THE MARQUAM BRIDGE UNDER CONSTRUCTION IN 1964.
THE BRIDGE TODAY VIEWED from the southwest, atop
The Marquam Bridge is a double-deck, steel-truss 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 Marquam was the first Portland bridge to
undergo a seismic retrofit in 1995.