The Cranston Street Viaduct is a three-span bridge approximately 500 feet long, carrying four lanes of traffic on Route 10 over Amtrak. The scope of the work included: demolition of the existing bridge in two phases (in order to maintain traffic flow), installation of 22 three-foot diameter drilled shafts at the abutments and four nine-foot diameter drilled shafts at the piers, concrete pier and abutment construction, setting and post tensioning precast concrete bulb-T girders, and placing the concrete decks with a self-propelled finishing machine.
An extensive retaining wall system was also installed along the Amtrak railroad line and other Amtrak facilities. A major portion of this construction included foundation piles which were driven deep adjacent to the sensitive active railroad. Special provisions had to be made for all work performed in proximity to Amtrak’s facilities such as: careful survying and monitoring of the railway, specialized equipment to minimize ground disturbance, Amtrak training for all personnel, and installation of extensive shielding and protective barriers.
Some ancillary work that was also performed included: complete replacement of a secondary bridge, temporary shoring of several neighboring bridges, paving, overhead sign installation, utility work, permanent Amtrak protective barrier installation, and traffic control to facilitate the work.