Vibrating Wires

Different from the foil type strain gauge, it operates on the principle that a tensioned wire, when plucked, vibrates at a frequency that is proportional to the strain in the wire. Similar to a mechanical strain gauge, the device is positioned on both sides of the crack so that the wire is held in tension. Movement of the crack would result in a change in the tension of the wire, which is picked up by using an electromagnet to pluck the wire and measure the frequency of vibration and deduce the strain.

Common applications include monitoring the crack propagation of:
– substructure/foundation
– roadways
– bridges
– overpasses and walkways
– dams
– offshore oilrigs
– airport taxiways