Seismic Reliability Analysis of Continuous Rigid Frame Bridge Using Probability Density Evolution Method

In engineering practice, ground motion has strong randomness in time and spatial distributions. In order to capture accurately the seismic response behavior of long-span bridge structures, the randomness of earthquake excitation should be considered in dynamic response and reliability analyses. By using the orthogonal expansion model for non-stationary ground motion processes and combining the probability density evolution theory, the random seismic response and reliability analyses of a continuous rigid frame bridge are researched under uniform excitation and non-uniform excitation. The research results show that the seismic reliability of long-span bridge structures under uniform excitation and non-uniform excitation are obviously different. When pier top displacement control is used as failure criteria of the seismic reliabilities under uniform excitation and non-uniform excitation, their relative error is up to 50%, and when pier top moment control as failure criteria, their relative error is up to 200%.