NATIONAL AWARD SPECIAL PURPOSE BOB KERREY PEDESTRIAN BRIDGE OMAHA, NEB.

摘要

The Bob Kerrey Pedestrian Bridge spans the Missouri River connecting the cities of Omaha, Neb., and Council Bluffs, Iowa. At more than 2,300 ft, the structure is one of the longest pedestrian-only bridges in the U.S. Visually transparent but dynamic and innovative, its curvilinear design gives it a signature look and makes it a visual icon for the area. The bridge's length made design and construction a complex matter, with wind-induced vibrations a particular concern. By keeping the girders relatively shallow and allowing a 4-ft gap between the edge girders and deck, designers provided for aerodynamic stability and kept wind-induced vibrations to a minimum. The girders are approximately 23 in. deep on a 24-ft-wide steel frame, and the 16-ft-wide deck is 12 in. deep at the curbs and 3 in. elsewhere. Had the girders been deeper, they would have been stiffer and stronger, but they also would have increased the potential for wind-induced problems.