New River Gorge Bridge: World's Longest Steel Arch
|Médium:||article de revue|
|Publié dans:||Civil Engineering Magazine, juin 1978, n. 6, v. 48|
For 45 years, the Bayonne Bridge had reigned as the worlds longest steel arch bridge. No longer. The New River Gorge Bridge in West Virginia has a steel arch spanning 1700 ft / ; 50 ft longer than the Bayonne. In this bridge, a nominee for this years Outstanding Civil Engineering Achievement Award, the main chords of the arch are steel box sections, each box made by welding together plates up to 4 in. thick. In erecting most steel arch bridges in the past, the arches were closed using a jacking procedure. Visualize two half arches about to meet at the center. Jacks were inserted in this gap of a few feet and extended until the stresses in the arch reached design value. Then the gap was filled with steel. The New River Gorge Bridge is the first major bridge to be erected without this jacking procedure. It showed the designers were willing to depend on the accuracy of fabrication. This is a good practice and could be a pace setter for future bridges.
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