The impact of vertical human-structure interaction for footbridges

To allow for a more accurate description of crowd-induced loading, the present study aims to provide the necessary insights into vertical human-structure interaction (HSI) phenomena, to date ignored in current load models. A parametric study is performed to investigate the effects of the mechanical interaction between pedestrians, represented by simple lumped parameter models, and the supporting footbridge. The most significant HSI-effect for the low-frequency modes of a footbridge, is in the effective damping ratio of the coupled system which is much higher than the inherent structural damping. The effective damping ratio increases monotonically with the pedestrian density but is highly dependent on the natural frequency of the footbridge. In order to verify the findings, a comprehensive full-scale experimental study is performed on two footbridges. It is shown that the crowd-structure model is able to reproduce the experimentally identified dynamic characteristics of the coupled system.status: publishe