Web crippling behaviour of cold-formed high-strength steel unlipped channel beams under End-One-Flange load case

Abstract

High-strength Cold-Formed Steel (CFS) members are widely adopted as structural members in building structures due to its higher ultimate capacity. The flexural members are often subjected to concentrated transverse loads which may leads to buckling instabilities including web crippling. However, there is no appropriate design rules and studies are available to estimate the web crippling strength of high-strength CFS members. Hence, this paper presents a detailed numerical investigation on high-strength CFS unlipped channel sections subjected to End-One-Flange (EOF) loading condition with nominal yield strengths of 700 MPa, 900 MPa and 1000 MPa. For numerical simulation study, non-linear Finite Element (FE) models were developed and validated with the experimental results followed by an extensive parametric study using ABAQUS. In total, 243 FE models were developed with different geometric and material parameters including section thickness, material strength, web slenderness ratio, inside bent radius to thickness ratio and bearing length to thickness ratio. The ultimate web crippling strength results were compared with the available design guidelines to check their suitability and accuracy in terms of strength prediction. Then, new design rules to predict the web crippling capacity of high-strength CFS unlipped channel section under EOF condition based on unified and Direct Strength Method (DSM) approaches were proposed.

Keywords

• High-strength cold-formed steel
• Unlipped channel section
• Web crippling
• End-One-Flange (EOF) load case
• Finite element analysis
• Direct strength method