Spiral stairs
close The structure of the rotating stairs being loaded causes the treads to shake up and down if walking on the outside of the stairs. This is a common disadvantage of all central column rotating stairs, and the larger the passage radius of the stairs, the more severe the shaking. The bearing capacity of the spiral staircase is generally 150KG to 200KG, in contrast, the bearing capacity of other finished steel and wood stairs is generally 400KG. There are also spiral stairs without central columns, which mainly rely on the double spiral beams under the steps to support the load, or the handrail of the stairs to support the load. Relatively speaking, the stairs without central columns are more complex than those with central columns. The stairs are subjected to bending, torsion, shear, compression and other combined forces, which are complex and difficult to calculate. In the staircases without central column, the stress on the railing is more complicated, because the railing is generally narrow, and the stability of the beam out of plane is not easy to control.