Bridges No.6 - Millennium Bridge

On now to the newest of London's bridge, the Millennium Bridge. The bridges links St Paul's Cathedral with Tate Modern and has been part of a major revitalisation of the South Bank of the Thames around the former Bankside Power Station (now Tate Modern). The Millennium Bridge is open to pedestrians only and is the first new crossing since Tower Bridge in 1894. Arguably this bridge, Tate Modern and other developments on the Southbank such as the London Eye are all lasting legacies of the millennium than the big white elephant a few miles downstream.

The London Borough of Southwark organised a design competition for a new bridge in 1996 which was won by a consortium of engineers and designers. Appropriately for a bridge to connect with a modern art gallery one of the designers was an artist: Sir Anthony Caro. He was joined by Norman Foster and engineers Arup. Compared to other London bridges the Millennium Bridge has a very shallow profile. It is a suspension bridge with a difference - the cables run alongside the bridge itself rather than above it. Planning policies restricted the height of the bridge, so this shallow, 'blade', design was ideal.

The bridge is 325m long and the eight suspension cables pull with a force of 2,000 tons against the piers on either bank. This is sufficient to support 5,000 people of the bridge at any one time. Now under normal circumstances than number of people probably wouldn't be on the bridge at the same time. However, when it opened in June 2000, it came close to capacity and didn't cope very well. The bridge started swaying as hundreds of charity walkers started to cross it. Needless to say, this was not expected and there were memorable TV pictures of the bridge swinging side to side rather eratically. It quickly earned it's alternative name 'The Wobbly Bridge'. Indeed as I passed it on my walk I heard numerous people using that name even though the wobble was fixed and it is now perfectly stable. The wobble was the reaction of people to small natural lateral movements in the bridge. Their readjustment set up driven harmonic motion in the bridge, thereby enhancing the wobble. It was decided to close the bridge after three days and Arup consequently fitted 89 dampers to control horizontal and vertical movements. It finally reopened in February 2002, wobble-free. The strangest thing to happen since must have been the sheep drive over this bridge on 17 Jun 2006 as part of the London Architecture Biennale.