INFLUENCE OF STRONG-MOTIONS DURATION ON SEISMIC INELASTIC DEMAND FOR COLUMNS OF RC BRIDGES

The influence of the duration of earthquake strong-motions on structural damage has aroused a broad at- tention of many researchers.In the process of nonlinear dynamic time history analysis on RC column by using real acceler- ograms and spectral matched artificial accelerograms with reasonable sealing,the influence of duration and that of ampli- tude or spectral characteristics on structural damage can be seperated.Comparison of the correlations between the duration of the ground motion and various demand measures reveals that the duration has no influence on demand measures using displacement and ductility,but is correlated to energy demand measures and cumulated damage measures.In establishing the probabilistic seismic demand model(PSDM),when the period spectral acceleration of the first mode and the reasona- ble energetic demand measures are adopted as the intensity measure (IM) and the engineering demand parameters(EDP) respectively,how to consider the influence of duration is important and expounded in the paper.