Author Archives: Sam Armijos

Fabric Structures and Horst, Hypars and Hospitals

This week The FabricArchitect looks at the letter “H”. The first things that come to mind are:

  • Horst (Berger)
  • Hypars
  • Hospitals

I first started studying fabric structures at Rensselaer in 1985. One of my thesis advisors was an Engineering professor named Bill Spillers. Bill recently passed away in 2010. When I asked him to help me with my thesis on Fabric Structures in Housing, he told me the person you need to meet first is Host Berger.


You cant’ talk about fabric structures without talking about one of the great pioneers in the industry: Horst Berger. Besides “Frei”, he is one of the few personalities in the industry who is recognized by a single name.

Born and educated in Germany,  Horst joined Severud Associates in New York City and worked on projects such as the St. Louis Arch, Madison Square Garden, and Toronto City Hall. In 1968, he formed Geiger Berger Associates with David Geiger and gained international fame for creating a specialized firm devoted to air and tension structures for permanent applications. There are a number of engineers around the world who gained experience in tension structures from their time spent at Geiger  Berger.

Berger  is credited for designing and engineering a number of structures and was instrumental in both the 105-acre roof for the Haj Terminal  and the Denver Airport which recently was awarded the 25 year award from the AIA.

He’s still around and loves talking fabric structures.

His book, Light Structures: Structures of Light inspired me to write my own book, Fabric Architecture


I can give you all the mathematical jargon on what a Hyperbolic paraboloid is but it wont help you get your fabric structure get built. What you need to know is that this is the starting point to any fabric structure. All fabric structures need to have some form of a hypar or saddle shape to be stable. Hypars must have at least four points (two high and two low and opposite each other). Designers as well as fabricators love hypars. You can create endless concepts but you have to follow the rules.


Hospitals need Fabric Structures. From covered parking to covered walkways to entry canopies to interior applications, a hospital has a number of places for fabric structures.  Besides UV protections, fabric structures are ideal for shading outdoor spaces for the elderly as well as playgrounds for the children. It can be used in outdoor seating areas for employees and screen mechanical equipment.

Next we go to “I”

3G’s for Fabric Structures

FabricArchitect is going way back to “old school” with the letter “G”:

  • Geiger
  • Green Fabric Structures
  • Gas Stations


When I was studying fabric structures in College (I went to NJIT for undergrad and Rensselaer for Graduate work), one of the main pioneers in the field was David Geiger. David Geiger was an engineer who invented the air-supported fabric roof system used for almost half the domed stadiums in the world. He unfortunately died young at the age of 54. Dr. Geiger received more than a dozen patents for long-span roof systems. His air-supported system cover the Metrodome in Minneapolis and he Silverdome in Pontiac, Michigan and he was part of the Geiger Berger team that introduced fabric structures to America. He also founded Geiger Engineers which is still around today. He also invented a cabledome roof system that is used at Tropicana Field in St. Petersburg, FL.

Green Fabric Structures

“Green” can mean so many things but when it comes to fabric structures, it means being sustainable.

Sustainable design (also referred to as “green design” or “eco-design”) is the art of designing physical objects to comply with the principles of economic, social and ecological sustainability. The essential aim of sustainable design is to produce places, products and services in a way that reduces use of non-renewable resources, minimizes environmental impact, and relates people to the natural environment.

I know you have heard that before.

My experience?

Everyone has different viewpoints: Owner, client, Architect/designer, Consultant, Contractor on sustainable design.

My answer?

Green Fabric Structures can be more expensive but provide benefits beyond providing basic shade, signage and shelter. The provide unique Design, Materials and Construction benefits.

Design benefits include:

  • Day lighting (reduce the need for artificial lighting)
  • UV protection (reduce the risk of skin cancer)
  • Water collection (water used for irrigating plants, etc.)
  • Solar shading (reduce energy on building’s mechanical system)
  • Education (structures that teach people about UV protection, recyclability, etc.)

