Testing and numerical modelling of web-stiffened cold-formed steel channel section compression members with web perforations and batten reinforcements

This study investigates the impact of perforations on the load-bearing capacity of C-section columns with different web stiffener configurations and proposes effective structural measures to mitigate capacity loss due to perforations. First, experimental tests were conducted on channel sections with a flat web, a V-shaped web stiffener, and a bow-shaped web stiffener. The specimens included unperforated columns as the control group, perforated columns, and perforated columns reinforced with batten panels. Subsequently, finite element modeling and parametric analysis were carried out based on the experimental results. Analysis of the experimental and finite element results indicates that flat-web C-section columns experience the least reduction in load-bearing capacity, while V-shaped web-stiffened C-section columns show significant stiffness degradation and the greatest reduction in load-bearing capacity after perforation, with reductions of up to 32.3 % in the tests and 35.9 % in FEA. When transverse support is provided by batten panels, the distortional buckling of bow-shaped web-stiffened C-sections is suppressed, resulting in a substantial increase in load-bearing capacity, up to 50.9 % in the tests and 74.3 % in FEA. The load capacity evaluation reveals that the Direct Strength Method is conservative and reliable for flat-web C-section columns but tends to be non-conservative and less reliable for C-section columns with web stiffeners. Finally, this study introduces the perforation strength reduction factor to directly calculate the load-bearing capacity of perforated C-section columns, providing more reliable and less dispersed calculation values. Similarly, the strength enhancement factor proposed for batten panels can be used to directly calculate the load-bearing capacity of perforated, web-stiffened C-section columns, offering accurate, consistent, and reliable calculation results.