The original U.S. 52 bridge that crossed the Mississippi River from Savanna, Ill., to Sabula, Iowa, was constructed in 1932 and served as a crucial connector for shipping goods across state lines. A 2010 bridge inspection identified 100 structural deficiencies that required $8 million in repairs and a projected nine-month full closure. This occurred only two years after a $2.9 million repair contract requiring a 28-day closure was implemented to extend the bridge’s life.
“At 20 ft wide between the barriers, the existing roadway did not meet current geometric standards and could not accommodate bicycles or disabled vehicles,” Robert Magliola, P.E., S.E., vice president and manager of Parsons’ Chicago Bridge Division, told Roads & Bridges. “Additionally, the existing bridge had an open-grid deck causing a safety problem for motorcycles and contributed to the accelerated deterioration of the exposed steel framing.”
Recognizing the need for a replacement bridge, the Illinois and Iowa DOTs agreed to fast-track the building of a new structure. The agencies set a goal to finish the job before more funding needed to be devoted to further repairs on the existing structure. By October 2011, the departments contracted with Parsons for planning, environmental clearance and design for the new bridge, which would become the Dale Gardner Veterans Memorial Bridge.
The Dale Gardner bridge was built approximately 100 ft south of the existing bridge. Configuring the vertical profile of the U.S. 52 bridge over the Mississippi River to provide navigational clearance was a particular challenge for the team. To accommodate clearance and to reduce the grade to make the bridge safer for large trucks, the team coordinated with the U.S. Coast Guard and shifted the navigational channel 150 ft to the west.
The team had to coordinate with the U.S. Fish and Wildlife Service to obtain approval of project impacts. Environmental concerns included limiting impacts to the Upper Mississippi Wildlife and Fish Refuge and wetlands; maintaining a zero-rise in the floodway; and removing the existing bridge, which was included on the National Register of Historic Places.
The design team selected the steel tied-arch option for the navigation span and steel girders for the approach viaducts. These structure types and the preferred offset alignment best satisfied the evaluation criteria, including environmental impact, maintenance of traffic, structure maintenance and aesthetics.
The contract for construction was let in 2015 to Kraemer North America. A multi-phase maintenance of traffic plan was developed with staging that kept U.S. 52 open to traffic throughout construction. The 40-ft roadway width on the new bridge eliminates restrictions for semi-trailer traffic across the bridge to one direction at a time.
Location: Savanna, Ill., and Sabula, Iowa
Owner: Illinois Department of Transportation
Contractor: Kraemer North America
Cost: $80.6 million (construction)
Length: 2,454 ft
Completion Date: Nov. 11, 2017