STRUCTURAL ENGINEERS on London's £18M Millennium footbridge believe they can eliminate its sway problem for significantly less than the £5M originally estimated, it emerged this week.
Pre-Christmas trials of a prototype damper installation convinced the design team it could scale down the complex retrofit proposals revealed last November.
The £250,000 trial was funded by the bridge's structural engineer Arup.
Test results and Arup's final proposals are now with client Millennium Bridge Trust's engineering advisor WS Atkins.
Sources close to the client confirmed this week that these showed significantly fewer dampers than the 30 sets of chevron braced viscous dampers and 30 tuned mass dampers under the deck. These were detailed in the original proposals submitted for planning permission late last year.
But complex and delicate negotiations involving Arup, the Millennium Bridge Trust and the Corporation of London, which will eventually take over the structure, are still unresolved.
Without approval from Atkins and agreement on who will pay for the retrofit, work to re-open the crossing will not start.
All those involved now acknowledge that the bridge will not re-open before its anniversary on 10 June. A major problem is the long waiting time for the high tech US manufactured viscous dampers, which are central to the Arup proposals.