Used for measuring strain in steel members the strain gauge can be arc welded to steel structures such as piles, load bearing beams and columns, struts and bridges. It can also be applied to sheet pile walling, reinforcement bars, tunnel linings and suspension bars

The strain gauge comprises of a wire sealed inside a gauge tube and is stretched between to anchor blocks welded to the surface of the structural member.  An electromagnetic excitation coil, within a sealed PVC housing installed at the mid-point of the gauge tube.

With the gauge arc welded to the structure, deformation of the steel mass (member) causes the two welded 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.