Study On Displacement Based Simplified Analysis Method Of Elasto-plastic Seismic Response Of Structures

Nonlinear static push-over analysis is regarded as an efficient method of seismic response evaluation of structure. This kind of simplified analysis method has attracted more and more attention from inland and overseas for its merits of simpliness and practicality.The state of the art of nonlinear static Push-over analysis and its advantages and limitation are described in the first part of this paper. Then based on the theory of nonlinear static push-over analysis, an analysis model has been established which is fit for the analysis of the RC structures and is applied in the latter study on push-over analysis. Based on the dynamic equation, the equivalent method from MDOF to SDOF and equations of the capacity spectra and the demand spectra theories are deduced in detail. A comparison is made between the results from nonlinear static push-over analysis and nonlinear time history analysis, which is performed based on the precondition of equivalent displacement. The implement and validity of push-over analysis on RC frame structure seismic performance evaluation is studied. In addition, the results of push-over analysis on the RC frame structures under different load patterns are compared and analysised.Nonlinear static push-over analysis is not a prescise analysis method , but an simplified one. The purpose of the study on the nonlinear static pushover analysis is to simplify the practical engineering analysis and use its result to instruct the practical engineering design. To achieve this aim, a simplified equation is proposed in this paper by which the target displacement of a MODF under design earthquake can be obtained using its equivalent SDOF and a paramenter study is conducted to get the rational value of coefficients in this equation. To test the validity of the simplified equation, a comparisons is made between the target displacement by the simplified equation and the maximum response of the structure under a series of seismic waves, and the results show a good agreement. Using the simplified equation proposed, the analysis of a practical engineering structure is more efficient than the traditional method, and avoid the perplexing nonlinear dynamic history analysis procedure.