BUILDING BIG Bridge basics
Bridge Basics
Tuesdays in October on PBS (check local listings) _  

Bridges | Domes | Skyscrapers | Dams| Tunnels

Image of New River Gorge Bridge
Arch bridge
being constructed with cables
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How are arch bridges built?
Building an arch bridge isn't easy, since the structure is completely unstable until the two spans meet in the middle. For years, engineers used a technique called centering, in which a wooden form supported both spans until they locked together at the top. A newer method supports the spans using cables anchored to the ground on either side of the bridge. This is how the New River Gorge Bridge in West Virginia was built.

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_There's even more to explore at the BUILDING BIG web site, check it out at www.pbs.org/buildingbig.



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BUILDING BIG is a coproduction of the WGBH Science Unit and Production Group, Inc., and is presented on PBS by WGBH Boston.

Major funding is provided by the National Science Foundation. Additional funding comes from the National Endowment for the Humanities, The Arthur Vining Davis Foundations, the Corporation for Public Broadcastin, and public television viewers.

National corporate sponsorship is provided by the American Society of Civil Engineers and by Siemens.

The BUILDING BIG web site was produced for PBS Online by WGBH.
BUILDING BIG web site ©2000 WGBH Educational Foundation.