Experimental Investigations on the Flutter Derivatives of the Pedestrian-Bridge Section Models

Abstract

Based on a suspension footbridge, the pedestrian-bridge section models were first proposed and designed. Then, the free vibration tests were carried out to study the influence of pedestrians on the flutter derivatives (H1*, A2*, A3*, H4*, and A1* × H3*) which significantly affect the flutter of suspension footbridges. It can be found that: 1) with an increase in the pedestrian density, the H1*, H4* and A1* × H3* increase, which will lead to the decrease in the positive vertical aerodynamic damping, the positive vertical aerodynamic stiffness and the positive vertical and torsional aerodynamic damping, respectively. Meanwhile, with an increase in the pedestrian density, the A2* and A3* decrease, which will lead to a decrease in the negative torsional aerodynamic damping and the negative torsional aerodynamic stiffness, respectively. 2) The arrangement of walking side by side is advantageous to the positive vertical aerodynamic damping and disadvantageous to the negative torsional aerodynamic stiffness. The arrangements of random walking with low-medium pedestrian densities and walking in line with high-medium pedestrian densities are disadvantageous to the vertical aerodynamic stiffness and the positive vertical and torsional aerodynamic damping. Besides, all the pedestrian arrangements have a significant influence on the torsional aerodynamic damping.