Analysis on global buckling performance of CFS double box-shaped built-up columns by energy method

This study provides a comprehensive investigation of the global buckling behavior of cold-formed steel double box-shaped built-up columns (CFS-DBBC). The research includes compression tests and numerical simulations to analyze the effects of slenderness ratio and fastener configurations. The test results demonstrated that decreasing the fastener spacing can improve the load-bearing capacity (Pu), and the end fastener groups (EFG) can enhance that by approximately 8-18 %. Besides, the simulation results indicated that the enhanced material properties at the corners of the CFS-DBBC, resulting from the cold-work hardening effect, had a limited influence on the Puof the column. The elastic global buckling load (Pcrg) of CFS-DBBC was derived using the energy method and validated against numerical simulations. Subsequently, Pcrg was incorporated into the AISI-S100 standards to determine the global buckling Puof CFS-DBBC. The results of the parametric analysis demonstrated that the proposed approach exhibited high accuracy in predicting Pu.