Dynamics: Vibration Reduction

The London Millennium Footbridge

Fig. 18-11: Two tuned mass dampers under the deck of the London Millennium Footbridge

A total of 26 pairs of vertical tuned mass dampers were installed over the three spans of the London Millennium Footbridge [18.5]. These comprise masses of between one and three tonnes supported on compression springs. The tuned mass dampers are situated on the top of the transverse arms beneath the deck. One pair of the tuned mass dampers is shown in Fig. 18-11.

These tuned mass dampers would become effective if the footbridge experienced relatively large vertical vibrations, though such vibrations were not the primary source of the well publicised problems when the bridge first opened.