Swipesy Cakewalk (Millennium “Wobbly Bridge” Footbridge, London, UK)

The British have a difficult relationship with commemorative projects. Apparently it’s been going on longer than I realised, as even the Festival of Britain was apparently condemned in advance as a waste of money. I’m sure grumblers grumbled that the money spent on the Great Exhibition’s Crystal Palace would have been much better employed improving their local gin palaces (or more pertinently, the public sewerage system). A lot of Britons love a good moan whenever some large project is announced, on the basis that the money should be spent on something else, and that it will never work anyway. They love it when these projects come in over budget; almost inevitable given that these aren’t off-the-shelf designs, and are completed late. And then, after a few years, they and everyone else forgets the completion delays because they’re almost inconsequential over the lifespan of such projects, and they forget the budget overruns because, frankly, who can keep numbers like that in their head anyway? Finally they decide they liked the project all along now that it’s part of the landscape. In fact, we all miss the Festival of Britain’s Skylon now it’s gone, and obsess over the Festival’s cool graphic design.

This week’s transport beauty, a pedestrian bridge in central London, illustrates all the downers the British have about commemorative buildings. Even more so, in fact, because the Millennium Footbridge was a Millennium project, one of a whole collection of expensive landmark projects to mark the Millennium, which cranked Britain’s cynicismometer up to 11. Just in London there was the Millennium Dome (waste of time/space/money, but now the O2 Dome over which many people get excited about visiting to see international music acts), the London Eye (ugly/pointless/frivolous/got stuck as it was being hauled upright confirming the sceptics’ opinion of it, yet now an enduringly popular tourist attraction and landmark on London’s skyline), the Millennium Pier at Millbank (largely overlooked because it was in the water) and the Millennium Footbridge. Joining in with the fun, although not strictly a Millennium project, was the Tate Modern – which had strong links with the Millennium Footbridge.

The Millennium Footbridge, London. Photo by Daniel Wright [CC BY-NC-ND 2.0] via this flickr page.

The Millennium Footbridge managed to avoid the criticisms of pointlessness levelled at the London Eye and the Dome. A pedestrian connection between north and south banks of the Thames had some evident utility, especially given the presence of the already-open Shakespeare’s Globe theatre and Bankside Power Station, under conversion to the Tate Modern. Although there was some degree of (unfounded, as it turned out) scepticism about the likely popularity of the Tate Modern, people ‘got’ the basic idea of improved access to this area of the south bank from north of the river. It would also be the only pedestrian-only bridge in central London, making for a uniquely peaceful way of crossing the Thames.

Local authority Southwark Council and RIBA’s (Royal Institute of British Architects) competition department invited submissions for a bridge design in the late 1990s, the Millennium happily providing a great excuse. The winner was a team effort from Foster+Partners, British sculptor Anthony Caro, and engineering firm Arup.

The north end of the Millennium Footbridge. Although it is a suspension bridge, clever design keeps the suspension cables low down, minimising their visual impact. Photo by Rod Allday [CC BY-SA 2.0], via Wikimedia Commons

Their design was radical, albeit based on a very traditional design, the suspension bridge. Most suspension bridges feature towers at either end, from which suspension cables are hung, and the bridge deck is then suspended by ties running from the cables down to the deck. Unfortunately, that wasn’t going to work in this case, because the cables and ties would have spoiled the views up and down the river from the bridge, not to mention blocking views of St Paul’s Cathedral or Tate Modern from the opposite riverbank.

The genius of the Millennium Footbridge was to splay the suspension towers out sideways, turning them into shallow, Y-shaped armatures with the cables running through the arms of the two ‘Y’s. Instead of traditional ties connecting the suspension cables to the bridge deck, every eight metres a transverse steel arm clamps onto the cables. The deck of the footbridge rests on these arms, so it is cradled, rather than hung. The bottom line is that although the Millennium Footbridge is a suspension bridge, it’s a very shallow one. It’s clever and heavy engineering that manages to look extremely delicate. It was designed so that at night, its lighting scheme gives the impression of a “blade of light” reaching across the river.

Millennium Footbridge at night, looking towards St Paul’s Cathedral. Photo by Bill Hunt [CC BY 2.0] via this flickr page

The north end of the bridge touches down neatly at the top of a set of steps which lead from Peter’s Hill down to the Thames embankment. The south side is a different matter. Because the embankment is flat here, the bridge effectively terminates in mid-air. Bringing the bridge deck straight down to ground level would have made it inconveniently steep. Instead, at the south end of the footbridge, the bridge deck divides into two halves. When pedestrians get to the end of the bridge deck, they have to execute a 180-degree turn, and use a central ramp which leads down to ground level. I never use it without feeling that somehow it’s a rather clumsy solution, in contrast to the directness with which you can get on or off the bridge at its north end. It was clearly something the bridge’s designers struggled with, and Foster+Partners’ website illustrates a number of other ideas for the southern end of the bridge, none of them entirely satisfactory and none of them quite in keeping with the lightness of touch that marks out the rest of the bridge.

South end of the Millennium Footbridge. Photo by Duen Ee Chan [CC BY-NC-ND 2.0] via this flickr page

It is, however, quite possible that I’m the only person in the world bothered by the south end of the Millennium Footbridge, because every time I mention it to anyone else they look at me like I’m quite mad, and should just be grateful that such a lovely and clever piece of engineering should have seen the light of the day. It’s a much loved local landmark, and is immensely popular, not least because it’s immensely useful.

