Multimode dynamic response of railway bridge superstructures to high-speed train loads

High-speed passenger trains can cause destructive vibrations on bridge structures. The possibility of resonance is particularly related to the bridge superstructure’s natural frequency and the frequency of moving loads, which is characterized by the train type and its speed. In this study, a multimode dynamic analysis has been performed for a variety of superstructures, span lengths, train speeds and train types. Numerical analysis has been applied to evaluate different girder support conditions such as simple, two-span continuous and three-span continuous. In addition, the train/structure interaction is included in the analytical models. The results are presented in terms of moment dynamic load factors for a practical range of the superstructure’s fundamental frequency, which include various superstructure types such as concrete, prestressed concrete and steel. Different high-speed trains are considered moving at various speeds to capture the configuration for highest responses. This study provides a set of diagrams for initial estimation of high-speed railroad bridge bending moment response. Proposed diagrams will help bridge designers to avoid an uneconomic bridge system in early design stages.