LAUSR

Continuous multispan beams in bridges experiences high negative moment at interior supports and the top flanges of these beams are laterally braced due to the concrete slab or steel deck above it. The negative moment can be resisted by increasing the cross sections of the beams at the supports. An earlier study on the elastic lateral torsional buckling of stepped beam with continuous lateral bracing was conducted to propose new design equations. The main focus of this study is to continue the previous research considering the inelastic buckling of stepped beams. ABAQUS, a finite element method program was used to conduct the buckling analysis of the beams. A total of five different load cases were used in the analysis. The effects of the residual stress and geometric imperfection were also considered for the inelastic buckling strength. Results showed that the inelastic buckling strength exceeds the plastic moment of the section and it is not needed to focus on the inelastic range when computing the lateral torsional buckling strength.