An experimental study on web-bearing resistance of cold-formed steel sigma-shaped sections with web holes under interior-two-flange loading case

• Cold-formed steel (CFS) sigma-shaped sections in web crippling was studied. • A total of 29 new experiment results were reported. • A finite element modelling method was proposed and its accuracy was verified. • The existing design codes cannot accurately predict the strength of such members. Cold-formed steel (CFS) sigma-shaped sections used as flooring joists and bearers are commonly fabricated with web holes to accommodate building services. These sections featuring web stiffeners and curved lips exhibit lower web-bearing resistance than traditional lipped channel sections. However, the web-bearing resistance of CFS sigma-shaped sections with web holes has not been thoroughly investigated. To address this gap, a detailed experimental investigation was conducted, testing 29 CFS sigma-shaped sections with web holes under an interior-two-flange (ITF) loading case. For comparison, specimens without web holes were also tested. Variables such as hole diameter ratio, hole location, bearing length, and flange condition were examined. A finite element (FE) model was developed and validated against the test results. The results indicated that the web-bearing resistance for specimens with web holes was reduced by 24.0% on average. To assess the accuracy of existing design specifications, the test results were compared against the design strengths predicted by the American Iron and Steel Institute (AISI) (2016), Australian and New Zealand Standards (AS/NZS) (2018), European Standard (EC3) (2006), and Uzzaman et al. (2012). The comparison revealed that the design strength predicted by Uzzaman et al. (2012) agreed well with the test results.