Before calculating the stairs, it is necessary to determine the boundary properties of the edges of the stairs. You can fix the edges of the stairs to rotation and/or translation with the Set Stair Boundary Conditions command, or you can solve it together with the structure with the semi-rigid diaphragm acceptance solution.

Location of Set Stair Boundary Conditions Command

You can reach it under the Concrete tab in the ribbon menu under the Concrete heading.

Usage Steps

  • Click the set stair boundary conditions icon.

  • The set boundary conditions dialog will open.

  • Click on the edge of the stair for which you want to change the support conditions.

  • In the set boundary conditions dialog, select the option you want.

  • Click the OK button to exit the dialog.

Set Boundary Conditions Dialog


Boundary conditions for separate solution

If a solution is made with the assumption of a fully rigid diaphragm, the stair is solved separately from the structure. In this case, the support conditions of the stair edges are determined by two options: rotation and translation. Stair loads should also be applied to the structure.

Translation restrained

If checked, the selected edge is restrained against translation.

Rotation restrained

If checked, the selected edge is restrained against rotation.

Boundary conditions for solution with building system

If the solution is made with the assumption of semi-rigid diaphragm, the structure - the stair is solved together. In this case, the objects to which the edges of the stairs are connected are determined by the options given in the dialog.


The edge of the stair is considered a fixed support.

Connection distance

Give the amount of distance that will be required for the stair edge to be attached to the support.