Architectural Record Article

Unconventional Geometries This article appeared in Architectural Record, December, 1997.

THE FUTURE Unconventional geometries:
Is composite construction
the wave of the future?

BY JOSEPH F. WILKINSON

Is plastic about to become the next best building material? Composites have been around since 1943, when a polymer (plastic) was reinforced with fiberglass to make the fuselage of Navy training planes, and they've been used so far in automotive bodies, boats, skis, bearing piles, golf clubs, freight cars, utility poles, bombers, sewer pipes, sewing machines, prosthetic limbs, and railroad ties – but not as key elements in many buildings.

William Kreysler, whose Penngrove, California company is a leading producer of composite decorative elements, predicts that composites will soon be accepted as structural material and will change our concepts of buildings.

"Composites got their foot in the construction door by pretending to be something else, mimicking other materials," said Kreysler. "This is unfortunate, because composites are so unique and so versatile and can open doors to so many new opportunities.

"Composites can take us out of our orthographic rut. These polymers are strong and light and they don't require the same structural system that conventional materials do. Frank Gehry is designing shapes that are ideal for composite elements because they have compound curves. Most architects think a compound curve is expensive to do, and it is – with conventional material. But a compound curve is cheaper to produce in composites than a orthographic shape. You could build an entire building with composites without a structural steel frame."

Composites such as beam sections (above right) have made inroads in infrastructure construction because they have a high strength-to-weight ratio, they are resistant to corrosion and rot, and they are light in weight. They aren't cheap, but they promise low life-cycle and maintenance costs in applications such as pedestrian overpasses, small vehicular bridges, and traffic decking.

Because they're transparent to radio waves, composite sections are used to build decorative towers and turrets to enclose communications equipment atop office buildings. Clinics use composite structures to house magnetic-resonance imaging (MRI) apparatus. Many hospitals want rooftop helicopter pads, and plastics make landing pads for roofs that can't take the weight of concrete. Immune to de-icing salts, FRP reinforcing bars and prestressing tendons are now specified for concrete parking decks.

Today, architects most commonly use composites for pre-formed bathtub/shower units and counter surfaces. The next most popular application for polymer building material is as decorative elements such as cupolas, pediments, railings, friezes, and steeples that never rot and don't need painting. An example of the architectural potential of composites is the 147-ft high, 180-ft diameter dome built for a Reno, Nevada casino (below). Made of 1,996 fire-resistant composite panels, the structure cost 20 percent less than a metal geodesic dome and weights half as much.

"We're saying and proving that composites can be used to replace primary structures," says James Irwin, president of Ratech Industries, Inc., the Sparks, Nevada designer and builder of the dome. The firm specializes in unconventional structures that requite spherical, non-spherical, or compound-curve shapes, and is currently working on another huge dome, for a 3-D IMAX theater in Seattle.

Composite construction is the wave of the future," says Irwin. "Architects nowadays are looking to do unconventional things. Historically, people have done the best they could with steel and conventional materials, but these limit design to conventional geometry. Composites will give people the opportunity to work in a nonangular dimension.

"Using composites, you could build a home using only half the time and half the materials. You can, literally, mold homes and make them modular in nature and assemble them on site. Building things of sticks and nails is pretty archaic."

But while composites offer the allure of the unconventional, they also carry the burden of the new, without the track record or predictable standards of steel, concrete, and wood. Only when national criteria are established will architects and clients find composites more attractive.

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Last updated: 09/21/06