Web crippling behaviour of web-perforated sigma sections under interior-two-flange loading condition

Despite the widespread structural applications, the web crippling response of web-perforated cold-formed (CF) Sigma sections remains unexplored. Hence, a combined experimental and numerical investigation was conducted under the present study to determine the web-bearing resistance of web-perforated CF steel, stainless steel and aluminium Sigma sections under the Interior-Two-Flange (ITF) load case. A total of 18 Sigma sections were tested and the results were used to develop and validate a finite element (FE) model. An extensive numerical investigation (480 FE models) was conducted to evaluate the effects of critical parameters on the web-bearing resistance of web-perforated CF Sigma sections. FE results were compared against the web crippling strength predictions of current design codes. Based on the limitations of the codified predictions, a novel unified design equation was developed for determining the web-bearing resistance of web-perforated CF steel, stainless steel and aluminium sections under the ITF loading condition. Moreover, comparisons were made between the web crippling resistance of web-perforated Sigma sections and identical lipped channel sections.