Seismic safety assessment of trains running on high-speed railway bridges with chloride-induced corroding piers

For the lifetime assessment of the running safety of a train in aggressive environments and earthquake-prone areas,the effects of corrosion on seismic performance must be considered.Research on the running safety of trains,including corrosion damage,is limited,despite the fact that seismic safety assessment of trains on high-speed railway bridges has been extensively examined.In this work,the running safety of a train was evaluated using a time-varying corroded bridge finite-element model established in OpenSees.Two pier types were considered,and three ground-motion types were selected for performing seismic performance evaluations.Subsequently,the seismic response of the corroded bridge-track structure under an earthquake was analyzed.The spectrum intensity was used as the structural response index for the running safety assessment of trains under earthquakes,and the long-term safety of trains on bridges with different pier heights and earthquake types,considering different corroding deterioration,was evaluated.The results indicate that under low-level earthquakes,piers are primarily in a linear elastic state and least influenced by corrosion;whereas under high-level earthquakes,the running safety of trains on a bridge significantly deteriorates after corrosion,particularly for high-pier bridges,mainly because the corroded piers are more likely to yield lower post-yield stiffness.The results of this study suggest that in the seismic safety assessment of trains on corroded bridges,timevarying seismic performance characteristics should be considered.

Seismic running safety of trains and a new type of seismic-isolation railway structure

Until now,seismic-isolation structures have not yet been applied in the railway field.The reason is that though a seismic-isolation structure can reduce the inertial force to the structure,the energy absorption causes big response displacement on the structure,which adversely effects the running safety of the trains supported by the structure.In this paper,a methodology for seismic running safety assessment is introduced,and a new type of seismic-isolation foundation is proposed,which can convert the seismic response displacement in the lateral direction of track to the longitudinal direction that has a less adverse effect on the running safety of the train.The isolation foundation is composed of FPS(Friction Pendulum System)slider,concave plate and guide ditch.Moreover,through model experiments and 3D numerical simulation,it is verified that the proposed foundation can keep both the effects of the seismic isolation and the running safety of the train during an earthquake.