Material and Fabrication benefits include:

  • Longer lasting materials (Silicone, Tenara, PTFE, ETFE, PVC)
  • Recyclable materials (recyclable PVC and polyofin)
  • Energy it takes to create materials is low compared to other materials.
  • Energy it takes to fabricate membrane compared to other materials.

Construction and Installation benefits include:

  • Less and Lighter is more. More structure on fewer trucks. Lighter equipment needed to erect.
  • Less impact on the ground (smaller concrete foundations, utility tension cable anchors)
  • Shipping cost. Light load.
  • Retrofit or reuse of the site. “Remove and reuse”

Need more info?

Gas Stations

All this talk about design and sustainability makes me think of the need for alternative energy and “charging stations” for our new devices.

The filling station, also known as a gas station, petrol  station or service station, has been selling fuel for motor vehicles since 1888.

OK, What does this have to do with fabric structures?

Not sure when the first gas station canopy was created but it is now very common to see them used for branding and signage. It would seem ideal to use a fabric structure over the fuel pumps but there are few examples.

Try one on for size.

See you next time at the letter H.

Sam in 30

Sam in 30.

See a 30 second video on what I’m all about.

The F word in Fabric Structures

When it comes to the letter “F”,  Besides Fun, the FabricArchitect can think of a couple or more things:

  • Failure
  • Fabric
  • Frei Otto


No one likes talking about structural failures but when a couple of fabric structures collapse due to unprecedented snow and ice storms, some things should be discussed. I recently read an article in the New York Times regarding ice falling from skyscrapers in New York. The temptation is to fault the designer, architect or engineer.

While fabric roofs have collapsed, traditional roofs are also collapsing too. The damage has been less below a fabric structures and they are much easier to repair and replace.

Fabric Structures are designed to the latest codes and these are 100 year storms we are experiencing. However, as one Architect friend put it, “Is there something in the design and engineering of these structures or is it just an Act of God or maybe the fact codes need to be changed to adjust to global warming snow levels?

The most important concern resulting from building failure is life safety . I believe that a fabric structure provides a great cost effective solution for shade and shelter and since it relies on few structural members its record for structural damage and loss of life is very low.

Frei Otto

I couldn’t wait until we reach “O” to discuss Frei Otto! He is the forefather, founder and pioneer of Tension Fabric Structures. His work is the reason I got into this business. From the German Pavilion at Expo 67 to the 1972 Olympic Stadium in Munich, he is most likely responsible for the hundreds (maybe thousands) of designers and engineers that have carried the torch of lightweight structures around the world. I have always wondered how many people were truly influenced by Lightweight Structure advocates like Frei Otto and Buckminster Fuller (another F). Architect Phillip Johnson once said “in Architecture, You cannot not know history”. In Fabric Structures, you cannot not know Frei Otto.


This is such a huge topic. Architectural fabrics in common use today include:

  • PTFE
  • Silicone-coated fiberglass
  • Woven PTFE
  • PVC-coated polyester
  • PVC-laminated polyester
  • Theatrical draperies
  • Stretch fabrics (spandex)
  • High-density polyethylene (HDPE)
  • ETFE

Without trying to reinvent the wheel, the best way to determine which material to use is to see what has already been used for the building type you are considering.

If you are interested in structures such as tents or umbrellas where the main objective is to provide temporary, nomadic shelter, you are probably looking at vinyl laminated or coated polyester.

If you are researching awnings and canopies, the options are endless. You are most likely to hear words like acrylic canvas and backlit fabrics and materials which you can apply graphics to.

If shade is your primary concern, the buzz word is structural mesh, high density polyethylene (HDPE), perforations and % of light transmission.

For warehousing, industrial applications and temporary buildings, a common term may be clear spans or pre-engineered fabric buildings with materials that are mold and mildew resistant.

The interior and lighting industry have their own variety of fabrics where flame resistance, UL ratings and % of reflectance are the most important issues.

