Folder: S.F. Bridges-Bay-Construction-Caissons.
On back: "SAN FRANCISCO-OAKLAND BAY BRIDGE; Walter G. Swanson; 500 Sansome St. - GA rfield 1415. File 900.11 B-12/AA. FIRST WEST BAY CAISSON - Caisson 'Chas. F. Swigert,' a steel and timber structure the size of a small apartment house was towed by four tugs out of Moore Dry Docks yesterday, (Friday) and anchored 1100 feet west of Yerba Buena Island where it will be sunk to rock approximately 170 feet below the water line to establish the most easterly tower of the suspension sector of the San Francisco-Oakland Bay Bridge. This caisson is 74 feet wide, 127 feet long, 65 feet high, drawing 20 feet of water, and contains 28 steel cylinders, each 15 feet in diameter, now filled with compressed air to supply buoyancy. The caisson is surrounded by huge timber fenders and anchored between stationary barges. The anchors, already laid out and secured in the mud surrounding the caisson, are now being attached to its sides by means of cables as the caisson is located by triangulation into an exact position.."
On back (continued): "This caisson marks the eastern end of one of the two 2310-foot suspension spans. It will support a steel tower 465 feet high. This is the second caisson to be placed on location, the other being for Pier E-5 in the East Bay Crossing. Engineers and officials of Transbay Construction Company, contractor on the West Bay substructure, estimated that concrete will be poured into this caisson beginning Tuesday. Two barges carrying Whirley derricks will be anchored alongside the stationary working barges. The concrete will be pumped through port holes in the side of the caisson. 10-13-33".
