反复荷载作用下焊接环式箍筋对高强混凝土柱的约束作用研究

通过6个配有焊接环式复合箍筋高强混凝土柱的水平低周反复加载试验及有限元数值模拟,研究了箍筋对柱受力性能和变形性能的影响。试验及数值模拟中考虑了轴压比、配箍率这两个参数的影响,由试验及数值模拟得到了力与位移的滞回曲线和骨架曲线,分析了箍筋对试件延性、滞回特性、耗能性能以及正截面抗弯承载力的影响。研究结果表明,在焊接环式箍筋的约束下,试件正截面的实际抗弯承载力明显要高于《混凝土结构设计规范》计算值,说明箍筋发挥了很好的约束作用;与一般的钢筋混凝土柱相比,所有试件的滞回曲线都更加饱满,没有明显的捏拢现象,证明这种箍筋的约束作用大大提高了柱的抗震能力和耗能能力;随着箍筋的约束指标增大,试件的延性可以得到提高,并且还能减小轴压比的增大对柱延性产生的不良影响。

Research on confinement of stirrups in the high strength concrete columns with welding ring stirrups under cyclic load

Based on low-cycle reversed lateral loading experiment and finite element numerical simulation of six high strength concrete columns with welding ring composite stirrups,the effects of the stirrups on mechanical and deformation behavior of the columns were studied.The influence of the axial compression ratio and stirrup ratio was considered in the experiment and numerical simulation,and the force-displacement hysteretic curves and skeleton curves were obtained.The effects of the stirrups on ductility,hysteretic characteristics,energy dissipation capacity and bending capacity of cross section of specimens were analyzed.The results show that test values of bending capacity of cross section of specimens are much higher than calculation values calculated by Code for design of concrete structures,the stirrups play an active role in confinement.Comparing with common reinforced concrete column,hysteretic curves of all the specimens are plumper and no obvious pinch phenomenon,which proves that the confinement of the stirrups can greatly improve the seismic capacity and energy dissipation capacity of the columns.As confinement index of the stirrup increases,ductility of the specimens can be improved,and harmful effects of the columns ductility by the increment of the axial compression ratio can be decreased.