Experimental study on adjustable tuned mass damper to reduce floor vibration due to machinery

This paper deals with the optimum design of a tuned mass damper (TMD) for the mitigation of machine-induced vertical vibration of structures. Theoretically, a TMD without damping tuning to the machine operating frequency will make optimum control performance. Considering zero damping is impossible, a new field-based design procedure and an adjustable vertically moving TMD (VTMD) are proposed. The VTMD is composed of variable mass blocks and changeable springs. A prototype of the VTMD was fabricated and tested on a simply supported beam and a reinforced-concrete floor of a school building. Both experimental results confirmed the control effectiveness and usefulness of the VTMD. In the beam test, more than 90% reduction in accelerations was observed. In the floor test, 41–56% acceleration reduction can be achieved even though the mass ratio of TMD to structure is very small. Copyright © 2009 John Wiley & Sons, Ltd.