Sunday, December 14, 2008

The Promise



The Tacoma Narrows Bridge was built to span the Tacoma Narrows strait between Tacoma and the Kitsap Peninsula in Washington. It opened in July of 1940. It promptly collapsed 5 months later, putting it at the top of the Biggest Engineering Blunders of All Time list. It is a textbook example of elementary forced resonance, with the wind providing an external periodic frequency that matched the natural structural frequency. In other words, something you want to avoid when designing a suspension bridge. This dramatic video shows the bridge wriggling in the wind with all the structural integrity of a licorice whip, just before it took it in the pooper and collapsed in a 42 mph gust. About 43 seconds in, you see a car ‘parked’ in the middle of the roadway. It is not unoccupied. There is a dog in it. Tubby, a black male cocker spaniel, was the only fatality of this doomed design disaster. His owner was driving with Tubby over the bridge when it started to vibrate violently. Mr. Sissyboy fled his car, leaving Tubby behind. Two bystanders attempted to rescue him, but Tubby was too terrified to leave the car and according to news reports of the time, he bit one of the rescuers. Tubby died when the bridge crumped, and his body was never recovered. Now, I’m not saying that driving over a bridge flapping in the breeze like that isn’t absolutely terrifying. My adrenals give me a squirt of JP5 just stopped in traffic on an Interstate overpass and I feel it vibrate just a little. Being a contestant in The Great Suspension Bridge Rodeo and wishing I was Sister Bertrille is difficult to imagine. But, I can say I wouldn’t abandon my dog. Why is that so easy to say? The Promise. The one I made to Nicky, the same one I made to Java and the same one I’ll make to the as yet unsigned 3rd baseman on this team.