CHELMSFORD- BRIDGE SUPERSTRUCTURE REPLACEMENT, C-08-048 (2LP), HUNT ROAD OVER I-495
The existing structure, five continuous spans, was constructed in 1961. The superstructure consists of 7 rolled beams with a reinforced concrete deck and bituminous concrete wearing surface. The substructure consists of pile supported reinforced concrete stub type abutments, pile supported concrete gravity type wingwalls, and reinforced concrete column bent type piers supported on spread footings. From the SI&A, the overall structure length is approximately 296.5 feet, the out-to-out deck width is 49.5 feet. As measured, the curb-to-curb roadway width is 40 feet, the east sidewalk width is 5 feet, and the west sidewalk is 2.6 feet. The bridge is structurally deficient but not functionally obsolete. The new superstructure shall be designed using the 2012 AASHTO LRFD Bridge Design Specifications, 6th Edition with current interim revisions for HL-93 loading and, where appropriate, the new MassDOT 2013 LRFD Bridge Manual. Upon verification of the adequacy of the existing substructure, the consultant shall investigate either superstructure replacement with new weathering steel stringers composite with a reinforced concrete deck or deck replacement and clean and paint the existing beams. Substructure elements shall be repaired as required, and approximately 100 feet of the approach roadways shall be reconstructed as necessary. The proposed work includes, a full replacement of the existing steel stringers with new weathering steel stringers, deck replacement, replacement of all existing bolsters and bearings, modifications of the existing abutment backwalls, bridge seats, and pier caps as required. Bridge railing shall be CP-PL2 with Protective Screen Type II. A preliminary rating shall be included in the design calculations as a quality assurance check.