Nonlinear behaviour of steel–concrete composite bridges: finite element modelling and experimental verification

To ensure public safety, existing bridges are often evaluated for their load-bearing capacity. Realistic evaluation must take into account the actual nonlinear stress–strain characteristics of the bridge materials and the interaction among its structural components at all stages of loading up to failure. The finite element method is particularly suitable for this type of analysis, but nonlinear finite element formulations involve many assumptions that must be verified before any practical application. In this study, the accuracy of a nonlinear finite element program developed by the authors for the analysis of composite steel–concrete bridges is checked by comparing its results with experimental data from simply supported and continuous beams tested by others and from a 1/3 scale multi-girder composite bridge tested by the authors. Good agreement is observed between the measured and the computed load–deflection responses and strains at all stages of loading up to the maximum load, which demonstrates the accuracy of the finite element formulation and the validity of its assumptions.