Influences of pedestrian SMD model parameters on dynamic characteristics of crowd-structure interaction

Model parameters' change characteristics of a pedestrian single-DOF spring-mass-damper (SMD) system were investigated. The coupled free vibration equation of a walking crowd-structure system was established. The structure natural frequencies and damping ratios were derived with the complex mode method. The influences of pedestrian model's natural frequency, damping ratio and elastic mass on change rates of the structure fundamental frequency and damping ratio were studied, respectively. Using Monte-Carlo simulation, a series of meaningful results were obtained under different mass ratios of crowd to structure. The results indicated that change rates of the structure's fundamental frequency and damping ratio are the maximum when the ratio of the structure fundamental frequency (no crowd) to pedestrian one is about 1.1; when the structure fundamental frequency (no crowd) is close to the allowed range of pedestrian model's natural frequency, the increase in mass ratio of crowd to structure causes the random distribution of the structure's fundamental frequency and damping ratio to expand.