Marquam Bridge

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Coordinates: 45°30′28″N 122°40′08″W / 45.5079°N 122.6690°W / 45.5079; -122.6690
Source: Wikipedia, the free encyclopedia.

Marquam Bridge
Clearance above
<35 feet (11 m) northbound
Clearance below130 feet (40 m)
History
OpenedOctober 1966
Location
Map

The Marquam Bridge /ˈmɑːrkəm/ is a double-deck, steel-truss cantilever bridge[1] that carries Interstate 5 traffic across the Willamette River from south of downtown Portland, Oregon, on the west side to the industrial area of inner Southeast on the east. It is the busiest bridge in Oregon, carrying 140,500 vehicles a day as of 2016.[2] The upper deck carries northbound traffic; the lower deck carries southbound traffic. The Marquam also has on and off ramps for Interstate 405 on the south end of the bridge, while the terminus on the east bank of the river is near the interchange with Interstate 84.

History

Planning for the span started in 1956 as the last link in Oregon for the new

Veterans Affairs Medical Center now stand.[3] Construction on the bridge's support piers began in January 1962.[5] Construction on the bridge finished on February 28, 1966.[4] The lower southbound deck was opened on October 4, 1966, and the upper northbound deck on October 18, 1966.[4]

The Marquam Bridge over the Willamette River, viewed from the southwest, atop Marquam Hill

The bridge was designed and built by the Oregon Department of Transportation at a cost of $14 million, equivalent to $131 million today. Funds for the project came from the Federal Highway Transportation Act.[4] The bridge was redecked in 1983.[4] In 1990, the approach lanes from both the east and west were widened to allow four lanes of traffic and an off-ramp to Water Avenue was built.[4] Due to its importance, the Marquam was the first Portland bridge to undergo a seismic retrofit in 1995, which included installation of Italian made bearings add to the piers.[6]

Design

The main span of the bridge is 440 ft (130 m) long and the two side spans are 301 ft (92 m) each for a total length of 1,043 ft (318 m).

ramp stub which was intended to connect to the later abandoned Mount Hood Freeway project.[7] The bridge was designed with four lanes in each direction.[4] It was the first double-deck freeway bridge in the state.[4] Part of the design process also utilized computers for various calculations.[8]

The Marquam Bridge was built with economy in mind and the public at large reacted unfavorably to the structure's bland aesthetics, which included a formal protest from the Portland Arts Commission.

Vera Katz Eastbank Esplanade
.

Future

A view of the bridge at dusk

Options to replace the bridge historically considered have been to reroute

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 remove the Marquam Bridge permanently.[citation needed
]

Proposals have been made to replace the Eastbank Freeway portion of I-5 with a tunnel, connecting with the existing alignment at the Marquam Bridge and the Rose Quarter. This would free up space along the Willamette River for development.[11]

See also

References

  1. ^ Bottenberg, R. (2007). Bridges of Portland. Arcadia Publishing. Retrieved June 20, 2012.
  2. ^ "Historical Traffic Data" (PDF). 2016 Traffic Volumes on State Highways. Oregon Department of Transportation. Retrieved July 3, 2018.
  3. ^ a b c d Hallman Jr., Tom (October 24, 2015). "Marquam Bridge lacks beauty and basic amenities but excels in function: 'Spanning Oregon'". Oregonlive / The Oregonian. Retrieved July 10, 2022.
  4. ^ a b c d e f g h i Dodds, Linda S. "Marquam Bridge" (PDF). Historic American Engineering Record (Willamette River Bridges Recording Project). Retrieved July 10, 2022.
  5. ^ Wood, Sharon M. (May 14, 1984). "Marquam Bridge signals new life in the fast lane". The Oregonian. p. B5.
  6. ^ "Seismic Protection Devices Study – Marquam Bridge" (PDF). Oregon Department of Transportation. April 2000. Retrieved July 10, 2022.
  7. ^ Federman, Stan (January 19, 1981). "Marquam interchange funding still far down road". The Oregonian. p. B1.
  8. ^ Boddie, Ken (October 23, 2017). "Where We Live: How the Marquam Bridge got its name". KOIN.com. Retrieved July 10, 2022.
  9. ISBN 0-87595-211-9
    .
  10. ^ Hamilton, Don (January 18, 2002). "East-side story" (PDF). Portland Tribune. p. 2. Retrieved May 23, 2015.
  11. ^ Maus, Jonathan (April 6, 2012). "Adams releases I-5 tunnel concept plan for public comment". Bike Portland. Retrieved August 16, 2015.

External links

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