MWRA, Spot Pond
SGH developed an emergency repair for a 48 in. dia. prestressed concrete cylinder pipeline penetrating the concrete core of the Spot Pond Dam. The pipe was cracked at the penetration point due to ground movement at a nearby bend in the pipeline.
SGH developed emergency repairs to reduce the risk of pipeline burst and stop leakage during a very short window of pipeline down time. We then designed a permanent repair for the pipe going through the dam core. Highlights of our work on this project include the following:
- Inspected the pipe at its interface with the shore face of a wall
- Performed finite element soil-structure interaction analyses of the pipeline, which indicated that the pipe leakage was caused by differential movement of the pipe and thrust block
- Designed external and internal emergency repairs, including immediate installation of circumferential post-tensioning tendons to strengthen the pipe and prevent pipe rupture under pressure along with installation of a continuous inner seal system to stop the leak
- Designed a permanent repair with a specially designed closure piece that would allow pipe movement relative to the wall