Influence of optimizing vibration-reducing measures on the post-earthquake running safety of trains in extradosed cable-stayed bridges

This study proposes a vibration mitigation scheme for seismic analysis of long-span bridges. Focusing on an extradosed cable-stayed bridge in high-speed railways, it investigates how damping-isolation devices affect both structural seismic responses and train operational safety. A coupled dynamics model of a high-speed train-ballastless track-bridge system incorporating friction pendulum bearings (FPBs) and viscous dampers (VDs) is established using the ABAQUS-SIMPACK co-simulation platform. Parametric analyses based on the uniform test method, multivariate regression, and random forest algorithm are used to optimize vibration isolation performance. Wheel-rail dynamic indicators, including lateral wheel-rail forces, derailment coefficients, wheel load reduction rates, and car-body accelerations are used to evaluate train operational performance on the optimized seismic-isolation bridge under earthquake excitation, along with the assessment of structural residual displacements. The findings provide a basis for assessing the effectiveness of optimized vibration-reducing measures in enhancing post-earthquake train running safety on extradosed cable-stayed bridges.