Cost of repairing wobbly bridge could rise to £10m


Within the next two weeks engineer Ove Arup will unveil its proposals to stop the wobbling Millennium Bridge from swaying at an estimated cost of £2 million. There are serious concerns, however, that Lord Foster’s Thames footbridge will need a further £10 million of remedial work before it can be opened to the public.

Ove Arup is expected to favour a system of dampers to bring stability to the £18 million "blade of light", a method which some experts believe will be ineffective. "Maybe dampers will work," said the Tokyo-based bridge specialist, Professor Yozo Fujino, "but I’m not very confident. The problem is that the bridge is very light and human forces are very large."

Fujino identified the problem of "synchronised footfall" in a paper written in 1993. This report has subsequently been consulted by engineers around the world including Techniker, the firm behind London’s Royal Victoria Dock footbridge that opened in 1998. "If you do advanced and sophisticated things, then you should make sure you read the literature first," said Techniker’s director Mathew Wells.

Ove Arup failed to consult Fujino’s paper, considering it to be obscure, but it did undertake "dynamic analyses" and wind tunnel tests as well as consulting an independent firm of engineers before proceeding with the design.

Another bridge expert, Dr Arvind Kumar, advises the Corporation of London and was one of over 200 entrants in the Millennium Bridge design competition. Kumar believes that more drastic measures are needed to make the bridge safe. "You can’t totally rectify the bridge except by raising the height of the cables which would cost up to £10 million," he said.

Whatever solution Ove Arup propose, it is clear that the cost will run into of millions of pounds. What is not clear as of yet is where this additional funding will come from. The Millennium Commission, private financiers and the project’s insurers can all expect a visit in the near future.

And then there's London's second Millennium pedestrian Bridge, by Lifschutz Davidson at Charing Cross. They'd got well on with sinking the piles into the river bed when London Underground called a halt by declaring that the river bed was littered with Second world War bombs that could go off if disturbed - and with two underground lines a few yards away, they weren't keen.

Estimated extra cost of clearing bombs is somehow estimated at £18m, which makes Foster's blunder look cheap.

No-one has yet explained why nobody told the bridge builders about the bombs until so far on in the process, or why London Underground suddenly thought of it...or why on earth it should cost so much to clear them...or why they weren't cleared years ago... etc etc.

"The problem is that the bridge is very light and human forces are very large."

Oh yeah? I hear recent trials showed that a mere fifty (50!) people, walking in unison, can made the bridge 'take off', swaying from side to side.

How does the song go? "...water under a troubled bridge"