By monitoring changes in vibrations of bridges it is possible to identify hidden cracks and fractures, according to a Queensland University of Technology researcher.
QUT engineering researcher Henry Shih said variations in bridge vibrations of a bridge could be a telling sign of its structural "health".
"It's not always possible to see damage to a bridge, but using vibrations it is possible to 'see' what can't be seen," he said.

Now we know where we got it from.