| 摘要 |
<p>In order to save concrete in the case of concrete joists, supporting slabs or the like, and thus to reduce the weight, as well as to achieve greater spans and a higher loading capacity, the upper and/or the lower curves (7, 8) of cavities (6) provided in the concrete joist are constructed in the form of ellipses or false ellipses. If a wire reinforcement is provided, some of the lower wires (9) are wrapped from their interface into the joist, over a section, in a foil (10) in order to prevent excessive stresses and facial cracks in the force-introducing region. Furthermore, in the case of a concrete joist, supporting slab or the like having a joint (12), the latter is provided as a recess (15) in the side face (14), bevels (16, 17) being provided at the top and at the bottom in order to form diagonal struts in the jointed concrete. <IMAGE></p> |
