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NASCC 2024

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Washington’s New Frederick Douglass Bridge Named NSBA Bridge of the Year

SAN ANTONIO - Steel bridge enthusiasts have spoken! The new Frederick Douglass Bridge in Washington is the 2024 Bridge of the Year, as elected by participants of the World Steel Bridge Symposium at NASCC: The Steel Conference.



As AECOM’s A.J. Cardini put it, the team behind Washington’s new Frederick Douglass Memorial Bridge had a challenge: create a bridge that is “classic but not classical, dramatic but not theatrical.” The result is a bridge with three arched spans, like the path of a stone skipping across the water, that is designed for a century-long service life. The 1,444-ft-long bridge over the Anacostia River consists of two 452-ft spans and a 540-ft center span, whose arch rises 30 ft higher than the side arches. The arch cross section is actually hexagonal, casting shadows that decrease the arches’ visual mass.



Taking full advantage of the tight tolerances and precise fabrication that are only possible with steel, the team designed arch splices that are not only visually clean but require fewer bolts than a normal splice connection. In keeping with the spirit of its namesake, the project was noteworthy for another innovation: a first-of-its-kind, federally funded, on-the-job training program designed to hire and train women and minorities.



The Prize Bridge Award jury had narrowed the field down to just three finalists going into Wednesday’s session at the World Steel Bridge Symposium.



The SeaTac IAF Pedestrian Walkway impressed with its sheer scale. At 780 ft, SeaTac’s new pedestrian walkway is the world’s largest structure over an active taxiway--and only the third such structure in the world. It’s actually a cable-stayed bridge, with the cables visible inside the walkway. The 320-ft-long center span was built in a cargo area to minimize disruption and allow for delicate operations, like placing those stay cables, to take place in a controlled environment. The center span, complete with its glass and metal facade in place, then traveled three miles away, down the airport’s central runway, before all 1,565 tons of it (with windows already installed) were hoisted into place 85 ft in the air.



In Detroit, 1.6 million lbs of structural steel make the country’s first skewed unbraced network tied arch bridge possible. The I-94 2nd Avenue Bridge Network Tied Arch’s 18-degree skew (that’s nearly 30-ft offset between the arches) and the roadway’s vertical curve meant that no connection could be square, all four corners of the finished bridge would be at different elevations, and no two steel floor beams would be alike. The bridge was carefully assembled offside on temporary supports and moved 500-ft into place--with a 20-ft elevation change along the way. It took less than a week to move the bridge’s 5-million-lb skeleton into its permanent location with a combination of both self-propelled modular transport devices (SPMTs) and longitudinal skidding, minimizing disruption to the 175,000 vehicles that travel that stretch of I-94 daily.

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