Description

DEMEC* reference bars manufactured by WH Mayes & Son of Slough. Fitted wooden box.

The box contains a block which houses a setting-out bar and a reference bar for use with a DEMEC strain measuring gauge. Both bars are set to measure 8 in (203.2 mm). The setting-out (or spacer) bar has two hardened steel tips (conical points) which are used to locate two steel discs exactly 8 in apart across an area over which strain is to be measured. The reference bar has two pre-drilled stainless steel discs set 8 in (203.2 mm) apart and is used to set a strain gauge to 8 in prior to subsequent measurements.

The strain gauge has one fixed point whilst the other pivots and moves a dial. The reading on the dial provides a measurement of any strain a matching strain is held in the collection (see here).

These bars were used in the Concrete Laboratory in Heriot-Watt University, Edinburgh, UK.

*DEMEC = demountable mechanical