Albina Pipe Bending rolled 128,894 pounds of 5" Sch120 and 5" Sch40 pipe (tilted at 45 degrees)to help create a striking 340-ft steel pedestrian bridge linking the current Museum of Flight (Seattle, WA.) to a remote exhibit space and future development site across a busy traffic arterial. The radiused bend of the hoops varied from 22 ft at the center of the span to 19 ft at the tapered ends. All of the material is Architecturally Exposed and this bridge is a perfect example of why steel is the sustainable, available, fast and econmical choice. Precast structural shapes and cast-in-place concrete solutions were studied, but the narrow apeture through which the structure needs to pass, above the roadway clearance and below the power lines, limited the amount of structural depth that could be accomdated below the bridge deck. Using a steetl truss allowed the structural depth to surround the partially enclosed interior space and also maintained consistancy with the existing museum's architecture. The bridge deck was also originally specified as cast concrete over metal deck, but the weight of the material remained a problem, so once an extruded aluminum deck plank was identified, the steel could be reduced in weight, resulting in a savings to the project and a more appealing and eye catching design. For more information on the Museum of Flight, please see the December Issue of Modern Steel Construction and Steel Bridge News"Taking Flight"
by Tim Richey AIA "Taking Flight"- December 2008 MSC