Formwork for Concrete Structures by R.L.Peurifoy and G.D- By EasyEngineering.net

428 Chapter Fifteen
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FIGURE 15-12 Slipform core of 785 ft for Two Liberty Place in Philadelphia,
Pennsylvania.
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started and stopped each day and on weekends to avoid the high
costs associated with continuous operations. Workers, equipment,
and material delivery are planned to permit a production rate of one
story height of walls per day. Figure 15-12 shows Two Liberty Place in
Philadelphia, Pennsylvania. This structure is the world’s tallest slipform
core, a total height of 785 ft.
Linings for Shafts
Slipforms have been used to place the concrete linings for vertical
shafts for tunnels and missile launching bases. The linings for the latter
frequently must be constructed to tolerances of ¹⁄8 in.
Figure 15-13 shows a section through the slipforms used to place
concrete linings in vertical shafts located in White Sands, New Mexico,
Victorville, California, and Helms Creek, California. These shafts
ranged in diameters from 33 to 48 ft and in depths from 200 to over
400 ft. Special cable lifting jacks were used both to lower the slipforms
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