic Systems: - Unintentional deflating and cost for this kind of repair is one of the few risks or problems with this sort of structure.

Geometric shapes are preferred for pneumatic roofs. Below are some common shapes. Cable patterns are visible as well.

1.2

Tensairity

Tension+Air+Integrity Designer: Mauro Pedretti Fabricator: Airlight

“Tension and compression are physically separated into cables and struts causing the struts to appear as free floating. Under load, the tension in the cables increases. This force is transferred to the compression element which becomes prone to buckling. However, due to the firm connection of the compression element with the airbeam membrane, buckling is prevented. As in the theory of beams on elastic foundation, the compression element is stabilized against buckling by the compressed air. Therefore, the compression element can be loaded to the material yield limit. The major property of Tensairity is that the air pressure is solely given by the external load and is independent of the span and slenderness of the beam. The load bearing capacity of Tensairity is, by orders of magnitudes higher than for the traditional air beam.” (www.airlight.com)

Flying Roof - Bellinzona, Switzerland

A test with done with an automobile supported by two identical parralell tensairity beams each with a diamter of 50cm. This bridge was able to support 3.5 tons of weight without buckling. Each beam weighs only 88 pounds whereas a steel beam designed to support a similar load weighs upwards of 800 pounds. A normal airbeam can only be pressurized to 15 bar whereas a Tensairity beam can be pressurized to 400mbar (1000 times more pressue) because of its other elements.

Above is a net based on helical cables wrapped around an transparent inflated membrane. Such a net works like a scissor mechanism. The air pressure squeezes the foil due to the elasticity into the meshes of the net reducing the curvature of the foil and thus the tension considerably compared to a structure without a cable net. For a cylinder, it can adapt forms between a very thin and long tube to a very short and thick tube.

1

1.3 Lanselevillard, France Skier Bridge

Tensairity

Tension+Air+Integrity Designer: Mauro Pedretti Fabricator: Airlight

-Charpente Concept

Tensairity beam technology can can incorporated into a design in other ways other than just straight horizontal beams. Tensairity trusses can be implemented permanently such as with the Lanselevillard Skier bridge in France. The bridge connects two small ski resort towns in the mountains of France. In addition to supporting the dead load of the wooden bridge itself, the Tensairity truss supports the live load of snow and any skiiers crossing the bridge during the main vacation seasons.

Steel Equivalents

Tensairity Shapes

- heavy weight - heavy loads - expensive transport costs - setup requires many tools - permanent - poor thermal barrier - very strong

- light weight - heavy loads - low pressure - small transport volume - fast setup - temporary - transparency

- lighting - adaptable

Leamouth Footbridge London, UK

There are various footbridges that have been built or proposed that take advantage of this Tensairity technology. The Tensairity element keeps the bridge from buckling in the center which allows the bridge to only need structual elements under the ends of the bridge. The cables in these bridges are just to hold the bridge and the Tensairity element together tightly. Sécheron-Nations Footbridge Geneva, Switzerland

1

2.0

2.1 Metrodome

2.2 TTU Practice Field

2.3 Tubaloon

2.4 Airtecture Hall

1

Hubert H. Humphrey Metrodome Architect: SOM

2.1

The Hubert H. Humphrey Metrodome in Minneapolis, Michigan was desgined by Skidmore, Owings, & Merril (SOM) The Metrodome’s roof structure is made of curved, double layered, teflon-coated fiberglass panels fastened to a skewed net of cables which span the dome. Weighing about 1.5 pounds per square foot, the roof is kept inflated by twenty 90-horsepower fans. It requires 250,000 ft³/min (120 m³/s) of air to keep it inflated. To keep the interior pressurized, every entrance uses revolving doors. The double-walled construction allows warmed air to circulate beneath the top of the dome, melting accumulated snow. The Stadium has a central contol room for the single purpose of monitoring the air pressure and maintaining the roof. Three times in the stadium’s history, severe weather has caused a collapse or deflation of the roof. Severe thunderstorms with extreme varying pressures have caused the roof to deflate in the past along with a very rapid accumulation of snow. The Pontiac Silverdome uses a very similar pneumatic system to support its roof. and the descision to use a pneumatic roof was based on finicial figures taken from the construction of the Silverdome.

1

2.2

The cables on the roof are covered with a protective fabric and when neceassry are held together where they cross with metal clamps (top left). To drain rainwater off of the roof there are drains in the small brick wall that hides the compression ring that the cables are attached to at the base of the roof membrane (top right). There are also larger drains that lead off of the small brick wall that are hidden by brick turning them into asthetic elements (far right).

