The Effect Of The Interaction Between Superstructure And Foundation Of High Rise Buildings On Seismic Performance

It is well known that the damage caused by the earthquake to the buildings is huge in all kinds of natural disasters,With the continuous development of modern urbanization,the construction and use of high-rise building is becoming more and more extensive.Most of the traditional seismic design using rigid foundation assumption,in fact this assumption ignores the interaction of superstructure and foundation on the seismic analysis results,restricts the accuracy and reliability of engineering seismic safety evaluation.In the actual building structure seismic design process,considering the interaction of superstructure and foundation on seismic performance can effectively and accurately reflect the state of internal force of structure system under earthquake and deformation.Especially for high-rise buildings located in high seismic intensity area,it is more important to consider the interaction between superstructure and foundation under seismic action.Usually,the traditional assumption of rigid foundation considering only the upper structure and foundation soil,the relative motion between the neglect of structure and foundation soil,this assumption only little on structural component quality,small size and construction of harden soil has been applied on buildings.However,for the high rise buildings located in the high intensity area,there is a complex relative movement between the upper structure and the foundation soil,In particular,the relative sliding and friction between the foundation and the foundation soil under seismic action often affect the dynamic characteristics of the superstructure.Firstly,this paper introduces the research background and current situation of the use of high-rise building structure,and introduces the theory of interaction between superstructure and foundation.Then selected by finite element numerical simulation analysis method,and some problems in finite element analysis method to solve,such as the structure and foundation soil elastoplastic constitutive relation model and the selection of foundation soil interception calculation model of artificial boundary selection.At last,the author makes a research on the project of Yinchuan City,which is located in the building of WEISIDE.The frame core tube structure used in this project,the base form of pile raft foundation,the construction site is located in the seismic region of high intensity,to build the three-dimensional model using finite element analysis software ANSYS,and the finite element analysis of the calculation model of modal analysis and seismic time history,draw relevant conclusions.This paper focuses on the influence of macro level interaction and dynamic characteristics of the frame core tube structure,and on the assumption of rigid foundation under the condition of internal force and deformation calculation results are compared.And to study the interaction between the pile foundation and foundation soil local contact model of the micro level in the static conditions of the interaction and seismic acceleration,were compared in different soil under the condition of mutual seismic system.The results of calculation are summarized:1.as the premise of the research foundation and the dynamic interaction of the foundation soil,the contact surface between the pile foundation and the foundation soil will produce the sliding phenomenon under the static force.The interaction between the pile foundation and the foundation soil is strengthened under the action of seismic force,the sliding of the contact surface increases,and the deformation of the surrounding soil is obvious.2.Considering the dynamic interaction of the system,the natural frequency of the structure is reduced,the period is extended,the equivalent stiffness of the structure is reduced,and the natural vibration effect is enhanced;The maximum displacement and acceleration of each position of the upper structure are increased under the assumption of rigid foundation,and the variation of shear strength is obvious.3.The interaction between superstructure and foundation is more obvious under different soil conditions.The results show that the larger the site type is,the softer the soil is,the pile top displacement increases and the axial force of the pile is reduced.The upper structure of the interlayer shear and displacement are changed,interlayer displacement increases,because the soft soil reinforced for the seismic dissipation ability,the bottom column total bottom shear decreased,with the floor height increase,due to gravity redistribution,and increase the floor shear.Based on the analysis,this paper verifies the necessity of considering the interaction of superstructure and foundation in the seismic design of high-rise buildings,which provides a reliable reference for the practical engineering design.