近断层地震下钢管混凝土加固RC桥墩地震响应分析

Seismic Response Analysis of RC Bridge Pier Strengthened with Concrete Filled Steel Tube Under Near-fault Ground Motions

为深入研究钢管混凝土加固RC桥墩的抗震性能,利用Open sees有限元软件建立了RC桥墩与钢管混凝土加固墩的数值模型,对模型输入近断层脉冲型地震动、近断层非脉冲型地震动、远断层地震动,进行增量动力分析。以墩顶最大位移角与震后残余位移角为指标,分析了RC桥墩加固前后的地震响应。结果表明:与近断层非脉冲型地震动、远断层地震动相比,近断层脉冲型地震动下的钢管混凝土加固墩与RC原墩的位移响应更大;钢管混凝土加固方式可有效抑制RC桥墩的最大位移响应,位移抑制率可以达到35%以上;钢管混凝土加固方式对于减小RC桥墩的震后残余位移效果有限,加固后甚至可能导致结构震后残余位移增大。

In order to study the seismic performance of reinforced concrete(RC)pier strengthened with concrete filled steel tube,the numerical models of RC pier and strengthened pier are established based on the Open sees software.The incremental dynamic analysis was conducted for all the models under the near-fault ground motions with velocity impulse and near-fault ground motions and far-fault ground motions.Based on the maximum drift ratio of pier top and the residual drift ratio,the seismic response of RC pier and strengthened pier was analyzed.The results show that the displacement response of strengthened pier and RC pier under near-fault ground motion with velocity impulse is larger than that under near-fault ground motion and far-fault ground motion.Concrete filled steel tube reinforcement can effectively reduce the maximum displacement response of RC pier,and the displacement restraint rate can reach more than 35%.However,the effect of the reinforcement on restraining the residual displacement of RC pier under earthquake is limited,and it may even lead to the increase of residual displacement under earthquake.