Pedestrian-Footbridge Dynamic Interaction: A Probabilistic Assessment of Vibration Serviceability

Recent footbridges are characterized by long span, light materials and increasing slenderness, which make them more sensitive to dynamic forces induced by pedestrians. The vibration serviceability under human-induced dynamic forces is the governing criterion for the design of these slender structures. To assess serviceability, the bridge response must be computed accounting for human-structure interaction, adopting reliable estimates of expected loading scenarios, accurate models representing pedestrians and suitable integration techni¬ques. The present contribution investigates the dynamic response of a lively footbridge due to a group of pedestrians described as bipedal mechanical systems able to reproduce the human gait. Based on a numerical procedure previously developed, extensive simulation activity is performed in order to characterize the structural response in a probabilistic way. The step frequencies of the pedestrians are considered as correlated random variables, where correlation is based on mutual distance among pedestrians.