Modelling criteria proposal for dynamic analysis of beam bridges under moving loads using fem models

Abstract

Regulations establish requirements to be met in dynamic analyses of moving loads, but do not establish any criteria for how to model a bridge for dynamic analysis. In other words, what spatial and temporal discretisation must the model comply with in order for the results to be accurate? In this article, four control coefficients and their limiting values are established so that, depending on the characteristics of the bridge and the speed of the moving load, it can be guaranteed that the results of the FEM models are accurate. A total of 35 cases, focused on beam bridges, are analysed and the computational models are compared with a proposed formula for moving loads. It is shown that with common geometric discretisation techniques and, independently of the time discretisation, a bridge can undergo resonance when the moving load passes but the model cannot represent this phenomenon. Finally, it is demonstrated that by complying with the modelling criteria proposed in this article, any structural response could be correctly captured by the calculation models.