The Concrete Surface Mounted Strain Gauge is used for measuring strain in concrete structures including load bearing concrete beams and piles. It is also used for the monitoring of strain due to load, for use on bridges & dams, tunnel linings and for monitoring strain and load during construction and service life.

The Vibrating Wire Concrete Surface Mounted Strain Gauge consists of a sealed tube containing the wire, which is attached via allen bolts to two removable anchors, one at either end. These in turn are site grouted using the setting bar as a template into holes drilled into the structure to be monitored. The gauge can be removed during anchor grouting to prevent damage.

With the gauge fixed to the structure, deformation of the concrete mass (member) causes the two embedded points to move relative to one another, thus altering the tension in the steel wire and its natural frequency. As the gauge is attached directly to the structure then an externally housed electromagnetic excitation coil, sealed within a PVC housing situated at the mid-point of the gauge tube, is used to excite the strained wire. Connected by tough 4-core, screened cable, the coil is activated by an electrical pulse from a vibrating wire readout unit, which then measures the resulting frequency of vibration. Using a gauge factor, the measured frequency may be converted directly into units of strain.