Why Did the Millennium Bridge Wobble?
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Why Did the Millennium Bridge Wobble?
The Clown Fish
Download film (right-click)Award Nominees , Engineering , Explanation , Investigation , Secondary
An explanation of resonant frequency and how it relates to the millennium bridge.
Director's Notes:
Experiments based on information and observations which we have condensed from what we have seen as a team over many years in both lessons and elsewhere.
SciCast Notes:
Nominee: Best Engineering Film, 2008
This is a very well put-together film, exploring its subject in some depth, and it makes good use of archive film (though we did replace some YouTube clips with similar public domain material from Archive.org).
My main criticisms are pretty nerdy, to be honest. As it happens, I was involved in making a BBC2 programme about the Millennium Bridge, many moons ago, and the science was remarkable because what happened there wasn’t a simple resonance effect. Resonance is thoroughly studied, and of course well-known to engineers. What happened with the swaying bridge was a related phenomenon, but one a whole lot more peculiar. There are some good notes about it at the Wikipedia page on the Millennium Bridge.
The second example in the film is the famous Tacoma Narrows suspension bridge collapse, which again is often cited as an example of structural resonance. And again, it isn’t, as (again!) Wikipedia describes.
This is complex stuff, but it’s surprising how many magazine articles and books — and films — get the science wrong. Wikipedia looks pretty good to me for both of these situations, and it’s a shame some of the nuances weren’t worked in here.
Nevertheless, it’s a very competently-made film.
— Jonathan