Study On Arrangement Method And Failure Mode Of Rubber Isolation Bearing In Frame-Shear Isolated Structure

Frame-shear structure as a kind of the structure of the system suitable for isolation technology,has been gradually applied in the practical engineering.Compared with the more widely used frame structure,the frame-shear isolated structure increases with the aspect ratio,and the overturning effect is more obvious under the horizontal earthquake.The shear wall of the frame-shear isolated structure bears most of the overturning moment,making the Isolation bearing under the shear wall prone to tensile stress.At present,most of the researches on the isolated structure are based on the structure of the frame,and the research on the frame-shear isolation structure is less.Therefore,it is necessary to study the influence of the force of the frame-shear isolated structure on the isolation bearing and its failure mode.In this paper,the characteristics of the frame-shear isolated structure are analyzed and studied.The main work is as follows:(1)Through the study of the force characteristics of the frame-shear structure under horizontal load,the working mechanism of the frame part and the shear wall part in the frame-shear structure is clarified.Based on the analysis of the mechanical properties of the isolation bearing,the influence factors of the vertical force under the action of the earthquake under the shear wall are obtained.(2)A new design method(G-RM)for the frame-shear isolated structure is proposed for the problem of the tensile stress in the frame-shear wall of the shear wall under isolation bearing.By using the traditional method(GM)and the new method(G-RM),the isolation model of the isolation bearing is selected and calculated.The results show that the traditional method(GM)has the problem that the tensile stress exceeds the limit value.The new method(G-RM)can choose the isolation bearing more accurately in the frame-shear isolated structure,which can effectively avoid the tensile stress of the isolation bearing beyond the limit value.(3)Based on IDA method,the time-history analysis of frame-shear isolated structure is carried out.The maximum displacement,maximum tensile stress and maximum compressive stress of the isolation layer are statistically analyzed.The results show that the failure probability of the frame-shear isolated structure is increasing with the increasing of PGA.The tensile failure of the isolation bearing before the shear failure and pressure failure occurred,but after the isolation bearing compression probability increased dramatically,and the failure probability of shear failure is always less than the failure probability of tension and compression failure.The Compared with shear damage,we can see that the frame-shear base isolation structure is more susceptible to pulling and pressing.(4)Frame-shear isolated structure in different seismic characteristics compare considering the P-? effect without considering the P-? effect.The results show that the P-? effect is considered in the far field seismic effect compared with the P-? effect,the displacement of the isolation structure,the displacement angle of the superstructure,the pull-out of the isolation bearing and the compressive stress are not big change.Under the action of near-field pulsed earthquake,the P-? effect is not changed greatly compared with the P-? effect without considering the P-? effect,and the compressive stress of the isolation bearing is slightly increased.Stress changes significantly,increased by about 10% to 12%.The effect of P-? effect on the base-isolated structure is mainly reflected in the addition of bending moment to increase the overturning moment,and the effect on the superstructure is not obvious.