05.27: Resistance of mono-axially bent beams of welded I-sections: FEM verification of Eurocode's buckling curve formulation

Present Eurocode's approach to design of steel I-section beams is based on the analytical resistance evaluation yielding from the interaction resistance criteria established for beam-columns that cover two design situations: a) the flexural in-plane failure (second order biaxial bending and compression), and b) the flexural-torsional out-of-plane failure (second order spatial bending, warping torsion and compression). The Eurocode's unified resistance ultimate limit state criteria of I-sections are depended upon the technological aspects of steel section production via the buckling curve differentiation for the evaluation of reduction factors for buckling in compression and lateral-torsional buckling in bending about the major axis. This paper attempts to verify the Eurocode's buckling resistance criteria in case of welded I-section in mono-axial bending on the basis of finite element simulations and on the separate inclusion of material and geometrical imperfections. The finite element shell model is utilized and built within the ABAQUS software. The Eurocode's resistance criteria are verified by results of FEM simulations in case of moment gradient loading conditions. Concluding remarks in relation to analytical formulations presented in Eurocode 3 are drawn.