Perforated Cold-Formed Steel Members in Compression. I: Parametric Studies.

This paper presents a comprehensive parametric study on the ultimate strength of perforated cold-formed steel columns using the finite element (FE) package ABAQUS. FE models were developed for columns predisposed to local (L), distortional (D), and global (G) buckling failures. The parametric study involved five cross-section types (i.e., C, stiffened C, Z, rack, and hat sections), five widths of holes, four lengths of holes, four different sizes of hole spacings, three material properties, two magnitudes and various directions of geometric imperfections, and three buckling modes (i.e., L, D, and G) and all of the possible interactions between them (i.e., LD, LG, DG, and LDG). Ultimate strengths, as well as failure modes, were obtained from the analyses and are plotted against the current codified direct strength method (DSM) in AS/NZS 4600. Significant discrepancies between the numerical results and the DSM-predicted strengths were observed due to the influence of holes, the interaction of buckling modes, and occasionally the inherent limitations of the DSM itself. The effects of column length, material properties, and centroid shift due to perforation are also discussed. A data pool including 146,207 column-ultimate strengths were obtained, most of which were used to formulate new design equations for perforated thin-walled columns based on the direct strength method, as presented in a companion paper. [ABSTRACT FROM AUTHOR]