Abstract: In order to overcome the shortcomings that traditional models of equivalent plastic hinge length do not take into account the influences of multiple factors and their uncertainties,a probabilistic model for equivalent plastic hinge length of reinforced concrete columns considering uncertainties was established.Based on the equivalent plastic hinge theory,an analytical expression was determined first by taking into account the influences of axial compression ratio,column height,longitudinal reinforcement ratio,yield strength and diameter of longitudinal reinforcement.Then a probabilistic model for equivalent plastic hinge length was established by adding the probabilistic model parameters to describe the influence of uncertainties and updating the probabilistic model parameters based on the Bayesian theory and the Markov Chain Monte Carlo method.Finally,probabilistic calibration of traditional equivalent plastic hinge length model is performed based on the experimental data and probabilistic model.Analysis shows that the proposed model exhibits high prediction accuracy,which not only reasonably describes the probabilistic distribution characteristics of equivalent plastic hinge length,but also calibrates the traditional deterministic model and determines the probabilistic characteristic values of equivalent plastic hinge length of RC columns with predefined confidence level.