As an alternative to the dampers to be installed on the Millennium bridge, I should like to suggest a solution which may not have been considered before.
If the swaying is solely due to the act of walking, why not ensure that pedestrians stand still while crossing the bridge.
This could be achieved by removing the walkway and replacing it with two flat rubber belt travelators and moving handrails running in opposite directions.
The bridge would probably be the only mechanical pedestrian river crossing in the world, making it a tourist attraction in its own right, and the elderly and children would love it!
A Lester (F), 13 Little Brownings, London SE23 3XJ