Elastic distortional buckling of corroded cold-formed steel columns

Many cold-formed steel (CFS) structures suffer from severe corrosion in long-term corrosive environments, which leads to the degradation of elastic buckling performance. Finite element (FE) models are developed to investigate the influence of corrosion region, size, and position on the elastic distortional buckling stress of corroded CFS columns. Based on the deformation characteristics of corroded columns, a calculation method for predicting elastic distortional buckling stress is proposed, and the predicted values are validated against the FE analysis results. The findings indicate that lip corrosion has the most pronounced effect on elastic distortional buckling stress, followed by web corrosion, while flange corrosion exerts the least influence. It is also observed that the length of the corrosion area significantly affects buckling stress when it falls within one half-wavelength of the column, suggesting a strong correlation between corrosion extent and the structural mode shape. In contrast, the distance of the corroded region from the transverse centerline of the web has only a minor effect. However, when corrosion is located near the web-flange junction, its influence on the buckling behavior becomes notably greater. When the corrosion area is located away from the column end, the distance from the longitudinal centerline has a limited impact on the elastic distortional buckling stress. However, when the corrosion region is near the column end, boundary conditions restrict distortional buckling deformation. The proposed calculation method provides accurate predictions of the elastic distortional buckling stress of corroded CFS columns.