Research On Seismic Design Method Based On Performance Of A Single-tower Structure With Large Chassis

With the continuous development of China's society and economy,urban land becomes increasingly scarce in China.From the perspective of architects,as the tower-structure with large chassis satisfies users' needs as well as reaches high plot ratio,it has great economic benefits.From the perspective of struactural engineers,the transfer storey on the junction of the chassis top and the tower results in the discontinuity of vertical components;the leaning tower leads to eccentricity,which is a typical complicated structure under complex stress in earthquakes.To solve this problem,it is necessary to conduct in-depth research to guarantee the structure's safety under rare earthquakes.Since accurately determining seismic response requires long time and a great amount of calculation,the design of seismic concepts and the evaluation of the structure's seismic performance are the key to the seismic design of structures.By analyzing Department D in Jiamusi China Town,this paper carries out a in-depth study on the anti-seismic performance of tower-structure with large chassis and provides suggestions on the engineering design of the structure.The following research methodologies are adopted:(1)The thesis uses software SATWE to conduct elastic analysis to the structure under frequent earthquakes of intensity 6 and 7.It compares and analyzes the cycle,formation,seismic response,storey displacement,storey displacement ratio,etc.by changing single parameter such as the height and the stiffness of the chassis;(2)Softwares EPDA&PUSH are used to make Pushover analysis to rare earthquakes of intensity 6 and 7.Capacity spectrum method is adopted to assess the structure's seismic performance.The impact that increasing seismic precautionary intensity has on the structure is studied.By comparing different load patterns,the thesis researches how these patterns influence Pushover results.The thesis proposes that for complicated structure,it is necessary to calculate at least two load patterns respectively and compare the results;(3)Elastic-plastic time-history analysis is conducted under the circumstance of rare earthquakes of intensity 7 with the help of softwares EPDA& PUSH.The structure's seismic performance is evaluated.The impact that improving seismic precautionary intensity has on the structure is studied.The results are compared with those made by Pushover analysis.The thesis finds out that when studing complicated structure by Pushover analysis,elastic-plastic storey drift angle multiples a certain amplification factor;(4)Elastic analysis of seismic-isolated structure is conducted with software SATWE.By changing single parameters such as the horizontal stiffness of seismic-isolatioin bearings and the position of seismic isolation storeys,the thesis compares and analyzes the structure's dynamic characteristics and seismic response.The influence that these parameters have on the seismic-isolation structures' overall seismic performance is studied.Seismic-isolated structures are compared with structures without seismic-isolation.The effects of seismic-isolation are researched.Advantages and disadvantages of storey isolation structure in engineering application are discussed;(5)The thesis reorganizes and summarizes the results of analogue computation,analyzes key parameters,proposes seismic designs and methods for large chassis tower structures withr large chassis,studies the influence that increasing seismic precautionary intensity has on structures of zonation of itensity 6 and corresponding seismic strenthening strategies,and puts forward reasonable suggestions for the engineering design of this kind of structures.