The historic Third Avenue Bridge in Minneapolis, Minnesota, is a reinforced concrete Melan arch bridge with seven spans and eight piers that anchor it to the limestone riverbed of the Mississippi River. Its distinctive shape—a shallow, reverse S-curve—was devised to avoid fractures in the bedrock. The bridge was considered a significant engineering feat when it was constructed during the height of World War I.
Ames Construction performed the challenging restoration of the bridge utilizing a CMGC project delivery method. In addition to repairing deteriorating elements, the project improved safety and accessibility and enhanced the bridge’s historical and visual features.
Construction access to the bridge via a water route was severely limited because of the bridge’s proximity to a hydroelectric dam, a horseshoe dam, and a permanently closed lock. Three of the seven spans were effectively inaccessible by water, and the remaining four were accessible by only small barges. To remove and replace the structural concrete and perform surface repairs, access was achieved from the top down. An elaborate hanging scaffold system was installed below the bridge with different levels to accommodate the work. Large sandbags diverted river flow around the horseshoe dam structure to allow rehabilitation of two piers, and cofferdams were installed and dewatered on four piers.
The bridge reopened in October 2023 with a celebration that included a ribbon-cutting, tours, food, and music.
Learn more:
Minnesota Department of Transportation
