Bipedal Crowd–Structure Interaction Including Social Force Effects

Abstract

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.

The Vertical Dynamic Properties of Flexible Footbridges under Bipedal Crowd Induced Excitation

“…The left end of the beam is defined as the origin of a planar coordinate system x-0-z; L B is span length; m (q) is the lump mass of the bipedal model; the superscript "q" means the ordinal number of pedestrians; x (q) and z (q) are longitudinal and vertical displacements of the center of mass (CoM), respectively; x stability improvement technique. Although the bipedal pedestrian model is successfully applied for crowd-structure interaction in Gao and Yang [11][12][13], the theoretical mechanisms between crowd size and structural modal properties by using this model have not yet been reported. Shahabpoor et al [3] studied the effect of crowd size on vertical modal parameters of an occupied structure by extensive Frequency Response Function (FRF)-based modal identification tests.…”

“…To consider gait details, a human-structure interaction with bipedal pedestrian model was proposed by Qin et al [4,5]. Gao and Yang [11][12][13] extended this model to a crowd-structure interaction, based on a stability improvement technique. Although the bipedal pedestrian model is successfully applied for crowd-structure interaction in Gao and Yang [11][12][13], the theoretical mechanisms between crowd size and structural modal properties by using this model have not yet been reported.…”

“…Gao and Yang [11][12][13] extended this model to a crowd-structure interaction, based on a stability improvement technique. Although the bipedal pedestrian model is successfully applied for crowd-structure interaction in Gao and Yang [11][12][13], the theoretical mechanisms between crowd size and structural modal properties by using this model have not yet been reported. Shahabpoor et al [3] studied the effect of crowd size on vertical modal parameters of an occupied structure by extensive Frequency Response Function (FRF)-based modal identification tests.…”

“…In this paper, the theoretical formulae between crowd size and vertical modal properties are proposed as an extension of the study in Gao and Yang [11][12][13]. Firstly, the dynamic equilibrium equation of a structure is established by considering the vertical interaction between bipedal crowd and structure.…”

Simplified theoretical treatment of lateral structural properties under crowd excitation

“…Qin et al [16] introduced a bipedal model with spring-damping legs for studying human-structure interaction dynamics. Gao et al [17][18][19] proposed an approximate relationship between crowd size and dynamic vertical structural properties based on the bipedal model. However, no quantitative investigation has been performed on crowd size and dynamic lateral structural properties, including the contribution of dynamic crowd properties.…”