Improvement of bridge structures to increase the safety of moving trains during earthquakes

The main purpose of this study is to investigate the improvement of bridge structures to increase the safety of moving trains during earthquakes using finite element analyses, where nonlinear moving wheel elements are used to simulate the contact and separation modes of rails and wheels. The bridges are standard multi-span bridges for a high-speed rail system. The results of parametric studies with over 320 analyses indicate that the improvement in the train safety for multi-span bridges with several continuous spans is not observable. Large gaps between two simply supported girders during earthquakes will increase the train derailment coefficient, and thus a reduction in the eccentricity between two girders can enhance the safety of moving trains. Additionally, because the first train natural frequencies are often in the low frequency range, large pier stiffness producing high bridge natural frequencies can confine the train derailment coefficients near a normal value, even in the resonance between bridges and earthquakes, so we suggest that large pier stiffness should be used to ensure the safety of moving trains during earthquakes.