Crackmeters and Jointmeters

Crackmeters and Jointmeters

The instrument family of Crackmeters and Jointmeters include a large number of instruments, able to monitor deformations and displacements over small cracks and joints up to large rifts. The most common applications are: Dams, Buildings retaining walls, Landslides and instable rock cliffs, Precast structures, Historical structures, Bridges and viaducts.

The most simple method to measure a movement of a crack is to use the tell-tale crackmeter. It is composed of two transparent plastic plates, one with a graduated grid and one with a reference cross, mounted over the crack or joint.

Uniaxial and tri-axial mechanical jointmeters are often used in application where automatic readings are not requested and where the engineer can take the readings with a dial gauge directly on the instrument (Note: It can be very difficult to take readings with a mechanical crackmeter installed 30m from ground level on a vertical rock-wall). Tri-axial jointmeters, they are frequently installed in concrete dam projects to monitor construction joints, can also be equipped with transducers to allow automatic readings.

Electrical crackmeters and vibrating wire crackmeters are available for accurate and automatic monitoring. Offered with both potentiometer and vibrating wire sensor technology, they can also be installed with special supports in 2D or 3D configuration. They are IP68 protected, and so suitable for projects that request waterproofing (e.g. dams, piers, tunnels, etc.).

Embedment jointmeters are often installed in concrete dams where construction joint monitoring is essential. Embedded between two concrete blocks of the dam, movements occur in the joint are detected. The USB Wire deformometers is designed for monitoring small cracks. it incorporates a simple datalogger for automatic data acquisition. The logger set-up and the data download is managed by connecting a notebook-PC to the instrument with a USB cable.

The electrical wire deformometers is a gauge able to detect relative movements between two points at a maximum distance of 10m connected with a Kevlar rope. The installation is very simple: install the instrument body on one point, extend the Kevlar wire to the second point and fix it to the reference anchor.

The Wire crackmeter is similar to the wire deformometers. It is used when distance between the points to monitor is larger than 10m and when a strong and rugged instrument is required. It is basically composed by a stainless steel instrument box that houses the sensor, a steel wire and a reference anchor. This kind of instrument is widely used to monitor landslides and large rifts.