Handbook of construction plant, its cost and efficiency (1918)
Dana, Richard Turner, 1876-1928 · New York, McGraw-Hill book company, inc., [etc., etc.] · leaf 364
nd until it has beenerected five times, and that a portable steel tower would be moreeconomical if its use is contemplated for more than five jobs. 360 HANDBOOK OF CONSTRUCTION PLANT The first towers used for hoisting concrete were naturally ofwood and were located entirely within an area to which… … angle of the chute (about 23° to 30°), and the height of the maintower. The steel tower was primarily substituted for the woodtower to provide a permanent knock down structure which couldbe used over and over. Its rigidity as compared with the woodentower has finally led to the portable feature.…
Contractors' operations · Building
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