On back: "SAN FRANCISCO-OAKLAND BAY BRIDGE; Walter G. Swanson; 500 Sansome St.; GA rfield 1415. File 900.11 B-12/AA. BRIDGE BUILDERS, INC. POURING CONCRETE IN PIER E-5 1,000 FEET WEST OF KEY ROUTE MOLE - Henry J. Kaiser, Inc. electric mixing barge (at right) is pouring concrete by means of 4-yard traveling belt conveyor into a bucket which is emptied into the hollow walls of the caisson. As the concrete is poured, the caisson sinks and another lift is added to its sides into which more concrete can be poured. One bucket is being filled from the mixing barge."
