The Iowa-Illinois Memorial Bridge was once the crown jewel of the I-74 Corridor, the gateway to the Quad Cities region. The bridge spans the Mississippi River and is a vital link to the seven-mile expanse comprised of bridges, interstates and communities. But times have changed, and recent economic successes in the Quad Cities region have led to ever-increasing traffic demands, outgrowing the corridor’s existing infrastructure. Today, the Iowa-Illinois Bridge is a major pinch-point for delays between the bi-state communities linked by the I-74 Corridor – Moline, Illinois and Davenport, Iowa.
The Iowa and Illinois Departments of Transportation decided on an ambitious corridor improvement plan. The plan’s ultimate goal: alleviate congestion and sustain the regional economies. There were several objectives, including an increase in roadway capacities and designs for new roadways and interchanges. Most notably, the strategy called for the design and engineering of a new I-74 Mississippi River Bridge to replace the existing Iowa-Illinois Memorial Bridge.
Modjeski and Masters, as part of the Alfred Benesch design team, was tasked with providing final design services for the new I-74 Mississippi River Bridge. Located on a new alignment to the east, this will be no ordinary crossing. The new I-74 Mississippi River Bridge will feature dual basket-handle arch bridges with main channel spans of 800 feet. The bridges support six design lanes in each direction, including an outboard bicycle and pedestrian path.
First, our engineers will employ analysis models and loading calculations to vet the conceptual design. Any changes found to be necessary, or improvements to the design, will not significantly impact the concept’s sleek and contemporary aesthetics. Continuous coordination with the design team is equally essential, ensuring seamless integration of the design with the overall corridor plan. In the end, the bridge design must meet traffic demands, be safe, and match the service life of its predecessor. Modjeski and Masters will complete final main arch bridge designs and engineering in 2012.
The design of the new I-74 Mississippi River Bridge marks the return of Modjeski and Masters to familiar territory. It also marks the renewal of longstanding relationships with our clients and key members of the design team. In 1933, our firm designed the original Iowa-Illinois Memorial Bridge. We later twinned the structure in 1959. We also recently worked with Alfed Benesch on the I-70 Mississippi River Bridge design for which Modjeski and Masters was the prime consultant. These are relationships built on, and reinforced with, trust. Our experience spanning the Mississippi River is also key to serving the regional clients. In total, five of our 15 Mississippi River bridge designs are located in the Quad Cities region. This latest addition will enable the Iowa and Illinois Departments of Transportation to sustain the growth of their communities well into the future.
Services for this project provided as a subsconsultant to Alfred Benesch & Company.
“We take special satisfaction when successful assignments mature into long-term relationships with our clients. Such is the case with the new I-74 Quad Cities Bridge. The new iconic structure will represent our fifth Mississippi River crossing in the area.”- Dr. John M. Kulicki, PE, SE