Sensors Could Stop the Next Bridge Collapse
Wireless devices far smarter than humans with binoculars
By Jonas Oransky,  Newser Staff
Posted Aug 13, 2007 5:43 PM CDT
Workers remove a school bus from the interstate 35W bridge collapse site in Minneapolis, Minn., Sunday, Aug. 12, 2007. The school bus was carrying 52 children from a visit to a water park when it dropped...   (Associated Press)
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(Newser) – New technology can diagnose bridge stress months before human investigators—currently armed with binoculars— could ever detect them. BusinessWeek compares the small wireless sensors to stethoscopes, as they’re capable of gauging vibration, temperature and corrosion beneath the paint. Testers ride trucks over the sensors and monitor signals, listening for the small sounds that signal weakness.

The good news is that they're cheap: a 100-foot bridge can be checked for $8,000. The bad news is that there is a dramatic shortage of technicians who  know how to use the technology. But BusinessWeek predicts that widespread implementation will come quickly in the wake of the Minneapolis bridge collapse; one study found that human inspectors found fatigue cracks only 4% of the time.