A Seattle Viaduct's Sibling Quietly Gets a Makeover
Despite the area's industrial history, the team encountered relatively little contamination. Most recovered water went to a wastewater treatment plant via storm sewers, while tainted soils were sorted by degree of contamination to help reduce the city's landfilling expenses.
PCL recommended using locally sourced precast concrete for the girders, instead of the originally specified cast-in-place material. That eliminated the need for span-to-span falsework and reduced the number of cross-street closures beneath the bridge, Richardson says. PCL also salvaged several steel beams from three demolished access ramps to the existing viaduct, reusing them as construction supports for the new girders and cast-in-place column caps.
Completion of the subsurface work also means an end to most construction-related unknowns. Given the current pace of building 100 to 150 ft of concrete deck a week, Schmidt expects the new structure to be ready by the end of summer. Work will then shift to repairing the existing deck and adding a new concrete overlay.
There will still be a lot of traffic maintenance issues to contend with, but we will maintain at least two lanes each way until the repair work is completed early next year, he says.
That work could coincide with the Alaskan Way Viaduct's replacement and several years of traffic disruptions in downtown Seattle. When that happens, Goldsmith says, everything down here should be ready to handle it.
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