Massachusetts Water Resource Authority, Beacon Street Line
Constructed in the 1870s, the Beacon Street Line carries water under the MBTA Green Line tracks in the busy Brookline neighborhood. Massachusetts Water Resources Authority (MWRA) identified a leak in the 48-in. dia. cast iron pipe below the train tracks and needed to make repairs. SGH evaluated the pipe to determine if workers could safely enter, designed the repair, and provided engineering support during construction.
MWRA selected internal repairs with a carbon fiber-reinforced polymer (CFRP) liner, which would allow them to avoid excavating and disrupting train operations. The cast iron pipe had only 4 ft of soil between it and the train tracks above. After determining workers could safely enter the pipe to execute repairs, we designed a CFRP liner for a 72 ft long portion of the pipe.
SGH assisted MWRA and Green International by preparing repair drawings and specifications for bid, reviewing bids, and helping to select a repair contractor. We also provided field engineering support, including helping the contractor resolve field conditions, and performed quality assurance inspections throughout construction. After construction, we performed tests in our laboratory to verify the installed CFRP’s tensile properties and the degree of cure prior to returning the pipeline to service.