McGaw Bridge Road over Baboosic Brook was a 23-foot span, historic jack arch bridge constructed in 1915. The bridge had remained largely unaltered, complete with original wood forms used to construct the concrete arches.
The bridge beams and deck were severely deteriorated with holes entirely through the concrete deck and traffic was limited to one lane. The bridge was also a restriction to flow in the brook and was on the NHDOT Municipal Redlist. The new replacement structure is a 42-foot span steel beam superstructure founded on cast-in-place concrete abutments with spread footings. The new bridge width is 28 feet curb-to-curb and features a 5-foot wide pedestrian sidewalk on its upstream side.
The new bridge also has an exposed concrete deck reinforced with stainless steel rebar. A water line is supported by the bridge steel and a sewer line is supported on an independent structure. The bridge replacement project was funded by the Town of Merrimack and the NHDOT Municipally-Managed Bridge Aid Program and was completed in the late fall of 2016.