Unified approach for the web crippling design of cold-formed channels: Carbon steel, stainless steel and aluminium

Cold-Formed (CF) structural members have become important in conventional and emerging modular building constructions. However, point loads can result in web crippling failure of floor joists, purlins and decks. Due to their enhanced structural, aesthetic and resistive properties, CF aluminium and CF stainless-steel beams are used as an alternative solution to CF carbon steel beams. This paper ultimately investigates the web crippling behaviour of lipped channel beams under Interior Two-Flange (ITF) loading conditions. Since there is no unified approach is available for web crippling behaviour of various materials, this study focused on it. Three structural materials were considered as part of the study: carbon steel, aluminium and stainless-steel. Available experimental studies were used to validate Finite Element (FE) models, before an extensive parametric study (378 FE models) was carried out. Commercially available lipped channels with relatively lower web depth were considered to examine the web crippling behaviour under lower slenderness. Current design codes showed inaccurate prediction up to 15% against the results. This paper ultimately proposes new unified design guidelines for predicting the web crippling capacity of CF carbon steel, CF aluminium and CF stainless-steel lipped channel beams under ITF loading conditions.