The DEMEC consists of a digital dial gauge attached to an Invar bar. A fixed conical point is mounted at one end of the bar, and a moving conical point is mounted on a knife edge pivot at the opposite end. The pivoting movement of this second conical point is measured by the digital dial gauge.
A setting-out bar is used to position pre-drilled stainless-steel discs which are attached to the structure using a suitable adhesive. Each time a reading is taken, the conical points are inserted into the holes of the discs and the reading on the dial gauge noted. In this way, strain changes in the structure are converted into a change in the reading on the dial gauge.
An Invar reference bar is provided for calibration.
Originally designed for use on concrete structures, the gauge is just as suitable for use on other types of structure, including steel when the locating holes can be drilled directly into the steel if required.
Measurement range is 200mm +3.2/-1.6mm.
*The 6.3mm Stainless Steel Locating Disc can be ordered using code DEMECDISC*