The Vibrating Wire Jointmeter is specially designed for measuring the relative displacement of two adjacent surfaces in three orthogonal directions.
The Vibrating Wire Triaxial Jointmeter is designed to monitor three way displacement at joints and cracks. The reference anvil design allows the Vibrating Wire transducers to show independent movement in all directions, irrespective of each other.
The Jointmeter comprises a 3D mounting system which consists of two arms and two groutable anchors. Three vibrating wire displacement transducers, which also monitor temperature, are installed within the mounting system and positioned for monitoring.
- Reads in X, Y and Z axes
- Uses proven Vibrating Wire technology
- Proven in long term monitoring
- Suitable for manual or remote monitoring
- Fully waterproof
- Fitted with thermistor for temperature monitoring
- Accurate and robust
- Three way independent movement monitoring in one easy installation
- Over 30 years of expertise in the design and manufacture of Vibrating Wire instrument technology
- Accurate, repeatable readings over long cable lengths
- Long working life, long term stability and reliability
- Over-voltage surge arrestor fitted to protect against electrical damage
- Connecting cable is strong, screened and flexible
The groutable anchors are installed either side of a joint or crack; the installation jig provided ensures that the two anchors are positioned correctly. Once the anchors are set in position the installation jig is removed and the VW transducers are installed. The VW transducers are positioned against the reference anvil face, most commonly set to their mid-point, and the cables wired up.
Movement in the monitored position will result in relative change between the two anchors; this in turn will cause one or more of the VW transducer rods to move independently, changing the frequency of the wire. This change in frequency is recorded and can be converted to show the movement in millimetres.
Typically signal cables run from the sensors to a data logger for remote reading. Alternatively, a terminal/junction box is used and a handheld readout or data logger is used to manually record the readings.
An initial datum reading is taken and this can then be compared to all subsequent readings to give the change and magnitude of displacement.
Vibrating Wire Jointmeter Application
Vibrating Wire Triaxial Jointmeters are used for monitoring of movements at construction joints; typical examples include:
- Concrete dams
- Masonry structures