Air and Tension Fabric Structures rely heavily on its fabric’s structural characteristics and tensile strength, sound absorption and solar transmission play a major role in their selection.

Material Choices

OK, so now you’ve seen what’s out there already, but you want to make a statement, solve your clients needs and have unlimited funds.

Yeah, right!

What material do you use?

Is your project near the water?

Is it meant to last 5, 10, 20, 30 years?

Do you want to see it from afar or do you want it to be dark inside at noon?

These are all important questions one should answer before you even start.

Make Mine Non Combustible

In most States, permanent, totally enclosed structures require a “non combustible” or Class A/B rating according to Building Codes. The most recognized and accepted material used for Architectural Applications is Teflon Coated Fiberglass or PTFE.

Recognized manufacturers include Saint Gobain, Verseidag, FiberTech, Chuko and Taconic. Teflon comes to the site brown like a pair of khakis but bleaches to a milky white over time (usually 4-8 weeks). The biggest problem with Teflon is that it is stiff and brittle and must be handled very carefully to avoid breaking the fibers. The best part is its life span (30 years) and “self cleaning” attributes.

Other “non combustible” materials include Silicon Coated Fiberglass, Sefar’s Tenara and  ETFE.

Make Mine PVC or PVDF

The majority of fabric structures being considered today are for uses which do not require complete enclosure. That means, they are most likely “open air” or do not require a Class A rating. Class C is the most common rating and NFPA 701 is the most accepted certificate for most Fire Marshals. Vinyl coated polyester (PVC) is the most common material used on the market today.

What’s not to like?

The material comes in a variety of colors, strengths, weights, thickness, perforations, translucency and textures. The material is pliable and stretches quite nicely. You can find material with 10, 12 and even 15 year warranties. You can find material that is 50 to 100” wide so you can have few, fewer or the fewest amounts of seams.

Manufacturers include Ferrari, Mehler, Naizil, Seaman and Verseidag, to name a few. These are the names most seen on Specifications, which means that these companies are directly marketing and assisting the Architect in the early stages of the design.

PVC comes in a variety of top finishes: acrylic, PVDF and PVF film. There is much debate about top finishes but all manufacturers agree that they are needed to protect the base fabric from UV degradation, water and wind.

Frankly, it’s all about the coatings.

PVF is a film applied to the main fabric while acrylic and PVDF are coatings. Both PVF and PVDF claim to be “self cleaning” or provide the base material with a much cleaner and maintenance free surface but both require additional work in the shop which may be unknown to the Architect.

Both top of the line PVF and PVDF require that the top coat or film where two panels are to meet be grinded off in order for them to be RF welded. This is time consuming and requires great care in order to keep the seams clear of dirt, model and mildew. There are “weldable” PVDF but their warranties are not as long as the high tech top coats.

PVC Structures love graphics and provide a great backdrop for projected images.

Made in the Shade

Today, more and more fabric structures are being designed for shade only. Structural mesh and perforated fabrics are being specified because of the need for shade, the need to allow the elements to go thru the material and the need for a space to “see thru and be seen”. The material most often used is high density polyethylene (HDPE). Manufacturers include Multiknit, Coolaroo and Shadesure. This material is a higher grade mesh than what one would see at a home improvement warehouse or at an outdoor furniture store.

HDPE is used for playgrounds, areas requiring hail protection, schools, day care centers as well as theme parks and spaces of public assembly. Mesh is hot so you can stay cool. Mesh comes in colors, fire rated and with different perforations. It has a life span of 8-10 years and in most cases lowers the size and loads on the structural system and foundations because it takes less wind.

Keep it simple

If you want to keep it simple, then work with materials which do not rely on their structural characteristics for its stability. These materials are usually clad on a frame. The materials are usually vinyl laminated polyester, acrylic coated canvas, and materials with a light topcoat. Sunbrella and Weblon are common brands. The material has less technical information available for applying them to fully engineered lightweight structures but when used as a cladding on a frame, they offer many opportunities to the Architect. One can apply graphics to the material, bring texture to the surface or make something truly unique.

