I-74 Bridge Project Kicks off in Iowa

FRIDAY, JUNE 30, 2017

Representatives of the Iowa and Illinois Departments of Transportation held a groundbreaking ceremony June 26 for the new I-74 River Bridge over the Mississippi, a $400 million project nearly two decades in the making.

The bridge—actually twin basket-handle arch spans—is part of the larger I-74 corridor project that’s been in the works since 2000 and, according to the Quad-City Times, is estimated to cost nearly $1.2 billion overall. The first hints at a major revamp of I-74 came in 1998 with a study of the Mississippi crossing.

The project is being led by the Iowa DOT, and is the largest project the agency has ever undertaken. According to financial plans, Iowa and Illinois will share most of the cost of Phase 2 of the I-74 project, which includes the bridge. Illinois is expected to shoulder more than $400 million for this phase of the project, which also includes approach spans and ramps, while Iowa will pay just under $300 million, and the cities of Bettendorf, Iowa, and Moline, Illinois, will pay about $10 million and about $5 million each.

Iowa Gov. Kim Reynolds and Illinois Gov. Bruce Rauner attended the groundbreaking event, along with local officials and representatives of the two state transportation departments.

Arch Design

The arch superstructure was designed by Modjeski and Masters, working with prime contractor Alfred Benesch. The main spans will be 800 feet long, according to Modjeski and Masters, and each arch will support 27 hangers. The arch structure will be made of a combination of steel and concrete, and the deck will be cast-in-place concrete.

Iowa DOT

The center spans of the twin bridges will be basket-handle arches, designed by Modjeski and Masters.

The bridges themselves will reportedly be about 3,400 feet long, and the I-74 corridor on the whole will cover about 6 miles, of roadway, from Davenport, Iowa, to Moline.

Construction will be carried out by Lunda Construction Co., of Wisconsin, on a $322 million contract; a viaduct and off-ramp on the Bettendorf, Iowa, side of the span will be built by Civil Constructors, of Freeport, Illinois.

Growing Traffic

The current bridges carrying I-74 across the Mississippi, opened in 1935 and 1960, are twin suspension bridges, designed by Ralph Modjeski. The decades-old spans aren’t built to handle the approximately 74,000 vehicles crossing the river between Bettendorf and Moline daily; according to Iowa DOT, traffic is expected to rise to nearly 100,000 crossings daily by 2035.

The greater width will also ease congestion related to traffic accidents; in a study leading up to the bridge project, Iowa DOT noted that in 2007, there were 77 incidents on the I-74 twin bridges. The narrow bridges meant “severe bottlenecks” on the road.

Construction is anticipated to run for about three-and-a-half years, with work on the new bridge and the approach spans on the Bettendorf side starting first. Iowa DOT expects the demolition of the old spans to take place in 2021.


Tagged categories: Bridges; Construction; Engineers; Infrastructure; North America; Program/Project Management; Roads/Highways

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