Web crippling behaviour of S690 and S960 high-strength steel channel sections under interior-one-flange loading

The present paper reports experimental and numerical studies on the web crippling behaviour and resistances of press-braked high-strength steel channel sections under interior-one-flange loading. Web crippling tests were conducted on ten specimens, including six for grade S690 high-strength steel and four for grade S960 high-strength steel. The obtained test failure loads, load–web shortening curves, load–web out-of-plane deformation curves and web crippling failure modes were reported. In conjunction with the experimental programme, a numerical modelling programme was performed, where a validation study was conducted to validate finite element models against test results and parametric studies were conducted to generate further numerical data. Based on the test and numerical data, current web crippling design rules for normal-strength steel channel sections under interior-one-flange loading, as specified in EN 1993-1-5, EN 1993-1-3 and AISI S100, were evaluated for the applicability to their high-strength steel counterparts. The evaluation results revealed that the codified design rules provided inaccurate and scattered web crippling resistance predictions. Finally, a slenderness-based design approach was developed and shown to offer a higher level of design accuracy, consistency and reliability for press-braked high-strength steel channel sections under interior-one-flange loading than the existing design standards.