Citation

Li X, Song W, Xu X, Zhang J, Xia L, Shi C. Safety Sci. 2020; 127: e104713.

Copyright

(Copyright © 2020, Elsevier Publishing)

DOI

10.1016/j.ssci.2020.104713

PMID

unavailable

Abstract

In crowd disasters, overcrowding is one of the causes for crushing and trampling. However, little research has been done on the physical interaction among pedestrians, especially the contact force. Therefore, a series of controlled experiments were conducted to study the contact force among pedestrians in static and moving states. The contact force can be extracted from flexible fabric pressure sensors that cover the upper body of a pedestrian. It is found that the forces are concentrated in the body regions including breast, shoulders, upper back, upper arms and infrascapular region. The space occupancy rate is defined to reflect the degrees of crowding under different densities. In the static state, the contact force increases as the space occupancy rate increases. In the moving state, the contact force increases as the velocity increases under different space occupancy rates. To combine empirical data under static and moving states, the polynomial relation is adopted tentatively to establish the numerical relations among contact force, velocity and space occupancy rate, which would be used to validate and calibrate numerical models. In addition, the autocorrelation coefficient is used to study the time series of forces. It is found that the contact forces of the upper body show similar periodic fluctuation characteristics in most cases. Some of the contact forces in divided regions show similar periodic fluctuation, which maybe be related to the steps to some extent. These results can be used to judge the crowd safety and prevent mortality.

Language: en

Keywords

Autocorrelation coefficient; Contact force; Crowd safety; Space occupancy rate; Velocity