Walnut Hill Water Treatment Plant
Marlborough, MA
Completed in 2004, the plant's144-inch diameter PCCP Cosgrove Intake Pipeline is part of Boston's water supply system. Less than a year after completion, a large leak developed near a deep manhole chamber. SGH provided emergency response; evaluated the risk of failure; determined the cause of the leak; inspected the pipeline; and repaired the leak. We performed internal inspection of the leaking pipe using a diver while the line was in operation and computed the effects on structural safety of internal pressure, dead loads, prestress, and hydraulic pressure induced thrust at elbows. We performed an internal inspection for anomalies. We also performed external inspection of the leaking joint. We designed repairs that included welding of the leaking joint and injection grouting in soil outside of leak areas.
Service Provided:
Investigation
Supporting Capabilities:
Structural Engineering
