近场地震作用下TMD-BIS混合控制体系的非线性响应分析

Seismic response analysis for nonlinear base-isolated structure with TMD under near fault ground motions

对一种已经提出的将TMD和BIS联合起来进行控震的策略进行近场地震作用下的非线性响应分析。采用Bouc-Wen模型模拟隔震垫的非线性力-变形行为,建立TMD-BIS混合控制体系的运动方程,使用四阶龙格库塔法并采用Matlab编程对该非线性方程进行求解。以某8层基础隔震结构为算例,采用隔震层位移减幅作为评价指标,研究了地震动脉冲周期、隔震垫屈服前刚度以及TMD调谐频率对混合控制体系控制效果的影响。研究结果表明:脉冲周期对体系的控制效果影响较大,当脉冲周期与结构基本周期接近时控制效果最好,在对TMD的相关参数进行设计时应考虑其影响;随着隔震垫屈服前刚度的增大,体系的控制效果也相应增大;TMD的调谐频率对体系的控制效果影响很大,它的确定取决于隔震层在地震作用下的变形状态。

The nonlinear seismic response anlysis for Base-Isolated Structure with TMD that has been proposed is carried out under near fault gound motions. The Bouc-Wen model is used to simulate the isolation layer's nonlinear forcedeformation behavior,the motion equation is established. The nonlinear differential equation is solved by using the fourthorder Runge-Kutta method in Matlab. A eight-story base-isolated structure is employed herein as an numerical example,The reduce quantity of the isolation layer's peak displacement is used as evaluation index and the effect ot the pulse period of the ground motions,pre-yield stiffness of the isolation bearing and the tuning frequency on the hybrid control system's effectiveness is studied. Analysis results indicate that the pulse period has an larger effect on the control effectiveness,and when the pulse period is close to the BIS fundamental period,this control strategy is very effective; the control strategy becomes more effective when the pre-yield stiffness becomes larger; in addition,the tuning frequency of the TMD has a large effect on the control effectiveness,and it depends on the state of the isolation layer under ground motions.