Twin Rotor Damper for Human-Induced Vibrations of Footbridges

Abstract

Footbridges often have a lightweight and slender design. As a result, they tend to be susceptible to human-induced vibrations. In this paper, the application of the twin rotor damper (TRD), an active mass damper consisting of two eccentrically rotating masses, for the control of human-induced footbridge vibrations is presented. A proof-of-concept prototype is developed for a real-world slender steel footbridge that is sensitive to human-induced vibrations. First, a numerical study is performed to design a TRD to mitigate human-induced vibrations. Based on these results, a TRD prototype was designed and built. Second, the performance of the TRD is evaluated on-site. The response of the footbridge to human-induced loading is measured under both uncontrolled and controlled conditions and compared to corresponding numerical simulations. The measurements confirm the results of the numerical simulations. They show that the TRD prototype is able to effectively damp human-induced vibrations of a real-world footbridge and validate the TRD design.