Location: Cambridge, MA
General Contractor: John Moriarty and Associates
Project Description: The Mass and Main project included two building foundation types. Our scope included a braced slurry wall foundation for building B1, and a steel sheetpile cofferdam lateral earth support system for building B2. A 23,000sf slurry wall in B1 was installed directly adjacent to and below the bearing elevation of an MBTA Red Line tunnel. Excavation depths of approximately 30ft required one level of cross lot bracing to control movement adjacent to the tunnel. Silty sands at subgrade were difficult to dewater and required deep depressurization wells.
Building B2 was founded on driven steel piles. Our scope included installation of perimeter steel sheetpile bulkhead to allow excavation in silty sands to a depth of approximately 10ft below water table. Site utility and landscape scope included extensive groundwater recharge systems, sewer, drain and water connections, and preparation for hardscape parks and walkways in Central Square Cambridge.