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More Shaking by Andrew Kerr September 2006 In the last CEISMC Gazette, we sat down with Civil and Environmental Engineering professor Reggie DesRoches to discuss the challenges of engineering for earthquakes. In the age of email and Internet we sometimes forget that the world economy still runs on the old fashioned principle of shipping: getting an item physically from one part of the world to another. Sea ports are the first front for international commerce. So if a natural disaster struck one of those ports it could significantly cripple our economy. (To save this video to your computer, right-click on this link and "save target as".) |
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West Lake High School teacher Will Zwingmann spent his summer working with Dr. Reggie DesRoches and Dr. Glenn Rix of Georgia Tech's School of Civil and Environmental Engineering this summer as a GIFT Fellow. He worked alongside six West Lake students. Together, the group explored the stability of cranes during simulated earthquakes. Dr. DesRoches admits that crane failure has not been an especially common problem in the past, but "in 1995 Kobe [during the Kobe earthquake] many of the cranes failed," he notes. "And one of the things that we've learned as a result in talking to crane manufacturers is that these newer jumbo trains, which are much bigger, and are faster at loading and unloading cargo, are more susceptible to earthquakes." Dr. Rix explains, "The cranes keep getting larger and larger because the ships keep getting larger and larger to take advantage of the econmy of scale. It's amazing how little we know about the seismic effects on these cranes." Research into this will begin in about a year's time, probably with enormous scale models of those cranes. Zwingmann found it very useful to see basic classroom science principles applied to research. "For example, when we consider the earthquakes, you know, force equals mass times accelleration, that's a basic physical science principle that they learned in the 10th grade. Then actually seeing how they were able to apply that considering earthquakes, the acceleration of an earthquake and the mass of a particular building, you know ultimately gives you the force that an earthquake causes. It was just phenomenal seeing how they were able to use those basic principles in a high tech lab here at Tech." One of the more striking images from the video on this page is the sight of a weight being set on some wet sand in a plastic container. A "thump" can be heard, and the weight plunges through the sand and out of sight. "The thumping was symbolic of an earthquake," Zwingmann explains. Afterwards, we see the same experiment again, only this time there are a number of poles in the sand. "The poles are hollow and actually have holes in them," says Zwingmann. "When you thump it again the water goes into the holes and then up and out the top of the poles. The water pressure is alleviated." In short, the poles act as shock absorbers by giving earthquake accelerated water in the sand a place to escape. Although the focus of the lab is on earthquakes, Dr. Rix notes that it has applications to hurricanes as well, "to the extent that in an earthquake the ground shakes the crane, whereas in a hurricane the force is caused by the wind," he says. Dr. Rix found that it was very useful to have high school students in the lab. "To some extent their minds aren't polluted by knowledge," he says, "so they bring a fresh curiosity to the whole thing. It's interesting because since we're around civil engineers all the time we take a lot for granted, so when you have to explain things to someone without a civil engineering background it helps you to focus your own understanding." "In the classroom the textbook has a finite number of examples," says Zwingmann, "and so getting out here and dealing with Dr. Ricks and Dr. DesRoches, they've given us a fresh example and a fresh application on how some of these basic basic principles are being used in everyday life." Georgia Performance Standards (-- Show --) |
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