Seismic Response And Stress Analysis Of Isolation Bearing Of High-rise Shear Wall Isolation Structure With Different Height Width Ratio

By extending the natural period of the structural system,the isolated structure reduces the energy transmitted from the earthquake to the superstructure.With the development and maturity of isolation technology,isolation technology began to be applied and popularized in high-rise structures.However,compared with the middle and low-rise structure,the natural vibration period of high-rise structure itself is longer,the damping effect of setting isolation layer may not be too significant,and the isolation effect is difficult to ensure;And the height width ratio of high-rise structure is relatively large.When using isolation technology,the isolation layer may have tensile stress due to overturning.Aiming at the above problems,this paper has carried out the following work:(1)This paper introduces the research and current situation of high-rise isolation technology,expounds the basic principle of isolation structure and the mechanical characteristics of isolation support,selects the appropriate analysis model and analysis method according to the isolation structure,simulates the superstructure and isolation support with the analysis software ETABS,establishes the high-rise shear wall isolation structure with height width ratio of 4,6 and 8 respectively,and checks the isolation layer.(2)The influence of the isolation layer on the natural vibration period of the isolation structure with different height width ratio is studied.After the isolation layer is set,the period of the isolation structure with different height width ratio increases obviously,and the period of the first three vibration modes is more than 1.9 times higher than that before the isolation,which effectively reduces the horizontal seismic action transmitted to the superstructure.When the aspect ratio is 4,the first mode period of the isolated structure is extended from0.876 to 2.102;When the aspect ratio is 6,the first mode period of the isolated structure is extended from 1.362 s to 2.723s;When the aspect ratio is 8,the first mode period of the isolated structure is extended from 1.643 s to 3.122 s.(3)The seismic shear force and overturning moment of isolated structures with different height width ratio before and after isolation are analyzed and compared,and the horizontal damping coefficient is determined.The seismic shear force of the largest floor of the isolation structure with height width ratio of 4,6 and 8 is reduced by 65%,60% and 57% respectively;The maximum floor overturning moment is reduced by 74%,63% and 62% respectively.The isolated structure has achieved good isolation effect.(4)The stress analysis of isolated structures with different height width ratio under rare earthquake intensity is carried out,and the maximum tensile stress and maximum compressive stress of isolation bearing are studied.With the increase of the height width ratio of the structure,the isolation layer of the isolation structure is more and more prone to tensile stress,and the tensile stress in the isolation layer begins to concentrate to the edge support and corner support.Under the action of rare earthquake,the isolation layer of the isolation structure with height width ratio of 4 does not appear tensile stress,the isolation layer support of the isolation structure with height width ratio of 6 begins to appear tensile stress,and 1 / 3of the isolation layer of the isolation structure with height width ratio of 8 appears tensile stress,with the maximum tensile stress of 2.99 mpa,which is far greater than the specification limit of 1.0MPa.Under the action of rare earthquake,the maximum compressive stress of the bearing of the isolation layer of the isolation structure with different height width ratio is15.56 mpa,24.02 mpa and 29.36 mpa respectively,which are not greater than the code limit of30 MPa.With the increase of the height width ratio of the structure,the maximum tensile stress of the bearing has become the main control factor.