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Bay Bridge West Span Seismic Retrofit
1999-2004
The seismic retrofit of the Iconic dual suspension spans of the western Bay Bridge was the largest construction contract awarded by Caltrans when it was announced in 1999. CEC and Joint Venture partner Modern Continental removed about 500,000 original rivets, replacing them with over a million high strength bolts and added 17 million pounds of new steel. From the tunnel on Yerba Buena Island to the anchorage in San Francisco at Beale Street, every major component of the bridge was subject to strengthening and upgrading. Essentially all the laced members of the trusses and towers were modified to have plates rather than lacing. The towers received internal and external strengthening with additional plys of steel. Specially designed canopies were installed over the upper roadway to store materials and allow the work to proceed while traffic continued on the deck, eliminating about 35 planned closures of the upper deck. Lateral bracing was added under the lower deck and above the lower roadway, all installed without any complete closures of the roadway. New hydraulic dampers, resembling giant shock absorbers, were installed where the truss met each tower. Finally, the cables were unwrapped at selected locations, inspected for corrosion and condition and large clamps and struts were installed to tie the cables to the roadway and the bottoms of their arc at the center of the spans. All the work was completed on time with without a single claim.
