Modeling and Optimal Semi Active Control Strategies for adaptive MRTMD

Abstract

In recent years the evolution of construction techniques and design of pedestrian bridges led to structures more and more slender and light. This process entailed the development of unexpected interaction phenomena owing to pedestrian and wind loads. The impact of wind or pedestrians loads on low stiffness structures resulted in including, in the design phase, the concept of vibrations control and design of structural damping devices. These aspects are the one that we tackled on the Nomi-Calliano footbridge located in the northern part of Italy (near Trento). Semi-active control systems, coupled with smart materials such as magnetorheological fluids, became more and more attractive. In this respect, the University of Trento, in cooperation with the Autonomous Province of Trento, decided to use a Magneto-Rheological Tuned Mass Damper (MR-TMD), in order to limit discomfort on the aforementioned footbridge. This paper presents the main dynamic characteristics of the footbridge and the preliminary experimental program devoted to the MR fluid characterization. Finally, the optimal clipped control strategy for the control of the MR-damper is outlined.