| 摘要 |
In order to erect a prestressed-concrete truss made up of two beams 1,3; 2,4, these two beams are juxtaposed horizontally end to end, they are mounted in a pivoting manner on a first horizontal axis A defining the top of an opening E, in the shape of an upside-down V, maintained between these two beams, a portion of one of the two beams is mounted so that it may pivot about a second fixed axis B, the other beam is left to move freely horizontally and a tension force is exerted on the prestressing reinforcement 8, 9 of the assembly, which reinforcement passes through the opening E, which successively closes this opening while raising the first axis A until the truss is formed and then provides the prestressing. <IMAGE>
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