Old Cedar Truss Bridge Rehabilitation in Bloomington, MN

Built in 1920, the Old Cedar Truss Bridge is a five-span, 865-foot Pratt-Camelback Truss bridge crossing over Long Meadow Lake in Bloomington, Minnesota. The bridge, which was closed to vehicular traffic in 1993 and pedestrian traffic in 2002 due to significant deterioration, had issues with steel stringers, floor beams, and bottom lateral gusset plates. Additionally, the trusses were supported by concrete piers that were in poor condition and tilting. The historic structure was listed on the National Register of Historic Places in 2013, marking its importance in both local history and transportation infrastructure.

SRF Consulting collaborated with the City of Bloomington, the Federal Highway Administration (FHWA), the MnDOT Cultural Resources Unit, and the Minnesota State Historical Preservation Office to rehabilitate the bridge. The project aimed to meet the Secretary of the Interior’s standards for rehabilitating historic structures while adhering to modern pedestrian loading standards. The bridge’s useful life was extended by 50 years, significantly reducing future maintenance costs. SRF also explored options to upgrade the bridge railing to meet current height and safety standards while preserving its historic character.

To tackle the challenging rehabilitation, SRF developed a detailed construction sequence for removing and replacing the deteriorated floor beams, stringers, and tilted piers. A complex shoring tower system was designed to lift the trusses, allowing the lower gusset plates, floor beams, and stringers to be replaced effectively. This approach also enabled the reconstruction of the piers using new piling and concrete. Additionally, 3D drawings were created to assist in evaluating potential construction conflicts, ensuring the rehabilitation process was smooth and efficient.

Resource links:
Old Cedar Truss Bridge
Federal Highway Administration (FHWA)
MnDOT Cultural Resources Unit
Minnesota State Historical Preservation Office 

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