July 21, 2010

JULY 2010 UPDATE

GOLDEN GATE BRIDGE SEISMIC RETROFIT

CONSTRUCTION PROJECT

 

Phase 3A retrofits the Marin (North) Anchorage Housing and the adjacent Pylon N1. A construction contract was awarded in April 2008 and the work is scheduled to be completed in 2012.

During Phase 3A, the Bridge roadway and sidewalks within the limits of the Marin Anchorage Housing will be entirely replaced (See photo below). The sidewalk replacement will be completed first. It will begin in late October 2010 with, first, the replacement of the 300 foot-long portion of the west sidewalk followed by the replacement of the 300 foot-long portion of the east sidewalk. The sidewalk work will take approximately 120 days per side. Then, the roadway replacement will proceed.

During the Phase 3A construction, the Bridge roadway and sidewalks will remain open for vehicles and bicycles to cross it, although the work will involve nighttime closures of the selected traffic lanes and detours of the bicycle traffic between the sidewalks.

Location When and How Long? Impact to Pedestrians and Bicyclists
West Sidewalk @ Marin Anchorage Housing roof, 300 foot-long section 120 days, from late October 2010 through late January 2011 West Sidewalk will be CLOSED to bicyclists on weekends and on weekdays from 3:30 to sunset (these are times when the west sidewalks is normally open to bicyclists). Instead, bicyclists will remain on the east sidewalk, 7 days a week during all hours.
East Sidewalk @ Marin Anchorage Housing roof, 300-foot-long section 120 days, from February 2011 through April 2011

The 300-foot-long section of the East Sidewalk @ the Marin Anchorage housing roof will be closed to bicyclists and pedestrians, seven days a week.

Pedestrians will be allowed to walk on the East Sidewalk; however, they will not be able to walk all the way across the Bridge due to the closure of the 300-foot-long segment. Bicyclists and those pedestrians requiring access across the entire Bridge will have access across on the WEST sidewalk, 24 hours a day, seven days week.

 

Additional Project Background
The Golden Gate Bridge Seismic Retrofit Construction project was divided into three phases, two of which are now completed. Phase 1 retrofit the Marin (north) Viaduct structures and was completed in December 2001 using $71 million in toll dollars. Phase 2 undertook the retrofit of the San Francisco (south) viaduct structures and Fort Point Arch. It was completed in spring 2008 at a cost of $189 million, with $112 million in federal funding and $77 million in regional and state funds.

Following the events of September 11, 2001, Phase 3 was redesigned to incorporate additional security measures to aid in protecting against manmade threats as well as to seismic vulnerabilities. Phase 3A is a $125 million project that will be funded with a combination of Bridge tolls, federal funds, and state and regional funds. Phase 3B is estimated at $260 million and is planned to go out for construction bids in 2010. It will retrofit the main span, the two main towers, and south tower pier and fender.

The race against time continues as according to the U.S. Geological Survey, there is a 62% probability of a magnitude 6.7 or greater earthquake striking the San Francisco Bay Area in the next 30 years. Once the seismic retrofit construction is completed, the Golden Gate Bridge will be able to withstand a nearby quake of 8.3 magnitude.