Study On Seismic Behavior Of The Tube In Tube Structure With CFST Outer Tube And SCS Inner Tube With Dissipation Devices

China is one of the most earthquake-prone countries in the world,it is located in the middle of the two most active seismic belts in the world,for a long time,the earthquake has brought great disaster to our country,especially the Wenchuan earthquake,the disaster is shocking.Therefore,in recent years,people pay more and more attention to the seismic performance of buildings,hoping that the seismic performance of buildings will be higher and better.The traditional method is usually to increase the cross section size of beams,plates,columns and walls to strengthen the whole structure,however,the section size of beams,plates,columns and walls can increase the energy input from the earthquake while increasing the stiffness of structures and reducing the displacement,it is also not economical.Therefore,concrete filled steel tube,composite steel plate and concrete shear walls and other new structural members that are good for earthquake resistance,and viscous dampers with good energy dissipation effects are increasingly applied to practical projects.Studies on various structural systems of concrete filled steel tube and viscous dampers have been extensive,but there are few studies on the tube in tube structure system of concrete filled steel tube and viscous dampers,for this reason,this paper has done the following research work:Based on ETABS finite element analysis software,a tube in tube structure with CFST(concrete filled steel tube)outer tube and SCS(the double plate steel-concrete composite shear wall)inner tube is built,and we studied it's seismic performance.The results show that the seismic performance of the structure is good.In order to further optimize and improve the seismic performance of the structure system and increase the seismic defense of the structure system,the viscous dampers with good energy dissipation effect were introduced into the structure system to form the damping structure system,we studied the effect of viscous dampers on the seismic performance of tube in tube structure system.The results show that when viscous dampers are introduced into the structure system,the seismic performance of the structure system will be greatly improved whether from the aspects of the story displacement,story drift,story shear force,base shear force,or dissipation energy of structure.At the same time,in order to study the law of the influence of the different location of the viscous dampers on the seismic performance of the structure,several different damping schemes were established,and the placement positions of the viscous dampers were different.According to the research and analysis,different damping schemes have different effects on the seismic performance of the structure,Considering comprehensively,When the viscous dampers are distributed upward along the vertical height,the damping effect will be better than that in the lower part,but it should not be too dispersed.