In the warping torsion analysis, it is necessary to consider both the global and the local imperfections. This chapter introduces three ways to apply a local precamber to the stair stringers. For this purpose, two new imperfection cases were created for the initial bow in +y and for the initial bow in -y.
The size of the imperfections is specified in the Eurocode and depends on the buckling curve of the respective cross-section.
The buckling curve is listed in the editing dialog box for the cross-section in the "Section Values" tab under Stability. Therefore, an initial bow of L/200 would have to be applied to the stair stringer.
You can use the shortcut menu of the imperfection cases in the "Data navigator" to create a new imperfection case. The imperfection type can be specified in the dialog box that appears.
If you activate the local imperfections in the "Display navigator", they are displayed in the graphic.
