The impact of vertical human-structure interaction on the response of footbridges to pedestrian excitation

The results show that for the low-frequency dynamic behaviour of footbridges (<6Hz), HSI leads to an effective damping ratio which is (significantly) higher than the inherent damping ratio of the empty structure. In addition, it is demonstrated that the detailed moving crowd model can be well approximated by a time-invariant crowd-structure model. Furthermore, the influence of inter- and intra-person variability in step frequency is observed to decrease as the impact of HSI increases. Finally, it is shown that in many cases accounting for HSI leads to a significant reduction in the response of footbridges to pedestrian excitation which may be considered in practical design.