Study On The Seismic Response Of Base-isolated Structure Under Near-fault Ground Motions

With the frequent occurrence of near-fault earthquakes,the research on the nearfault ground continues to deepen in the academic circles.The velocity pulse effect is also known as the important characteristic of near-fault ground motion,compared with the ordinary ground motion,the pulse-like ground motion has larger amplitude and higher energy.As the same time,the application of the base-isolated buildings is more and more mature,and its good isolation ability under has been reflected under the ordinary ground motion.However,how the pulse-like ground will affect the baseisolated structure,is still to be studied.Some of the major cities in China are located near-fault region,facing the threat of pulse-like ground motion,and these studies will also basis for the analysis and design of the base-isolated structures in the near-fault region.In order to study the near-fault pulse-like ground motion and the characteristics of the dynamic response of the base-isolated structures under the pulse-like ground motion,this paper has done the following work:(1)The parameters such as PGA,PGV,PGV / PGA and so on were analyzed,extraction of seismic pulse period,and analyse the feature of the pulse-like ground motion,the relationship between the pulse period and other parameters.(2)By analyzing the response of the base-isolated structure under the action of pulse-like ground motion and ordinary ground motion,shows that the isolation ability of the base-isolated structure is adversely affected under the pulse-like ground motion,and the structural response increases compared with the ordinary ground motion.(3)By inputting different pulse periodic ground motion,analyze the influence of pulse period on the dynamic response of base-isolated structure.It is found that the seismic response significantly increased when the pulse period is 1.5~3.5 times of the self-vibration period of the structure.(4)Analyze the relationship between the characteristic parameters of the ground motion and the response index of the isolated structure.The results show that PGV/PGA,PGD/PGV have little effect on the response of base-isolated structure,and the parameters such as PGV,Arias intensity and energy density have higher correlation with the response of the base-isolated structure.