Probability Analysis Of Top Displacement For Pushover Analysis Method Of Three-dimensional Reinforced Concrete Frame Structure

FEMA research report has pointed out that the framework of performance-basedseismic design should base on the reliability theory, so the future developmentdirection of seismic design is performance-based seismic design theory. As the core ofthe performance-based seismic design theory, the pushover analysis method alsoshould base on the reliability and probability theory. There are many scholars at homeand abroad to do a lot of research on random pushover analysis method and hasobtained some achievements, but the method is still not mature enough to be used inpractical projects which are still quite difficult. In such a case, it’s necessary to studythe applicability and reliability of the certain-pushover analysis method.First of all, this article expounds the research of pushover analysis method on thedomestic and foreign. Then the fundamental, lateral load loading modes and SAP2000program of pushover analysis were introduced in detail. Pushover actual demandspectrum analysis method of the basic principle and general steps is also put forward.After that the certain pushover analysis method of the general steps is proposed bycomparing these models and the result reveals that floor affects the performancepoints and the top displacement of the frame structure.Secondly, in order to simplify the probability analysis of the top displacement forthe pushover analysis method, the sensitivities of the top displacements to theuncertainty factors are discussed from five aspects in this article, such as the seismicintensity, the site characteristics, the lateral load loading mode, the structural weightand the material properties. The results show that the sensitivity of the topdisplacement to demand curve is far stronger than the capacity curve. Therefore, froma simplified perspective, when studying the probability distribution of topdisplacement for pushover analysis method, this article just considers the uncertaintyof the demand curve and ignores the uncertainty of the structural resistance curve.At last, a7-storey model of the three-dimensional framework is established toanalyze the top displacements of the certain pushover analysis method and thepushover actual demand spectrum analysis method under various conditions.According to the principle of statistical analysis, the guaranteed rate and applicabilityof the certain pushover analysis method are analyzed by studying the top displacementof probability distribution. The results of the analysis suggest that under the earthquake action, if the deformation of the structure steps into the elastoplastic state，the reliability of the certain pushover analysis result is high, in this case this methodis a reliable seismic performance evaluation method, if the deformation of thestructure remains in the elastic condition, the reliability of the certain pushoveranalysis result is very low, the results of the analysis tend to be insecure. So, as a kindof static elastoplastic analysis method, pushover analysis method is not suitable forelastic static analysis.