钢筋混凝土柱压弯剪扭滞回性能试验研究

Experimental investigation on hysteretic performance of reinforced concrete columns under constant axial compression and cyclic reversed flexure-shear-torsion loading

为揭示钢筋混凝土柱在压弯剪扭反复荷载作用下的破坏机理,以扭弯比、剪跨比、配筋率和配箍率为变化参数,采用同步但不同位移幅值的加载方式完成了6个试件的低周反复加载试验并获取了试件试验数据,分析各变化参数对抗震性能的影响。试验结果表明:裂缝主要集中在试件中下段,呈现斜向交叉形式,破坏模式主要呈现弯扭破坏形态;随着扭弯比和配筋率的增大,试件扭矩-扭转角滞回曲线更为饱满,耗能能力强;增大剪跨比,试件扭矩-扭转角滞回曲线则呈现为捏缩状,耗能能力变差,但后期变形能力增强;通过增大试件的扭弯比、配筋率和配箍率,均可提高试件受弯延性和耗能能力,同时可延缓其强度和刚度的退化。

To study the reinforced concrete columns hysteretic behavior under constant axial compression and cyclic reversed flexure-shear-torsion loading, six specimens were designed and tested, in which the torsion-bend ratio, shear-span ratio, reinforcement ratio and stirrup ratio were considered, and cyclic loading with different displacements and amplitudes was performed. The failure modes and the relation curves between the torsion forces and the torsion angles for specimens were obtained. Based on the experimental data, the influences of abovementioned four parameters on the hysteretic performance were analyzed. The test results indicate that the failure patterns of specimens mainly appeared as bend-torsion composite failure, in which the cracks are diagonal and almost concentrates in the root. The torque-twist angle hysteresis back curve is full with enhanced energy dissipation capacity when the torsion bending rate and the reinforcement ratio are increased. As the torsion, the bending rate as well as the reinforcement ratio increase, the torque-twist angle hysteresis back curve becomes smoother, and more energy is dissipated. When the shear span rate increases, the torque-twist angle hysteresis back curve becomes more pinching, less energy is dissipated and the flexural ductility is improved. By increasing the torsion bending rate, the reinforcement rate and the stirrup rate, the flexural ductility of the specimen can be improved and the degradation of the rigidity and stiffness can be slowed down.