Whittier Covered Bridge Design-Build


Ossipee, New Hampshire

The design-build team of DuBois & King and 3G Construction provided design and construction services for the rehabilitation the 132 ft long, single span Whittier Covered Bridge. This one lane bridge, constructed in the 1870’s, utilizes a Paddleford Truss, a unique framing style only used in a few northern New England covered bridges. The bridge superstructure was moved off the abutments and relocated on land on the south approach road. Project includes repair/replacement of deteriorated/broken timber members, increasing live load capacity to 6 tons, increasing snow load capacity of roof members to comply with current code requirements, and increasing wind resistance capabilities of all lateral bracing members.

A three-dimensional computer model was made of the superstructure for analysis of all loading conditions and to identify members needing to be strengthened. Completed field observations and condition assessment report with recommendations and cost estimates for extensive repairs. Repairs include strengthening roof purlins for snow loads; modifying lateral brace member connections for increase wind load resistance; replacing deteriorated (rotted) truss chord and truss diagonal members; and repairing/replacing stringers, floorbeams, and lower lateral bracing. Prepared preliminary repair/rehabilitation drawings and submitted to the NH Division of Historic Resources and the NH Department of Transportation for review and concurrence. The project received a National Historic Covered Bridge Preservation Grant. Services include:

Assessment of existing conditions
Preparation of investigations/recommendations report
Preparation of contract documents

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  • Whittier Covered Bridge Whittier Covered Bridge
  • Whittier Covered Bridge Whittier Covered Bridge

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