Crowd dynamics on a moving platform: Mathematical modelling and application to lively footbridges

This paper proposes a mathematical model and a computational approach to study the complex multiphysical non-linear coupled system that results from the interaction between a moving platform and the pedestrians who walk on it. The described method is based on the mathematical and numerical decomposition of the coupled system into two subsystems and on the two-way interaction between them. In particular, the dynamics of the crowd is modelled referring to a macroscopic description in analogy to that of a compressible flow. The proposed approach is applied to the lateral vibrations of footbridge decks under human-induced excitation. First, the computational parameters of the model are optimized. Then, the effects of the crowd initial density and of the runnability conditions are evaluated on a motionless platform. Finally, the results obtained from the simulations of the crowd–structure interaction are commented on.