| 摘要 |
PURPOSE:To constitute a beam by providing compression steel cables of long sizes in three stages from top downward on a compression edge side of a pier head block, with the top stage securing the pier head block, the second stage securing a first projecting block, and the bottom stage securing a second projecting block. CONSTITUTION:A beam of box-shaped cross section has a pier head block 2 on a pier 1. Compression steel members 3, 5, 7 in three stages are embedded in advance on the compression side of the pier head block 2. After stretching and securing the compression steel member 3 to the pier head block 2, the middle stage steel member 5 is stretched and secured to the outer end of the first projecting block 4. Then, the second projecting block 6 is secured to the outer end of the first projecting block 4 by stretching and securing the lowermost steel member 7 to form a unitary beam. This makes it possible to prevent the compression steel members from buckling and to minimize the frictional loss of the members at the time of being introduced under prestressing. |
