Controlled Damping of Cable-Stayed Bridges

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Diss. ETH No. 18948 by Charles Boston 2010.

Cables on large span cable-stayed bridges may be prone to vibrations of large amplitude due to their inherent low damping and length. In order to prevent premature material failure within the cable anchor system, and to ensure public confidence, an intelligent damping system is being developed. Together with the industrial partner Maurer Söhne, a damping system using feedback controlled magnetorheological fluid dampers (MRD) is being investigated. These dampers provide a varying Coulomb friction force with varying current, and therefore offer new opportunities in the application of control algorithms for the system. However, the behaviour of both damper and cable are complex, and a robust and accurate model of the system is needed. With such a model a variety of control laws can be applied depending on the situation. There are an increasing number of large span cable-stayed bridges under construction in the world, and the necessity for such a control tool is real and urgent.