Spiral Stair Load Calculations

Considerations

• The method of calculating the maximum structural load for a spiral staircase depends on the materials and style of construction. In some cases, a central pole carries the entire weight of the system and in other cases, the steps carry the weight.

Options

• Online calculators exist to help predict the structural load for different styles of support. To perform these calculations, you need to know the elastic modulus of the stair material and the area moment of inertia, figures that determine how the material will deflect or deform under pressure. Alternatively, an engineer can perform these calculations for you, ensuring they are correct for your particular application.

Expert Insight

• Lichtgitter, one manufacturer of spiral staircases, designs their products to withstand a concentrated load of 1.5 kN or 337.2 lbs, and a distributed load 3.5 kN or 786.8 lbs.