Bridge News

GOLDEN GATE BRIDGE SEISMIC RETROFIT PHASE 2 GOES TO BID

October 10, 2000

On October 10, 2000, the Golden Gate Bridge, Highway and Transportation District (District) announced the availability of the construction bid documents for Phase 2 of the Golden Gate Bridge Seismic Retrofit Project. Bids will be opened in January 2001 with construction starting as early as spring 2001 and completion in late 2004. Bid documents may be ordered at the Office of the District Secretary, Toll Plaza Administration Building, San Francisco, weekdays from 9 am to 4 pm or by mail by clicking here for Bid Order Information available on this web site. Interested bidders may click here for the Contractor's Notice.

Phase 2 construction is estimated at $120 million. This includes the construction contract and other expenses such as contract administration and management, inspections, design engineering support services, materials quality assurance testing and inspection, and environmental compliance monitoring services. Phase 2 will retrofit the south approach structures of the Golden Gate Bridge that include the south viaduct and anchorage housing, Fort Point arch, and south pylons. Retrofit construction will not impact daily traffic but nighttime lane closures will be required. The structural steel of the south approach viaduct and the Fort Point arch will be retrofitted with foundation strengthening, member strengthening and replacement, installation of seismic motion isolators and dampers, and linking of the separate spans so that they will move together during an earthquake. The foundations and walls of the south pylons will be strengthened. The west wall of the south anchorage housing will be replaced, the foundation strengthened, and the east wall and internal concrete frames reinforced.

In August 1997, the first of three seismic retrofit construction phases began. The first phase retrofits the north viaduct at an estimated cost of $69 million. Phase 1 construction, once completed next summer, will make the north viaduct significantly less vulnerable to major earthquakes. The main span and south approach structures of the Golden Gate Bridge remain vulnerable to earthquakes and to survive intact must be retrofit to withstand a nearby earthquake up to magnitude 8.3.

The Golden Gate Bridge is considered a lifeline structure and must be retrofit to remain in service after a major earthquake. Retrofit measures have been designed to allow the structure be opened to emergency vehicles shortly following a major nearby earthquake and to be open to limited traffic within a few days. Bridge retrofit measures will fine tune the structures to reduce violent actions caused by the ground motions of an earthquake and strengthen the structures to reduce the damage caused by these actions. All retrofit measures have been designed to maintain the Bridge's aesthetic and historic integrity.

The total cost for Golden Gate Bridge seismic retrofit construction is now estimated at $297 million. The full replacement cost of the Bridge is estimated at $1.4 billion. Since the District possesses no taxing powers, 100 percent of Golden Gate Bridge maintenance and operations costs, approximately $33.6 million annually, are supported solely by the use of tolls. Bridge tolls alone are insufficient to complete the seismic retrofit while sustaining vital Golden Gate Bridge, Bus transit and Ferry transit operations. An additional $88 million in federal or state funding is critical to ensure completion of all three phases of the project.

Construction Phases Grant Funds Allocated ($millions) Remaining Request for Grant Funds ($millions) Bridge Tolls Allocated ($millions) TotalCost ($millions) Duration of Phase
1 North Viaduct $0 $69 $69 4 years
2 South Viaduct & Anchorage, Ft Point Arch, South Pylons $120 $120 3.5 years
3 Suspension Span, South Pier & Fender, North Anchorage & Pylon N1 $20 $88 $108 3.5 years
Construction Total $140 $88 $69 $297