Old Cedar Bridge over Long Meadow Lake Rehabilitation

Bloomington, Minnesota

Built in 1920, the Old Cedar Bridge is a five-span, 865-foot-long Pratt-Camelback Truss that crosses over Long Meadow Lake in Bloomington. The bridge was closed to vehicle traffic in 1993 and to pedestrian traffic in 2002 due to significant deterioration of the steel stringers, floor beams, and bottom lateral gusset plates. The trusses are supported on concrete piers that are in poor condition above the mud line and are tilting. The bridge was listed on the National Register of Historic Places in 2013. SRF was retained by the City to develop a rehabilitation plan. Key project goals were to provide a structure that meets the Secretary of Interior’s standards for the rehabilitation of historic structures, meets current pedestrian loading standards, and minimizes future maintenance costs for the City.

Additional goals for this challenging rehabilitation project include:

  • Using rehabilitation strategies to extend the bridge’s useful life by 50 years while minimizing future maintenance costs.
  • Meeting the Secretary of Interior’s standards for the Treatment of Historic Properties guidelines for the rehabilitation of historic structures.
  • Evaluating options to upgrade the bridge railing to meet current height and safety standards compatible with the historic bridge.
  • Meeting current pedestrian loading standards within the context of SOI guidelines for historic structures.
  • Keeping all stakeholders informed and engaging stakeholders to provide constructive input at key milestones.
  • Building consensus among FHWA, MnDOT Cultural Resource Unit, and State Historic Preservation Office on the rehabilitation strategies to satisfy Section 106 requirements.

The project scope includes the following activities:

  • Truss Rehabilitation: Remove deck stringers, remove and replace floor beams and lower lateral gusset plates, and repair or replace gusset plates as necessary. Remove and replace lower cord for span five and repaint the entire truss.
  • Substructure Reconstruction: Reconstruct titled piers below existing truss.
  • Deck Replacement: Evaluate several lightweight concrete deck options to minimize loads to truss and gusset plates.
  • Railings: Provide new railing (that is compatible with the structure’s historic character) to meet current safety standards.
  • Constructability Coordination/Reviews: Conduct independent peer analysis and constructability reviews (provided by subconsultant Modjeski and Masters).

The first step in the rehabilitation of the Old Cedar Avenue Bridge spanning Long Meadow Lake is surveying the condition of the 94-year-old structure.

Watch the progress.

Client:
City of Bloomington

Awards:
2016 City Engineers Association of Minnesota: Municipal Project of the Year

2017 American Council of Engineering Companies – Minnesota: Engineering Excellence Grand Award