Flexural Capacity of Locally Buckled Steel I-Beams Under Moment Gradient

Lateral-torsional buckling (LTB) and flange local buckling (FLB) are treated as two independent phenomena in AISC-LRFD 360-10 in which the flexural capacity of locally buckled beams is determined as the minimum value obtained for the limit states of LTB and FLB. A 3-D nonlinear finite-element model using ABAQUS is developed in this research to investigate the interactive flexural capacity of steel I-beams with compact web under moment gradient. It was found that the AISC approach is adequate for beams withcompact or noncompactsections, however, too conservative for beams withslender flangesrepresenting a considerable interaction between LTB and FLB limit states.

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