Control of a Pedestrian Bridge by a Damped Single-Sided Pounding Tuned Mass Damper: Modeling, Simulation, and Field Test

Abstract

Long-span steel pedestrian bridges usually have the characteristics of high flexibility and low damping due to the usage of high-strength and light-weight materials. Therefore, they are extremely sensitive and prone to vibration under human-induced excitations. The resulted large-amplitude vibrations significantly influence the comfort of pedestrians and the long-term serviceability of pedestrian bridges. This paper proposes a damped single-sided pounding tuned mass damper (DSS-PTMD), which is a passive control device with a damped mass-spring system and a viscoelastic (VE) pounding boundary. The energy dissipation capacity of the DSS-PTMD is primarily depending on the pounding mechanism and its inherent damping. The dynamic parameters, including the optimal frequency ratio and equivalent damping ratio of the DSS-PTMD, are obtained from the theoretical analysis. Based on the response of a single degree of freedom (SDOF) system controlled by a DSS-PTMD, the effectiveness of the optimal parameters is discussed. A steel pedestrian bridge with low damping ratio, which may produce large-amplitude vibrations under human-induced excitations, is selected as the control objective, and its dynamic properties are obtained by field tests. Numerical simulations are carried out to investigate the vibration mitigation effect of the DSS-PTMD on the pedestrian bridge under human-induced excitations. Finally, a DSS-PTMD is designed and manufactured for vibration control of a pedestrian bridge. The results show that the DSS-PTMD exhibits better control performance and wider control frequency domain than the conventional tuned mass damper (TMD). Simulations show that when the peak acceleration of the bridge is limited to less than 1.0 m/s2, the number of pedestrians on the bridge after installing the DSS-PTMD is about 1.5 times that under the uncontrolled condition. The results from the field tests exhibit that the damping ratio of the pedestrian bridge is increased from 0.34% to about 1.83% after installing DSS-PTMD with 500 kg.