Monitor The Movement of Cracks with A Crack Meter

Posted by PCTE on September 5th, 2016

Cracking occurs in steel-reinforced concrete and may sometimes be a symptom of a defect or delamination, or it could happen as the result of improper curing or casting. Having the right crack investigation tools can help in determining precisely the crack's visible width. Proper concrete cracking monitoring tools, like a crack meter, can help monitor the rotation and movement of cracks and measure their width. 

Applications 

The vibrating wire crack meter is one of the best tools for monitoring the movement of cracks across surfaces and joints in rock, soil, structures, and concrete. Crack meters are used to monitor the crack movement in brick and stone buildings, tunnels, dams, pipelines, rock formations, construction joints, and concrete structures. They act as a digital version of crack tell-tale, with an inner free-sliding rod and sensor outer body tube. A plucked wire connects the rod at the internal end to a vibrating wire sensor. Anchors are attached at the external end of the rod and the outer body's sensor end, and these can be fixed on either side of the crack that must be monitored. 

Crack meters are easy to install and read, with high accuracy and resolution. They have an internal thermistor, and they are insensitive to lengthy cable runs. Crack meters have a range from five to 100mm and they are waterproof up to 16 bar. They may be used with data loggers, too. 

How it works 

A vibrating wire crack meter is installed by bolting, grouting, fixing, or bolting the expandable anchors to the structure. Anchors use ball joints, and they send signals to the gauge when any differential cross-axis movement occurs while preventing the inner rod from binding with the device's outer casing. A crack monitor operates based on the principle that when the tension wire, is plucked, it vibrates at a resonant frequency. The square of that frequency is proportional to the strain within the wire. There is a magnetic coil around the wire and when it is pulsed, a data logger interface or vibrating readout plucks the wire to measure the resulting resonant frequency of the vibration. 

The distance between anchors may change due to the crack closing or opening, and this leads to the inner free-sliding rod moving within the device's outer body, which changes the tension on the vibrating wire and the spring. This way, the wire's resonant frequency is altered. Temperature information may be used if you need to log regularly to find the fast changes in temperature when there may be exaggerations on the crack movement readings. 

About the Company:

PCTE supplies a range of equipment from around the world to offer you a one stop shop with all of the latest equipment. Concrete Non Destructive Testing (NDT) comprises testing a property of concrete, largely without damaging the concrete to assess some parameter that either directly or indirectly provides a required characteristic of the concrete or its embedment. For more details, you can contact us at the website