PG&E Tunnel Closures and Shoreline Maintenance

LOCATION:

San Francisco, CA

DESCRIPTION :

The objective of this project was the permanent closure and filling of 16 concrete cooling water tunnels at PG&E’s Hunters Point Power Plant facility, which was shut down in 2006. PEC conducted a number of pre-dive inspections to determine the existing site conditions, and then worked with PG&E on a tunnel closure scheme.  Work included sediment removal work, underwater dowelling, forming, rebar installation, and concrete placement of new cast-in-place concrete closure walls at the tunnel entrances. There were 16 openings all together in five different locations, varying in size from 5’x7’ to 11’x15’ to 5’x 20’.  Additional scope included miscellaneous shoreline maintenance and removal of old in-water structures. The job was a tightly scheduled and safety driven job with 90% of the work dive related.

This job demanded a heavy construction minded dive team. We had three 4-5 men dive teams that consisted of a diver, stand-by diver, radio or box tender and a tender, along with crane support. With the flow of the outgoing and incoming tides it made the work challenging and communication was imperative for safety and job efficiency.

The project was on time and on budget with no Contractor initiated changes to scope.