Hearing the noise a bridge makes when water falls on it can tell engineers if it is structurally sound or not, the researchers discovered.
Since it is a simple, effective and cheap method it could lead to potentially dangerous examples being discovered before it is too late, found the study by Brigham Young University in Utah, US.
Engineers already listen to the noise bridges make - which they call 'singing' - using a system called impact-echo testing. But this currently involves hitting all the various parts of a bridge with a hammer or dragging a chain across to detect any hidden corrosion within the structure, the Daily Mail reported.
The sound changes when the chain or hammer hits a section where there is corrosion beneath the surface.
However, it takes a long time to go over every bit of the structure and it may not be totally effective.
The new method could be as simple as driving a truck over a bridge while spraying it with water and recording the sound it makes.
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They discovered that when water hits concrete the sound is different when the structural layers have been separated - a process called delamination which leads to flaws.
There is a difference between water hitting intact structures and water hitting flawed structures.
"We can detect things you can't see with a visual inspection; things happening within the bridge itself," researcher Brian Mazzeo said.
"The infrastructure in the US is ageing, and there's a lot of work that needs to be done. We need to be able to rapidly assess bridge decks so we can understand the extent of deterioration and apply the right treatment at the right time," researcher Spencer Guthrie said.