<p>This study evaluates the seismic performance of high-speed railway continuous girder bridges with concrete-filled steel tube piers (CFST) and the corresponding running safety of trains. A refined three-dimensional finite element model considering ductile damage of steel, plastic-damage evolution of confined concrete, and a main-crack insertion technique was developed and validated against shake-table test results. Based on this model, a coupled train–CRTS III slab ballastless track-continuous girder bridge model was established to perform nonlinear time-history analyses under six peak ground acceleration levels from 0.07g to 0.38g and train speeds of 150, 250, and 350 km/h. The results indicate that the predicted wheel–rail forces, vehicle accelerations, and rail/slab displacements under the benchmark service condition are all below code limits and within or close to published field ranges. Under seismic excitation, pier-base plastic damage increases progressively with ground-motion intensity, whereas stirrup-confined concrete-filled steel tube piers (SCFST) show delayed damage initiation and lower damage severity than conventional CFST piers. Both seismic intensity and train speed increase the derailment coefficient and wheel-rail lateral force, while the wheel-load reduction rate is influenced mainly by train speed. The maximum safe train speed for SCFST bridges is 350 km/h at 0.15g and 150 km/h at 0.20g, and train operation should be suspended when the peak ground acceleration exceeds 0.25g. Stirrup confinement, therefore, improves both the seismic resistance of CFST piers and the running safety margin of high-speed trains.</p>

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Seismic performance of continuous girder bridges with concrete-filled steel tube piers and earthquake-induced train-track-bridge responses: Assessment of train running safety

  • Hao Sun,
  • Yan-zhe Li,
  • Zhi-wu Yu,
  • Said-Ikram Sadat,
  • Fa-xing Ding,
  • Fei Lyu,
  • Qing-yuan Xu,
  • Tao Zhang

摘要

This study evaluates the seismic performance of high-speed railway continuous girder bridges with concrete-filled steel tube piers (CFST) and the corresponding running safety of trains. A refined three-dimensional finite element model considering ductile damage of steel, plastic-damage evolution of confined concrete, and a main-crack insertion technique was developed and validated against shake-table test results. Based on this model, a coupled train–CRTS III slab ballastless track-continuous girder bridge model was established to perform nonlinear time-history analyses under six peak ground acceleration levels from 0.07g to 0.38g and train speeds of 150, 250, and 350 km/h. The results indicate that the predicted wheel–rail forces, vehicle accelerations, and rail/slab displacements under the benchmark service condition are all below code limits and within or close to published field ranges. Under seismic excitation, pier-base plastic damage increases progressively with ground-motion intensity, whereas stirrup-confined concrete-filled steel tube piers (SCFST) show delayed damage initiation and lower damage severity than conventional CFST piers. Both seismic intensity and train speed increase the derailment coefficient and wheel-rail lateral force, while the wheel-load reduction rate is influenced mainly by train speed. The maximum safe train speed for SCFST bridges is 350 km/h at 0.15g and 150 km/h at 0.20g, and train operation should be suspended when the peak ground acceleration exceeds 0.25g. Stirrup confinement, therefore, improves both the seismic resistance of CFST piers and the running safety margin of high-speed trains.