MANUFACTURING METHOD OF EXTERIOR CONCRETE PIPE AND FORMWORK FOR MANUFACTURING THEREOF

PROBLEM TO BE SOLVED: To easily remove a formwork embedded in a concrete layer. SOLUTION: In a manufacturing method of an exterior concrete pipe, the outer periphery of a pipe body 1 having a flange part 6 at an insertion port 3 side is covered with a cylindrical exterior frame 10, and concrete is cast in an annular space between the outer periphery of the pipe body 1 and the inner periphery of the exterior frame 10 at the socket 2 side of the flange part 6 to be integrated, and the pipe body 1 and an excavating machine 21 can be connected through the bolt 26 inserted in a through-hole 22 provided on the flange part 6. Before placing the concrete, the formwork 15 is displaced at the socket 2 side of the flange part 6 to close the through-hole 22, and after placing the concrete, the bolt shaft 25 is screwed in the formwork 15 and the tip end 25a contacts the pipe body 1 to release the formwork 15 in the outside diameter direction. Since the formwork 15 is released by the reaction force of the bolt shaft 25, the fixed formwork 15 can be easily removed. Moreover, the peripheral concrete layer 9 is not damaged. COPYRIGHT: (C)2008,JPO&INPIT