Hennepin County Franklin Avenue Bridge Restoration
Award of Merit
Owner: Hennepin County Transportation Dept.
Lead Design Firm: HNTB Corp.
General Contractor: Kraemer North America LLC
The Franklin Avenue Bridge is a 1,000-ft-long, five-span arch structure that has been a vital link over the Mississippi River since 1923. Placed on the National Register of Historic Places in 1978, the bridge—also known as the Cappelen Memorial Bridge—last underwent a major rehabilitation in 1970 and was overdue for an update. Some of the historic elements removed in the 1970 update were replaced in this project.
The team used accelerated bridge construction techniques—a first for the state of Minnesota—and precast elements to remove and replace 47 spandrel/pier cap beams and 72,000 sq ft of bridge deck in a compressed 116-day schedule. Work included repairs to the bridge’s substructure surface and two cofferdams. Kraemer worked with the Hennepin County Transportation Dept. to develop a removal-and-erection sequence that minimized movement and unwanted stresses within the bridge’s arch ribs. The contractor also collaborated with the owner, designer and utility owner to mitigate a fiber optic relocation challenge when geotechnical issues prevented boring under the Mississippi River, threatening to delay the project.
The project team staged three 440-ton and two 350-ton cranes at both ends of the bridge, working from the river barges to support crews during removal and replacement. Contractors cast the bridge project’s 360 unique deck panels at an onsite facility and then barged in the panels before placing them with cranes.
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