Flexural Strength of High-Strength Steel-Concrete Composite Beams with Varying Steel Grades

In order to investigate the bending capacity of composite beams constructed with high strength steel (HSS) sections, a three-dimensional finite element model allowing for both material and geometric non-linearity is described and validated against previous experimental results. An extensive body of parametric studies incorporating selected steel grades and degrees of shear connection is further undertaken. The flexural strength of such composite beams are analysed, and the effects of the steel yield strength and cross-sectional residual stresses are elucidated. Based on a comparison with composite beams using conventional mild steel, it is found that the method of rigid plastic analysis that is normally utilised to design composite beams with mild steel sections somewhat overestimates the bending strength of composite beams with HSS. There is no significant difference in the strength of a composite beam when considering the cross-sectional residual stress. A reduction factor is proposed for the adaptation of rigid plastic analysis, from which the prediction of the bending strength of composite beams with HSS becomes more accurate. This research has the potential to promote the practical application of HSS in composite construction, which is more environmentally sustainable due to the better efficiency of material utilisation compared with composite beams with lower-strength mild steel.