Bay Bridge Info

The West Span lies between Yerba Buena Island and San Francisco. It is composed of two complete suspension spans connected at a center anchorage. Retrofit work included adding massive amounts of steel and concrete to strengthen the entire West Span.

The West Span seismic retrofit project strengthened the bridge while allowing for a wider range of movement during an earthquake. This work, though not easily visible to motorists, was essential to ensuring that this vital transportation lifeline can withstand a major earthquake. Crews installed new, state-of-the art devices to isolate, absorb or diffuse the impact of an earthquake.

Much of the work came down to simple "nuts and bolts" retrofitting. The bridge's twin suspension spans were strengthened by adding new steel plates and replacing half a million original rivets with almost twice the number of high-strength bolts. In total, 17 million pounds of structural steel were added. New bracing was added under both decks, and all of the "laced" diagonal crossbeams connecting the upper and lower road decks were replaced with perforated steel. Piers were encased in heavy concrete jackets and additional anchor bolts were installed to fasten tower legs to pedestals.