| 摘要 |
<P>PROBLEM TO BE SOLVED: To economically and efficiently form a through-hole in a beam-column joint of a precast concrete structure. Ž<P>SOLUTION: A form 21, which is formed of three arc-shaped cross-section form forming members 21a, combined together to form a cylinder and which has a rib 22 provided on an outer surface, is installed in the beam-column joint 2 before the placing of concrete 7. The form 21 is arranged, in such a manner as to make a gap 23 between the form forming members 21a along the outside diameter of the through-hole 6, and an expansion tube 26 is inserted into the form 21. Air, water, or the like, is pressed into the expansion tube 26, and the expansion tube 26 is inscribed in the form 21 and expanded, in such a manner as to protrude from the gap 23 between the forms 21. After the concrete 7 is placed and the concrete 7 is hardened, the expansion tube 26 is contracted, and the expansion tube 26 and the form 21 are detached to form the through-hole 6. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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