| Seismic isolation technology can prolong the natural vibration period of the structure and increase the damping of the structure,thereby eliminating or reducing the damage caused by the earthquake to the structure itself.Base isolation is currently the most widely used seismic isolation technology.A large number of tests and engineering experiences at home and abroad have shown that the base isolation technology can effectively reduce the horizontal seismic action of the structure.As the theoretical research of seismic isolation technology continues to mature and deepen,more and more high-rise buildings have begun to try seismic isolation technology.This paper takes the high-rise Frame-External Shear Wall（hereinafter referred to as FESW）structure as the research object,and studies the isolation effect after adopting the base isolation design.The main research content and results as follows:（1）This paper describes the historical process of the development and maturity of base isolation technology,the research results and difficulties at this stage,the principle of seismic isolation structure,the classification and performance parameter of seismic isolation bearings,seismic isolation design method and the common tensile stress control methods for seismic isolation bearings.（2）A complex high-rise building adopting reinforced concrete FESW structure system with a fortification intensity of 8 degrees,a design basic seismic acceleration peak value of 0.20 g,a height of 99.2m,21 floors,a plane size of 40.8m × 58.8m was subjected to base isolation design.Establishing seismic isolation and non-seismic idolstion structure models through ETABS software.The modal analysis results show that after adopting the base isolation scheme,the first three-order period of the seismic isolation structure is more than 2 times longer than that of the non-seismic isolation structure,effectively isolating the impact of seismic action.（3）Using the FNA method,the FESW structure was designed for the superstructure under the fortification earthquake and the seismic isolation layer under the rare earthquake.The analysis results show that the horizontal seismic action can be reduced by half degree after seismic isolation.The isolation efficiency of the seismic response under the action of fortification earthquake includes inter-story shear force,floor overturning moment,inter-story displacement,inter-story displacement angle,and the top layer acceleration are above 50%.The tensile and compressive stresses and the displacement of the seismic isolation bearing under the action of rare earthquakes are in compliance with the regulations of the code.It shows that the base isolation can be applied to the FESW structure,and the seismic isolation effect is good.（4）In view of the special situation of the FESW structure whose transverse shear wall cylinder of the upper structure was externally arranged along the longitudinal ends due to the layout of the building plan,three types of base isolation using different methods of seismic isolation bearing under the shear wall are designed.The seismic isolation bearing adopt a combination arrangement of laminated rubber bearing and super high damping rubber bearing.The finite element models of three types of seismic isolation structures are established by ETABS software,and the time history analysis and comparison of fortified earthquakes and rare earthquakes are carried out using the FNA method.The results show that the arrangement of different seismic isolation bearing under the FESW structure shear wall has little effect on the horizontal shock absorption coefficient,but has a greater effect on the tensile and compressive stress and horizontal displacement of the seismic isolation bearing.Adopting a combination of large and small diameters seismic isolation bearing and arranging large-diameter and high-stiffness seismic isolation bearing under the shear wall is beneficial to control the tension and compression stress of the seismic isolation supports and is more economical. |
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