Wireless Sensors Could Prevent Another Bridge Collapse

Thirteen people died last month, when Minneapolis Interstate 35W collapsed. I-35W, along with more than 70,000 of the nation’s bridges, are rated "structurally deficient," and the American Society of Civil Engineers predicts that it would take $9.4 billion a year for 20 years to repair all of them. So how do you know which ones need work first?

Bridges across 20 states are experimenting with wireless sensors that can pinpoint cracks and stresses. The sensors are simply attached to different areas of the bridge hearing out where rust or crack beneath paint is causing the structure to groan.

According to Business Week:

Los Angeles-based Material Technologies places sensors between metal sections of a bridge. The company then drives a heavy truck over that area while a computer monitors the emitted signals, watching for that one crack out of many thousands that could cause havoc. "In 10 minutes we get a readout that's equivalent to an electrocardiogram for your heart," says CEO Bob Bernstein. A system like this can test a typical 100-foot bridge for as little $8,000. Installing sensors on just a fraction of bridges classified by authorities as "deficient" could save hundreds of thousands of dollars—and avert a catastrophe.

[image via NY Times]