The Sellwood Bridge—at 1,972 ft long, 75 ft high and 28 ft wide—is among the state’s busiest bridges with 30,000 vehicle crossings each day. On Jan. 19, 2013, a Pacific Northwest-based Omega Morgan crew will slide the entire structure, in one piece and on a radius into a new position over the Willamette River. It will then become a temporary route beginning Jan. 24 while a new $307.5 million bridge is built in the original location.
“We are really pleased to be involved in this high important, complex and exciting project,” said John McCalla, Omega Morgan’s CEO and president.
The project has been called one of the longest bridge moves ever. It is complicated by the fact that this will not be a straight-across move. Instead, the east end of the bridge needs to be moved only 33 ft while the west end must be moved 66 ft. The new bridge will open in 2016.
Both Omega Morgan and Slayden/Sundt Joint Venture have successfully used this detour-bridge method on other projects. “Omega Morgan has moved bridges weighing upwards of 8 million lb, but this one does offer some additional challenges,” McCalla said.
Devising a strategy to move the bridge in one piece helped Omega Morgan win the contract after showing that it will save time, money and duplication of efforts, according to parties involved in the project. Other proposals had suggested expensive and redundant structural features and extensive staging
Omega Morgan created a plan to slide the aging Sellwood Bridge on skid gear to the north of the existing bridge and then mount it on new piers that have been built in the river. This will then become the “shoofly,” or detour, while construction begins on the new bridge. For those who are unsure about the old bridge’s stability, they can rest easy that it will be secure before traffic resumes, officials on the project said.
The 87-year-old bridge replaced a ferry called the John F. Caples. The steam-powered ferry took an average of 582 vehicles and 482 pedestrians across the Willamette River every day, compared with the 30,000 vehicles crossing each day in 2012.