Study On Isolation Performance Of Mega-Sub Structure

In this paper,the vibration control mechanism and control performance of the mega-sub structure with the form of isolation sub structure are studied,through theoretical model study and engineering case analysis,and further reveals the mechanism of the tuned vibration control,analyzes the influence of the parameters of the isolation layer on the seismic performance of this kind of system,and gives suggestions for the optimal design parameters of the isolation layer.combined with the isolation scheme of the mega-sub structure project in Shenzhen Changzhen,it provides a reference for the optimal design of the isolation scheme of the mega-sub structure.The research contents of this paper mainly include:(1)In view of the scheme of setting isolation layer at the bottom of substructure,the layer model of theoretical analysis of mega-sub structure is established,and the performance law of its seismic response is analyzed,Through the analysis of transfer function,it is found that when the natural frequency of substructure is equal to that of mega structure,the vibration absorption effect of mega-sub structure is better,showing the nature of tuned vibration absorption.Considering the comprehensive demand of interlayer isolation for the performance of mega and sub structures,it is found that with the increase of additional damping value of the isolation layer of substructure,the damping effect of the mega-sub structure becomes better.So the optimal arrangement scheme of the isolation layer in an engineering case is given,so that there is an optimal frequency bandwidth between the multiple substructures,and then the mega-sub structure can achieve the optimal damping effect.(2)This paper studies the isolation and damping scheme of the mega-sub structure project in Shenzhen Changzhen,analyzes and compares the control system of the mega-sub structure with the control system of the tuned mass damping,it is found that with the increase of the stiffness of the isolation layer,the change trend of the optimal damping effect curve of the two kinds of damping structures is the same,and the interlayer displacement of the isolation substructure can be controlled within the allowable range of design,when considering the additional viscous damping between the substructure and the mega structure of the mega-sub structure,the arrangement of the damper between the top layer of the substructure and the mega column of the main structure is relatively optimal.(3)In this paper,the optimal design of the isolation layer of the mega sub structure in Shenzhen is studied,the results of numerical analysis show that the design scheme reduces the inter story displacement and the maximum absolute acceleration of the mega structure,as well as the inter story displacement and the maximum absolute acceleration of the substructure at the same time,and achieves better damping effect,which provides a reference for the engineering isolation and damping scheme.