Performance Analysis And Shaking Table Test Of Series Isolation System Considering The Limit Deformation Of Laminated Rubber Bearing

In recent years, earthquake occurs frequently and causes great damage and casualties in seismic areas, especially for the near-fault earthquake the losses and casualties is more serious. With the rapid development and application of isolation technology, many isolation buildings occur. Because of the need for engineering, there are many forms of isolation building including based isolation structure and mid-story isolation structure and series isolation structure. There are obvious requirements for based isolation structure and mid-story isolation structure in the code for seismic design of building except the series isolation structure. With the construction of many series isolation structures, it is a common phenomenon that the laminated rubber bearing is set on the top of reinforced concrete column, and is difined as series isolation system. The study of mechanical properties and experimental research for series isolation system is rare, and is more important with the widely application of series isolation system in the series isolation structure. In this paper, firstly, the horizontal stiffness of laminated rubber bearing for the defferent boundary conditions is analyzed, and the horizontal stiffness of series isolation system is studied. Secondly, performance analysis of series isolation system is done considering the limited deformation of laminated rubber bearing under the rare earthquake. Thirdly, restoring force model and the mass model and dynnimic responses of series isolation system is further discussed using the finite element method and the theoretical analysis. Finally, shaking table test of series isolation system is carried out for the near-fault and far-fault ground motion, and dynamic response and seismic reduced ratio is analyzed, and the theoretical and the experimental research for series isolation system should be finished.The main research content of this article is as followed:1. Considering the connection of top and bottom of laminated rubber bearing in the isolation structure, horizontal stiffness of laminated rubber bearing is derived for the different boundary conditions. The influence of different boundary condition for horizontal stiffness of laminated rubber bearing is analyzed using a case and the influence of boundary constraint ability for horizontal stiffness of laminated rubber bearing is further discussed under the different boundary conditions. Series isolation system is a typical boundary condition that the bottom of laminated rubber bearing is constrained by the conlumn. Based on its characteristic, the equation of horizontal stiffness for series isolation system is derived under the bending-shear-axial force considering the interaction of the laminated rubber bearing and reinforced concrete column. Horizontal stiffness for series isolation system related to nine given common laminated rubber bearings are analyzed using the related parameters, and the simplified equation is proposed. The influence of the related parameters for horizontal stiffness for series isolation system related to certain laminated rubber bearing is studied. Finally, the condition is given that the simplified equation is used2. Substructure and component under the isolation layer in the isolation building is done by deformation and bearing capacity checking calculation under the rare earthquake in the code for seismic building design. The analytical method is proposed, which performance analysis of series isolation system is done considering the performance levels of reinforced concrete column based on the limit deformation of laminated rubber bearing. Performance indexes are proposed. Finally, the analysis results of the performance indexes are compared to that of static test.3. The restoring force model of series isolation system is important when the dynamic calculation for isolation structure is done considering the series isolation system as an isolation layer. The nonlinear mechanical properties of series isolation system with the lead laminated rubber bearing are analyzed using the finite element software MARC, and mechanic properties including the relationship of deformationand force and equavilent horizontal stiffness and damage are studied systematically. Parts of mechanic properties are compared to the results of shaking table test for series isolation system. The restoring force model of series isolation system is analyzed based on the restoring force model of lead laminated rubber bearing, and the influence of parameters including the horinzontal stiffness ratio and mass ratio on its natural vibration properties are analyzed for the two mass model compared with the single mass model. Dynamic response and seismic reduced ratio of the series isolation system are studied and the influence of the peak grond acceleration for the seismic reduced ratio of series isolation system is further discussed.4. The shaking table test of series isolation system is carried out under the near-fault ground motion and far-fault ground motion. The characteristic of dynamic response for series isolation system is studied. Dynamic responses under the near-fault and far-fault ground motion are compared and seismic reduced ratio for series isolation system is analyzed. The effect of input patterns of the earthquake waves for seismic reduced ratio of series isolation system is discussed, and the damage characteristics and laws of series isolation system are analyzed and the influence of the peak grond acceleration for the seismic reduced ratio of series isolation system is further discussed. The acceleration time history response and for series isolation system displacement time history response of shaking table test are compared with that of theoretical model.