sentences:  In order to make early use of the staircase, precast concrete was used in the floor plates and the elevator shafts.Because of the pattern in which two days of steel-frame work were followed by two days of precast-concrete work, the staircase was completely operational by the time the framework was finished.On-site construction of the elevators was shortened by incorporating the 3-D frames, the rails, and anchor indicator boxes in the precast concrete elements and by employing prefabricated cages.