CONTROL OF PEDESTRIAN-INDUCED BRIDGE VIBRATIONS BY TUNED LIQUID COLUMN DAMPERS

In this paper tuned liquid column dampers (TLCD) are proposed for vibration control of footbridges. TLCD are innovative vibration absorbing devices applicable to the low frequency range (< 3 5 4 0 . . − Hz ) of bridges. Oblique bending and torsional motions of a continuous bridge with several TLCD installed are described mathematically and analyzed numerically. The dynamic behavior due to pedestrian excitation of the original Millennium Bridge in London is considered and it is shown that the installation of three TLCD to the main-span would have been necessary to secure its serviceability. The numerical simulations indicate that the TLCD increase the natural material damping of the bridge, which suppresses the instability phenomenon of synchronization, as discussed by Newland [1]. It is concluded that TLCD are effective and economic damping devices for the control of pedestrian-induced vibrations of footbridges.