Unified design equations for web crippling failure of cold-formed ferritic stainless steel unlipped channel-sections with web holes

• Published in: Journal of Building Engineering Vol. 45; p. 103685
• Main Authors: Yousefi, Amir M., Samali, Bijan, Hajirasouliha, Iman, Yu, Yang, Clifton, G. Charles
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.01.2022
• Subjects: Cold-formed steel; Corrosion; Stainless steel; Steel structures; Structures & design; Web crippling; Structures & design; Web crippling; Cold-formed steel; Corrosion; Steel structures; Stainless steel
• ISSN: 2352-7102; 2352-7102
• DOI: 10.1016/j.jobe.2021.103685

This paper addresses the design of cold-formed ferritic stainless steel unlipped channel-sections with offset web holes and fastened flanges subject to web crippling under one-flange load scenarios. The results of a total of 18 new experimental tests, not reported previously, are presented; these were conducted on ferritic 1.4016 grade unlipped channel-sections under both interior- and end-one-flange loadings. The results are used to validate a non-linear quasi-static finite element model to simulate the behaviour of such sections. A comprehensive parametric study including a total of 576 FE models is then undertaken to determine the web crippling strengths for unlipped channel-sections with different web heights, web thicknesses and location of web holes under both interior- and end-one-flange loadings. In addition, the experimental and FE results are compared against strengths predicted in accordance with the American Iron and Steel Institute (AISI S100-16) for cold-formed carbon steel plain lipped channel-sections as well as the equations proposed in previous studies for stainless steel plain lipped channel-sections. It is found that the current design equations are unreliable and unconservative to use for cold-formed ferritic stainless steel unlipped channel-sections by as much as 22%. To address this issue, based on the results of this study, two new reliable web crippling strength reduction factor equations are proposed for such unlipped channel-sections. The proposed equations should prove useful for practical design of cold-formed ferritic stainless steel unlipped channel-sections with offset web holes and fastened flanges. For practical design application, the equations are then unified by combining the proposed equations with existing equations from the literature to allow a unified design equation to be developed for ferritic stainless steel unlipped channel-sections with centred and offset web holes and with both flanges fastened and unfastened to the bearing plates under one- and two-flange load scenarios. •The novel results of a total 18 experimental tests of cold-formed ferritic stainless steel unlipped channel-sections with offset web holes and fastened flanges under one-flange loadings are presented.•Non-linear quasi-static finite element models are developed and verified against experimental test results.•A comprehensive parametric study including a total of 576 FE models with different sizes of circular web holes and cross-sections sizes is performed.•Evaluating reliability of current design equations, two new design equations are proposed.•For practical design application, unified design equations developed for ferritic stainless steel unlipped channel-sections with centred and offset web holes and with both flanges fastened and unfastened to the bearing plates under one- and two-flange load scenarios.