Cold-formed ferritic stainless steel unlipped channels with web openings subjected to web crippling under interior-two-flange loading condition - Part I: Tests and finite element model validation

Web openings are commonly used in beams of buildings to facilitate services. In this paper, a combination of tests and non-linear finite element analyses is used to investigate the effect of such web openings on the web crippling strength of cold-formed ferritic stainless steel unlipped channel-sections under the interior-two-flange (ITF) loading condition; the cases of both flanges fastened and flanges unfastened to the bearing plates are considered. The results of 54 web crippling tests are presented, with 18 tests conducted on unlipped channel-sections without web openings and 36 tests conducted on sections with circular web openings. In the case of tests with web openings, the circular web openings are located either centred or offset to the bearing plates. A quasi-static finite element model is then presented. Good agreement between the tests and finite element analyses is obtained in terms of failure load, failure modes and post-buckling behaviour.