Permission to use this image must be obtained from the San Francisco History Center, San Francisco Public Library: www.sfpl.org/permissions.
Folder: S.F. Bridges-Bay-Construction-Piers. Permission to use this image must be obtained from the San Francisco History Center, San Francisco Public Library: www.sfpl.org/permissions. On back: "SAN FRANCISCO-OAKLAND BAY BRIDGE; Walter G. Swanson; 500 Sansome St. - GA rfield 1415. File 900.11 B-12/BD. The Concrete Center Anchorage of the San Francisco-Oakland Bay Bridge, to which are tied the two suspension bridges of the West Bay Crossing, now has its two A-frames erected on its north and south sides. The huge steel A-frame (shown in this photograph) weighing 320 tons, is anchored by eyebars extending twelve stories down into the concrete walls of this monument. To the sloping sides of this steel A-frame eyebars will be attached, to which in turn are pinned the strand shoes at the cables' ends. Concrete will be poured around this steel A-frame after the eyebars are attached. These two steel frameworks will resist a combined pull of 11,200,000 pounds when the two cables of the west suspension bridge have been completed this year, prior to the spinning of the cables of the east suspension bridge. The A-frames are 92 feet long and 58 feet high. On back (continued): "Both suspension bridge cables will be spun this year and attached to this A-frame as they are spun, according to Chief Engineer C. H. Purcell.
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Bridges--Bay--Construction--Piers San Francisco (Calif.)--Photographs