Probability Analysis Of Top Displacement For Pushover Analysis Method Of RC Frame Structure

The method of performance-based seismic design is the development direction ofthe structure seismic design in the future. The FEMA research report pointed out thatthe framework of performance-based seismic design should base on the reliabilitytheory. As the core method of performance-based seismic design, the pushoveranalysis method also should base on the probability and reliability theory. At present,many scholars at home and abroad have made a lot of research on random pushoveranalysis method and acquired great achievements. But this method is not matureenough and difficult to use in real project. So, it’s necessary to study the reliabilityand applicability of the certain pushover analysis method.In the beginning of the article, the research status about the pushover analysismethod both at home and abroad is summarized. Then the fundamental, lateral loadloading modes, the method of solving the target displacement and the basic analysissteps of the pushover analysis method were introduced. After that, actual demandspectrum pushover analysis method is proposed and the result of an example showsthat this method is a feasible method for evaluating the seismic performance.Secondly, to simplify the probability analysis of the top displacement for thepushover analysis method, the sensitivities of the top displacements to the uncertaintyfactors such as the seismic intensity, the site characteristics, the hysteretic model, thelateral load loading mode, the structural weight and the material properties and so onare discussed. The results show that the sensitivity of the top displacement to demandcurve is far stronger than the capacity curve. So when study the probabilitydistribution of top displacement for pushover analysis method, just considering theuncertainty of the demand curve and ignoring the uncertainty of the structuralresistance curve.Finally, the top displacements of the certain pushover analysis method and theactual demand spectrum pushover analysis method of the7-story plane framestructures under various conditions are compared. The reliability and applicability ofthe certainty pushover analysis method is discussed by studying the probabilitydistribution of the top displacements. The results show that under the earthquakeaction, if the deformation of the structure steps into the elastoplastic state，thereliability of the certain pushover analysis result is high, in this case this method is a reliable seismic performance evaluation method, if the deformation of the structureremains in the elastic condition, the reliability of the certain pushover analysis resultis very low, the results of the analysis tend to be insecure. So, as a kind of staticelastoplastic analysis method, pushover analysis method is not suitable for elasticstatic analysis.