Select your localized edition:

Close ×

More Ways to Connect

Discover one of our 28 local entrepreneurial communities »

Be the first to know as we launch in new countries and markets around the globe.

Interested in bringing MIT Technology Review to your local market?

MIT Technology ReviewMIT Technology Review - logo

 

Unsupported browser: Your browser does not meet modern web standards. See how it scores »

It doesn’t look much different from California’s other arroyo crossings, but peek under the deck of the Kings Stormwater Channel Bridge on Route 86 in Riverside County and you’ll find something surprising: plastic, carbon and glass where steel girders and reinforced concrete ought to be. The California Department of Transportation’s recent completion of the bridge could mark the beginning of a move away from traditional construction materials in favor of lightweight, rugged composites.

Though “polymer matrix composites” (fibers like carbon or glass encased in plastic) have found their way into a smattering of smaller structures in the past decade, the new bridge is the first to face the test of highway traffic and long-haul trucks. It boasts a fiberglass composite deck with a thin veneer of special concrete supported by carbon-fiber composite tubes just 355 millimeters in diameter. The materials are so lightweight two men can do what normally requires a crane. That translates into faster construction, which is critical when a busy bridge is out of commission, says the Federal Highway Administration’s Eric Munley, a composites expert. “If you can replace the thing in a week, you’re going to be very interested in composites,” Munley says.

In fact, the Kings Stormwater bridge went up in one-third the usual time-but at twice the cost, because composites are relatively pricey. Still, says California Department of Transportation chief deputy director Jim Roberts, the materials’ superior durability could make them worth the expense, not only for bridges but also for highway decking in areas where ice and salt readily do in steel and concrete. “All you have to do is get 20 to 30 years out of it, and you’re way ahead of the game economically,” Roberts says. His department is planning to begin another composite bridge in San Diego in mid-2002.

Jim Cooper, the director of bridge technology for the Federal Highway Administration, is also optimistic: “It’s my belief that composites will form a major construction material in the future.” But until the cost of composites comes down, the gap between present and future may be a difficult one to bridge.

0 comments about this story. Start the discussion »

Tagged: Computing, Materials

Reprints and Permissions | Send feedback to the editor

From the Archives

Close

Introducing MIT Technology Review Insider.

Already a Magazine subscriber?

You're automatically an Insider. It's easy to activate or upgrade your account.

Activate Your Account

Become an Insider

It's the new way to subscribe. Get even more of the tech news, research, and discoveries you crave.

Sign Up

Learn More

Find out why MIT Technology Review Insider is for you and explore your options.

Show Me