I-74 Bridge

The Interstate 74 Bridge, officially known as the Iowa-Illinois Memorial Bridge, and often called The Twin Bridges, or the I-74 Bridge, is a pair of suspension bridges that carry Interstate 74 across the Mississippi River and connect Bettendorf, Iowa and Moline, Illinois. It is located near the geographic center of the Quad Cities.

Interstate 74 Bridge
The Interstate 74 bridge as seen from the Iowa side of the Mississippi River
Coordinates41°31′12″N 90°30′48″W
Carries4 lanes of I-74 / US 6
CrossesMississippi River
LocaleBettendorf, Iowa and Moline, Illinois
Official nameIowa-Illinois Memorial Bridge
Characteristics
DesignTwin suspension bridges
Total length3,372 feet (1,028 m)[1]
Width27 feet (8 m)[1]
Longest span227 metres (745 ft)
History
OpenedNovember 1935 (northbound)
December 1959 (southbound)
Statistics
Daily traffic80,000[2]

The bridge was designed by engineer Ralph Modjeski. The first span opened in 1935 as a toll bridge. In 1961, an identical twin span, built from the same blueprint, opened to facilitate increased traffic demands. Tolls were discontinued in 1970. The twin spans were merged with Interstate 74 in 1975.

Built for a daily crossing of 48,000 vehicles, the daily average is 80,000,[2] making it by far the most traveled bridge in the Quad Cities. Both the Interstate 80 and 280 bridges are up to Interstate standards, while the Interstate 74 Bridge is functionally obsolete and was not built to Interstate standards, as it has two narrow lanes, no shoulder, and a 50 mile-per-hour (80 km/h) speed limit.

I-74 bridge replacement
Construction of the new span in 2019.
Arist rendering of the new bridge.

The I-74 Corridor Study was completed to study replacing the bridge with a larger one with 4 lanes in each direction. The study claimed that the I-74 Bridge project would spur economic growth, create construction jobs, reduce traffic backups, and improve air quality.

Funding for the construction of the new bridge has been earmarked for $22 million in 2017 and $50 million in 2018. Former Illinois Governor Pat Quinn said the state is committed to bridge improvements to help traffic flow and "boost economic growth in the region".

As of 2012, the Illinois Department of Transportation also budgeted more than $34 million for engineering, design and land acquisition for the new bridge. The conceptual design of the arch bridge was completed by CH2M Hill and Boston-based bridge designer Miguel Rosales from Rosales + Partners. Final design was completed by Modjeski and Masters in association with Alfred Benesch & Company. The portion of the bridge spanning the Mississippi River is estimated at more than $700 million, while the project as a whole, including all approach routes and connectors, is estimated at $1.2 billion.

While on a tour at the base of the bridge in Bettendorf in May 2012, U.S. Transportation Secretary Ray LaHood said that, in comparison with other bridges that he has seen in other states, the current I-74 Bridge is one of the worst he's seen.[3][4]

The new bridge will be just upstream of the existing bridge and will be a basket-handle, true-arch twin bridge with four lanes in each direction and a pedestrian/bicycle path. A ground-breaking ceremony for the new bridge was held on June 26, 2017. The westbound bridge is expected to be completed in late 2019 and the eastbound span is expected to be completed in late 2020.[5] The existing I-74 bridge is anticipated to be removed in 2021. Winter weather conditions and the resulting high water over an extended period of time, however, have created delays and the opening of the first span has been pushed to the first half of 2020.[6]

See also

References
  1. "Bridges: Iowa, Illinois order safety inspections". Quad City Times. Retrieved December 19, 2007.
  2. http://www.helmgroup.com/documents/HelmGroup-Fall2011_CS5.pdf%5B%5D
  3. Funding Back For I-74 Bridge - KWQC-TV6 News and Weather For The Quad Cities Archived May 17, 2012, at the Wayback Machine
  4. "Archived copy". Archived from the original on June 25, 2012. Retrieved May 27, 2012.CS1 maint: archived copy as title (link)
  5. Staff report (June 26, 2017). "I-74 bridge replacement project applauded by Q-C, state leaders". The Dispatch / The Rock Island Argus. East Moline. Retrieved October 22, 2019.
  6. Katrina Lamansky (June 7, 2019). "Project leaders say new I-74 Bridge is delayed". Moline: WQAD-TV. Retrieved October 22, 2019.
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