Keep it inside

If you want to look at materials for interior application, look no further than the industrial fabric industry and Theatrical Drapery. There are lightweight PTFE materials used for ceilings in dome stadiums, PVC fabrics are used for interior tensioned fabric sculptures while theatrical drapery materials from companies like Rosebrand and Dazian are used for a softer look. Spandex/Lycra is another common material used for transforming temporary and permanent spaces but require the material be fire treated prior to fabrication.

The Future of Fabric?

Lastly, it doesn’t hurt for the Fabric Architect to dream about the future of architectural fabrics. My wish list would include “Smart” fabrics, fabrics that change color according to weather, light or mood. Fabrics made with optic and photovoltaic fibers. Materials with longer life spans, higher tensile strength, improved self cleaning, higher translucency and more environmentally friendly.

The future of Architectural Fabric Structures depends on the continuing effort of manufacturers to improve its existing products and introduce new materials.

Less is more, lightweight is more. Fabric is even better.

We go to “G” next.

Egypt, ETFE and Electricity in Fabric Structures

FabricArchitect continues his look at Fabric Structures from A to Z.

The first thing that comes to mind when I think of the letter “E” and Fabric Structures is:

  • Egypt
  • ETFE
  • Electricity


Obviously, its tragic what’s happening in Egypt.

Good and bad, these events put a spot light on a place few have been to or read about.

I know pyramids and camels come to mind but Egypt has some beautiful hotels, resorts and fabric structures. Here’s a fabric structure at the Marassi Beach Resort. Overlapping triangles and hypars. Not bad.

We all need shade to protect us from harmful UV rays.

What you can do in Egypt, you can do in your own backyard.

Just remember, design takes time, engineer it to code and choose finishes that are built to last.


I’m sure you have already seen or heard about “The Nest” or the “Ice Cube” from watching the Summer Olympics in Beijing. This material is clear and its the HOT material on the market.

ETFE (ethylenetetrafluorethylene) is a polymer resin from the same family as PTFE. It is produced in very thin sheets and is manufactured to be installed in single layers or as inflated “pillows”, “cushions” or “foils”.

It is used an alternative to structural glass for long-span structures and, because of its light weight, is helps reduce the size of the primary structural system. Check out The Eden Project by Nicholas Grimshaw if you don’t believe me.

You gotta love ETFE!

ETFE foils are UV resistant, inert to chemicals, and 100-percent recyclable. Multiple layers of ETFE can provide an effective thermal enclosure. It can also be designed with unique patterns on the film, providing a range of light transmission.


Can you install electric wiring in a fabric structure?


The key is to get an electrician involved ASAP and work out the wiring ASAP too. Most fabric structures come as a kit of parts to site.

I hate welding on site because we spend so much time fabricating in the shop and providing a top of the line finish that having to weld and prime and paint just never looks as good as a shop finish.

Running wires requires coordination from the foundation, to the hand hole location for pulling main wires to providing stubs or openings for specific wiring and fixture connections.

Remember, there is no hiding in fabric structures. Everything is exposed. Plan early.

Next come the “F” words!

5 New Small Building Ideas for Architects

Here’s 5  new small building ideas Architects, Designers and Developers can use in 2011.

One. “Show your sustainability”

Go alfresco if you’re designing a restaurant or an outdoor classroom incorporating it with a large shade structure would be a great way to show people how sustainable you are.

Two. “Park it  right here”.

Some ideas for designers and developers would be to incorporate a shade structure over parking lots to reduce the heat island effect also to provide an area for added revenue. Pay for shade or shelter.

Three. Human comfort?

