BRIDGE RETROFIT

Golden Gate Bridge,  San Francisco, California

Since the Golden Gate Bridge opened in 1937, bridge maintenance has been proactive and several improvements have been incorporated into the original design. However, recent advances in our understanding of earthquakes and lessons learned from the 7.1, 1989 Loma Prieta earthquake  mandate that extensive seismic upgrades be part of the comprehensive inspection and retrofit program recently initiated by the Golden Gate Bridge Highway and Transportation District.

Current research suggests that the north and south viaduct approaches would not survive a strong earthquake (7.0 or more on the Richter Scale).  The San Andreas Fault is seven miles west of the bridge; the Hayward Fault  is ten miles to the east.

In connection with Phase I of the Golden Gate Bridge seismic retrofit started in 1998, Balfour Beatty Construction, Inc. (BBCI) hired William Tucker Associates (WTA) to design temporary bracing for one pier of the North Approach Viaduct. As our work for BBCI has progressed so, too, has our project involvement. WTA designed bracing for the four towers and five truss spans that make up the 1200 ft. North Viaduct Section. 

Client Reference

Sean Tarp

Balfour Beatty Construction Inc.

1001 Bridgeway, #943, Sausalito, CA

415/885-0601