A Bathtub for the South Tower

To reach the site of the south tower foundation, workers built a temporary roadway on a timber access trestle, or wharf, from the San Francisco shore. The exposed location proved dangerous in 1933, when a freighter struck the trestle, and two months later more than half of the repaired structure collapsed in a storm. The workers rebuilt it and continued. Plans for the south tower called for a huge oval-shaped concrete barrier, or fender, to protect the tower base from ship collisions during fog. Workers formed the fender by placing concrete underwater through tubes into wood forms, and after it rose above the water and became visible, they called it a giant bathtub. For the foundation pier, the base on which the tower would stand, workers placed concrete underwater to fill the bottom portion of the fender, then pumped out the remaining 9.4 million gallons of seawater and completed the reinforcing steel and concrete inside the bathtub. After the concrete work was finished, erection of the steel for the south tower began in January 1935 and was completed in six months.

San Francisco, California · United States