The Sellwood Bridge is the most southerly bridge within the city of Portland, Oregon. It is owned and maintained by Multnomah County. It crosses the Willamette River to connect SE Tacoma Street and the Sellwood neighborhood on the east to Oregon Highway 43, which leads north to John's Landing and south to Lake Oswego, on the west. It has two relatively narrow lanes and a narrow sidewalk on the north side. The Sellwood Bridge was originally intended as a community connector but is now regionally important. It is one of the Portland area's most overtaxed bridges and is in desperate need of repair or replacement.
The Sellwood Bridge was designed by Gustav Lindenthal, a well-known bridge designer in the late 19th and early 20th centuries who designed, among many others, the Hell's Gate and Queensboro bridges in New York City. It was constructed by the Gilpin Construction Company of Portland, and the steel was produced by the Judson Manufacturing Company. It opened in 1925 at a cost of $541,000. The bridge's overall length is 1,971 feet, which includes three separate sections. The main section is a four-span continuous truss, which is 1,092 feet long. The east approach is 586 feet long and is comprised of 15 concrete spans and one steel girder span. The west approach was originally built to be 269 feet long, with seven concrete girders and one steel girder span. In 1961, earth settling necessitated the addition of a 25-foot concrete girder span, to bring the west approach to 294 feet.
The bridge carries a 24-foot roadway and a 4'3" sidewalk on the north side. The bridge was designed to carry 12,000 vehicles per day, while that has risen to over over 32,000 today, making it the most heavily-travelled two-lane bridge in Oregon. Traffic is expected to increase to 40,000 vehicles per day by 2015.
When the Sellwood Bridge opened in 1925, it was the first fixed-span bridge in Portland; all other bridges at the time had lift or swing spans. The bridge is a four-span continuous steel Warren Deck truss, a rare type of bridge construction, and one of only three continuous truss bridges built in Oregon before 1941. The bridge's construction was not only groundbreaking in terms of bridge technology, but was also an impressive example of early recycling. Approaches to the original 1894 Burnside Bridge, torn down in 1925, were used in the construction of the Sellwood Bridge. Thus, some parts of the Sellwood Bridge are over one hundred years old.
The bridge is showing its age; it is falling apart. Even with a ban on trucks, traffic on the bridge overtaxes the light design; design capacity is 12,000 vehicles per day, which is quite exceeded by the over 32,000 vehicles that cross it daily now. Settling of earth prior to 1960 fractured the piers on the west end, and necessitated the addition of a 25-foot span to extend the west approach. The bridge's deterioration continues; concrete spalls (chips off and falls) often, and the expansion joints present problems. The bridge is also not earthquake-safe; a moderate earthquake (5.0-6.0) centered in Portland would likely collapse or damage the bridge beyond repair, while the Big One (8.5-9.0 coastal subduction quake) would almost certainly destroy the bridge. The bridge desperately needs to be repaired or replaced.
Several options have been studied by a study group of local and regional government leaders and community members for repair or replacement of the Sellwood Bridge. Options include repairing the bridge, replacing it with a two-lane structure, replacing it with a four-lane structure, or demolishing it. Also, construction of additional Willamette crossings to the south, between Sellwood and Oregon City at Lake Oswego or Milwaukie has been proposed. Replacement of the Sellwood bridge with a four-lane structure was rejected due to neighborhood concerns about increased through traffic, while construction of additional more southerly crossings has been rejected due to concerns of the local communities there. Demolition of the bridge without replacement has been disregarded as well, as the bridge carries too much traffic to simply be diverted to other connections. The group's final recommendation was repair of the bridge or replacement with a two-lane structure, with improvements for bicycle and pedestrian access, given the very narrow existing sidewalk. Highway expansion, such as widening SE McLoughlin Boulevard to six lanes, and improvements of transit and bicycle connections were recommended to accommodate ever increasing transportation demands, as well as encouraging development of employment in Clackamas County to reduce long-distance commuting.
However, repair or replacement of the Sellwood Bridge is not likely any time soon. Metro Regional Services identifies the cost of repair or replacement to be roughly equivalent. Repair costs would run between $40 and $60 million, while replacement would cost $63 million or more. There is currently no repair or replacement of the bridge planned, save minor deck rehabilitation and repainting, which will cost approximately $7 million and be completed by 2007. Funding for eventual repair or replacement is doubtful in the near future, as ODOT (the Oregon Department of Transportation) has all funding through 2027 committed to other projects, and Multnomah County, the owner of the bridge, has identified no appropriate source of funding either.
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