US Coast Guard Command Center

Project Summary

Yerba Buena Island houses the US Coast Guard Station, San Francisco.  This project sits on the northeast side of the island just below the east span of the newly rebuilt San Francisco Bay Bridge.  The site has been used since the late 1800’s and has undocumented fill, old docks, and debris that have long been filled over.  The Coast Guard’s plan to build a new Interagency Operations Center would allow for cooperation for federal, state and local stakeholders to improve information sharing and tactical coordination.  But liquefaction would hold back plans until a solution was provided to stabilize the ground and provide a solid foundation for the new IOC structure.

The soil generally consists of 10 to 15 feet of fill over soft clay bay mud, loose sand, and then bedrock to depths of 25 to 30 feet.  Farrell collaborated with the structural and geotechnical engineers to provide a solution that solved both liquefaction and foundation support.  Using the vibro-rod Impact® Pier system (IRAP), Farrell increased the ground density and installed ground improvement that support 5,000 psf bearing capacity for the new structure.  Farrell worked with the Coast Guard and contractor to minimize the effects of vibrations on their daily operations of the adjacent acting command center.  The project was a success with no command center interruptions and opened on June 28, 2011.