Nominal moment capacity of hybrid composite sections using HSB600 high-performance steel

This paper contains a parametric study to develop provisions for predicting the nominal moment capacity of hybrid composite girders using HSB600 high-performance steel in the positive bending region. The ultimate moment capacity and the ductility of a wide range of hybrid composite sections are calculated using moment-curvature analysis, and the plastic moment of each section is obtained using simple plastic theory. The obtained moment capacity and the ductility of hybrid composite sections are compared to the previous research work and the current AASHTO LRFD’s design equations. The comparison results show that there are considerable differences in moment capacity distribution between the hybrid composite sections and the conventional composite sections. It was also observed that the hybrid composite sections have sufficient rotation capacity similar to the conventional composite sections. Based on the results of the parametric study, new design equations are proposed for predicting the nominal moment capacity of hybrid composite sections. It is expected that the new design equations can be applied to simple supported or continuous hybrid composite beams in plastic design.