Sundt’s work on Sellwood Bridge in Portland, Oregon took a major step toward completion earlier this month when the last major deck pour was completed on the main structure. This is a huge milestone for the project that allows the team to start sidewalks and parapet construction in preparation for opening early next spring.
The first deck pour was performed Oct. 20. Sundt and joint venture partner Slayden Construction are replacing the present Sellwood Bridge, a 2,000-foot structure that crosses the Willamette River.
In order to place a concrete deck, the specifications requires less than a 30 percent chance of rain before, during and after the pour, which required a 12-hour window. Finding this window in Portland during the winter is a challenge, requiring pours to start as early as 3 a.m. The specifications additionally require the concrete to be above 60 degrees, posing a problem when temperatures dropped into the 20s, requiring the concrete to be heated to remain within specifications.
Rather than rebuilding the bridge in sections and shifting traffic back and forth between the old structure and newly completed segments, the team created a ”shoofly” (detour) bridge to keep traffic flowing throughout the project. The approach involved lifting the old bridge deck and truss with hydraulic jacks and moving it to one side, then placing it on a set of temporary piers and connecting it to temporary approach spans so that traffic could continue using it while the new bridge is constructed.