| 摘要 |
PROBLEM TO BE SOLVED: To reduce cost by making the thickness of an approximately rectangular cross-section segment unit smaller than before. SOLUTION: An approximately rectangular segment ring 10 comprises a plurality of circumferentially arranged segment pieces 11 and 12, and the respective segment pieces 11 and 12 are bound to each other by means of a prestressing steel wire 13 which penetrates in a circumferential direction. In the segment ring 10, the L-shaped cross-section segment pieces 12 and 12 are arranged at corners, and the block-like segment piece 11 is fitted and inserted into a section between the segment pieces 12 and 12. Through-holes 14a and 14b are formed at the segment pieces 12 and 11 which constitute approximately rectangular sides, and the prestressing steel wire 13 is inserted from a recessed portion 12a so that the segment pieces 12 and 11 can be bound to each other by means of anchoring devices 15A and 15B. Prestress is introduced into a section between the segment piece 11 and the L-shaped segment pieces 12 and 12 on respective sides. The prestressing steel wire 13 is arranged at the side of an approximately rectangular inner peripheral surface. Tensile stress generated on the segment 10 is canceled by the prestress which is introduced by the prestressing steel wire 13, so that a great bending load can be resisted. COPYRIGHT: (C)2008,JPO&INPIT
|
