Research And Application On Structural Dynamic Analysis Using Incremental Earthquake Excitation

Earthquake is one of the most serious natural disasters threatening human life and property security.It is extremely destructive and random,and seriously affects the social development of human being.The frequent occurrence of earthquakes caused a great deal of damage to buildings,resulting in extensive casualties and huge property losses.At present,the common methods for anti-seismic capacity evaluation of structures are static elastic-plastic Pushover analysis and incremental dynamic analysis(Incremental Dynamic Analysis,IDA).However,for some complex structures,such as high-rise buildings,seismic performance analysis of these two methods often has the shortcomings of inaccurate analysis results or low analysis efficiency.Therefore,a number of scholars have proposed a method to evaluate seismic performance of structures by increasing seismic excitation with increasing strength over time,the Endurance Time Method.The whole capability curve of the structure from slight damage to collapse failure can be obtained by means of a single time history analysis.The dynamic characteristics of the structure can be fully considered,and the computational efficiency can be greatly improved while the analysis results are accurate.In this paper,the corresponding improvement measures are proposed according to the inaccuracy that may occur in the analysis of strong nonlinear stage of ET analysis.The accuracy and reliability of anti-seismic capacity analysis are improved by using incremental earthquake excitation.The main contents are as follows:(1)Based on the elastic response spectrum,the corresponding earthquake excitation is made up by using the ET method.Dynamic response analysis of structures is done.The calculated results are compared with the IDA results.The shortcomings of the method of making up incremental earthquake excitation using elastic spectrum are pointed out.(2)Aiming at the shortcomings of ET method,the inelastic response spectrum is used to be the target response spectrum of incremental earthquake excitation,and the concrete constructed method is put forward.The accuracy and rationality of the analysis results are compared with the results of elastic spectrum analysis and IDA benchmark.(3)In view of the fact that the ET analysis method has no uniform theory for the determination of the duration of incremental earthquake excitation,The Arias intensity of the ground motion is chosen as the physical quantity of the incremental earthquake excitation duration.And the prediction formula of earthquake excitationduration is obtained by using the law of the intensity index with time variation of incremental seismic excitation.A specific method for determining the duration of incremental earthquake excitation is proposed,and its accuracy is verified by an example.(4)Using the incremental earthquake excitation constructed method in this paper,the responses of structures under specific earthquake intensities are calculated.Compare with the structural response of the actual earthquake under the same strength.To evaluate the accuracy and reliability of incremental seismic excitation analysis for anti-seismic capacity evaluation of structures.