'Mood Ring' For Bridges Could Indicate Poor Structural Condition
PITTSBURGH (KDKA) – We are a land of bridges, and as this year's Liberty Bridge incident clearly illustrated, losing a bridge even for a short time has a wide-ranging impact.
Structurally deficient bridges keep bridge inspectors busy all over the region year-round.
But what if a bridge could tell the inspectors when it's being stressed to the point of damage?
It's being called a mood ring of sorts for bridges, and the brainiacs at Vanderbilt University in Nashville say the early tests show it works.
With the Liberty Bridge incident, we came close to the worst case scenario they experienced in Minnesota when the I-35 bridge over St. Anthony's Falls came down.
So the Mensa crews at Vanderbilt have gone to work and come up with something called the broad-spectrum white light nanocrystal to detect the worsening condition of a structure.
"It can see things that we can't see, see degradation happening in these materials," Doug Adams, Ph.D., at Vanderbilt University said.
The chemistry in this is difficult to understand. But the result is a material that warns by changing colors as stress conditions change.
"Everybody had mood rings growing up, tells you if you're happy, sad, in love," Vanderbilt University grad student Cole Brubaker said. "Why can't we apply this to materials? Why can't we give materials some ability to sense themselves, and we're doing that with these quantum dots through changes in color."
And it's not just theory.
"We are at the point where we've demonstrated in surface coatings, we've demonstrated in bulk materials the ability to observe this material's self-reporting capability," Adams said.
So once you get the nano-dots of this stuff in the bridge materials...
"If the bridge is experiencing a very heavy traffic day, and it's much, much heavier than it's ever experienced before, that might push that bridge beyond a point that it's ever experienced before and might cause a crack to initiate," Adams said. "We'd like that material to know that that's happened and then when that inspector comes out, we'd like that material to tell the inspector that."
So steps can be taken before there's a failure.
PennDOT's chief bridge inspector for District 11, Lou Ruzzi, told KDKA's John Shumway there are a lot of pre-warning products and efforts in the experimental pipeline. He says the nano-dots are intriguing, and they're always open to anything that can let them know there's going to be a problem in advance.
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