PURPOSE: To provide the manufacturing method for a concrete member with a hollow section for using hollow molded members a number of times without leaving the hollow molded members in concrete and releasing the hollow molded members from the concrete easily.
CONSTITUTION: A tube 14 working as a hollow molded member is disposed in a form 11, and compressed air is filled from a filling and exhausting section 14a into the tube 14 to make the tube in the expanded state. The tube 14 and grating reinforcing bars 12 and 13 are disposed on the given positions in the form 11, and ready mixed concrete C is placed in the form 11, and when the placed ready mixed concrete is hardened to a certain extent, the compressed air in the tube 14 is exhausted to set air pressure in the tube at the atmospheric pressure or lower, and the tube 14 is contracted and released out of the hardened concrete C. Thus the compressed air is exhausted and the air pressure in the tube is at the atmospheric pressure or lower and the tube is contracted so that the outer peripheral face is peeled off the inner peripheral face of a hollow section, and the tube can be released easily.
ENOGUCHI MASAMITSU
OHATA KATSUTO
MATSUZAKI TAKASHI
