Investigation On Base-isolated High-Rise Building Structure Under The Very Rare Earthquake

Base-isolation technology as a kind of Passive vibration control technology, has been widely applied in multistory building, and good effect is obtained in actual earthquake disasters. Along with the isolation technology increasingly mature and the research gradually deeper, the base-isolation technology has been applied to high-rise building. Abroad, there have been many high-rise-base isolation structures; Internal, as the damping mechanism of isolation structure gradually understand, high-rise base-isolation technology is developing rapidly. But the application of base-isolation in high-rise buildings still exist the following problems:(1) The limit value of the aspect ratio of base-isolation structure is 4 specified by the seismic code, the limit does not apply to different structure types.(2) The existing theoretical formula of the aspect ratio of base-isolation structure dose not consider the tension strength and difference between pulling stiffness and pushing stiffness of RB&LRB,(3) The vertical bearing capacity of RB&LRB decreases with the increasing of shear deformation.Under the very rare earthquake, the large shear deformation will cause the failure of isolation bearing, the damage mechanism of isolation bearing and the design methods of isolation layer should be further discussed(4) During the very rare earthquake, the damping effect and damage evolution process of the isolation structure still need further research. In view of the above problem, The main work of this paper is as follows:(1) The existing formula of aspect ratio of base-isolation structure is modified, to consider the tension strength and difference between pulling stiffness and pushing stiffness of RB&LRB(2) Establish frame, frame-shear wall and shear wall structure with different aspect ratios.Time history analysis of the three kinds of isolated structures with different aspect ratios are conducted. Research results show that The suggested aspect ratio limit of isolated frame structure is not greater than 4, frame-shear wall structure is not greater than 6, shear wallstructure is not greater than 7. And as the aspect ratio increases gradually, the damping effect of the based-isolated structure diminishes.(3) Under the very rare earthquake,time history analysis of the isolated shear wall structures with aspect ratio 4 is conducted, Dynamic response of isolated structure is studied.And the stress characteristics of RB&LRB with critical shear deformation are investigated The results show that.When the shear deformation reach the limit, Compressive pressure of isolation bearing does not exceed the ultimate bearing capacity.Under the very rare earthquake, compressive stress of isolators in isolated shear wall structure is more likely beyond the limit. The isolation bearing will be out of operation because of the yield in compression.(4) Aimed at the shear wall isolated structure with aspect rate 4 under the very rare earthquake, proposed two kinds of improved measures: increasing the bearing diameter and isolation layer added viscous dampers. Compare two kinds of design methods,the results show that the compression and shear deformation diminish when the two improvement measures are adopted, But increasing bearing diameter can make the isolation bearing more likely to appear tensile stress, and reduce the isolation effectiveness under the earthquake.(5) Nonlinear elasto-plastic time history analysis for non-isolated and isolated shear wall structure with aspect rate 4. Elastic-plastic deformation, mechanical characteristics, and damage energy dissipation of the two structures are studied to illustrate the damage evolution process of shear wall structure under the very rare earthquake...