The option is used to determine the location of stiffeners along the member length. It is available after pressing the Stiffeners button located in the Member Definition - Parameters dialog box.
The above dialog box enables defining the distribution of transverse stiffeners over the beam length (in real or relative coordinates with respect to the beam length).
Based on the positions of transverse stiffeners the program determines the length of an unstiffened web; if slenderness of the web of a beam in bending exceeds allowable values specified in point 10.1 of the code, the program runs check of the min./max. stresses (10.2-(10.2)) calculated on the basis of the critical normal stresses σcr (10.2-(10.4)) and the critical shear stresses τcr(10.2-(10.5)).