Vibrating concrete in east training wall, using Jackson 2-man machines operating at 4,800 r.p.m. 145 volts.
Description
After dropping four-yard load of concrete workers used large and unwieldy Jackson Two-man concrete vibrators to remove air bubbles in the concrete and allow a stronger structure. The technique for vibrating concrete first appeared in the construction of the Hoover Dam and construction engineers used it widely in the construction of the Grand Coulee Dam to ensure the stability and longevity of the Dam structure.