Analysis Of Seismic Isolation Mechanism Of Frame-shear Wall Structure Considering Site Characteristics

Earthquake is a sudden natural disaster,when the earthquake occurred to release a huge amount of energy,resulting in strong ground vibration,resulting in the destruction and collapse of buildings,seriously endangering the safety of people’s lives and property.As an effective means of damping and disaster prevention,isolation technology is widely used in high-rise or super-high-rise buildings.Frame-shear wall structure as a common structural form of high-rise or super-high-rise buildings,its seismic isolation dynamics analysis has a good practical value.The key to dynamic time-history analysis of isolation structures is input ground motion.In addition to the energy,magnitude and epicenter distance of the earthquake,the seismic motion is also closely related to the site characteristics,and the seismic response of different site categories is obvious difference.The degree of anastomosis between the ground motion and the site characteristics of the building,which has a great impact on the seismic response of the isolated structure.The study on the seismic response of sites in different site categories and the influence of site characteristics on the seismic response of isolated and non-isolated frame-shear wall structures have important theoretical significance and application value for geotechnical engineering and seismic engineering.Based on the example of a frame-shear wall structure project,this paper studies the isolation mechanism of the frame-shear wall structure considering the site characteristics through numerical analysis.The main research contents and achievements are as follows:(1)Based on the actual engineering site data of our country,four typical stratigraphic profiles are selected for each of the four types of sites,and the equivalent linearization software SHAKE91 is used to analyze the seismic response of the site.The variation law of soil layer acceleration,surface acceleration response spectrum and amplification coefficient affected by depth and covering soil thickness of four types of sites was obtained.(2)By using the finite element software ABAQUS,a three-dimensional finite element frame-shear wall structure isolation model and non-isolation model is established,and its rationality is verified by vibration characteristic analysis.It is found that the self-vibration period of the isolation structure is about 2~3 times longer than that of the non-isolation structure,and the first three-order deformation of the isolation structure is mainly characterized by the whole flattening of the rigid body,while the first three-order deformation of the non-isolation structure is mainly shown as shear deformation.(3)Under the Ⅱ site,the finite element software ABAQUS is used to input the bidirectional seismic waves considering and not considering the characteristics of the site respectively,and the dynamic time-history analysis of isolation and non-isolation frame-shear wall structures is carried out under the action of multiple earthquakes.The results show that the reduction rate of the top layer acceleration,interlayer acceleration,interlayer displacement angle and interlayer shear force of the isolation structure is more than 40%.It can be seen that the foundation isolation structure shows excellent damping effect.The seismic response of the isolated and non-isolated structures without considering the site characteristics is less than the seismic response considering site characteristics.(4)Under the Ⅰ,Ⅱ and Ⅲ sites,the finite element software ABAQUS is used to analyze and calculate the interlayer displacement angle and top displacement of the isolated and nonisolated frame-shear wall structures under the action of multiple earthquakes,and the comparative study shows that the damping effect of the isolation structure under the Ⅰ and Ⅱ sites is better than that of the Ⅲ sites.