Texas Tech Practice Field Lubbock, Texas

The Texas Tech practice field uses a very similar structural system as many larger pneumatic structures. The roof is air supported and the field itself is below grade making the low profile pneumatic roof appear to be a high profile pneumatic structure. Revolving doors are used at grade to enter the building (right). The larger loading bay doors are sealed off from the main field so they can be opened for extended periods without deflating the roof.

1

2.3 rial by using low pressure air to prevent compression elements from buckling”. A Tensairity beam consists of a cylindrical membrane filled with pressurized air, a compression element tighly connected to the airbeam, and two cables running in a helical form around the airbeam. (greenlineblog.com) The structure of the Tubaloon was desgined by Tensairity’s creator’s son Andrea Pedretti. He and one of SNØHETTA AS architects, Teas, adapted the traditional Tensairity beam, but instead of using helical cables he used galvanized-steel armatures. This meathod uses Tensairity beams composed of segments with brackets, which the air tub es nestle into. Instead of a by-the-book application of Tensairity, Tubaloon represents “an inflatable, tension-membrane structure in which most of the supporting structure is internalized,” Teas explains. The frame mounts to two poured-concrete foundation pads, with four additional connection points for cables and a compressor that maintains air pressure. (archrecord.construction.com)

The Tubaloon

Architect:SNØHETTA AS

Location:Kongsberg, Norway Typology:Performance Shelter Client:Kongsberg Jazz Festival Completed: June 2006 The “Tubaloon” is a large fabric cochlear shaped band stand designed for Norway’s Kongsberg Jazz Festival. The program called for a design that could be erected rapidly and that was tough enough to be taken down and redeployed elsewhere. The Tubaloon also posses accoustic qualities inherent in its design that keep small, quite performances intimate with its clamshell cantilever side while the PVC coated fabric has almost no effect on amplified performances. However the horn-like shape on the back of the Tubaloon amplifies louder performances across the townscape. The combination of pneumatics with a tension membrane gives the Tubaloon a unique shape and appearance because of its internal structure. The steel skeleton that helps give the Tubaloon its shape is dependent on both the pneumatics and the membrane for support similar to the way the skin and tendons of the human body work to keep the skeleton correctly positioned. The structure of the Tubaloon consists of cables, rods, and fabric that create a volume using an innovative structural technique called Tensairity. The technique was developed by a Swiss engineer named Mauro Pedretti and is used to create large-span beams that “minimize strut mate-

1

2.4

Airtecture Exhibition Hall Architect: Festo

This temporary exhibition hall is one of the first pneumatic structures with a cubic interior and a structural system primarily supported by air inflated elements. The hall consists of approximately 330 individual air-inflated structural elements such as transparent window cushions made of Hostaflon ET, 40 Y-shaped columns, roof beams with translucent, intermediate membranes and pneumatic tension elements. A computer system controls the pressure in these diffrent elements and actively changes based on dynamic environmental conditions such as precipitation or strong winds. The structure is considered to be lightweight and can be moved quite easily because most of the elements can be folded up when deflated.At each side of the expedition hall are two L-shaped pieces that come together to make the entrances. Above each “doorway” are vents to let air in and out of the hall. Each Y-shaped support on the exterior is held in place by three cables on each side untimately connected to the “foundation” of the system.

1

3.0

3.1 Study

3.2 Bouncehouses

3.3 Seals

3.4 Seams

1

3.1

Pneumatic Roof Study Model

Based on Metrodome and Practice Field



Air Flow

Structures using a large pneumatic roof span require the spanned space to be constantly pressurized. Although this pressure can be felt when it is let out of the space, it is not to large of an amount to be maintained by small compressors and fans. For scaled down versions of pneumatc structure like our study models a regular air mattress pump provides the plenty of air pressure. This pump is used in the same way as a larger version in the way it provides a constant stream of pressure.

In order to push and keep air inside the structure, a hole was left in one of the corners of the membrane. This hole was made to seal around the air pump. We discovered that the air pump put out so much air that as long as the air flow was pointed at the hole, no seal was required unless the roof was loaded. The combination of the duct tape (compression ring) and the string (steel cables) kept the membrane sealed against the base allowing it to hold pressure.

Above is a study model of a pneumatic roof span. The membrane is relatively thin clear vinyl cut to the shape of the base. The base is a geometric shape as suggested in our research. String was used in place of the cables that would normally span the roof in order to hold the membrane down and keep it from breaking free from the compression ring. In this model duct tape along the bottom of the base acts as the compression ring.

