WHEN the Tacoma Narrows Bridge opened in July 1940, Washington state locals nicknamed it “Galloping Gertie” and lined up to experience the roller-coaster undulations as they drove across it.
The effect was not intended by engineer Leon Moisseiff; it was a consequence of his ambition to build the world’s slenderest suspension bridge. After a mere four months, high winds twisted Galloping Gertie into a catastrophic corkscrew. When the newspapers demanded an explanation from Moisseiff, he said he had no idea why his bridge fell, because it was “built according to regular rules”.
In To Forgive Design, engineering professor Henry…
