Seismic behavior of high strength steel welded beam-column members

• Seismic behavior of high strength steel column was experimentally evaluated.
• Effects of width to thickness and height to thickness ratios were investigated.
• Moment-curvature hysteretic curves were calculated and presented.
• A trilinear hysteretic model for welded high strength steel column was proposed.

This study presents the evaluation of seismic performance of high strength steel (HSS) beam-columns. Quasi-static experiments were carried out on four welded H-section and four box-section beam-column members fabricated from flame-cut Q460C HSS. The specimens were subjected to combined constant axial load and cyclic lateral load. The axial load was held at 30% of the yield strength of specimen during the loading history. The effects of width to thickness ratio and height to thickness ratio on the seismic behavior of HSS beam-columns were evaluated. It is found that component plate slenderness ratio has a significant effect on the deterioration behavior of beam-column under cyclic loading. According to the test results, welded Q460C HSS beam-columns with compact cross-sections show a good capacity of energy dissipation. No significant degradation was observed for the moment capacity of very compact cross-sections as class 1 under large inelastic rotation. The moderate compact cross-section belonging to class 2 shows a decrease in the moment capacity accompanied with the occurrence of local buckling when storey drift ratio is around 1/30. In addition to the obtained end moment–rotation hysteretic curves, the end moment–curvature hysteretic curves were developed to achieve more accurate descriptions of the cyclic performance of HSS specimens. Based on the generalization of experimental hysteretic curves, a trilinear hysteretic model was proposed in terms of the normalized moment–curvature relationship. This model was further compared with the experimental study to validate the accuracy in predicting the seismic behavior of HSS beam-column members.