Steel Bridge

Steel Bridge is a double-deck, vertical-lift truss bridge spanning the Willamette River in Portland, Oregon. Completed in 1912, it is a critical multimodal transportation link, carrying railroad tracks, light rail, vehicular traffic, and pedestrian pathways. Owned by Union Pacific Railroad, its unique double-lift design allows independent operation of its upper and lower decks, accommodating river traffic with minimal disruption. The structure is a defining feature of the Portland skyline and is listed on the National Register of Historic Places.

History

The current structure replaced an earlier iron bridge of similar design, which had opened in 1888 but proved inadequate for growing rail and streetcar traffic. The project was spearheaded by the Oregon Railway and Navigation Company, a subsidiary of the Union Pacific Railroad. Construction commenced in 1910 under the engineering firm Waddell & Harrington, with John Alexander Low Waddell as the chief engineer. Its opening on July 4, 1912, coincided with the annual Rose Festival celebrations. Throughout the 20th century, it survived numerous proposals for replacement and was pivotal during World War II, supporting heavy industrial traffic for the Kaiser Shipyards in nearby Vancouver, Washington.

Design and construction

The bridge is a through truss double-lift span, a rare design where the upper and lower decks can be raised independently. The lower deck lifts for most river traffic, while both decks can be raised together for tall vessels. The massive counterweights and original electrified machinery were engineered by the American Bridge Company. Key materials included open-hearth steel and concrete piers founded on the riverbed. The structure's clearance when closed is 26 feet for the lower deck and 72 feet for the upper, with a maximum lift height of 163 feet. Its construction required innovative techniques to maintain existing rail service on the old bridge during the build.

Operation and use

The upper deck carries two tracks for the Union Pacific Railroad and the westbound lanes of Oregon Route 99W. The lower deck accommodates eastbound Oregon Route 99W, the TriMet MAX Blue and Red Lines, the Portland Streetcar NS Line, and dedicated pedestrian and bicycle pathways. Lift operations are managed from a control tower on the west bank, coordinating with the United States Coast Guard for river traffic on the Willamette River. It is one of the busiest railroad bridges in the Pacific Northwest, with frequent freight movements for BNSF Railway and Union Pacific Railroad. The pedestrian walkway offers views of the Portland waterfront and events like the Portland Rose Festival fleet.

Engineering significance

It is considered a masterwork of John Alexander Low Waddell, a pioneer of vertical-lift bridge design. The independent double-lift mechanism is one of only two such operational examples in the world, the other being the ASB Bridge in Kansas City, Missouri. Its design influenced later movable bridges and is studied in engineering programs at institutions like Oregon State University. The structure was awarded the American Institute of Steel Construction "Prize Bridge" award in 1913. Its robust construction has allowed it to withstand significant seismic activity, leading to its designation as a critical lifeline structure in the Oregon Department of Transportation's seismic retrofit plans.

Cultural impact

The bridge is an iconic symbol of Portland's industrial heritage and is frequently depicted in photography, film, and art. It serves as a central backdrop for major city events, including the Portland Rose Festival and waterfront fireworks displays. The surrounding area, including the Eastbank Esplanade and the Oregon Museum of Science and Industry, has developed into a major recreational and cultural district. It has been featured in episodes of the television series *Leverage* and in the graphic novel series *Portlandia*. Its distinctive silhouette is a protected view corridor under the Portland Bureau of Planning and Sustainability guidelines. Category:Bridges in Portland, Oregon Category:Railway bridges in Oregon Category:Vertical-lift bridges in the United States Category:National Register of Historic Places in Portland, Oregon Category:Buildings and structures completed in 1912