A Parametric Study of Pedestrian Vertical Force Models for Dynamic Analysis of Footbridges

Footbridge vibration has received much attention in recent years. However, stochastic models for crowd loading are not common, and estimation of crowd-induced vibration is typically done through enhancement factors applied to single pedestrian loading models. This work compares two such models, a moving force model and a spring-mass-damper model (SMD). Typical ranges for various pedestrian parameters are examined, and it is found that the pacing frequency has by far the greatest influence on bridge vibration response. It is also found that the magnitude of the response for pacing frequencies near the bridge natural frequency is lower for the SMD model, but otherwise the results prove similar. This suggests that moving SMD models may be more suitable than moving force models when the bridge natural frequency is in the critical frequency range.