Weight tests were undertaken to see how much live load the roof could hold. These tests are representative of the live loads of snow and ice that can cause a collapse in pneumatic roof structures. Various loads were added and were all held up by the roof. If scaled these loads would be more than would ever be put on a real roof span. This model served its purpose in that it educated us on the potential of air pressure and showed us that air tight seals are not completely necessary.

1

Seam Reseach Bouncehouses

3.2

We began to look at how air tight seals were made on high profile structures that did not involve compression rings or cables. On the Texas Tech University campus there were multiple inflatable bounce houses setup for an advertising event. These structures showed us an example of how seals could be made between various pieces of membrane. There are two kinds of seals: hidden inside seals and visible exterior seals. Both of these seals are done by stiching the edges together. The interior seals are stiched then turned inside out in order to hide the edges of membrane. The exterior seals must be visible however because it is difficult to stich inside of a closed object. The fan used to inflate these structures seems relatively small compared to the size of the structures. Also we noticed that the seals are not completely airtight in every instance. There is a small amount of air that is always escaping from somewhere but it is a negligible amount and does not cause the structure to deflate.

1

3.3

Air Tight Seam Studies Heat

Our initial attempt at sealing membrane together was done using heat. Using heat to melt the edges together seemed like the most effective way to get a completely air tight seal. To melt the vinyl membrane a hair straightener was used on medium heat.

To inflate these heat sealed elements a small hole was left along one edge and a straw was placed inside this hole.

Inside Seam

Outside Seam

The intention of this process is to heat up the two pieces of vinyl enough for the two edges to bind together. The best method to do this was to apply the heat for just one or two seconds. If the heat is left on the vinyl for much longer the plastic would melt so much that it would become to thin to have any strength left.

Faccum dolorem ip et lutat. Ignisis cidunt alisl utate feuisl elisissequis eugiat lum adignismolor irilisim nos aliquat. Uscing ex ex ex eros ad molessi. Quat nullam iustio odit nulla at adit, consequat. Exerat landit wis et ea faciduis dolutpat num inim del exer am zzriustrud modolore magna faccum dolor aut nulputat duis del duisl diamcon hent accum velisim zzrit ut vullaorer in essim quam veros alis adio dipsum dunt wis ad exer irit, commy nu

1

Seam Test

Clear Vinal+Thread

3.3

Hicaelic astarta tiamdi priont. Musper alis. Eperra? interae diusaticaet viliem us. mentiam probutebatum habus, crum. Serediemus, Patuus, dientea rendam los int. Simantius hos cum optiquis. Habus it facie firimus atilis egervid cureortua tre dem medient ervivignocae autem esenaribus, senditri, coentiam pubissa inte firi por quit. Habit vivis, qua primili capere, etod reo conox ne querferibem inc facies vis. Acta, quam ocrum mus fue hi, cuppliust nonclartum hactem nu quis laritemnes es murn

Hicaelic astarta tiamdi priont. Musper alis. Eperra? interae diusaticaet viliem us. mentiam probutebatum habus, crum. Serediemus, Patuus, dientea rendam los int. Simantius hos cum optiquis. Habus it facie firimus atilis egervid cureortua tre dem medient ervivignocae autem esenaribus, senditri, coentiam pubissa inte firi por quit. Habit vivis, qua primili capere, etod reo conox ne querferibem inc facies vis. Acta, quam ocrum mus fue hi, cuppliust nonclartum hactem nu quis laritemnes es murn

Hicaelic astarta tiamdi priont. Musper alis. Eperra? interae diusaticaet viliem us. mentiam probutebatum habus, crum. Serediemus, Patuus, dientea rendam los int. Simantius hos cum optiquis. Habus it facie firimus atilis egervid cureortua tre dem medient ervivignocae autem esenaribus, senditri, coentiam pubissa inte firi por quit. Habit vivis, qua primili capere, etod reo conox ne querferibem inc facies vis. Acta, quam ocrum mus fue hi, cuppliust nonclartum hactem nu quis laritemnes es murn

Hicaelic astarta tiamdi priont. Musper alis. Eperra? interae diusaticaet viliem us. mentiam probutebatum habus, crum. Serediemus, Patuus, dientea rendam los int. Simantius hos cum optiquis. Habus it facie firimus atilis egervid cureortua tre dem medient ervivignocae autem esenaribus, senditri, coentiam pubissa inte firi por quit. Habit vivis, qua primili capere, etod reo conox ne querferibem inc facies vis. Acta, quam ocrum mus fue hi, cuppliust nonclartum hactem nu quis laritemnes es murn

