Test on mechanical behavior of SRC L-shaped columns under combined torsion and bending moment
【摘要】：Investigations of the seismic behavior of steel reinforced concrete L-shaped columns under constant axial compression and cycled bending-shear-torsion load were performed. Six specimens, which considered two parameters, i.e., the moment ratio of torsion to bending(γ) and the aspect ratio(column length-to-depth ratio, φ), were prepared for the experiment. In this study, the failure process, torsion-displacement hysteresis curves, and flexure-displacement hysteresis curves were obtained. The failure characteristics, mechanical behavior of specimens such as the failure patterns, hysteresis curves, rigidity degradation, ductility and energy dissipation, are analyzed. The experimental research indicated that the major failures of the specimens were bending failure, bending-shear failure and bending-torsion failure as the moment ratio of torsion to bending(γ) increased. The torsion-displacement hysteresis curves were pinched in the middle, formed a slip platform, and the phenomenon of "load drop" occurred after the peak load. The bending-displacement hysteresis curves were plump, which showed that bending capacity of the specimen was better than its torsion capacity. Additionally, the energy dissipation of the specimen was dominated by torsion in the early stage and ultimately governed by the bending moment in the later phase. Test results also indicated that the displacement ductility coefficient and interstory rotation angle of the failure point were less than 3.0 and 1/50, respectively, which means the test specimen performance does not meet the requirement of the Chinese Code for Seismic Design of Buildings(GB 50011-2014) in this respect.