Research On New Lateral Resistance System Of Assembled High-rise Seismic Isolation Structure

There are still many problems to be solved in the process of current development of assembly structure.The mature assembly structure design system has not yet been formed,and the traditional design concept of "equal cast-in-place" is still used for reference.The low level of design standardization leads to too many component specifications and the problem of universality has not been solved.At the same time,the design of base isolation structure has not changed substantially compared with the conventional seismic structure,and the superstructure is still in accordance with the seismic design ideas.The coupling relationship between structural stiffness and structural deformation requires continuous iteration calculation and checking calculation to meet the design requirements of the code.The design process is too complicated and complicated.The principle of "one column and one base" is adopted in the isolation layer,which leads to a large number of bearings,increases the rigidity of the isolation layer and reduces the isolation efficiency.In this thesis,based on isolation technology,by optimizing the stiffness design of isolation layer,the stiffness of isolation layer is reduced and the isolation efficiency is improved.At the same time,by controlling the stiffness ratio between isolation layer and upper floor,the vibration mode optimization of high-rise isolation structure is controlled,and a new lateral resistance system is explored,which linearizes the allocation of lateral stiffness of high-rise structure according to the need of elastic deformation of the floor.The rapid allocation of structural stiffness and isolation layer stiffness can provide theoretical basis for standardized and universal design of assembly structure components.Through the research,the main research results are as follows:(1)The concept of stiffness ratio alpha is put forward.Taking the high-rise structure with shear deformation characteristics as the research object,the natural vibration period,mode shape and mass participation coefficient of the superstructure under different stiffness ratio alpha are analyzed,and the variation law is studied.(2)It is found that when the number of stories of the superstructure is less than 20 and the stiffness ratio is greater than 10,the first mode mass participation factor of the high-rise isolation structure can reach more than 90%.The influence of higher modes can be neglected in the superstructure,only the first modes need to be considered.When the stiffness ratio is greater than 100,the second derivative of the natural vibration period curve of high-rise isolation structure is basically zero,that is,the natural vibration period of high-rise isolation structure tends to be stable.(3)Through the study of high-rise isolation structures with irregular vertical stiffness distribution,it is found that increasing stiffness ratio alpha can effectively reduce the impact of high modes in high-rise isolation structures,which provides effective technical support for the allocation of stiffness according to deformation requirements in high-rise isolation structures.(4)On the basis of optimization of stiffness ratio,through simplified calculation and Simulation of single-particle model and double-particle model of superstructure,it is found that when stiffness ratio is greater than 100,single-particle model has better accuracy than doubleparticle model,and the error is less than 3%.(5)By deriving the formula of the minimum stiffness of isolation layer,the relationship between the diameter of isolation bearing and the stiffness,efficiency and displacement of isolation layer is analyzed.By putting forward the transfer floor structure at the bottom of the structure and changing the isolation layout of the isolation structure "one column and one support",the feasible method of optimizing the stiffness of isolation layer is studied.It is concluded that under the condition of satisfying the large stiffness ratio,the diameter of the support needs to be greater than 1200 mm to achieve the minimum stiffness of isolation layer.(6)Based on the optimization of isolation layer stiffness and the large stiffness ratio,the first mode of vibration is the main mode of high-rise isolation structure,and a new type of lateral stiffness system with discontinuous configuration according to lateral displacement is proposed.Through calculation and analysis of Engineering cases,the applicability,feasibility and convenience of the new structure system in design are verified.This paper demonstrates the modularization and standardization improvement effect of the new structure system on the assembly structure,and provides the corresponding design method.