Answer:
In this case, we recommend using the module extension RF‑/STEEL Warping Torsion:
RF‑/STEEL Warping Torsion is an extension of the RF‑/STEEL EC3 and RF‑/STEEL AISC add-on modules (see Links under this FAQ). It performs lateral-torsional (flexural-torsional) buckling analyses of members according to the second-order theory with seven degrees of freedom and application of imperfections with regard to mode shapes.
You can find more information by clicking the links below this FAQ.
