PROVIDENCE, R.I. (WPRI) — From potholes to cracks, it’s easy to see with your own eyes failures on the surface of a bridge. Issues underneath the surface – which compromise the structure of Rhode Island’s deteriorating bridges – are far harder to find and repair.
Researchers at Roger Williams University are changing that by repurposing technology to effectively take an X-ray of a bridge.
Dr. Nicole Martino, an engineering professor at RWU, said problems within the bridge are often invisible to crews. “Usually, damage tends to occur within the deck far before you can actually see it on the surface,” says Martino.
“Usually, damage tends to occur within the deck far before you can actually see it on the surface,” says Martino.
Martino, a Rhode Island native, started working with the state’s Department of Transportation last July on a two-part system that sees through concrete using infrared thermography and ground penetrating radar.
“It would save a lot of money,” said David Fish, a top engineer at RIDOT. He said using and combining the radar and thermography allows crews to pinpoint exactly where hidden damage could be lurking, and lets them know where work needs to be done.
He said the process works by attaching a specialized camera to a car and driving slowly over a bridge.
Martino told Eyewitness News researchers at RWU combine the readouts of what the infrared and radar images capture.
They compare the two data sets to find consistent strong points and weak points, then associate colors with those spots. Green is good. Red means crews will likely need to make repairs.
“We’re excited – we think it’s going to save us a lot of time. It’s going to save us a lot of money,” Fish said.
In this case, a “lot” could amount to millions of dollars.
According to Fish, instead of tearing down and building a new bridge, “We can go out there and do small repairs to prolong the life cycle of that concrete deck.”
For specific numbers, he broke it down by the cost per square foot. He said, “If you’re able to do a preservation activity, it’s $160 per square foot. If you have to go in there and do a major rehab, or replacement, it’s just under $700 a square foot.”
Add that up over thousands of square feet of a bridge deck, and the difference – depending on the size of each bridge – is well into the millions. Those savings could be vital for a department charged with repairing and replacing some of the nation’s worst bridges.
On top of finding problems in bridge decks, Dr. Martino believes the technology could do the opposite, too. She said the technology will help the state avoid unnecessary repairs on older bridges that are still in good shape.
“You can put your focus and your time and your money into what is needed now,” Martino told us.
This technology is still in the research phase. RIDOT said about 10 bridges have been scanned so far, and they all have exposed concrete decks. They hope to expand it to bridges with asphalt pavement in the future and do a complete rollout in the Spring of 2017.
Eventually, if this goes well, RIDOT said they could use these scans on other infrastructure – like roads and even dams – to find serious problems before anyone can see them with their eyes.