Seismic Behavior Analysis Of Irregular Base-isolated Multi-tower Structure With A Floor

The application of seismic isolation technology improves the safety,applicability and economy of the structure,especially in the fortification intensity of 8 degrees and more than 8 degrees of primary and secondary school buildings and hospital buildings have been widely used.When the buildings that need to set seismic joint or the adjacent buildings is applied to the seismic isolation,the isolation layer of the group floor can share the same large floor for isolation to avoid the excessive joint.This paper refers to this structure for multi-tower with the large floor isolation structure.For multi-tower with a irregular floor isolation structure,the center of mass of upper structure and the center of stiffness of seismic layer are easy to have some eccentricity,and the effect of horizontal two-way earthquake on the structure can not be neglected.Therefore,in this paper,the seismic performance of this kind of isolated structure is analyzed and the selection method of ground motion in seismic isolation design is studied.The main computation are as follows:(1)In this paper,the effects of eccentricity on the torsional response of double-tower with a large floor isolation structure is studied from three aspects,which provides the basis for the analysis of seismic performance of multi-tower with a irregular floor isolation structure.(2)An example model of multi-tower with a irregular floor isolation structure was established by Perform-3D finite element software,and the modal analysis was carried out.The basic period of the isolation model is nearly 3 times larger than that non-isolated.And its low-order mode to do the overall movement,so that the structure of the model becomes more simple.(3)At present,most of the wave selection models based on seismic design are based on the non-seismic isolation model which has not been arranged.Therefore,it is obviously not suitable to check the seismic isolation model under rare earthquakes,And the calculation results of the damping coefficient also have a large discrepancy.This paper presents a wave selection method that Tg,T1 a and T1 b as the index of the three frequency scheme to calculate damping coefficient and check structure.The results show that the optimal discretization and reliability.(4)In this paper,the incremental dynamic analysis and vulnerability analysis of the example structure are carried out under uniaxial seismic action and two-way seismic action,and the seismic performance of the structure is evaluated.The results show that the eccentric isolation structure can also achieve better isolation effect,and the effect of the two-way earthquake can amplify the seismic effect of the structure under certain ground motion intensity.