The Marquam Bridge is a double deck cantilever bridge that carries Interstate 5 traffic across the Willamette River south of downtown Portland, Oregon. It is the busiest bridge in Oregon, carrying 135,900 vehicles a day as of 2008. The upper deck carries northbound traffic; the lower deck carries southbound traffic.
The bridge was designed and built by the Oregon Department of Transportation at a cost of $14 million. The lower southbound deck was opened on October 4, 1966, and the upper northbound deck on October 18, 1966. The main span of the bridge is Template:Convert long and the two side spans are Template:Convert each. The vertical clearance of the lower deck is Template:Convert and the upper deck is Template:Convert above the lower. The bridge is named after Philip Marquam, a state legislator and Multnomah County judge, who owned much of Marquam Hill where Oregon Health & Science University and the Veterans Affairs Medical Center now stand. At the eastern end of the bridge, on the lower deck, is a ramp stub which was intended to connect to the cancelled Mount Hood Freeway. As it has great importance, the Marquam was the first Portland bridge to undergo a seismic retrofit in 1995.
It was built with economy in mind and the public reacted unfavorably to the structure's aesthetics, including a formal protest from the Portland Arts Commission. (In particular, it obliterated the view of downtown from the Union Avenue Viaduct.) This led to public input in the design of the Fremont Bridge. During Mayor Vera Katz's State of the City address in 2001, she said, "It’s like having the Berlin Wall dividing east and west, with all the subtle charm of the Daytona 500 smack dab in the middle of our city."
In recent years, there has been much talk about replacing this bridge. Originally, the bridge was designed with three lanes in each direction with shoulders on each deck. Today, it carries four narrow lanes and no shoulders on each deck. Options historically considered have been to reroute I-5 over the existing I-405 alignment, connecting I-84 to I-5 at the Fremont Bridge interchange, following the US-30 alignment, and removing the Marquam permanently. Another option would build a tunnel under the Willamette River approximately following the existing I-5 alignment, and removing the Marquam Bridge permanently. No proposed replacements as of 2008 have kept the existing bridge, or have made it out of committee.Template:Fact
- Historical photo of construction
- ODOT: Trans Dev - Transportation Data Traffic Counting Program
- Photo gallery of the completed Marquam Bridge