An air of excitement certainly gripped London on June 10, 2000, as 90,000 people queued up to cross the first new bridge to span the Thames River in over a hundred years, a bridge for pedestrians only, stretching from the Globe Theatre to St. Paul’s Cathedral, aptly named the London Millennium Footbridge. It didn’t take long for the bridge to become more known by its nickname, the Wobbly Bridge.
Seems the designers had not given enough attention to a phenomenon with the catchy title, synchronous lateral excitation. Even if you’ve never heard of it, it doesn’t sound like anything you’d want to be on a bridge with.
People, according to engineers, sway when they walk. People walking and swaying cause sideways oscillations in lightweight bridges. These, in turn, cause the people (some two thousand on the bridge at any given time) to sway even more to keep from falling over. And they all sway at the same time. It’s as if two thousand Londoners were doing the tango above the Thames. Result? Wobbly.
Access to the bridge was limited later in the day, and on June 12 the bridge closed for modifications It reopened in 2002 (with tango forbidden). It was again closed in 2007 because of strong winds and a worry that pedestrians foolish enough to cross might be blown off the bridge.
The footbridge was not the only British millennial faux pas: a little number called the Millennium Dome elicited this derision from MP Bob Marshall-Andrews: “At worst it is a millennial metaphor for the twentieth century. An age in which all things, like the Dome itself, became disposable. A century in which forest and cities, marriages, animal species, races, religions and even the Earth itself, became ephemeral. What more cynical monument can there be for this totalitarian cocksure fragile age than a vast temporary plastic bowl, erected from the aggregate contribution of the poor through the National Lottery. Despite the spin, it remains a massive pantheon to the human ego . . .”