1

4.0

4.1 Bowers Project

4.2 Materials

4.3 Method

1

4.1

Materials Research

Bowers Airplane Project

Acil dolor adiamet essim ip estrud duis alis ad dignisi eummy nulput pratiscipit ilis eniamet lor senis eum eugait aut wisi. Tue velesed tio odo odolortie modip ex eriliquat. Ommy nostions nummy nonse consecte magnisl essed dolobor sectet lorpero odit landigna feu facil ullandigna am niam, quate vel erostrud magnis aliquam consed modit lortis augiam voloboreet, quipsum alit nisi te tet lor sum velendignit dolortie minim in exeros duipsummy niam ad tie con ecte verit del doluptat. Pute feugueros nostisc illaorper at lam inim in hent eugiat nonumsan ullan hent digna aci et amconse tisl doloreraesto odiam, se dolesto conum essim dunt lute duisi. Modolore delit dio del doleseq uamconsectet illaor sequat. Ut adionsequat, cons ectetue rcinit lobor irilla feugiam consequat dit ipit nulput acin hendre diam, vel ut nonsed ese con hendre magna ad minci tatin ulla con verat wismod euisit vullaor aliquam, quationsed minibh eril dionsed del ent nullam dignibh ea am, vulput wisi.

Acil dolor adiamet essim ip estrud duis alis ad dignisi eummy nulput pratiscipit ilis eniamet lor senis eum eugait aut wisi. Tue velesed tio odo odolortie modip ex eriliquat. Ommy nostions nummy nonse consecte magnisl essed dolobor sectet lorpero odit landigna feu facil ullandigna am niam, quate vel erostrud magnis aliquam consed modit lortis augiam voloboreet, quipsum alit nisi te tet lor sum velendignit dolortie minim in exeros duipsummy niam ad tie con ecte verit del doluptat. Pute feugueros nostisc illaorper at lam inim in hent eugiat nonumsan ullan hent digna aci et amconse tisl doloreraesto odiam, se dolesto conum essim dunt lute duisi. Modolore delit dio del doleseq uamconsectet illaor sequat. Ut adionsequat, cons ectetue rcinit lobor irilla feugiam consequat dit ipit nulput acin hendre diam, vel ut nonsed ese con hendre magna ad minci tatin ulla con verat wismod euisit vullaor aliquam, quationsed minibh eril dionsed del ent nullam dignibh ea am, vulput wisi.

Locciam habefec red sid me fitilic iverita es hilina, vivirmium ium hacre verceps, quonsuam in stortis, dit. Pullemus Maedo, Ti. Ast? Ina, sentil videripici se aperis? Ro et consusperum pulis cerfirmium seservi ginemus, dinatrarte, Ti. Maressesigin Etrentu rnihilina, Pat, fuem que aciactusci publintem me ina Sercerfex simis aude me tam auctus voctemus, et idees! Bem quod rehebem am uter popultur quos, nonempl icasdam ia? Habeffrei inerunc rei peres vo, quam noc,

1

4.2

Materials Study Membrane Materials

Hicaelic astarta tiamdi priont. Musper alis. Eperra? interae diusaticaet viliem us. mentiam probutebatum habus, crum. Serediemus, Patuus, dientea rendam los int. Simantius hos cum optiquis. Habus it facie firimus atilis egervid cureortua tre dem medient ervivignocae autem esenaribus, senditri, coentiam pubissa inte firi por quit. Habit vivis, qua primili capere, etod reo conox ne querferibem inc facies vis. Acta, quam ocrum mus fue hi, cuppliust nonclartum hactem nu quis laritemnes es murn

Hicaelic astarta tiamdi priont. Musper alis. Eperra? interae diusaticaet viliem us. mentiam probutebatum habus, crum. Serediemus, Patuus, dientea rendam los int. Simantius hos cum optiquis. Habus it facie firimus atilis egervid cureortua tre dem medient ervivignocae autem esenaribus, senditri, coentiam pubissa inte firi por quit. Habit vivis, qua primili capere, etod reo conox ne querferibem inc facies vis. Acta, quam ocrum mus fue hi, cuppliust nonclartum hactem nu quis laritemnes es murn

