| 摘要 |
The invention concerns a formwork wall with variable geometry for producing the lower surface of a spiral or helical concrete staircase. The invention is characterised in that it comprises: a deformable formwork skin (1) associated at the underside with a rigid and integral support structure (2) in its angular portion (4) to be spaced away therefrom in the wings (5) thereby producing an adjusting space and, means (3) for modifying the spacing between the structure (2) and the skin (1) such as screw jack (3)/captive nut type actuators which as they evolve force the skin (1) to be deformed by being supported at the tip (2') of the wings of the rigid structure (2). |
