Dorchester Avenue over the MBTA Red Line, Cabot Yard Spur, and Old Colony Main Line consists of replacement of the existing three-span highway bridge with a new, two-span precast reinforced concrete deck panel slab and cast in place closure pours, sidewalks and barriers, on weathering steel multi-girder superstructure. A new pile supported abutment will be constructed behind the existing reinforced concrete rigid frame south abutment of the south span, using drilled and driven pipe piles and a reinforced cast-in-place concrete cap. A new pile supported pier will be constructed between the existing granite block south abutment of the north span and the reinforced concrete rigid frame north abutment of the middle span, using drilled and driven pipe piles and a reinforced cast-in-place concrete cap. The existing granite block north abutment of the north span will be reused, and a new precast reinforced concrete cap will be placed on top to support the new superstructure. To relocate the existing utilities from the existing Dorchester Avenue bridge, a prefabricated temporary utility bridge will be erected on a reinforced concrete foundation supported by drilled micropiles. Work also includes the rehabilitation of an existing 300’ long bin wall by installing soil nails and a reinforced concrete face.
