State Street MBTA Station Rehabilitation (S09CN11)
Location: Boston, Massachusetts
Contract: MBTA Contract S09CN11
Contract Value: $41,709,842
Project Dates: October 2004 – April 2010
As part of the MBTA’s Blue Line Modernization Project, Barletta was contracted to perform the renovation of State Street Station.
The new station features lengthened platforms to accommodate six-car trains, two new elevator equipped entrances connected to the lobbies of the buildings at 53 and 60 State Street, and an accessible ramp joining the Orange Line and Blue Line concourses.
The work was completed in eight stages to minimize disruption to service and to the surrounding area, and access to the station was from street level at the intersection of State and Congress Streets.
The project required the design and installation of an elaborate earth support system in the midst of one of Boston’s busiest intersections, in very constricted work zones adjacent to 40 story office buildings. The intersection contains several historic landmarks including the site of the 1770 Boston Massacre, and the Old State House, built in 1713, with Boston’s Freedom Trail directing hundreds of tourists through the area each day. Maintenance of vehicular, pedestrian and subway traffic necessitated limited day work; the majority being completed at night or on weekends.
The earth support system consists of 50 foot steel piles in pre-drilled 24” steel caissons which were drilled through various obstructions encountered, including the remains of granite foundations and seawalls. Once the piles were in place, the excavation was decked and steel bracing and wood lagging installed to complete the excavation. Numerous public and private utilities including 12”, 16” and 24” water mains, 12” gas mains, 8” and 12” steam mains, 13.8KVA electric lines, 30” sewer/drain lines and telecommunications systems were temporarily relocated, and two 115,000KVA steel, oil filled electric transmission mains were supported in place.
Barletta completed the demolition of 100 feet of tunnel outbound of the existing State Station, and constructed 100 feet of station walls, roof, inbound and outbound platforms and station finishes while maintaining MBTA rapid transit service.