School street bridge extension

Steere provided bridge and highway design and overall Design Package management for design and construction of the extension of the MassDOT-owned School Street bridge as part of the 4.3-mile Green Line Light Rail Extension Project that will serve to reduce traffic congestion, support municipal plans for sustainability, and urban redevelopment. The School Street bridge extension consisted of supporting the existing prestressed box beam superstructure in place over active rail traffic while a new “back span” including a pier, abutment, and superstructure were constructed along the west approach. The “back span” was required to traverse a new Green Line track as part of the corridor widening.

The bridge extension also included extensive coordination with MassDOT, the City of Somerville, and numerous utility owners to ensure that bridge and roadway design, drainage, and utility relocations met the needs of all owners and stakeholders.   

Steere established a construction baseline and profile for the project. The profile was established in conjunction with the Proposed Typical Section to match the existing grade at the proposed pier such that no modifications to the existing bridge would be necessary. The roadway profile south of the new span was established to match existing grade to the extent practical and to match all back of sidewalk grades such that no ROW actions would be required. The project also included the milling and resurfacing of the approach roadways, resetting of granite curbing and reconstruction of the existing sidewalks such that all accessibility requirements would be met. This work will be coordinated closely with the proposed construction of the adjacent community path being constructed near the bridge.

Location: Somerville, MA

Owner: Massachusetts Department of Transportation (MassDOT) & Massachusetts Bay Transportation Authority (MBTA)

Timeline: Design Completed in 2019; Construction Completed in 2022