Seismic Response And Fragility Analysis Of Frame-Shear Wall Base-isolated Structure

The base-isolation is a safe and effective building damping technology whose application is the earliest and the most mature.It is not only applied to the seismic design of new engineerings,but also applied to the seismic reinforcement of historic buildings.A large number of shaking table experiments and theoretical studies show that the isolated buildings have excellent seismic performance,and the performance of isolated buildings in several large earthquakes over the past decade has also proved this.At present,with the development of technology and research,the isolation technology has gradually developed into high-rise buildings.Therefore,it is of great significance to study the seismic response of such seismic isolation structures to protect the safety of people's lives and property.Firstly,this paper introduces the basic principle of isolation technology,establishing the single particle vibration isolation system model to deduce and slove dynamic balance equation,and then describe the performance parameter and mechanical model of the isolation bearing.Secondly,based on the finite element software SAP2000,the base-isolated structure with frame shear wall is established to make the modal analysis and the dynamic time history analysis of the frequently occurred earthquake and rare earthquake,and in order to analyze the damping effect of the isolated structure,the calculation results are compared with the corresponding traditional non-isolation structures.Finally,in view of the fact that there are not many records of damage data of such structural systems due to the small number of historical earthquake damage data,the seismic vulnerability analysis of the baseisolated structure is carried out,it can describe the seismic performance of the isolation structure from the perspective of probability.Through the above analysis,the following conclusions are obtained.(1)The vibration period of the structure is obviously increased when the isolation technology is applied,the long period can avoid the remarkable period of the site effectively,reduce the possibility of resonance,and achieve a good damping effect.(2)It can see that the first and second modes of the two structures are translational and the interlayer displacement of the traditional structure is much larger than that of the isolated structure by comparing with the front three order mode shapes of the traditional seismic structure and the isolated structure.The third modes of the two structures are all torsional,the difference is that the traditional seismic structure has large torsional deformation,while the torsion deformation of the isolation structure is small,mainly occurring in the isolation layer.(3)It can see that the interlayer shear,interlayer displacement and interlayer acceleration of the base-isolated structure have different degrees of decrease by comparing with the traditional seismic structure,and the isolation effect is more prominent in the rare earthquake.(4)The seismic vulnerability curve of the traditional seismic structure and the base-isolated structure is obtained by a performance-based vulnerability analysis method.Comparing with the vulnerability curves of the two structures,the damage degree of the base-isolated structure is lower than that of the traditional seismic structure.The vulnerability curve provides a data basis for the formulation of disaster prevention measures,the loss assessment after the disaster and the reinforcement and reconstruction of the structure,which is of great significance.