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-Caissons. 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/AA. A BRIDGE CAISSON AGAINST THE SAN FRANCISCO SKYLINE - This unusual picture taken from a corner of the caisson for Bridge Pier 6, 1160 feet west of Yerba Buena Island, shows the world's largest caisson for the concrete center anchorage of the bridge, midway between Yerba Buena Island and San Francisco. On either side of the caisson are the working platforms built on piles, each equipped with a derrick. In the foreground are the domed cylinders of Caisson 6. These domes contain compressed air and add buoyancy to the huge structure. As the caisson is built up and sunk the domes are cut off by welding torches, a lift of 20 feet of 15-foot diameter pipe added, and the dome rewelded on. On back (continued): " The structure is the first utilization of the Moran compressed air, flotation caisson method of building under-water foundations, and was created by Daniel E. Moran of the Consulting Board of Engineers of the San Francisco-Oakland Bay Bridge, of which C. H. Purcell is Chief Engineer. 11-15-33".
1 photographic print:
Bridges--Bay--Construction--Caissons San Francisco (Calif.)--Photographs