Massachusetts Water Resource Authority, Walnut Hill Treatment Plant, Cosgrove Intake Pipeline
The Cosgrove Intake pipeline, a 144 in. dia. prestressed concrete cylinder pipe (PCCP), at MWRA’s Walnut Hill Water Treatment Plant Project was completed in early 2004 as a part of the water supply system for the City of Boston. Less than a year after construction of the pipeline, a large leak of approximately 700 gpm developed near a deep manhole chamber in a section of the pipeline with multiple elbows. SGH provided emergency response and evaluated the risk of failure resulting from the leak, inspected the pipeline to determine the cause of the leak, and developed a repair scheme.
For this project, SGH:
- Performed internal inspection of the leaking pipe using a diver during a brief shutdown while the line was in operation
- Evaluated the structural safety due to the combined effects of internal pressure, dead loads, prestress, and hydraulic pressure-induced thrust at elbows
- Internally inspected and measured all harnessed joints to determine if any joints opened more than the design limits, inspected the pipeline for visible signs of anomalies, and externally inspected the leaking joint
- Designed repairs that included welding of the leaking joint and soil grouting.
Repair & Rehabilitation
Structures | Advanced Analysis
Infrastructure & Transportation
Barletta Heavy Division
Repair & Strengthening | Buried Infrastructure | Failure Analysis
Key team members
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. SGH evaluated the pipe to determine if workers could safely enter, designed the repair, and provided engineering support during construction.
Casey Arborway Project, Demolition of Bridge No. B-16-367
SGH assisted the demolition contractor by evaluating the effects of proposed construction loading and sequencing on the overall structural stability during demolition.