MBTA Tunnel: Forest Hills T Beam Repair

Project Overview:

SPS was tasked with repair of the concrete ceiling at six roof expansion joints, some spanning up to 70’ in legnth, over the Forest Hills storage tracks on the Orange Line.  Over the years the freeze-thaw cycle had allowed water infiltration at the joint. This subsequently caused damage to the concrete at the joints, the track infrastructure below and posed a hazard once frozen to on-foot personnel working in the area.

During the course of nine weekend diversions, the crew performed overhead demolition, installation of welded wire mesh and formwork, pumped a self-consolidating concrete, stripped forms, and installed a neoprene rubber gutter system to direct the water appropriately away from the infrastructure and walkways.

Key Challenges Overcome:

The storage area is made up of four storage tracks. Each of the six joints spanned across these tracks. A combination of staging and hi-rail lift trucks were used to access the work. The planning, coordination and communication effort within the project team and with the MBTA prior mobilizing equipment to the site was key in running an efficient operation.