The Analysis And Study Of Vibration Isolation Effectonthree-dimensional Basicisolation Technique

An advanced technique of base isolation building as the vibration control,through the isolation layer isolation and energy dissipation element forming high damping is arranged between the base and the upper structure,isolation of seismic energy to transfer,prolong the vibration period of building,reduce the resonance effect,the dissipative element consumes the earthquake energy input structure.In order to effectively reduce the seismic response of structures,to avoid structural damage in the earthquake.At present,the building isolation is generally considered only horizontal isolation,which does not consider the vertical isolation.However,the Tangshan earthquake and Chi Chi earthquake and the Kobe earthquake,valley earthquake and Wenchuan earthquake occurred in recent years,domestic and foreign(special)obtained in earthquake seismic records and seismic data show that in the high intensity areas,especially in the near fault region,the vertical seismic ground motion components are relatively strong,even more than the horizontal earthquake component,become the leading cause of structure collapse.Therefore,this paper puts forward that building 3D seismic isolation design can effectively solve the problem of building 3D seismic isolation and provide useful reference for 3D seismic isolation design.This paper comprehensively reviews the domestic and foreign study situation on the 3D isolation for buildings.It focuses on the analyze on the structure and principle of the typical independent type and combined type 3D isolation device such as 3D base isolation with cable reinforced air spring,3D base isolation device with hydraulic system and rubber bearing,3D isolation with air spring and rubber bearing,3D isolation with Laminated rubber and disc springs group,Intelligent 3D isolation system etc.On this basis,combined with the construction of 3D isolation typical cases at home and abroad,the research progress in the construction of 3D isolation theory is reviewed and summarized,in a comprehensive analysis of earthquake mechanism,mode of transmission and influence factors,the horizontal and vertical seismic wave were analyzed,and selected the character of seismic wave and the norms of the state.Based on the full study of the structural characteristics of 3D base isolation,the upper structure and isolation layer of some reasonable assumptions and analysis,a calculation model is established;and high practical engineering cases,the 3D finite element model modeling method,established the 3D base isolation structure model,LRB-DSB LRB horizontal isolation structure model and seismic structure model analysis,computer simulation,comprehensive system of two types of structural response,vibration characteristics and dynamic model respectively in 3D seismic excitation,and the effect of the change of vertical stiffness of isolation layer on horizontal and vertical isolation effect;finally,in order to further verify come to the conclusion that the seismic performance evaluation method based on multilayer structure elastoplastic analysis.The results show that the multi and high-rise structure of nonlinear space in 3D seismic response time history analysis,three dimensional finite element model can comprehensively and accurately reflect the seismic response of the structure;LRB has better horizontal isolation effect,but does not have the vertical isolation effect,and may even cause amplification of vertical seismic action the adverse effects on the structure;horizontal isolation effect of the structure by the horizontal isolation components of the LRB control,and the vertical isolation effect by vertical isolation components of the DSB control,and DSB units will have a certain impact on the LRB isolation effect,but the impact is very small,can be neglected in engineering application point of view;LRB-DSB has both horizontal and vertical the isolation effect is good,can make up for the lack of LRB in the vertical isolation effect,improve the seismic performance of the structure;the vertical stiffness of structure vibration characteristics Little effect and horizontal displacement of the isolation layer,but has significant influence on the vertical vibration and the vertical displacement of the isolation layer;in the construction of 3D seismic design,the design of vertical to the stiffness of isolation layer for the reasonable and scientific,so according to the vertical analysis results suggest that the 3D base isolation structure of isolation layer stiffness for seismic isolation level the vertical stiffness of the layer structure of 1/20 ~ 1/30.This paper presents the design method of 3D seismic isolation,which is of great significance to the research and development of 3D seismic isolation technology,and has broad application prospects.