Sellwood Bridge, Spanning Willamette River at Southeast Tacoma Street, Portland, Multnomah County, OR

Significance: The Sellwood Bridge, the busiest two-lane bridge in Oregon, is the southern-most span in an ensemble of twelve monumental highway bridges across the lower Willamette River at Portland, Oregon. The only four-span continuous truss in the state, it appears to be an extremely rare bridge type anywhere. Sellwood is also: 1) one of only 215 known truss highway bridges of any type or age surviving in Oregon; 2) one of only five known continuous highway trusses (of any type or span length) in Oregon; and 3) the state's only known highway continuous deck truss. In addition, Sellwood is one of five Portland spans associated with Gustav Lindenthal during the period 1924-1928 and is among the last bridges of this master American bridge designer's career. A rare example of a Lindenthal highway-only deck truss, Sellwood is made more significant because of its unusually finely subdivided Warren Truss with Verticals, that part of its superstructure and its entire substructure designed by Kansas City engineer Ira G. Hedrick, a one-time partner of J.A.L. Waddell. The Sellwood Bridge was Portland's first Willamette River bridge to open without a movable span, and was built without trolley tracks and with only one under-sized sidewalk. As such, it was the first major Portland bridge designed almost exclusively for the automobile. Except for its west end approaches, it remains intact as constructed, with both ends of its superstructure incorporating girders from the 1894 Burnside Bridge an example of early recycling efforts. Opened in December 1925 the same month and year as the birth of the modern discipline of geotechnical engineering in the United States the Sellwood Bridge serves as a precise but ironic benchmark because of extensive damage to its west end approach due to significant movement from one or more landslides. The sole vehicular crossing of the Willamette River in a ten-mile stretch between Portland and the cities of Oregon City and West Linn, the Sellwood Bridge particularly reflects challenges faced by local agencies charged with maintaining structurally and functionally obsolete bridges into the twenty first century.

Unprocessed Field note material exists for this structure: N877
Survey number: HAER OR-103
Building/structure dates: 1925 Initial Construction