Response Analysis Of High Damping Rubber Isolated Ancient Masonry Tower Under Different Earthquake

Earthquake has characteristics of unpredictability and huge destructivity,and causes serious damage to structures,especially to the ancient masonry towers.Among the earthquakes,near-fault ground motion is significantly different from the normal vibration of far-field characteristics and is fatal to the constructions in consideration of its large amplitude velocity pulse.Base isolation technique has been widely used because of good damping effect.As a new type of isolation bearing,high damping rubber bearing(HDRB)is outstanding and being used more frequently in the construction engineering because of its high-performance with no pollution.So,that using HDRB to protect masonry towers is worthy studying.Performing experimental study and finite element analysis,the dissertation focus on the research about the horizontal properties of HDRB and its two mechanical models.Taking the Islamic style tower as research project,the results of the response under different kinds of earthquake are compared.Therefore the dissertation not only makes a further step in studying the dynamic response of HDR isolated structure under earthquake but also makes a useful exploration in the protection of the ancient masonry tower.The paper discusses the mechanical properties of high damping rubber bearing.The bilinear model and four element model are introduced,and the mechanical parameters of the bilinear model are calculated through the horizontal shear test of the bearing.On basis of this,the relevant parameters left in the four element model are determined by fitting the test curve,which provides the basis for the finite element analysis of the HDR isolated structure.The three-dimensional solid model of the masonry tower is established in ABAQUS,previous experimental results and related data on the dynamic properties of masonry towers are used to get more accurate dynamic calculation model.Two mechanical models are separately built to simulate the HDRB and respectively put at the bottom of the tower.With the nonlinear time-history analysis method,both the structural responses and the bearing responses are compared between near-fault and far-field earthquake.The results show that HDR isolated masonry tower structure is effectively protected under each kind of earthquake and the rate-dependent four element model which simulates the HDR has a better seismic isolation behavior than bilinear hysteretic model under the near-fault earthquake.