Random Walking Crowd Model Considering Pedestrian Synchronization Rate

In order to study the influence of walking crowd synergy on the human-induced vibration of structures, the vertical vibration of a footbridge under the action of walking crowd was analyzed using the random walking crowd model considering pedestrian synchronization rate. Firstly, a random walking crowd centralized model and discrete model considering pedestrian synchronization rate were proposed by random analysis of the walking crowd. Secondly, a method for vertical vibration response analysis of structure subjected to random walking crowd was established by considering the vertical coupling effect between human and structure under the two models. Finally, change rules of vertical acceleration responses and dynamic characteristic parameters of the footbridge under the two different random walking crowd models were compared and analyzed. Results show that the 1-s root-mean-square (RMS) acceleration responses of the footbridge under the two pedestrian walking models both increase first and then decrease with the crowd density increasing. Beyond the crowd density of 0.2 person/m², the 1-s RMS acceleration of the footbridge in the random walking crowd discrete model is greater than that in the centralized model, and increasing the pedestrian spacing in the synchronization zone of the centralized model is beneficial to reducing structural vibration responses. As crowd density increases, the instantaneous frequency of footbridge decreases constantly; the instantaneous damping ratio of the footbridge increases first and then decreases, with a maximum 6-fold and 7-fold increase under the centralized model and the discrete model, respectively. In short, the random walking crowd model considering pedestrian synchronization rate can accurately reflect the actual crowd walking load of footbridges and therefore provide reference for the analysis and evaluation of human-induced vibration responses of footbridges.