Nonlinear web crippling analysis and design of cold-formed high strength steel channel sections having different stiffened flanges.

• Web crippling analysis and design of channel sections were presented. • Parametric studies were performed on sections having different stiffened flanges. • FE strengths, load-displacement relationships and failure modes were predicted. • A reliability analysis was performed. • NAS, AS//NZS, EC and previously published design rules were assessed. Web crippling analysis and design of cold-formed high strength steel channel sections having different stiffened flanges are presented in this paper. 3D finite element models were developed for the analysis of sections with unstiffened flanges, stiffened flanges with simple lips, stiffened flanges with inward return lips and outward return lips loaded under End-Two-Flange (ETF) and Interior-Two-Flange (ITF) loading conditions. The models were verified against tests recently reported by the authors on cold-formed high strength channel sections having different stiffened flanges. The web crippling strengths, load-displacement relationships and failure modes were predicted numerically and compared well against that measured experimentally. Extensive parametric studies were performed using the validated models on 280 channel sections having different web slenderness, ratios of bearing length to web thickness, cross-section geometries and shapes of flange lips. The web crippling numerical strengths were compared with the web crippling design strengths specified in North American Specification, Australian/New Zealand Standards and Eurocode as well as with other proposed design equations in the literature. In addition, a reliability analysis was performed to assess the reliability of the design rules. It is found that the design strengths were either unconservative or conservative, and generally unreliable for the cold-formed channels with unstiffened and stiffened flanges investigated. Therefore, a modification for the North American Specification design equation was proposed. The modified proposed design equation provided more accurate and reliable web crippling strengths compared with specified and available in the literature web crippling design strength predictions. [ABSTRACT FROM AUTHOR]