| 摘要 |
A connecting element (4) interconnects the parallel bars (2, 3) of a lattice girder segment (1) for securing the walls of an underground construction e.g. mine gallery or tunnel working. The element is formed as a three dimensional closed polygon of steel rod having a min. yield stress of 520 N/mm2 and a smooth surface. The bending radii of the polygon are at most twice the rod dia. Prior to bending, the rod is cold formed by rolling, stretching or draw forming. Connecting flanges (16) pref. join the girders together via bolt holes (17). A lattice girder for securing the walls of an underground construction has adjoining segments each formed of parallel bars interconnected with above connecting elements. |
