Study Of Isolation Design For Structure Supported By Stepped Foundation On The Slope

There are two grounding layers with different elevations in the structure of falling stories in mountainous areas,which lead to significant differences in the mechanical and seismic properties between the structure and the ordinary flat ground structure.Generally speaking,the grounding component of the upper grounding layer is the place where the deformation of the falling layer structure is large and the damage is easy to occur.Therefore,the application of base isolation technology to the falling layer structure in mountainous areas can be considered.In this paper,based on the SAP2000 finite element analysis software of CSI company,the main research results of the isolated structure are as follows:(1)The applicability of the existing isolation analysis methods in the base isolation structure is analyzed.The analysis results show that the mode decomposition response spectrum method can be applied to the base isolation structure in practical application.(2)By establishing the frame model with different layers and spans,the dynamic characteristics and linear elastic response spectrum of the model are analyzed,and the effects of layers,spans,upper floors and stiffness of isolation bearing on the dynamic characteristics of the frame structure with base isolation are studied.(3)Through the design of typical three-dimensional spatial frame structures,the value of horizontal damping coefficient in three-dimensional frame structures is studied,and the rationality of the existing horizontal damping coefficient is qualitatively judged.Then,by establishing the SAP2000 finite element model of frame structure and frame-shear wall structure with different layers and spans,the applicability of existing isolation design methods in frame structure and frame-shear wall structure with layers falling off is analyzed,and the influencing factors of the horizontal damping coefficient of base isolation structure are explored,including the number of layers falling off,the number of layers falling off and the number of layers falling off.The influence of the number of storey spans on the maximum interstorey shear ratio and whether to consider the influence of connecting beams on the maximum interstorey shear ratio of storey structures are considered(4)Taking an office building project as an example,by changing the layout of isolation layer and the stiffness distribution of main structure,the SAP2000 finite element analysis model with different stiffness distribution of six layers and upper structure is established.By comparing the shear force,maximum displacement angle,maximum displacement and time-history displacement of isolation layer under the action of frequent earthquakes and rare earthquakes,the models are compared.Seismic performance index,the influence of the layout of isolation layer and the stiffness distribution of main structure on the dynamic response of isolation structure is analyzed.