The Seismic Performance Analysis Of Enlarged-Base Multi-Tower Structure With Thick Plate Transfer Layer

Most tower structures are multi tower structures.As a special structure system with chassis connected and independent building on the upper part,the seismic response of multi tower structure is different from that of single building.The coupling vibration between towers through chassis makes mechanical characteristics complex.In China,there are some simple regulations on the seismic design of multi tower structure.However,the research of multi tower structure is not mature.There is a great uncertainty.So the seismic analysis method and seismic measures of multi-tower structure have not been clearly stipulated.Nowadays most of the tower structure projects are twin-tower structures,few are three-tower structures and multi-tower structures.Most of academic research objects are also mostly focused on the twin tower structure,and the research and analysis of the multi-tower structure are relatively few,and no systematic analysis theory has been formed.So it is of great significance to study the seismic response characteristics of multi tower structure.To research the dynamic characteristics of multi tower structure and study the seismic response characteristics of multi tower structure,this paper introduces the five tower structure with large chassis and thick plate on the upper cover of Shenzhen Metro,pays attention to the layout of different tower numbers,and makes a deep analysis and comparison of five different multi tower structure’s seismic response characteristics.The main research work and conclusions are as follows:1.This paper introduces the analysis method of structural seismic response analysis.Five kinds of structures are builded in this paper,including single tower structure,twin-tower structure,three tower structure,four tower structure and five tower structure.The response spectrum of mode decomposition is analyzed,and the variation rules of period,displacement and seismic response force of different models are obtained.Among them,the transfer thick slab shows a strong restraint effect in the structure,its high stiffness leads to the mutation of floor shear and overturning moment;the transformation from single tower to multi tower will lead to the gradual increase of displacement,floor shear and overturning moment.2.Furthermore,the dynamic time history analysis of the five models is carried out,and the variation rules of the period,displacement and seismic response force are compared and verified,and the two conclusions are relatively consistent.The stress analysis of the transfer structure shows that the stress concentration of the transfer plate of the multi tower structure mainly occurs in the floor in the middle of the towers.The damage analysis of five models is carried out,and the change law of the damage is consistent with the seismic response of the structure in the time history analysis.In the time history analysis,the coupling beam,as the main energy dissipation component,yields first to produce plastic hinge,thus dissipating seismic energy;with the increase of the number of towers,the damage degree of coupling beam presents an increasing relationship.