What makes a building predisposed to using a fabric structure design?
Fabric structures, as most other building materials, are used when it is cost effective. It is usually feasible when there is a large clear span necessary. Architecturally, these structures are used when a dramatic effect is desired, i.e. Harbor Place in Vancouver, Canada.
What about storage facilities, a large open span is required, but fabric structures do not seem to be utilized?
These type of structures are not more widely used for storage type facilities due to the access problem, i.e. airlocks are usually needed and this is usually not feasible. Studies have been performed for industrial sites, such as BC coal terminal, but even though the cost is low it is higher than industry wants to spend to cover an area.
What about expense relative to traditional types of structures?
Air supported roofs are definitely less expensive for a large clear span, however, it is an active system and the drawbacks must be taken into account. Tension membrane structure may or may not be less expensive depending on the circumstances.
Has the demand for fabric structures been increasing or decreasing?
Internationally, the market has been growing rapidly. Especially in the Far East where there is a desire for state of the art architecture and large sports stadiums are being built for the first time. Domestically, the market has been generally flat, and smaller scale project starts have been declining. Sports facilities , with long span roofs,have a solid market.
What types of materials are used for membranes?
Basically,there are two types of membranes used: Teflon-coated Fiberglas and silicon-coated Fiberglas. Teflon is the more commonly used. Recently, Teflon has become relatively expensive in comparison to other building materials. Actually, we have been leaning toward seven strand wire, which has a low cost, although it does require more handling. There are always new materials that may be used, but they are usually not cost effective for typical circumstances. Since the weight is already a small portion of the total load, using more lighter, but more expensive composite materials is not feasible. Kevlar is a wonderful material and may be considered when a great deal of geometric stiffness is required.Entertainment structures, such as those for rock concerts, have been booming lately. The need for structures that collapse and erect quickly and can be constructed by hand may change the type of materials that are being used currently.
Is there any commercially available software used for design of fabric structures or are propriety programs normally used?
Geiger Engineers uses their own software, such as that written by N.J.I.T's Dr. William Spillers. The kernel is FORTRAN, but the front-end is C++. FORTRAN is still one of the best for performing computations for non-linear analysis. As of yet, there aren't any commercial programs available that combine all the elements needed to design a fabric structure.
What was the most challenging project you have worked on?
Most of our projects are challenging and interesting. It depends on what you define as challenging, from the standpoint of design, management, or analysis. The most challenging engineering projects are those where the engineer work closely with the project such as I did with Lindsay Place in Calgary.
What effect does Denver Airport have on the fabric structure market?
Although there has been negative publicity, it has not been due to the fabric structure, therefore it doesn't have an effect in that sense. I do think it will be an architectural landmark and expand the exposure of fabric structures.
How do you market such a specialized field of engineering?
Networking in the marketplace is important, as it is with any other firm.It is important to be known, through publications and so forth. You need to know your market. Architects and sports facility owners are the main clients in the industry, so its important they know you.
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