Implementation of passive and active vibration control on an in-service footbridge

SUMMARY The current trend toward lighter and slender pedestrian structures, with new aesthetic requirements and high-performance materials, has resulted in structures with increased susceptibility to vibration. Notable vibrations under human-induced excitations might appear, and the vibration serviceability requirements might not be accomplished. The Valladolid Science Museum Footbridge (Spain) is an example of a lively structure that might achieve excessive vertical acceleration under walking or running excitation. The control of excessive footbridge vibrations via passive and active devices is dealt with in this work. More specifically, this paper is concerned with the design and experimental implementation of a passive tuned mass damper (TMD) and an active mass damper (AMD) to mitigate human-induced vibrations on this in-service footbridge. The TMD, with a mass ratio of 1%, is designed by a numerical method based on H∞ controllers. The AMD consists of a proof-mass actuator, with a mass ratio of approximately 0.2%, controlled by a strategy based on acceleration feedback with a phase-lag network. The performance of both devices has been assessed. Copyright © 2011 John Wiley & Sons, Ltd.