Optimization Of Isolation Layer And Response Analysis Of High-rise Base-isolated Buildings Under Long Period Ground Motions

The isolation layer of the isolation structure weakens the seismic action transmitted to the upper structure,which makes the response of the upper structure significantly smaller than that of the anti-seismic structure.It not only protects the upper structure,decoration,indoor facilities and instruments,but also keeps the use function of the building uninterrupted.In recent years,the isolation technology gradually shows the trend of high-rise,more and more high-rise buildings try to use the isolation technology.In this paper,the development status of high-rise isolated buildings,the principle of shock absorption of isolation technology,the performance of isolation device,the design method and process of isolation are described.The finite element analysis software ETABS is used to calculate and analyze the high-rise isolated buildings.The main research contents of this paper are as follows:first,optimize the configuration of isolation device to improve the performance of isolation layer;second,adopt special long-period ground motion verification not yet Seismic response of isolated structure and isolated structure.In this paper,the base isolation design of a high-rise building located in an8-degree area(0.20g)with a height of 120m and a reinforced concrete frame core tube structure is carried out.The seismic wave matching with the isolation response spectrum is selected,and the ordinary isolation scheme is composed of natural rubber bearing and lead rubber bearing.The calculation and analysis results show that the horizontal seismic action can be reduced by half,but under rare seismic action,The maximum compressive/tensile stress of the isolation bearing at the corner of the core tube exceeds the specification limit.In order to reduce the equivalent stiffness of the isolation layer,the isolation device is designed as a combination of natural rubber bearing and elastic sliding plate bearing.In order to improve the structural damping,the combination isolation device with additional viscous damper is designed.The optimal configuration scheme of isolation device and the optimal combination isolation scheme are proposed The action can be reduced by one degree,and the maximum compressive/tensile stress of the bearing under rare earthquake can meet the requirements of the code limit.Because both high-rise buildings and high-rise isolation buildings belong to long-period structure,which may cause serious damage due to resonance under long-period earthquake.The construction site is located in Lanzhou sedimentary basin,so far-field harmonic long-period seismic wave is selected for verification.Under the action of long-period ground motion,the floor shear force,the displacement at the top of the structure and the floor acceleration of high-rise buildings and high-rise isolated buildings are significantly higher than those of ordinary ground motion.When the peak acceleration is 70 cm/s~2,the maximum bearing pressure/tensile stress of the common isolation scheme exceeds the specification limit,and the maximum bearing pressure/tensile stress of the combined isolation scheme can meet the specification requirements.