A Methodology for the Dynamic Analysis of Railway Bridges Subjected to Vehicular Loads

Railway bridges are subjected to various types of dynamic loading. Among these, earthquake, wind and vehicular loading deserve attention. Only vehicular loads are considered in this work. In many codes, such loads are considered as static loads which are multiplied by an impact factor to account for dynamic effects. Such procedure, although very likely conservative, does not consider the forces due to mass, damping and stiffness as in a typical dynamic analysis. Thus, it is the objective of this presentation to discuss a methodology that considers the interaction between railway vehicle and bridge in which both structures are modeled separately and have their specific dynamic characteristics. The bridge is modeled by finite elements and the vehicle is modeled as an assemblage of rigid bodies. The source of dynamic loading is track irregularities, which may have specific profiles associated with specific causing phenomena or may have a random profile as a result of the superposition of several causes. The analytical methodology is a complex result from the association of many modeling aspects that are put together to better represent the behavior of the bridge structure.