Post-earthquake running reliability assessment method of high-speed railway simply supported beam bridge-track system based on probability density evolution method

In view of the problems that the current post-earthquake running safety assessment of trains mostly relies on the deterministic analysis under a single earthquake, lacks the consideration of seismic randomness. And it’s difficult to provide the driving reliability evaluation results and speed reduction recommendations after the earthquake. This paper proposes a post-earthquake running reliability assessment method of high-speed railway simply-supported beam bridge-track system based on probability density evolution method. Random non-stationary ground motion simulation under different PGA is realized by using the number theoretical method and spectrum method, considering the randomness of ground motion spectrum characteristics. Through incremental dynamic analysis of the track-bridge system, to construct a database of post-earthquake track residual deformation, and further establish key index of post-earthquake track residual deformation. Moreover, the OpenSees-TRBF co-simulation method is used to carry out post-earthquake running safety speed threshold analysis, and then the mapping model between different track damage grades and running safety speed thresholds is established. Finally, the probability density evolution method (PDEM) is used to solve the probability distribution of track residual deformation under different PGAs, which is combined with the mapping model to obtain the post-earthquake running reliability corresponding to each grade of driving speed. Additionally, a five-span railway simply supported beam bridge is used as an example to verify the method proposed in this paper, and the recommended speed with 95% running reliability under each PGA is given. The method realizes a more accurate and comprehensive post-earthquake running safety assessment of high-speed railway bridges, and can provide guidance suggestions for deceleration operation with high assurance rate, so as to guarantee the post- earthquake resilience of high-speed railroad network.