Millennium Bridge, London
A new River Thames crossing for the new millennium
Firmly positioned in the 'A list' of London attractions, the Millennium Bridge is a 330m steel bridge linking the City of London at St. Paul's Cathedral with the Tate Modern Gallery at Bankside.
Millennium Bridge at night, looking at St Paul's from the south bank, 2003.
In 1996, the Financial Times held an international competition in conjunction with the London Borough of Southwark and the Royal Institute of British Architects to design a new footbridge crossing the Thames between Southwark and Blackfriars bridges.
It would be the first pedestrian river crossing over the Thames in central London for more than a century, opening in time for the first year of the new Millennium.
Well, that was the plan anyhow.
The bridge cables dip below the deck at midspan enabling unimpeded views of London
The winners of the competition, Foster and Partners/Sir Anthony Caro/Ove Aru & Partners, proposed an innovative and complex structure, featuring a 4m wide aluminium deck flanked by stainless steel balustrades, supported by cables to each side.
Using cutting edge design, the new bridge would have a profile 6 times shallower than a conventional suspension bridge, with the bridge being supported by eight highly tensioned cables on each side of the deck, anchored at each abutment and propped by two river supports.
One of the tapering elliptical piers under construction
Work started in February 1999 as the old jetty for Bankside power station was removed to make room for the bridge.
With the bridge crossing such an old part of London, archaeological excavations were undertaken on both banks before construction started, with remains of structures from the Middle Ages being uncovered.
In May 1999, piling began on the South bank with the middle sections joining in April 2000.
Autumn sunset, looking west
Such was the interest in the new bridge that when it opened to the public on 10 June 2000, an estimated 80,000 to 100,000 people crossed it.
And then the problems began.
Although the Millennium Bridge, like all bridges, was designed to cope with a degree of movement it soon became clear that things were going seriously awry as the deck swayed about like a drunken sailor.
Elderly walkers clung on to the side of the bridge. People reported feeling seasick. The swaying bridge was looking like an expensive fairground ride.
Looking east, with the unfinished 'Erotic Gherkin' tower in the distance.
So the bridge was instantly renamed as 'The Wobbly Bridge', and after two days of random swaying, swinging and oscillating wildly, the bridge was closed down by embarrassed engineers.
Naturally, the press had a field day (in Britain we love failure!), questions were asked in Parliament and the public began to sense that perhaps another large white elephant had just landed on the shoreline of the Thames (the fiasco of the Dome was only a few miles downstream).
Things didn't get much clearer when the engineers decided that the problem was apparently due to people walking the wrong way! claiming that the infamous wobble (or 'synchronous lateral excitation', as they put it) was due to the 'chance correlation of footsteps when we walk in a crowd'.
This - apparently - 'generated slight sideways movements of the bridge which made it more comfortable for people to walk in synchronization with the bridge movement'. In other words, once it started to sway people tried to counteract it, en masse, making the problem worse.
The south end of the bridge, where pedestrians double back to the stairs.
After a prolonged series of tests, it was decided to adopt passive damping system which would harness the movements of the structure to absorb energy.
Two forms of passive damping were deployed: Viscous dampers and Tuned Mass Dampers.
Viscous dampers are located under the deck, around the piers and the south landing to control the lateral motions and act much like shock absorbers.
The tuned mass dampers are also located beneath the deck and reduce vertical movements. Acting like weights on strings, these inertial devices are tuned to a specific frequency and attached to discrete points on the structure.
Londoners and tourists trudge across the bridge in a winter storm
While work continued on the bridge, visitors were treated to the occasional sight of hundreds of paid volunteers walking over the bridge in army-type formations as the engineers battled to correct the swaying.
After nearly two years of testing, the alterations were deemed a success and the bridge finally reopened to the public in February 2002 - and the swaying was banished forever!
Like many others, I couldn't wait to finally cross the new bridge and so joined the bizarre throng aimlessly wandering up and down the bridge in an horrendous February storm!
After all the excitement of its rocky birth, the bridge has now settled down to prove itself a valuable asset to London, appreciated by both tourists and the throngs of tourists who flock across it every summer.
Linking the two major tourist attractions of St Paul's Cathedral and the fabulous Tate Modern, the Millennium Bridge is a worthy addition to London's riverside and well worth a visit.
The twin ramps at the south end of the bridge, outside the Tate Modern.
MILLENNIUM BRIDGE FACTFILE:
Designed by: Architect Sir Norman Foster with sculptor Sir Anthony Caro and engineers Arup
Opened: 10th June 2000
Closed: 12th June 2000
Reopened: 27th February 2002
Height above river at high tide: 10.8m
Handrail height: 1.2m
Piers: Concrete and steel
Cables: 120mm locked coil
Handrail: Bead blast stainless steel
Construction cost: £18m
Subsequent modifications: £5m