配置CRB600H箍筋混凝土柱抗震抗剪性能研究

Research on seismic shear behavior of concrete columns with CRB600H stirrups

为研究配置CRB600H高强箍筋混凝土柱的抗震抗剪性能,进行了6根配置CRB600H箍筋混凝土柱的低周反复加载试验,对试件的破坏形态、滞回曲线、位移延性以及纵筋和箍筋的应变进行了分析。试验结果表明:高强箍筋混凝土柱均呈剪切破坏形态,失效时的位移延性系数均达到3.0以上,极限位移角达到或接近1/50;各试件中的箍筋在峰值荷载状态下均能达到屈服。将试验结果与我国《混凝土结构设计规范》(GB 50010—2010)以及美国规范ACI 318-14中抗震抗剪承载力计算公式的计算结果进行了对比。结果表明,采用上述规范公式计算高强箍筋混凝土柱的抗震抗剪承载力时,如果高强箍筋的强度取实际屈服强度,与试验结果相比计算结果偏高。根据试验与收集的39个配置高强箍筋混凝土柱的抗震抗剪试验结果,提出了适用于屈服强度为500～600MPa高强箍筋混凝土柱的抗震抗剪承载力计算公式,并建议了高强箍筋强度上限值的取值。

Low frequency cyclic loading tests for 6 concrete columns with CRB600 H stirrups were conducted to evaluate the seismic shear behavior of the concrete columns with CRB600 H stirrups.The failure patterns,hysteretic curves,displacement ductility,longitudinal reinforcement strain and stirrups strain of the specimens were studied.The experimental results show that the specimens of columns with high-strength stirrups(HSS)are in shear failure modes.The displacement ductility factor is above 3.0 when the column fails,and the ultimate displacement angle reaches or is close to 1/50.The HSS in each specimen can yield under the peak load condition.The experimental results were compared with the calculated results of the formulas for the seismic shear strength in Chinese code Code for design of concrete structures(GB 50010—2010)and American ACI 318-14 code.It shows that when calculating the seismic shear capacity of columns with HSS using the above formula,if the actual yield strength of HSS is taken,the calculation results are higher than the experimental results.Based on the results of 39 seismic and shear tests of columns with HSS which are from experiment and collection,the formulas for calculating the seismic and shear bearing capacity of columns with HSS of 500~600 MPa and the upper limit value of HSS were proposed.