| 摘要 |
PROBLEM TO BE SOLVED: To provide a hole forming method for a concrete structure that forms a hole, having a groove in a desired high-precision shape on an inner surface, in a concrete structure.SOLUTION: A method of forming a cylindrical hole, having a groove on an inner surface, a concrete structure 20 comprises the processes of: forming a prepared hole 21, having a larger diameter than the cylindrical hole, in the concrete structure; inserting and setting a concrete form 10, having a projection 11 formed spirally in a desired sectioned shape in an outer peripheral surface of a cylindrical main body, in the prepared hole; installing concrete 30 between the concrete form and a prepared hole inner surface; and forming the hole 40 having the spiral groove 41 in the desired sectioned shape on the inner surface by extracting the concrete form while rotating it reversely of the spiral of the projection after the installed concrete is hardened.SELECTED DRAWING: Figure 2 |
