Owner: Golden Gate Bridge, Highway, and Transportation District
Contract value: $154,474,832
The project provided seismic retrofit to the South Approach Structures, reinforcing the historic bridge to withstand an 8.3 magnitude earthquake. The South Approach Structures include the south approach viaduct, south anchorage housing, Fort Point arch, and south pylons S1 and S2.
At the south approach viaduct the steel support towers and bottom lateral bracing were replaced, and seismic isolation bearings and joints were installed underneath the roadway. The west wall of the south anchorage housing was completely replaced, and the east wall was strengthened. New internal shear walls and new concrete struts and columns were constructed within the anchorage house.
The Fort Point arch received an extensive overhaul which included new steel members, energy dissipation devices, isolation joints, and new arch bearings.
Both the exterior and interior walls of the four 240-ft tall south pylons were overlaid with steel plating. The exterior faces of the pylons were then covered with a 4-in concrete overlay to match the original appearance.