Testing, numerical modeling and design of perforated advanced high-strength steel channel section columns

This paper examines the influence of perforations on the buckling instability and load-bearing capacity of advanced high-strength steel channel section (C-section) columns. Experimental tests were first conducted on 19 column specimens made of complex phrase steel HC700CP980 under axial compression, followed by finite element (FE) analysis. Two section types, the flat web C-section and the web-stiffened C-section, were considered, with perforations categorised as web-only or both web and flanges. Material tests and initial imperfection measurements were conducted and reported. Using test results, finite element models were established and parameter analysis was carried out. Analysis of test results and finite element data revealed that perforations had a noticeable impact on the buckling deformation of flat web C-sections but had a minor effect on load-bearing capacity. In contrast, web-stiffened C-sections exhibited intensified deformation post-perforation, significantly reducing their axial stiffness and load-bearing capacity. The Direct Strength Method (DSM) was assessed based on combined test and FE data. It revealed that the DSM resulted in a high level of inaccuracy and scatter in the load-bearing capacity predictions of high-strength steel C-sections after perforation. To address this, a modified method incorporating a perforation strength reduction factor was proposed, offering straightforward and intuitive calculations with improved design accuracy and consistency.