PROJECT: Transportation

Allen Bridge

Salmon, Idaho


Lemhi County & Local Highway Technical Assistance Council (LHTAC)

Construction Value:



Allen Bridge was a federally funded bridge project sponsored by Lemhi County and administered by LHTAC. T-O Engineers performed the CE&I for the project. The project consisted of a 70 foot clear span bridge over the Lemhi River. The bridge was constructed of concrete bulb tee girders, supported by steel piles and concrete pile caps. The roadway approaches were also reconstructed as part of the project and the new bridge overlaid with five inches of pavement.

The bridge was closed during construction and a 12 mile detour was implemented to route traffic around the project. The most difficult elements of the project were its remoteness as well as addressing the public concerns associated with the length of the detour, emergency services access, and economic impacts to the community. The project was completed 46 days ahead of the original project schedule and was delivered on budget. The County and public were very satisfied with the project.