Bipedal Crowd–Structure Interaction Including Social Force Effects

This paper proposes a vertical crowd-structure interaction (CSI) model, considering the social force interaction effect among pedestrians. Pedestrian, as the basic unit of crowd, is modeled by a dynamic bipedal system with one lump mass and two compliance legs. The CSI model can be applied to self-determining the walking velocities of pedestrians instead of the sensitive passive control force for a stable gait from the original human–structure interaction (HSI) model. The damping compliance legs are responsible for the energy transfer between the pedestrian and the supporting structures during the dynamic walking process. Numerical studies with several pedestrians walking on a simply supported beam show an improvement of the damping property of the structure, but a decrease of the deterioration of natural frequency of the structure. The experiences gained in this study can be adopted for further study on the more complicated social force interaction among pedestrians in a large crowd passing some slender structures such as large-span footbridge.