Services for the rehabilitation of a historic truss bridge on Saunders Hill Road over the Baker River consisted of evaluating existing conditions and designing emergency repairs. Initial repairs were limited to floor framing in order to eliminate structural deficiencies and reopen the bridge as soon as possible. Improvements included replacement of 56 steel stringers, 7 floor beams, 7 fixed stringer bearing pads, 7 expansion stringer bearing pads, and minor repairs to the timber deck.
Phase II scope included design for complete rehabilitation of the truss bridge and approach roadway to current NHDOT and AASHTO standards, while retaining the historic features of the bridge. A new timber deck, timber bridge and transition rails, and approach beam guardrails were provided. Significant repairs were made to the concrete abutments and wingwalls. All steel components of the bridge (trusses, floor beams, stringers, and bearings) were stripped to bare metal and a new 3-coat polyurethane paint system was applied in accordance with NHDES, NHDOT, and OSHA guidelines and specifications.
Services included preparation of Project Review and Compliance form, coordination of photo documentation for the New Hampshire Division of Historical Resources, preparation of contract documents, and preparation of an Engineers’ Estimate of probable costs. Provided bid and construction phase administration and resident engineering services.
Rehabilitation of the bridge increased the load carrying capacity from six tons to exceed the legal load requirements. The bridge has been removed from the NHDOT Redlist and posting of the bridge for weight restriction is no longer required.