Vertical crowd load models for vibration serviceability assessment of footbridges

Most pedestrian load models prescribed in existing design codes of practice do not consider any interaction between the pedestrian and the moving structure. However, it is now widely accepted that this interaction is critical to the forces exerted on the bridge and thus the bridge response to such forces. Several new approaches to modelling crowd loading, including some stochastic methods have been proposed in recent times. Nonetheless, these do not fully simulate the effect of the interaction between the pedestrian and the structure on the load pattern exerted by the pedestrian. This paper examines some of these approaches and presents an innovative technique for modelling vertical crowd forces. This deterministic load model may provide the basis for a meaningful probabilistic approach to the issue of footbridge vibration serviceability.