Inelastic buckling capacity of beams considering load height effect, stepped flanges, and compact or noncompact sections

Abstract

This study aims to investigate the effects of load height, stepped beam configuration and section compactness on the inelastic lateral buckling strength of doubly and singly stepped I-beams. To study the effects of load height, the loads are situated at three points: at the center of the top flange, at the shear center and at the center of the bottom flange. To check for the effect of stepped beam configuration, beams were stepped either at both top and bottom flanges or at top flange only. Meanwhile, to investigate the effects of section compactness, two sections are analyzed: one section with compact flanges and web and another section with non-compact flanges and a compact web. The loadings are limited to those having an inflection point of zero. To also check the effect of steps, stepped parameters α, β and γ are varied. The buckling strengths of the beams investigated are obtained by conducting nonlinear analysis using the finite element program, ABAQUS. In conducting the nonlinear analysis, the residual stresses and geometric imperfections are taken into consideration to clearly simulate the inelastic behavior of the beams. The results of the analysis would then determine if the location of the loads, configuration of stepped flanges and compactness of flanges have significant effect on the inelastic buckling strength of the stepped beams.