Research on the elastic buckling of composite webs in cold-formed steel back-to-back built-up columns – Part I: Experimental and numerical investigation

Abstract

Cold formed steel (CFS) built-up members are increasingly used in buildings because of their better mechanical performance. In this paper, the elastic buckling behaviors of the composite plates extracted from CFS back-to-back built-up columns were investigated using a combination of tests and finite element (FE) analyses. A total of 18 CFS back-to-back built-up columns were tested in this study. The built-up sections were fabricated from two identical C-section components and were assembled with self-drilling screws at their webs. The effects of screw number and screw spacing on the critical buckling loads and buckling modes of the built-up column were investigated in this paper. Moreover, extensive parametric studies were conducted in detail by developing CFS FE models based on the validation process with available experimental results. In addition, both the critical buckling loads as well as the buckling modes predicted from the FE analyses were in good agreement with the laboratory test results.