No matter where you happen to be, human comfort is key. Take for example watching a local sporting event. No luxury boxes or suites. A Great opportunity for many local school clubs, public and private schools would be to incorporate a fabric structure over pre-engineered metal bleacher system or at your sports complex. The seating canopy can be sponsored or donated and could become a main feature of your facility.

Four.  “Transit Stop Here”.

How many people can fit in your a bus shelter booths?

I recently stopped by a New Jersey Transit bus stop in Wayne, New Jersey and noticed these pre-engineered bus stop shelter booths that are typically seen around the country. They never seem big enough to handle the capacity of riders and are sometimes lost when they are blocked by SUV’s and Trucks. I propose a larger structure be placed over them to incorporate overflow and provide a visual icon as a means for signage and way finding.

Five: Go inside and play

All this talk about building made me think of the  inside too. Renovation are certainly needed around the country. Have you noticed how many commercial building are for sale or rent. Dormant buildings need new life and a building’s function will need to change as well. Take a spec building and turn it into some thing else with fabric. Soft walls and “rooms within a room” can save both time and money.

Advice to Architects, Developers and Building owners?

Lets keep dreaming of new and exciting ways to build,  rebuild and celebrate life.

3D Fabric Architecture: Design, Development, Details

Today, The FabricArchitect looks at Fabric Structures and the letter D.  I could have mentioned the Denver Airport (that’s me on the right walking on the roof) or dealing with dirt but I thought I would focus on the fun part:

  • Design
  • Development
  • Details


Designing fabric structures is fun if you understand structures and the basic forms. Each component is both visible and structural, and relies on all parts to function properly.

The first step in designing a fabric structure is to create a form with sufficient pre-stress or tension to prevent it from fluttering like a flag or sail.

How do you do that?

Understand the forms.

The three basic forms associated with tensioned fabric structures are the hypar (hyperbolic paraboloid), the cone, and the barrel vault.

The hypar, or simple saddle, is often a square or rectangular form in plan that in elevation is a series of high and low points in which the columns are located along the perimeter.

Mast- and Point-supported structures is where  internal columns are used to support the membrane  are cone or conical forms.

Arch- and Frame-supported structures, in which the membrane is supported by a rolled compression member are barrel vaults.

The second step of the design process is to determine the boundaries of the tensioned fabric. The fabric is either continuously clamped to frames, walls, or beams or attached to columns and anchor points with membrane plates with adjustable tensioning hardware.

Once the primary points have been determined, the next step is form-finding (you will learn more on form finding when we get to the “F’s”).

Today, Fabric Structures are primarily done on the computer using sophisticated softeware in combination with with programs like Autocad and SketchUP.

Designing fabric structure on the computer is only as good as the people working the computer. My favorites are Chris Griffin and Andrea Zamora at FabriTec. They got their drawing templates set up so you can take a basic sketch and get REAL revised plan and 3 d drawing rather quickly.

Don’t believe me?

Try them.

The last step in the design process is analysis of the structure’s response to loads, including dead loads and live loads such as snow, wind, people, and equipment. Sould have told you about “analysis” in chapter A but I will talk some more about when I get to “E”.


It wasn’t that long ago when one use to hear about a “circus in town” .The circus was a traveling business. One would drive around the country and rent a space and set up a tent. You would charge admission and hopefully make more than what you paid for rent and then move on.  Today, these nomadic structures are much smaller and are part of short term villages as popup tents for flea markets, farmers markets and tail gate parties. Their are fewer moving large temporary structures around but one can still see them for Fashion Shows ans Special Events. The lost art of the Circus in Town is left to Big Apple Circus and Cirque du Soleil.

What’s the future?

Three quick suggestion to my Venture capitalist.

A Tent for Teens. Teens like to go to Malls to see and be seen but they have nothing to do. What if you leased a space in the parking lot of a mall and created a place for teens to go that isn’t a club or a movie and charge a fee. If you build light, they will come.

