Marquam Bridge
- Mile: 13.5
- Opened: (Lower deck) October 4, 1966 (Upper deck) October 18, 1966
- Type: double deck steel through (Double-deck steel through cantilever truss)
- Engineers/Designers: ODOT
- Owner: State of Oregon
- Total Length: 1,043.’ 8”
- Main Span Length: 440’
Happy 45th Birthday in 2011
Designed by the Oregon State Highway Department Bridge Section, the Marquam is a through-truss, fixed bridge with a suspended cantilever center span. It opened in 1966 as an element of Portland’s Interstate transportation system and was the city’s first double-deck highway bridge built exclusively for vehicular traffic.
It was named for Philip Marquam, a 19th century transportation advocate, but its strictly functional appearance engendered, ironically, an outcry for public participation in future bridge designs—and periodic discussions of the merits of its removal.