Needless to say, all the people who were sceptical of London’s Millennium projects in advance have conveniently forgotten that that was the case. They had a field day at first though. The Millennium Footbridge opened in summer 2000, just after the Tate Modern. Both proved enormously popular, justifying the bridge’s existence. The plan had been to open both of them together, but the bridge itself was delayed by a couple of months, and it was also a couple of million pounds over its original £16m budget. Nevertheless, it attracted the crowds. And therein lay a problem.

With some 100,000 people crossing the bridge on the first day, pedestrians noticed that the bridge developed a significant sway. It’s one of the drawbacks of suspension bridges that they have to be able to flex to cope with forces imposed by the wind and by traffic. Marching troops are required to break step when they cross suspension bridges because the repeated and regular footsteps can cause the flexing to build to the point where it matches the bridge deck’s natural resonant frequency. If reinforced by the marchers adapting the timing of their footsteps to cope with the flexing of the bridge deck, and effectively falling back into step, a positive feedback loop results in which the bridge flexes more and more. Here is why it becomes a problem when a suspension bridge starts flexing at its resonant frequency (although I ought to note that some authorities disagree over the exact role of resonance in the following).

It was no surprise that the Millennium Footbridge swayed, but the amount of sway was. Although its users weren’t in step as they got onto the bridge, they began to fall back in step in response to the swaying of the bridge, amplifying the sway. Although pedestrian numbers were restricted in response, the situation was clearly unsustainable, and after three days the bridge closed. The Millennium schemes sceptics had another cause célèbre. They called it, mockingly, the Wobbly Bridge.

Arup worked out an engineering solution which muted the swaying without ruining the careful aesthetics of the bridge. But manufacturing it, fitting it, and testing it would take two years. It would also add another £5m to the bill. It was February 2002 before the Wobbly Bridge opened to pedestrians again, and this time not a wobble was to be felt.

One of the dampers which tackles the Millennium Footbridge’s inclination to sway. Photo by Dave Farrance (Own work) [CC BY-SA 3.0 or GFDL], via Wikimedia Commons

And that’s it. Ever since, it has been behaving beautifully. It’s become a firm favourite with its regular users and the many, many tourists who cross it to access St Paul’s Cathedral or the South Bank. Like many London landmarks, it has taken its nickname and made it its own. You’ll still hear it called the Wobbly Bridge, but these days it’s done with a degree of fondness and an understanding that the nickname is the only reminder of its early teething troubles. It’s what Londoners do with their landmarks. You know a building has been accepted when its nickname sticks. The Gherkin (properly 80 St Mary Axe) got its name when its unusual design was initially mocked as “the erotic gherkin”. But, of course, once everybody got used to it, they decided they’d liked it all along, so the nickname lost its derogatory component, and stuck fast. The Millennium Footbridge has become such a landmark of London that it was destroyed by death eaters in the film version of Harry Potter and the Half-Blood Prince.

I took my transport mad nephew to see the Millennium Footbridge a few weeks ago. It turned out he’d seen it before (disappointing). But the Wobbly Bridge has one other transport surprise up its sleeve. As I mentioned earlier, a set of steps lead down from the north end of the bridge to the embankment. But what if you can’t manage steps? Never fear, the Millennium Inclinator is here.

The Millennium Inclinator, London. Photo by Daniel Wright [CC BY-NC-ND 2.0]

It’s one of Britain’s newest – and shortest – funicular railways. A small glass cabin, balanced by a counterweight, makes it way over no less than 26.85m of track to connect the top of the steps with to the bottom. It opened in 2003, but if you believe in the curse of London’s Millennium projects, you won’t be surprised to hear that the original funicular didn’t work very well and had to be replaced. The new Inclincator opened in 2012 (just in time for the London Olympic Games, another project everyone said would be a disaster, until it wasn’t, at which point they decided it had been a brilliant idea all along).

My nephew hadn’t seen the Inclinator before, and he absolutely loved it (that’s more like it). On reflection, perhaps not least because my brother-in-law suggested that “Millennium Inclinator” sounded like something out of Star Wars (if pronounced In-Clin-A-TOR). We also took my nephew on a New Routemaster, a regular London double decker, several Underground lines, Thameslink, and all around the London Transport Museum. But I think it was the Inclinator he liked the best. He and I do love a funicular.

Bibliography and Further Reading

Foster+Partners project page for the Millennium Footbridge, here

Funicular Railways of the UK, Millennium Inclinator page, here

…and anything linked to in the text above

How to find the Millennium Footbridge

Click here for The Beauty of Transport‘s map

3 thoughts on “Swipesy Cakewalk (Millennium “Wobbly Bridge” Footbridge, London, UK)

  1. I was going to “correct” your assertation that this would be the only pedestrian bridge in central london, because unless you’re claiming them to be shared with trains, which is a stretch imo, the Hungerford bridges already existed.

    And then I went and double-checked before opening my virtual mouth and found they only opened in 2002, so at the time, this would have been the first and only. Weird, I never thought of them as contemporaneous!

    1. There was an earlier version of the Hungerford Bridge walkways, one side only, if I remember correctly. But yes, I didn’t count Hungerford on the basis that it’s a shared train/pedestrian bridge (and very noisy too when a train goes past!). Thought about including this in the article, decided against it on grounds of length, now wish I had!

  2. I’ve only recently heard of the Inclinator and now want to go to London for a ride on it.

    As for the public not appreciating things until they happen, it always amuses me to see old Episodes of Have I Got News For You where panellists are snide about the Olympics, they hold the solution to the public finances. All we need to do is announce a new Millenium Dome and then cancel it for money to be spent elsewhere. As I recall, cancelling the old one would have funded the NHS, new everything for the armed forces, rebuild every school, restored the railways so we all have a personalised coach, widened every road to 4 lanes and several dozen other things…

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