Marquam Bridge
Categories: Bridges completed in 1966 | Bridges in Oregon | Transportation in Portland, Oregon | Cantilever bridges
| Image:MarquamBridge.jpg | |
|---|---|
| Official name | Marquam Bridge |
| Carries | Interstate 5 |
| Crosses | Willamette River |
| Locale | Portland, Oregon |
| Maintained by | Oregon DOT |
| ID number | 08328 |
| Design | Cantilever truss |
| Longest span | 440 feet (134.1 m) |
| Total length | 1043 feet (318.2 m) |
| Width | 57 feet |
| Vertical clearance | <35 feet northbound |
| Clearance below | 130 feet |
| Opening date | October 1966 |
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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 140,100 vehicles a day as of 2002. 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. 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. This led to public input in the design of the Fremont Bridge. The lower southbound deck was opened on October 4, 1966 and the upper northbound deck on October 18, 1966. As it has great importance, the Marquam was the first Portland bridge to undergo a seismic retrofit in 1995.
The main span of the bridge is 440 ft. long and the two side spans are 301 ft. each. The vertical clearance of the lower deck is 130 ft. and the upper deck is 15 ft. 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 ghost ramp which was intended to connect to the cancelled Mt. Hood Freeway.
External links
- ODOT: Marquam Bridge
- Portlandbridges.com: Marquam Bridge
- Historical photo of construction
- PDF file containing seismic data on the Marquam Bridge from ODOT
Books
Wood, Sharon. The Portland Bridge Book. Portland: Oregon Historical Society, 2001. ISBN 0-87595-211-9.
| Bridges in the metropolitan area of Portland, Oregon See also: Transportation in Portland |
| Across the Willamette River (north to south)
St. Johns Bridge - Burlington Northern Railroad Bridge 5.1 - Fremont Bridge - Broadway Bridge |
| Across the Columbia River (west to east)
Burlington Northern Railroad Bridge 9.6 - Interstate Bridge - Glenn L. Jackson Memorial Bridge |