| 摘要 |
<p>Prestressed pretensioned concrete beam making plant uses an expanding inverted 'V' frame (4e to tension the stressing wires (12). The frame has a pinned joint (6) at the top and is expanded by a jack (8, 9, 11) on a fixed portal frame (7) pressing down on the apex of the 'V' members so that their rounded ends slide over a falt surface (1) below. The wires (12) extend between the lower ends of the 'V' members where they are attached to end plates (5). After the 'V' frame has been jacked down and the wires tensioned, the concrete unit is cast embedding the wires. When the concrete has set the 'V' frame is released. The wire anchorages may include end plates (5) with keyhole slots anchorage plates (3) and packing plats (18). The wires may have end anchorage nipples (15). The equipment may include formwork for the concrete pouring.</p> |