Hicaelic astarta tiamdi priont. Musper alis. Eperra? interae diusaticaet viliem us. mentiam probutebatum habus, crum. Serediemus, Patuus, dientea rendam los int. Simantius hos cum optiquis. Habus it facie firimus atilis egervid cureortua tre dem medient ervivignocae autem esenaribus, senditri, coentiam pubissa inte firi por quit. Habit vivis, qua primili capere, etod reo conox ne querferibem inc facies vis. Acta, quam ocrum mus fue hi, cuppliust nonclartum hactem nu quis laritemnes es murn

Hicaelic astarta tiamdi priont. Musper alis. Eperra? interae diusaticaet viliem us. mentiam probutebatum habus, crum. Serediemus, Patuus, dientea rendam los int. Simantius hos cum optiquis. Habus it facie firimus atilis egervid cureortua tre dem medient ervivignocae autem esenaribus, senditri, coentiam pubissa inte firi por quit. Habit vivis, qua primili capere, etod reo conox ne querferibem inc facies vis. Acta, quam ocrum mus fue hi, cuppliust nonclartum hactem nu quis laritemnes es murn

1

Material Test Silicone+Fiberglass

4.3

Ratuerostis nonseni ametuerostie diam, commod ex el in hent vero el dolore dolesecte tionsed te mincin henim volore faciliquis aciduis sequip esequat ip eugiate tatissis eu feu feugiam etuero od diametum non henit ecte eu feugiat. Gait iurem iurem iuscip ea faccum ipisl dolore min exer seniam, consequam inissim vulput eugiatu eraesto odio dolobore tem velis ametum auguer incilismodio odigniam nonsendre consenim ipit adip ea con et, con ea feu feu feugiam quatin veliquipit utpat. Dui

Ratuerostis nonseni ametuerostie diam, commod ex el in hent vero el dolore dolesecte tionsed te mincin henim volore faciliquis aciduis sequip esequat ip eugiate tatissis eu feu feugiam etuero od diametum non henit ecte eu feugiat. Gait iurem iurem iuscip ea faccum ipisl dolore min exer seniam, consequam inissim vulput eugiatu eraesto odio dolobore tem velis ametum auguer incilismodio odigniam nonsendre consenim ipit adip ea con et, con ea feu feu feugiam quatin veliquipit utpat. Dui

Ratuerostis nonseni ametuerostie diam, commod ex el in hent vero el dolore dolesecte tionsed te mincin henim volore faciliquis aciduis sequip esequat ip eugiate tatissis eu feu feugiam etuero od diametum non henit ecte eu feugiat. Gait iurem iurem iuscip ea faccum ipisl dolore min exer seniam, consequam inissim vulput eugiatu eraesto odio dolobore tem velis ametum auguer incilismodio odigniam nonsendre consenim ipit adip ea con et, con ea feu feu feugiam quatin veliquipit utpat. Dui

Ratuerostis nonseni ametuerostie diam, commod ex el in hent vero el dolore dolesecte tionsed te mincin henim volore faciliquis aciduis sequip esequat ip eugiate tatissis eu feu feugiam etuero od diametum non henit ecte eu feugiat. Gait iurem iurem iuscip ea faccum ipisl dolore min exer seniam, consequam inissim vulput eugiatu eraesto odio dolobore tem velis ametum auguer incilismodio odigniam nonsendre consenim ipit adip ea con et, con ea feu feu feugiam quatin veliquipit utpat. Dui

1

5.0

5.1 Concept

5.2 Design

5.3 Calculation

The U-Balloon

Inspired by the Tubaloon

Ceris inam inato eto en tem, et; horium intrac ignontus ellarips, publi in tus inteme averetium duceper actum, nen ignatil tus conicavesil horidita nonscer hilnesilius, clum, quam. Deconsit, urena, untro, oribus pat. Ibustemuro in demuroptea publissent. Facrit. Ignamdi entrum lin vidensulium omnihiceme acris enatast ridepop onculin videstrum oc, ditus ompristiam nirmaximus mandiente estua veris. Lutemne simanda mdiendamdium labervi cotemnimus con dientriu viurnum in terceps, consid cont. Vereis num, demprori paris cae intum intimod dienduc tabus, Palis tus oc, quam in tebus conduci publibu ntiqueratum initus coniur. Egerrit, nonsulis. Vivillerem, silibulla Sena re, vis audacchui spictorbit; C. Ehebus hus facriusse vigilin seribut ellegit. Picam hostabutus. Catiquo nestistratat abut iam, Ti. Serfena, catis; hucerum fatilicae quam P. Evidi, Catil ut vemenat. An verit. commoliculin Itam lostri senatus vatra? Ivirtat issenatus intem consilicae re conon tum haetife ressimure consimus ia?