Study On Seismic Performance Analysis Method Of High-rise Frame Core Tube Structure

The frame core tube structure system is the first choice of high-rise building structure due to its reasonable force distribution and low cost.How to evaluate and ensure the reliability of high-rise structure under earthquake,has become an important topic of structural seismic design.It is of engineering practical significance to study the optimization design and seismic performance evaluation method related to high-rise frame-tube structure.Based on one high-rise frame-tube structure,the existing theory of structural seismic design is summarized,including static theory,response spectrum theory,dynamic theory and performance-based seismic design theory.The structural spatial analysis model was established by using SATWE,SAP2000,Midas-Gen and EPDA-PUSH,and the structural verification and performance evaluation were carried out.Cycle tatio,shear to weight ratio,ratio of shear strength between layers,interlayer displacement angle,stiffness ratio,stiffness-to-weight ratio and axial compression ratio were considered as model overall control indexes.After the structure was convinced to be reasonable,dynamic elastic time history analysis,static analysis and dynamic elastic-plastic analysis were carried out.The effects of different lateral load patterns and P-Δ effect on Pushover Analysis results was studied.The application and performance evaluation methods of incremental dynamic time history analysis in high-rise frame-tube structure were discussed.Finally,the current commonly used 16 seismic intensity index were summarized.With the single degree of freedom system and the actual frame tube model considered,the applicability of different ground motion intensity indices was discussed and an improvement was proposed on the intensity index of the first periodic response spectrum.The main results and conclusions are as follows:(1)For the main control parameters of the structure,the calculation results from different mechanical models analyzing software are similar,which can meet the requirements of the specification limits and have relatively low cost.The calculaed results based on vibration mode decomposition response spectrum method are conservative and can be used in the design of structural reinforcement,and the elastic time history analysis can be used as a good complement.Steel reinforced concretecolumn and shear wall can meet the requirements of non-yield design under the effect of moderate earthquake.Under the action of strong earthquake,the results of the static and dynamic elastic-plastic analysis show that the displacement angle can meet the requirements of the specification limits and performance.(2)The effects of different loading modes and the P-Δ effect on the analysis results are studied based on the average results of the basement shear-top displacements under the elastic-plastic dynamic time history analysis.The results show that for the high-rise frame-tube structure with the bending-shear deformation,the real-time loading distribution pattern with the minimal impact of P-Δ effect is the most similar to the time history analysis result because the dynamic characteristics of the structure were taken into account.It is recommended to use real-time load distribution model for static elastic-plastic analysis on high-rise frame-tube structure.(3)With the interlayer displacement angle considered as control index,the structural performance was divided into five levels,which are normal use,basic use,repair use,life safety and near collapse.The incremental dynamic time history analysises(IDA)of single and multiple seismic waves are carried out by using the most widely used PGA as the seismic intensity index.,Based on the probability analysis method,the84%,50% and 16% percentile statistical regression curves of 7 seismic waves are drew up,The results show that the incremental dynamic time history analysis of IDA can predict the response and damage of structures at different levels of ground motion at the probability level.(4)Ground motion intensity indexes were divided into four categories.Using time history analysis,the correlations between each index and response of a single degree of freedom system from 0.5s to 12 s were investigated.The ground motion intensity index selection method of high-rise structures influenced by higher modes was considered.The research shows that:(1)The correlations between most of the ground motion intensity indexes and the SDOF responses are quite different and it is decreased with the extension of period.(2)The intensity of the first mode response spectrum and the energy intensity index are highly correlated with displacement and base shear in the whole period.(3)PGV is correlated with displacement and base shear highly;PGD is highly correlated with displacement and lowly with base shear.PGA is lowly correlated with displacement and base shear,except for the short period.(4)For the high-rise structure with long period,the vibration mode combination can be used to improve theapplicability of the seismic intensity index of the response spectrum,and the PGV is recommended as the ground motion intensity index.