Temperature Correction on Crackmeters
The
crackmeter working elements are made primarily of steel and stainless
steel and are affected by changing temperature to a certain predictable
degree. In case of large temperature changes application of temperature
correction will improve the accuracy of the measurements. The
approximate temperature effect on the gauge is -0.02mm per degree
Celsius. Hence for a temperature increase of 10°C a crackmeter will
indicate (-0.02 x 10) -0.2mm to the result indicated by the crackmeter
reading. A fall in temperature will result in a positive change in
linear measurement which can be corrected accordingly. Physical
dimensional changes due to temperature in the crackmeter and the
structure on which it is mounted are of the order of 10-6mm/m/°C and can
be neglected.
For strain gauges installed on concrete with no loads are acting, the thermal concrete strains are given by:
µɛ(thermal) = (T1-T0)xCF1
CF1 represents the coefficient of expansion of concrete. Unless this figure is known, assume a nominal value of +10.4 microstrain/DegC. As assumptions are made for the thermal coefficients of concrete the equation should be considered as a general guide.
For strain gauges installed on concrete with no loads are acting, the thermal concrete strains are given by:
µɛ(thermal) = (T1-T0)xCF1
CF1 represents the coefficient of expansion of concrete. Unless this figure is known, assume a nominal value of +10.4 microstrain/DegC. As assumptions are made for the thermal coefficients of concrete the equation should be considered as a general guide.