Construction Cost: $1.6M
Under an On-call Bridge contract with NHDOT, GM2 was assigned Preliminary and Final Design services for this bridge replacement project. The previously existing timber bridge carried Mill Street traffic over the Ammonoosuc Rail Trail to Wilson Avenue in the Town of Haverhill. Constructed in 1940, the 147FT long bridge consisted of a timber deck, curbs, railings, beams, pier bents, and bracing. The bridge section provided a 16.6FT curb-to-curb width and an overall width of 18.8FT. The bridge was posted for a 6-ton weight limit. The new bridge is a fill over structure consisting of a precast concrete arch supported on cast-in-place abutment walls.
The abutment walls are approximately 17FT tall and the precast arch has a 30FT span with a 13.5FT rise. The proposed geometry of the structure was predicated on standard railroad clearances to accommodate any possible future reactivation of the rail line. The roadway width over the bridge is 24FT. The removal of the structure required mitigation to satisfy the requirements of the historic regulatory agencies.
GM2 completed the Part A & B design and NEPA documentation for this project. Environmental tasks included reviewing the site for wetlands and invasive species, surveying the bridge for bats and potential bat habitat, and completing the NEPA Categorical Exclusion/Section 4(f) Evaluation document. GM2 also attended public informational and public officials meetings and coordinated with historic and archaeological resource consultants.