Generalized direct strength design approach: steel cold-formed columns under buckling mode interaction
Palavras-chave:
Cold-formed steel member, Local-Distortional buckling interaction, Local-Distortional-Global buckling interaction, Direct Strength Method, Finite Element MethodResumo
Thin-walled steel cold-formed members exhibit local (L), distortional (D), and global (G) buckling modes. These modes can interact in various ways, depending on the relationship between the corresponding buckling loads (PcrL, PcrD, and PcrG). The direct strength method (DSM) provides equations for designing columns experiencing global, local, distortional, and local-global buckling interaction (LG). This study focuses on the most general buckling mode interaction (LDG), building upon a recent approach by the authors that covers local-distortional buckling (LD). To develop the design equations, extensive numerical (FEM) and experimental databases were utilized, covering the relevant ranges of slenderness factors (λL, λD, and λG) associated with L, D, and G buckling modes, respectively. The proposed approach combines the existing DSM equations from the Brazilian code NBR 14762:2010 and the design equations for LD buckling interaction, recently proposed by the authors. After identifying the main variables and calibrating the design equations using FEM and literature-based experimental results, the contribution of the global mode is incorporated. The resulting set of design equations takes into account all the possible buckling modes, L, D and G, and the buckling interactions (LG, LD, and LDG)
for axial compression of steel cold-formed members.
