MBTA Sullivan Square Station
Sullivan Square Station, a busy rapid transit stop on the Massachusetts Bay Transportation Authority’s (MBTA) Orange Line, serves as a major multimodal transfer point for surface transit. The MBTA retained SGH to perform a condition assessment of the platform canopies after reports of falling concrete in 2014. SGH performed a structural safety evaluation, designed canopy and platform repairs, directed a multidisciplinary team in the design of station brightening options, and performed construction phase services during an on-call contract with a large portion of the work occurring outside of rail service hours.
SGH visited the site for an emergency inspection to assess the structural stability and look for signs of loose concrete that could become falling hazards. We subsequently planned a detailed investigation to assess the condition of the two platform canopies. Our investigation included the following:
- Inspecting the topsides and undersides of the canopies
- Identifying significant concrete cracks, delaminations, and spalls requiring immediate repair
- Computing the strength of elements of the canopy in their as-designed and current conditions
- Developing concepts for immediate and long-term repairs
- Correlating the most severely damaged areas to leakage through an expansion joint in the elevated roadway above the station
SGH designed concrete repairs, specified a new membrane coating and additional protective measures below expansion joints, prepared construction documents for the repair work, and developed track-protection details. We provided construction phase services, including working with the MBTA to develop a phasing plan that provided larger work windows while maintaining service to the public, reviewing contractor submittals, visiting the site to observe ongoing construction, and modifying our design to help the contractor complete repairs during the specified construction hours.