A Tent for Gamers. Traveling tournamet for Video Gamers in a unique tent. They will see the tent and know “the tournament is in town”. To enter the tournament, there is a fee. Have game? They will pay to play.

A Tent for Seniors. Wouldnt it be great if Seniors could find a place to meet and get some special treatments. Music, food and medical services could be made available by sponsors.

Got an idea for using a pre-engineered tent or custom fabric structure to make money? Let’s talk.


All this design and development requires great details. Mies van der Rohe is acknowledge for saying “God is in the Details” and that can certainly be said about fabric structures. It’s just steel, fabric and cables but everything is exposed and working out the details is your key to success. We will talk about membrane plates in “M” but when it comes to details, start at the base. The base plates are the “feet” of your fabric structures. Moment or pin connected, they can be easily forgotten. If you are making pin connected bases, a beautiful pin will be a give a great impression. Anchor bolts at bases can be exposed , covered or below grade and covered. Its all part of the architecture.

You want to see some thing real cool?

Check out this link on details.

Its from the School of Architecture of Barcelona.

Lets talk about “E” next time.

“C” and Learn more about Fabric Structures

FabricArchitect continues his series on the ABC’s of Fabric Structures.

When you “C” a structure like the one on the right that I worked on in New York City at South Street Seaport, you will know the difference between a tent and a fabric structure.

Todays words are:

  • Cables
  • Catenaries
  • Cutting Patterns
  • Cost


Most fabric structures have an “edge” which is made of a fabric pocket or “cuff” in which a cable is placed inside of it.

This cable is then connected to a membrane plate or directly to the structural steel component.

Cables are usually associated with permanent structures but can be used in temporary structures as well. The issue with cables is that they require an end fitting and can be quite bulky to store as opposed to kevlar rope and webbing belts which are more often used for tents and moveable canopies.

As for cables, they come in all shapes and sizes and strands. I like designing structures with edge spans less than 25′ feet in order to keep cables at a cost effective nice size (3/8″ to 5/8″) with small end fittings.

Otherwise, the price jumps fast when they get bigger and they are harder and heavier to move around. I also prefer stainless steel or coated galvanized over any other cable being offered.

I always say “pay now, pay later or have a plan”. Cables are the visual jewelry of a fabric structure. They will look bad if not taken care of or made of an inferior material.

As for end fitting, we can talk more when I get to “E”.

Want to get a sneak peak at  cables and end fittings?

Visit Ronstan, Jakob or Pfeifer.


I never used Catenaries in a sentence until I started designing fabric structures!

Good word to know.

Catenaries describes the scalloped edge shape of the boundary of a  fabric structures from one specific  end point or node. Fabric structures rarely have straight edges. They always have curved edges if they are only being held at two points.

An old friend of mine in the industry once told me that a typical catenary “scallop” is usually 10% of the distance between the two points. I use that as a rule of thumb before it goes into “form finding”. For example, if the distance between two points is 20 feet, the catenary “scallop” in plan will be about 2′. Try it at home.

Fabric Structure computer software allows one to get not only the forces but the cable lengths of those tricking catenaries.

Want to know more about fabric structure software?

Fabritec Structures has Marty Brown in their offices. He is the developer of NDN, the specialized Finite Element Method (FEM) modeling and analysis software that is used around the world by leading consultants and fabricators for the engineering, design and patterning of tensile membrane systems.

Cutting Patterns

I always like to use the analogy of a tailored suit to describe a fabric structure.

You have the body or the design to start with. You pick out the materials and the tailor measures, cuts the materials and fabricates a custom outfit.
fabric structures is done much the same way but all the work is done in 3D using fabric structure software.

However, one inputs material characteristics into the program because no two materials stretch alike.

The program and then unfolds the 3D image into 2D to determine what the structures will look “unstretched” and ultimately provide the fabricator with “cutting patterns”.

