Research On The Layer Stiffness Ratio And Simplified Calculation Method Of Inter-story Isolated Structures

With rapid development of urbanization process,rail transit has also been rapid development,more and more cities try to take advantage of the subway station,car depot,interval and around the upper space and underground space for the secondary property development,can greatly improve the efficiency of urban land resource utilization,optimize the urban pattern,to reduce traffic pollution way of urban planning.First of all,this paper puts forward the problems in the design of inter-story isolated structures from the design point of view,and briefly describes the design process of the inter-story isolated structures and commonly used separation design methods.That is,the upper structure model of the isolation layer is calculated independently,embed the upper structural model to the ground,analysis of the horizontal seismic effect after the isolation;Using the equivalent column method to simulate the isolation pad for the isolation layer,performance based design of the whole structure.Then from the design point of view,the problems of this design method are put forward,since the Code does not specify the specific floor corresponding to the calculation of the fixed stiffness ratio of the storey spacer structure,there is a dispute in the implementation of the project.In this paper,the concepts of seismic layer stiffness,superstructure stiffness and substructure stiffness are distinguished,and the meaning of controlling stiffness ratio is put forward,as well as the understanding of controlling stiffness ratio required by the code.And Then,using elastic-plastic finite element software sloss-pi,numerical model verification was conducted to establish the model of five-storey shear wall structure and ten-storey shear wall structure on a large chassis,verify the results obtained from the simplified model,considering the influence of damping ratio on seismic structure with interval,a simplified model is proposed to simulate damping ratio,and a numerical model is used to conduct dynamic elastoplastic analysis on the structure.Choose 2 natural seismic waves and 1 artificial seismic wave to analyze the overall structure model for dynamic time,the numerical model is compared with the simplified model in terms of natural vibration period,inter-layer shear ratio,overturning moment ratio,damping coefficient,inter-layer displacement,ultimate deformation of isolation pad,ultimate surface pressure and ultimate tension.The feasibility of the simplified model method to determine the stiffness ratio of isolation layer for the shear wall structure with large chassis is demonstrated.the use of simplified calculation methods can save the time to arrange the isolation layer,select the vibration isolation cushion,improve the efficiency of the isolation design.At the same time,the use of the overall analysis method is more accurate than the separation design method more in line with the actual project..Finally,the design flow of building multi-particle simplified calculation is summarized,which can provide guidance for the design of the layer interval seismic structure.The research in this paper has reference significance for the preliminary design of the inter-story isolated structure with a large chassis.