Post-Earthquake Multi-Level Connectivity Reliability Assessment Method for Regional High-Speed Railway Bridge Networks

Post-earthquake connectivity assessment of regional high-speed railway bridge networks should consider train running safety on bridges,multi-level speed restrictions,and route selection.A multi-level connectivity reliability assessment method is proposed for regional high-speed railway bridge networks after earthquakes.Random ground motion simulation,OpenSees-TRBF co-simulation,and the probability density evolution method were used to obtain the post-earthquake running reliability of a typical high-speed railway bridge under different seismic intensities and train speeds.The multi-level traffic function of the bridge was then classified with a 95% reliability guarantee.A regional bridge network topology model was constructed by incorporating the multi-level traffic reliability of bridge nodes.Combined with the ground motion attenuation relationship,the seismic intensity at each bridge site was determined for different seismic sources and magnitudes,and the connectivity reliability and safe travel time of origin-destination paths were calculated.The example results show that seismic source location and magnitude significantly affect the bridge functional damage distribution and the optimal travel path.Under magnitude 6.5 and 7.0 earthquakes from source E1,the safe travel time of the optimal path increased by 9.3% and 51.4%,respectively.Under the same magnitudes from source E2,the increases were 12.8% and 45.1%,respectively.The proposed method can support post-earthquake traffic state assessment,speed restriction control,and emergency route selection for regional high-speed railway bridge networks.