This contract involves the seismic retrofit of the Bay Bridge West Span structures Bents A & B at Main Street, Pier W-1 at Spear Street, Yerba Buena Island Anchorages Cable Bent, demolition of the City's Bay Bridge Pump Station and construction of new pump station.
Retrofitting the cable bent and Bents A & B will involve adding additional steel plate and replacing rivets with high-strength bolts. Bracing between the towers of Bents A & B will be added in the form of an x-frame above the roadway level of Main Street (see photos and move cursor over it). The tower struts will have to be modified to accommodate the new isolator bearings, which will be jacked into place while the bridge continues to carry traffic. The concrete foundations below Bents A & B are going to require retrofitting. This will entail placing a steel jacket around the pedestals down to the top of footing. The pedestal was sized to accommodate the temporary legs used to install the bearings.
Pier W-1 will be strengthened by placing a concrete jacket completely around the columns and shear wall. The columns will get a 1'-6" jacket while the shear wall will be increased 2'-6" on each side. This jacketing will go all the way down to the footing. The City of San Francisco pump station located at the west face of the pier will be demolished and a new pump station will be constructed at Caltrans paint yard located at the northwest corner of the Main and Bryant streets intersection.
Retrofit work on this contract will impact the parking spaces and sidewalk access adjacent to Pier W1, Bents A & B and the San Francisco Anchorage and at Bryant Street. Sheet piles will be used for the excavation and retrofit work at the foundations of Pier W1, Bent A and Bent B. Crane, hoisting and excavation equipment will be needed for the work.
Construction has started early October 1999 and is scheduled for completion by fall of 2001.