Detecting Bridge Problems Goes High-Tech
Using hammers and binoculars, engineers listen for the sound of corroded steel, looking for evidence of cracking. This is the way America inspects its bridges.
If inspectors can't see a problem, they can't know something's wrong.
But in Europe, with some of the most spectacular new bridges and some of the most beautiful old ones, bridge owners are turning to new technology to check on the health of their bridges around the clock.
"Inspection is a very useful tool, but it's restricted to the surface of the bridge — and not all the deficiencies can be found," says Daniel Inaudi of Smartec. "You'd like to make the analogy to your doctor."
Like your doctor's tests, high-tech bridge sensing gets to the heart of the matter, reports CBS News correspondent Sheila MacVicar.
Only On The Web: More Than Meets The EyeFiber-optic sensors are embedded into the concrete, "and by measuring the time the light takes to travel through the fiber, we can measure the deformation of the bridge," Inaudi explained.
For older bridges, there's a special tape that's embedded with a fiber-optic filament. It will be glued to a 40-year-old bridge in Sweden.
"We can install a tape like this that can be several kilometers long and then pinpoint to one-meter precision where the problem is happening," says Inaudi.
The technology isn't restricted to Europe; it's also made in America.
"We're able to capture data that is less than one-tenth the width of a human hair," says Atlanta's Peter Vanderzee, who markets a similar kind of remote sensing for bridge managers in the U.S.
"Every time we go to them and present our technology, we generally hear a big 'Wow. That's a very interesting piece of technology. We'd like to use it, but we don't have the money,'" says Vanderzee.
Across America, transportation authorities say they are financially strapped. Some say they have a hard time even finding the money to buy paint.
Until they know exactly what caused the catastrophic collapse in Minneapolis, advocates of remote bridge sensing say they won't know for sure if the new technology would have given a warning. But they do say inspectors and engineers would have had a much better idea of what shape the bridge was in.