In this study, the dynamic behavior of the 3D train-bridge system subjected to different hydrodynamic loads (TBW model) is established. By taking a continuous bridge with box girders as a case study, the dynamic responses of the bridge which is under train passing and subjected to several sea hydrodynamic loads are analyzed. Hydrodynamic forces are applied on piers according to Morison's theory and car body is modeled by a 27-DoFs dynamic system. Model validation has been performed with other research by considering vessel collision load. In continuation, the dynamic responses of the bridge and the running safety indices of the train on the bridge under several conditions are analyzed. Consequently an assessment procedure is proposed for the running safety of high-speed trains on bridges subjected to wave loads. Results of TBW's sensitive analyzes have shown the importance of sea-states conditions for train safe and comfortable running. These outputs indicates that in stormy conditions, the speed of the train crossing the bridges should be reduced and it is possible for the train to pass at low speeds in stormy conditions.

Dynamic performance of the 3D train-bridge system (TBW model) subjected to different hydrodynamic loads and applying AAR track irregularity is established in this study. By taking a continuous bridge (32 + 48 + 32) m with box girders as a case study, the dynamic responses of the bridge which is under train passing and subjected to several sea hydrodynamic loads are analyzed. The substructure of the bridge includes four concrete solid piers with rectangular sections and piers are fixed at seabed. Piers and decks are designed and analyzed based on dynamic finite elements methods, and hydrodynamic forces are applied on piers according to Morison's theory. Also, car body is modeled by a 27-DoFs dynamic system. Model validation has been performed with another research by considering vessel collision load. Then, the dynamic responses of the bridge and the running safety indices of the train on the bridge under several types of sea wave states when train speed is 300 km/h analyzed. Results of TBW's sensitive analyzes have shown the importance of sea-states conditions for train safe and comfortable running. Also, irregularity has an obvious effect on the dynamic responses of the bridge. It has greater effect on vertical acceleration and displacement than horizontal ones in presence of hydrodynamic load. Combination of these two phenomena (wave and irregularity) jeopardizes the running safety of train when crossing the bridge.

A study about the running safety of trains moving over bridges subjected to hydrodynamic loads under one-direction and two bidirectional high-speed train passing is presented. Dynamic performance of the developed 3D train–bridge–wave system (TBW model) subjected to different hydrodynamic loads and applying Association of American Railroads track irregularities is established in this study. The dynamic responses of the bridge, which is under one-direction and two bidirectional high-speed train passing and subjected to several hydrodynamic loads and rail irregularities, are analyzed. The dynamic responses of the bridge and the running safety indices of the trains on the bridge under several types of sea states in one-direction and two bidirectional train passing are analyzed. Results of developed TBW’s sensitivity analyses have shown the importance of sea-state conditions for safe train running. Irregularities have an obvious effect on the dynamic responses of the bridge. Between comparing one-direction and two bidirectional high-speed train passing modes, bidirectional train passing has a greater effect on vertical acceleration and displacement than horizontal ones in the presence of a hydrodynamic load. Therefore, the combination of wave forces, rail irregularities, and bidirectional train passing jeopardizes the running safety of high-speed trains by increasing both lateral and vertical displacements and accelerations. Furthermore, the effect of wave force on the running safety indices of the train is investigated by considering different train speeds. As expected, the tendency observed in all the derailment criteria is similar, indicating that the risk of derailment increases with the increasing of the running speed and wave height.