SOUTH PARK BRIDGE

Seattle, Washington

As part of a joint venture, Massman constructed a new bascule span bridge over the Duwamish Waterway parallel to, and downriver of, the existing bridge, which had been prematurely closed due to its poor condition. Funded in part by a USDOT TIGER grant, the new structure reconnected South Park’s main business district with the rest of Seattle.

The new South Park Bridge spans the navigable channel of the waterway, which is used for industrial, commercial, and recreational purposes. It is founded upon dredged caissons that, along with a number of other design innovations, made the structure the first bascule bridge designed to enhanced AASHTO seismic requirements and capable of reopening after a 1,000-year return-period earthquake. In addition to the bridge itself, the project included intersection improvements; rain garden construction; roadway and drainage construction; utilities removal and relocation; riverbank rehabilitation and restoration; and incorporation of historic elements from the original National Register of Historic Places listed structure. To mitigate the environmental impact associated with construction, and to not impact tribal fishing rights, the project team completed certain in-water work within a 6½ month annual work window, and structured work activities to limit the amount of in-water noise impacts to marine life. 

Among its many awards, the project was named the No. 1 Bridge Project in America for 2015 by trade publication Roads & Bridges.