Research On Standard Effect Of Rare-Earthquake Design Method On High-rise Structures

Although two-stage design is still the main idea of seismic design method in China,anti-seismic design based on the idea of rare-earthquake design has become more and more popular.It is believed that seismic excitation simulation method is the basis of reliability of rare-earthquake design method.Currently,there are two major methods,one is based on static theory,the other is based on dynamic theory.And each method has its own deficiency--the former always ignores duration action in an earthquake while the computing results of the latter are often dispersed as the result of difference among different types of seismic wave.By building a lateral loading method based on multi-stage reciprocating action pattern,this thesis providing a standardized seismic excitation simulation method for high-rise structure.The method could be used to stimulate whole process of how a structure is affected by earthquake under strong earthquake and help us improve seismic design method based on rare-earthquake design.The thesis includes four sections:Study on multi-stage lateral loading method based on structure plasticity development.In this section,the author separates the process of pushover into several phases according to structure plasticity development,and use different lateral force distribution in each phase to show variation of earthquake on the structure.The author,then,separately adopts improved method,self-adaption method to get two capability curves of a high-rise frame-core wall structure.By comparing the curves,the author finds that even though there is little difference of accuracy between the two methods,the former is more convenient in application.Study on lateral loading method when taking earthquake into account.In this section,the author does a mass of elasto-plastic time history analysis on typical SDOF systems,which shows effect of natural vibration period,strength reduction factor,site classification on structure displacement history and concludes rules of variation of displacement history.And the author builds a lateral loading method based on reciprocating action pattern to find out frequency and variation on lateral loading method.Study on inelastic demand spectrum when taking damage into account.In this section,after improving Park-Ang damage model and taking structure natural vibration period,damage index,ultimate displacement ductility,site classification into consideration,the author builds inelastic displacement spectrum and corresponding fitting formula that have statistic meaning,and the demand spectrum could be used to find out the maximum amplitude of lateral loading method.Nonlinear analyzing method based on standardized seismic excitation simulation method.In this section,the author,firstly,uses lateral loading method based on multi-stage reciprocating action pattern,inelastic demand spectrum which takes damage into account and MPA method to come up with a standardized seismic excitation simulation method.In the light of this,the author build a corresponding nonlinear analyzing method.And by applying the method to case of OCT tower,the author compares computing results of the improved method,pushover analysis,nonlinear time history analysis and it could be concluded that the method of this thesis has is convenient and reliable.