New Sellwood Bridge
Type: Steel Deck Arch
Built: 2013 - 2016 (opened February 29, 2016)
Length: 1976 ft, including main river spans and approaches
Width: 64 ft
Traffic: 30,000 vehicles/day
The new Sellwood Bridge is a steel deck arch structure, with three arches supporting the deck of the main river spans. After an extensive public process, the Board of County Commissioners determined in 2009 that the new bridge would:
Be built in its current alignment and widened to the south to allow for continuous traffic flow during construction
Be 64 feet wide at its narrowest point with two travel lanes, two 12-foot shared use sidewalks, and two bike lanes/emergency shoulders
Include a grade-separated and signalized interchange at the Highway 43/SW Macadam Avenue intersection on the west end
Include a pedestrian-activated signal at the intersection of SE Tacoma Street and SE 6th Avenue on the east end
Be consistent with Portland’s Tacoma Main Street Plan
Restore bus and truck traffic; and accommodate possible future streetcar
After the planning process was complete, including the necessary approvals from state and federal agencies, Multnomah County and its partners sought to reduce the project costs and shrink the overall footprint, particularly at the west end connection with Highway 43. Planners succeeded in trimming the project back and reducing environmental impacts while maintaining multimodal functionality, safety and traffic performance.
Refinements made to the Locally Preferred Alternative, approved by the Multnomah County Board of Commissioners in 2011, include:
Compressed interchange design that saves money and shifts project away from hillside
Reduction in size of the west end rock (cut by 50% - 40 feet high rather than 80 feet high)
Alignment revision to accommodate future streetcar at a safer location
Bicycle/pedestrian spiral ramps replaced with switchback ramps
Less impact to Riverview Cemetery
Original Sellwood Bridge
Type: Fixed Span
Length: 1971 ft
Width: 28 ft
Traffic: 30,000 vehicles/day
The original Sellwood Bridge, built in 1925, was the first fixed-span bridge on the lower Willamette River and a pioneer in area bridge technology. Originally intended to be a local community connector, the Sellwood Bridge became a primary connector for eastside residents headed for I-5 and Washington County, with more than 30,000 vehicles crossing the bridge every day. In 2011, construction of a replacement began, starting with a detour bridge. The new Sellwood Bridge opened February 29, 2016.
The original Sellwood Bridge’s designer was Gustav Lindenthal, renowned late 19th/early 20th century bridge engineer. Lindenthal was New York Commissioner of Bridges, and designer of New York City's Hell’s Gate and Queensboro bridges, and many other bridges. Sellwood was one of four Portland bridges that Lindenthal worked on in the mid-1920s, the last bridge projects in the master engineer's long career. The bridge was constructed by the Gilpin Construction Co. of Portland. Judson Manufacturing Co. fabricated the steel.
The main river span was a 1,092 foot, four-span continuous steel Warren Deck truss. The two 300-foot interior spans and two 246-foot end spans supported a six and a half inch thick concrete deck. The original east approach was made up of 16 spans (one steel girder span and 15 concrete spans) for an overall length of 586 feet. The west approach was originally 269 feet long and consisted of one steel girder span and seven continuous concrete girders. In 1961 an additional concrete girder span was added, making the west approach 294 feet long. Before 1961, the west approach settled and shifted 33 inches towards the river, due to a landslide. New concrete columns had to be added at three locations.
The Detour Bridge
How do you build a new bridge on the same spot as the old, while still allowing traffic to cross the river there? Easy- you move the old bridge over!
It’s not really that easy, of course, but we did it. In January 2013, the 1100-foot long steel truss spans of the old Sellwood Bridge were lifted on jacks and moved north onto temporary piers to make space for the new bridge to be built. Its east end moved 33 feet north, and its west end moved 66 feet. Then it was connected to its new temporary approaches and re-opened. The temporary detour bridge closed on February 25, 2016 before the new Sellwood Bridge opened that week.