Research On Seismic Reduction Performance Of Interlayer Isolation System Under Near-fault Ground Motion

The layered isolation structure system is to set up an isolation layer in the structure of high-rise buildings.The flexibility of the layered isolation arrangement is used to improve the limitations of the application conditions of basic isolation and effectively expand the scope of application of high-rise building structure isolation The layer-seismic structure can be widely used in the construction of modern high-rise structures.The main content includes the following aspects:(1)The modal analysis of tall regular frame structure shows that the torsional deformation of the layered seismic structure is mainly dominated by the third-order mode.However,as the number of higher-order vibration modes increases,the torsional effect of the fixed foundation structure increases,while in the layered-seismic structure system,the structure is dominated by translation.(2)The seismic response analysis of the layered seismic system of high-rise regular building structures under frequent earthquakes shows that when the directional effect of rupture forward,no velocity pulse effect,and upper and lower disk effects,each floor of the three-layer seismic isolation structure Both the shear and floor acceleration are small.Under the effect of sliding and impact,the interlayer shear force of the layered earthquake system is greater than that of the foundation fixed structure.However,the displacement angle of each floor is larger than that of the foundation fixed structure.It can be seen that the damping performance of the layered-seismic structure is not good.(3)Seismic response analysis of the high-rise regular building structure layer-seismic earthquake system under the action of a rare earthquake shows that the displacement of the base-isolated bearing of the layer-seismic structure exceeds the limit,especially the maximum displacement of the bearing under the action of the sliding impact.At the same time,the shear force of the bottom layer under the effect of sliding and impact is greater than that of the foundation fixed structure.Under the effect of slippage effect and no speed pulse effect,the floor acceleration has floors larger than the fixed structure.Therefore,it is necessary to improve the seismic performance of the floor-seismic structures under the action of rare earthquakes.(4)Seismic response analysis of the layered seismic system after adding anti-buckling constrained energy dissipation support shows that,under rare earthquakes,compared with the layered seismic system without buckling support,in addition to the inter-story shear force and floor acceleration indicators,The inter-story displacement angle of each floor of the seismic isolation system is also smaller than that of the foundation fixed structure.It can be seen that the addition of anti-buckling restrained energy dissipation braces is beneficial to strengthen the seismic performance of the layered seismic structure system.(5)The comparative analysis of the seismic isolation layer after adding the anti-buckling constrained energy dissipation support shows that the displacement of the lead rubber seismic isolation support meets the specification requirements,and the displacement of the support is reduced by half compared with the undamped layer isolation system many.The hysteresis curve of the rubber-isolated bearing is fuller under the action of the directivity effect and the sliding and rushing effect of the rupture forward,and the area occupied by a hysteretic loop is larger.However,there is little difference under the effect of no speed pulse effect.Therefore,the addition of anti-buckling constrained energy dissipation braces is beneficial to enhance the energy dissipation and shock absorption performance of the seismic isolation support and the overall stability of the layered isolation structure.