压弯剪扭钢筋混凝土十形柱抗震性能试验研究

为研究压弯剪扭复合受力钢筋混凝土十形柱的抗震性能，以扭弯比、轴压比为变化参数，设计6个钢筋混凝土十形柱试件进行恒定轴力反复弯剪扭的加载试验，观察试件的破坏过程和形态，获取扭矩-扭转角滞回曲线和荷载-位移滞回曲线以及试件的开裂、屈服、峰值和破坏等特征点参数。基于试验数据，详细分析了压弯剪扭复合受力该类柱的极限承载力、位移延性、层间侧移角、能量耗散、强度及刚度退化等抗震性能指标。结果表明:在扭弯比小于0.21且轴压比小于0.34范围时，低周反复压弯剪扭钢筋混凝土十形柱的破坏形态表现为弯扭和扭剪破坏，滞回曲线呈捏拢状的S形，位移延性系数超过3.0，开裂时的侧移角大于1/550，破坏时的侧移角大于1/40，能满足我国建筑抗震设计规范要求；扭矩的存在使得材料的损伤更严重，耗能更大。

EXPERIMENTAL STUDY ON SEISMIC BEHAVIOR OF REINFORCED CONCRETE CROSS SHAPE COLUMNS UNDER COMPRESSIONFLEXURE-SHEAR-TORSION COMBINED ACTIONS

To reveal the seismic behavior of reinforced concrete cross shape columns under compressionflexure-shear-torsion combined actions, the torsion-bending ratio and axial compression level were considered as parameters in an experiment, and six specimens of reinforced concrete cross shape columns were designed for reversed cyclic flexure-shear-torsion loading test with constant compression. The failure process and failure pattern were observed, the hysteretic curves of torque-torsion angle and loading-displacement as well as the characteristic results of the cracking, yielding, peak and failure points were obtained. Based on the test data, the seismic indexes of the specimens, such as the bearing capacity, ductility, drift angle, energy dissipation, strength and stiffness degradation, were analyzed deeply. The research results show that when the torsion-bending ratio is less than 0.21 and the axial compression level is less than 0.34, the failure pattern of the specimens are of a bending-torsion or torsion-shear failure mode. The hysteretic curves are of an "S" shape and pinch obviously. The ductility coefficients are larger than 3.0, the crack point drift angles are larger than 1/550, and the failure point drift angles are larger than 1/40. All of them can meet the needs of the Chinese code for seismic design of buildings. The presence of the torque makes the material damage more serious and improves the energy dissipation capacity of the specimens.