MBTA Orange line bridge inspections

Steere Engineering Inc., as a subconsultant, performed inspection and load ratings for MBTA Orange Line tunnels, including several bridge structures. Steere inspectors worked collaboratively with our Prime consultant on teams in the field to complete the inspections. Steere worked on inspection teams for a total of 17 tunnels.

The Orange Line Tunnel runs a length of approximately 3.8 miles below the neighborhoods of the South End, Back Bay, Chinatown, Government Center, the North End and western Charlestown.  The majority of the Orange Line Tunnels were constructed using cut-and-cover techniques with the Southwest (South Cove) and Northwest Corridor sections being box sections of cast-in-place reinforced concrete. A portion of the Northwest Corridor tunnel (Charles River Crossing) is an immersed tube tunnel (ITT) with a concrete lining. The Orange Line also includes portions of the Southwest Corridor shared with AMTRAK.

Steere was responsible for reviewing available drawings and background information, researching, identifying, and compiling pertinent data available on each of the tunnels from the MBTA Plan Room and Railroad Operations Plan Room. Additionally, Steere assembled and reviewed available data from the MBTA including existing inspection reports, plans, and applicable standards, developed National Tunnel Inventory Element Database (NTIED) sheets for each TIN, and calculated tunnel elements from the existing design plans. As part of Steere’s efforts, the team completed two inspection reports – Forest Hills Tunnel, a commuter rail tunnel carrying the Needham Line and Stony Brook Tunnel.

Location: Boston, Massachusetts

Owner: Massachusetts Bay Transportation Authority (MBTA)

Timeline: 2022