Fremont Road Bridge Replacement

Chester, New Hampshire

Planning, design, and construction services for the replacement of the Fremont Road Bridge over Towle Brook. DuBois & King engineers conducted a study and provided recommendations regarding alternatives to replace the bridge. A 14-ft clear span, precast concrete rigid frame was designated as the most cost-effective bridge type for this location. The bridge foundation consists of cast-in-place concrete strip footings bearing on ledge. In addition to design services, DuBois & King provided permit application assistance and bid and construction phase administrative services.

The pre-existing bridge had insufficient hydraulic capacity and had a history of scour damage. However, a hydraulic analysis, using a HEC-RAS model to evaluate the bridge hydraulics, showed that increasing the hydraulic opening would increase the potential for downstream flooding of several homes. DuBois & King consequently recommended a structure with an opening equivalent to the existing bridge. To prevent scour, it was recommended that the new footings be placed well below the stream channel.