MULTIPLE THREAD SCREW JOINT, STEEL PIPE WITH JOINT, STRUCTURE, CONSTRUCTION METHOD OF STRUCTURE, AND DESIGN METHOD AND MANUFACTURING METHOD OF MULTIPLE THREAD SCREW JOINT

摘要

To provide a multiple thread screw joint capable of eliminating fitting mistakes, and a steel pipe with a joint, a structure, a construction method of the structure, and a design method and a manufacturing method of the multiple thread screw joint.SOLUTION: A multiple thread screw joint 1 of this invention comprises an inner joint pipe 7 having a male thread 5 and an outer joint pipe 13 having a female thread 11 that are attached to an end portion of steel pipes 3, 9. The threads of the inner joint pipe 7 and the outer joint pipe 13 are multiple thread screws with four or more of even-numbered threads, and threads constituting the multiple thread screws satisfy a requirement specified below. The threads comprise two or more kinds of threads, and each kind of thread has even number of threads. All of thread ridges and thread bottoms have the same pitch. All of straight lines and polygons satisfy a requirement specified below: as to a straight line and a polygon formed by connecting positions of neighboring threads of the same kind with each other with a straight line, the straight line passes the center of the pipe and a center of gravity of the polygon accords with the center of the pipe, except a case where all of formed figures are regular polygons.SELECTED DRAWING: Figure 1