Some thoughts on the dynamic modeling of bridges

Abstract

Because of the highly different bridge types and designs used in bridge engineering which derive on largely different dynamic mechanisms of response, one of the most important problems to solve concerning their theoretical dynamic modelling is to choose the most adequate FEM model for a particular bridge. The paper deals with the work carried out related with dynamic testing of several bridges in order to check the feasibility and accuracy of different finite element analytical models assumed for the dynamic behaviour of different bridge types: continuous prestressed concrete box girder bridges, continuous prestressed slab bridges with small and large width sections, cable-stayed bridges, etc. The experimental data coming from the tests is used to derive the real dynamic properties of the bridge (natural frequencies and mode shapes). The most appropiate and simple analytical models and dynamic properties of the elements to be used in the FEM mesh are derived for each bridge type based on correlation between theoretical and experimental results. Taking into account these results a set of practical recommendations for the dynamic modelling of different bridges is derived.