Buckling of Welded Hybrid Steel I-Beams

Abstract

Allowance is made in the analysis for the effects of the residual stresses produced by welding and sections fabricated from both Universal Mill (UM) plates and flame cut (FC) plates are considered. Early yielding of the beam's web is shown to have little effects upon lateral stability, the stiffness of the compression flange being the most important factor. For a constant weld size, hybrid sections and sections fabricated from the flange material throughout are found to have very similar lateral buckling strengths. Plotting the results on an equivalent lateral-torsional slenderness ratio basis actually causes the hybrid sections' curve to be the highest. Use of this technique also minimizes the effect of variations in cross-sectional shape although the level of residual stresses in the sections remains an important parameter. Sections fabricated from FC plates are found to possess slightly differently shaped lateral buckling curves to sections fabricated from UM plates.