Comparative Research On Pushover Analysis And Nonlinear Time History Analysis Of RC Structure Based On Component Deformation

Performance-based seismic design method relies on reliable results of structural nonlinear analysis,which includes pushover analysis and nonlinear time history analysis.Theoretically,nonlinear time history analysis can accurately predict the force and deformation of a structure under strong earthquake,but the randomness of ground motions will bring discrete calculation results and consume large computational resources.The pushover analysis method is simple,intuitive and fast in calculation,but it has certain theoretical assumptions and defects in itself,and the calculation results have certain errors.How to reasonably choose the best nonlinear analysis method to take into account the accuracy of calculation results and calculation efficiency has become a question encountered in engineering practice.This paper takes typical frame structure and typical shear wall structure as the research object,applies RC member deformation index to assess the real performance state of members,compares and studies the similarities and differences between pushover analysis and nonlinear time history analysis,and evaluates the accuracy and applicability of pushover analysis,the main research contents and results are as follows.(1)Typical frame structures and shear wall structures are established.Nine typical frame structures and nine shear wall structures are designed with the fortification intensity and structure height as variables.The combined modal pushover method is used to perform pushover analysis and nonlinear time history analysis with the input of ground motions conforming to the code requirements from the two main axes of the structure respectively,and a total of 36 cases are obtained.The conclusions obtained from the typical structural analysis are also verified by engineering examples.(2)The performance of the structure under rare earthquake is evaluated using both pushover analysis and nonlinear time history analysis methods.The results of the cases show that the performance states of the vertical members of the structure are basically the same,and the performance states of the energy dissipating members differ.(3)Pushover analysis and nonlinear time history analysis are used to reveal the yielding mechanism of the structure.The first vertical member failure criterion is used as the basis for determining the collapse of the structure,and the member performance at the time of collapse failure is evaluated to reveal the yielding mechanism of the structure.The results of the cases show that although there are some differences in the performance states of the members,they do not affect the damage mode of the structure,and the yield mechanisms of the structure calculated by pushover analysis and nonlinear time history analysis are basically the same.(4)Suggestions for the application of the pushover analysis are given.The results show that for frame structures and shear wall structures up to 150 m,pushover analysis can be used to evaluate the damage of structures under rare earthquakes,and pushover analysis can be used to supplement the analysis of the yielding mechanism of structures and the damage development process of the members.(5)The modal orders to be considered when using the combined modal pushover method and the effects of different target displacement calculation methods on the results of pushover analysis of the structure are discussed,and relevant suggestions are given.