The simplified method of the equivalent compression flange - Development based on LTB tests and residual stress measurements

Extended version of the Tomáš Vraný SDSS Award 2019
The method of the equivalent compression flange simplifies the verification of lateral torsional buckling of steel beams to flexural buckling of an equivalent part of the cross-section that is in compression. The current simplified method is based on outdated normative rules and the design results may be both, uneconomic and non-conservative. To remedy these shortcomings, the simplified method is modified based on the basic structural behaviour of steel beams taking into account the effects of material, cross-sectional geometry and residual stresses. This paper presents a comprehensive experimental study on the lateral torsional buckling behaviour and residual stresses of welded doubly- and mono-symmetric I-shaped steel beams. Moreover, an improved simplified method of the equivalent compression flange is proposed for design purposes.