Vibration Serviceability Assessment of a Multi-Span Footbridge

Footbridge designs are becoming ever more innovative and creative. This can result in footbridges with structural forms that are complicated and slender, and so potentially lively. Serviceability problems due to excessive vibrations have been reported in many recent footbridges. Further, current vibration serviceability approaches can be overly-conservative resulting in unattractive changes to designs. This paper evaluates the vibration serviceability of a multi-span footbridge (denoted as NB Bridge) using a novel approach. The NB Bridge is modelled as a I-D beam model using finite elements (FE) method. This model is calibrated against a complete 3-D structural model of the bridge using model updating techniques. Moving loads are applied to the bridge model to simulate crossing of random (1) single pedestrian, and (2) pedestrian crowds. Vibration serviceability is evaluated using current guidelines, namely the European Guideline HiVoss (2008) and French Guideline Setra (2006), both of which are commonly applied in practice. This paper therefore illustrates this 1D finite element beam modelling approach for vibration serviceability assessment of footbridges with similar complexity.