These patterns are made using a series of x, y coordinates that a CAD/CAM machine can read in order to cut the pattern from a sheet of fabric. Adjustments and modifcation to the cutting pattern report needs to be made before the membrane is cut to accomodate seams, overlaps, reinforcements and cuffs.

What do you need to know?

Ask to see the report.

You need to make sure they have input the correct material charateristics and thay you are aware and have apporved the seams orientation and the location of reinformcements and pockets.

See Tensys for more info on cutting patterns.


“How much does it cost any way?” That’s the number one question I get all the time.

Do a simple exercise.

Take the plan area of your space.

Multiply it by 1.5. This will give you an estimate of the surface area of your fabric structure and include a small amount of fabric that is wasted on the cutting room floor.

Take the surface area and multiply if by $100.

In 2011, that’s the range for designing, engineering, fabricating, and installing a fabric structure. The range does not include foundations and it does not take into consideration the material finished, the size of the overall project or the material chosen.

Surface Area X $100= Budget

It will tell you if you can afford a custom structure.

I got fabric structure ideas in all shapes and sizes and cost.

Contact me and lets “C” if I can help you.

Next in the series: Design, Details and Dirt.

Fabric Architect Looks at Bandshells, Birdair and Biaxial Testing

Series continues on Fabric Structures: A to Z

Today I’m going to comment on the B’s (That’s me on the right in Bangkok)

  • Bandshell
  • Birdair
  • Biaxial Testing


bandshell is a large, outdoor performing venue typically used by bands and orchestras. The roof and the back of “the shell” protect musicians from the weather and reflect sound through the open side and out towards the audience.

They can be made of concrete, wood and just about anything but my favorite is fabric (of course). Fabric Structure bandshells can be temporary or permanent and come in all shapes and sizes. They can even be designed to work indoor.

Personally, I like the temporary bandshell from Anchor Industries and Tentnology. Both good buddies of mine. If you need to go permanent, I like to bring along FTL Design Engineering Studio with me (FYI: I use to work there myself). They have a lot experience with these kind of structures.


It’s hard to talk about Birdair because they are my biggest competitor but my role  is to promote the industry and encourage more use of fabric structures worldwide. Birdair is the most recognized name  associated with large-scale fabric structures. The have been involved in the many of the large-scale structures built for Olympics, World Cups and a number of sports stadiums. They have recently made news because they were the roof manufacturers of the Metrodome in Minneapolis and Skyline Stage at Navy Pier in Chicago which both collapsed  during a2010 winter storm in the midwest.

They are big users of Sheerfill teflon coated fiberglass from Saint Gobain and they now push a product call tensotherm which is a roofing material which has some thermal properties.

Birdair is located in Upstate New York but is owned by the Japanese company Taiyo Kogyo. They advertise heavily in Architectural Record in order to be “first in mind” with Architects but there is no such thing as “birdair structures”. The company which started in 1957  under the direction of Walter Bird and rose to prominence in the 1980′s with projects like the Haj Terminal is a skeleton of itself with many of the designers, engineers and employees now retired or gone elsewhere to work.

“Companies don’t build projects, people do”. Be comfortable with the people you want to work with before you proceed to build a fabric structure.

Biaxial Testing

No two fabrics are alike. They stretch differently and subsequently require what is called a biaxial test. A Biaxial test stretches a membrane in both the warp and fill direction to determine the elongation behavior under certain loads.

How much do you need to know?

As an owner or designer of a small-scale structure, you should at least ask to make sure one has been done if not on your specific fabric but on a sample of the material you have purchased. On bigger projects (i.e. stadiums), a biaxial should be done and recorded. Anything to do with fabric, testing and performance, I always go to Tensys. They are the best.

With all this talk about fabric testing, competitors and bandshells, it make me want to help someone get something built.

Next I will comment on cables, catenaries, cutting patterns and COST.

Fabric Architect Class begins Today: A to Z

Learn and understand the basics of Fabric Structures.

I thought I would start 2011 by taking a step back and giving you the things you need to know about Fabric Structures from A to Z.

