Road Safety
Vibrating Wire Crackmeter / Jointmeter
Vibrating Wire (VW) Crackmeter or Jointmeter: Vibrating Wire (VW) Crackmeter or Jointmeter is a high-precision geotechnical instrument designed to monitor the movement …
Vibrating Wire (VW) Crackmeter or Jointmeter
Vibrating Wire (VW) Crackmeter or Jointmeter is a high-precision geotechnical instrument designed to monitor the movement of cracks, joints, or structural gaps in harsh environments like mountain rock faces. The device operates on the principle of vibrating wire technology, where a high-strength steel wire is tensioned between a fixed sensor body and a movable sliding rod anchored across a joint. The Mechanism The VW Crackmeter measures the distance between two points on a rock face to detect if a crack is widening.
Installation: You anchor two mounting blocks across a visible crack or joint in the rock face. The sensor body is attached to one block, and a sliding rod is attached to the other.
The Tensioned Wire: Inside the sensor is a high-strength steel wire. As the rock crack opens (even by 0.01mm), the sliding rod moves, which changes the tension on that internal wire.
The Pluck: An internal electromagnetic coil plucks the wire, causing it to vibrate.
Frequency Analysis: Just like a guitar string, a tighter wire vibrates at a higher frequency. The sensor measures this frequency and converts it into a digital measurement of how far the rock has moved.
Digital Alert: If the crack widens beyond a set Danger Threshold, the system triggers an alert.