10. Semi-Active TMD Concept for Volgograd Bridge

The Volgograd Bridge in Russia is known not only for its record length but also for the large amplitude vibrations induced by wind in May 2010. This paper describes the development of a new semi-active TMD with a magnetorheological damper (MR-STMD) that was installed on the Volgograd Bridge in fall 2011. The main feature of the MR-STMD concept is that the real-time controlled MR damper emulates a controllable stiffness force and a controllable friction force. The controllable stiffness force augments or diminishes the stiffness of the passive springs and thereby tunes the MR-STMD frequency to the actual frequency of the bridge. The controllable friction force generates frequency dependent energy dissipation. The small-scale prototype was experimentally tested on the 19.2 m long Empa bridge for various modal masses and disturbing frequencies. After that, the full-scale MR dampers were tested at Empa by hybrid testing for the expected frequencies and amplitudes of the bridge. Finally, the frequency controllability of one full-scale MR-STMD was verified at the University of the German Armed Forces, Munich. All tests confirm that the new technology can compensate for the frequency sensitivity of passive TMDs and works at high efficiency.