A
whirley crane places a second crane, June 1961.
Thomas E. Petermann Collection (S-2005-89-57)
Two electric whirley cranes were used to build the dam. Each crane revolved 360 degrees on its base, allowing the operator to move heavy construction materials and concrete in all directions. The cranes were mounted on 75-feet- tall gantries, movable steel towers perched atop a steel trestle (bridge) spanning the length of the dam.
Care had to be taken to keep the crane from overextending and toppling over. The heavier the load hanging from the end of the long boom, the closer it needed to stay to the center of the crane.
Height
of crane operator above trestle: 80 feet |
|