Today, I am going to start with the letter A.

  • Awnings
  • Anchors
  • Amphitheaters


Awnings are lightweight fabric structures made of  acrylic, cotton or polyester, just to name a few. It is stretched over a frame made of wood, steel or aluminum. Most awning forms are made in traditional architectural shapes such as a simple gable, shed or barrel vault. However they can come in all shapes and sizes too. Awnings are still made the old fashion way by sewing panels of material together but they are also “RF welded” together or “stapled” on a frame. Personally, I like the “steelstitch” or staple system awning systems. Its clean, attractive and cost effective.

Today, in addition to providing protection from the elements and reducing direct solar heat gain on a building, awnings are mini billboards and branding opportunities for any one who choses to take advantage of this product. They can increase the amount of your living, working and selling  space and can transform your space and give it new life.

Extend your entrance, Expand your dining area, create shelter for your employees or patrons. Doing more with less.

Want to be sustainable?

Ask for Sustainable materials or go retractable (Open and close and you wish).


Fabric Structures are anchored in a number of ways: Either with a concrete footing or to a structural steel plate attached to a building. When you are designing a custom fabric structure, it is common to have reactions or loads provided by the Engineer or fabricator in order to properly size and build the anchors. Some loads on fabric structures are in tension only and that allows one to consider another type of foundation or anchor.  That type of anchor comes in the form of “earth” anchors. In simple terms, that’s using the earth to support your fabric structure. You can put stakes in the ground like tent companies do for easy removal and temporary structures, but for larger and more custom applications, earth anchors can be cost effective and sustainable.

The anchors are driven with conventional hydraulic equipment similar to what you might see a Utility company use for installing communication lines. Once driven to the proper depth, the rod/tendon attached to the anchor is pulled to rotate the anchor into undisturbed soil – like a toggle bolt. The anchor is pulled upon to reach the holding capacity required and has very little impact on the existing soil. My preference? Manta Rays.

Another type is an” helical auger stake” which I see more for small and medium size structures. They work much like a wine cork opener in which you screw a plate and rod into the ground and do the same test for holding capacity. What’s nice about these is that they have minimal soil disturbance. I like the augers from A.B. Chance.


All this talk about Awnings and Anchors makes me want to design!

An amphitheatre or amphitheater is an open-air venue used for entertainment and performances. Modern amphitheatres feature a theatrical style stage with the audience only on one side, usually at an arc of less than a semicircle. They are typically man-made, though there are also  natural amphitheatres using the existing slope of the land. Open air venues are nice but there is increasing need to have these performance facilities covered.


1. The Show must go on and a little rain or too much sun shouldn’t cancel an event. Fabric Structures can cover the performers, the audience or both. Most major city’s have incorporated a covered amphitheater as part of their city scape. Don’ Believe me? See Boston, Chicago, Baltimore, Miami, Charlottesville. Need more proof? I got more.

2. Skin Cancer. Too much sun can be bad for both performer and audience. Skin cancer is the fastest growing cancer in the nation. Research indicates that most people receive as much as 80 percent of their total lifetime sun exposure during their first 18 years. One severe sunburn during childhood may double the risk of developing melanoma, one of the deadliest forms of cancer, later in life. Being exposed to the sun for a 1-3 hour event could be quite dangerous.

3. Acoustics.  Covered or uncovered, there are so many forms of entertainers and they all have different needs. Some use amplified sounds, others use none at all. The design of a covered amphitheater needs to be able to adapt to a number of different sounds. If you are looking at covering an amphitheater, make sure you bring on an acoustical consultants with you. I like JaffeHolden.

Ampthitheaters, like all fabric structures, come in all shapes and sizes AND Costs. Don’t think you can’t afford one until you do your research. You may only need a bandshell (I’ll tell you more about them when we get to the B’s).

Got an idea for your town to build new or transform an existing amphitheater?

Let’s do it.