【摘要】 为了减小底层柔性结构的地震反应,防止结构因底层位移过大而倒塌,提出了一种底层柔性结构减震控制体系,在柔性底层安装磁流变阻尼器对其实施半主动控制。考虑到竖向地震的不利影响,建立了结构在双向耦合地震作用下的动力分析模型和振动控制方程,采用LQR控制算法对结构进行地震反应分析。研究表明,在无控情况下,结构的位移主要集中在底部柔性层;实施半主动控制后,结构的底层位移、顶层位移、各层加速度和倾覆力矩均明显减小,其中底层位移减小60%以上。在耦合地震作用下结构的地震反应比单纯水平地震作用下有所增加,以倾覆力矩的增加最明显,因此在高烈度地区应该考虑竖向地震对结构的影响。层间刚度比对结构的控制效果也会产生较大的影响,结构层间刚度比的确定应该在底层位移、顶层加速度和倾覆力矩之间权衡考虑。考虑土与结构相互作用会使结构的控制效果降低。更多还原

【Abstract】 In order to reduce the earthquake response and prevent collapse with oversize bottom displacement of soft-first story structure,this paper proposed a seismic control system for a soft-first story structure. The structure adopted a semi-active control method with magnetorheological dampers in the soft-first story. Considering the adverse influences of vertical earthquake,this paper established the dynamic model and vibration-control equations of structure under bi-directional coupling earthquake action. The LQR control algorithm was used for the earthquake response analysis of the structure. The analysis results indicated that,the displacement response of the structure concentrates mainly on the flexible bottom layer in the uncontrolled case. For the semi-active control case,the displacements of bottom and top layer,acceleration and overturning moment at each layer are reduced significantly.In particular,the displacement of the bottom layer was reduced by 60% and more. Compared with horizontal earthquake,the seismic responses increased in the case of coupling earthquake. The increase of overturning moment is the most obvious. Therefore,the influence of vertical seismic motion should be considered in high seismic intensity region. The layer stiffness ratio can affect the control effect of the structure more greatly and it should be determined considering the displacement of the bottom,the top acceleration and the overturning moment.The SSI effect can reduce the control effect of structure.更多还原