# In PLATE‑BUCKLING, the reduction factor due to column buckling χc is calculated using the modified slenderness of the sheet metal ${\overline{\mathrm\lambda}}_{\mathrm p}$. Why is it not calculated using the slenderness of the equivalent compression member ${\overline{\mathrm\lambda}}_{\mathrm c}$ ?

RF-PLATE-BUCKLING performs the plate buckling analysis in compliance with Chapter 10 "Reduced Stress Method" of EN 1993‑1‑5. According to EN 1993‑1‑5, 10 (5) a), it is necessary to determine all reduction factors with the modified slenderness ratio of the sheet metal ${\overline{\mathrm\lambda}}_{\mathrm p}$ according to Equation (10.2).