| 摘要 |
1,000,741. Reinforced-concrete beams. RHEINBAU G.m.b.H. Nov. 4, 1963 [Nov. 9, 1962], No. 43459/63. Heading E1V. In a process for producing lattice girders, the lower boom 3 of which consists of prestressed concrete, the lower ends of the latticework diagonals 2, the upper ends of which are connected to the upper boom 1, are concreted into the lower boom 3 after the upper boom1 has been elongated to an extent by which the concrete lower boom 3 contracts after release from the tension used for prestressing. The elongation is preferably carried out simultaneously with the tensioning of the reinforcement of the prestressed lower boom 3 and may be done by subjecting it to preload or by electrical heating. Specification 873,793 is referred to. |
