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

Abstract

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 with compact or noncompact sections, however, too conservative for beams with slender flanges representing a considerable interaction between LTB and FLB limit states.