An Investigation of the Temperature-Drift Effect on Strain Measurement of Concrete Beams

This study investigates the temperature-drift effect on strain measurement of concrete beams and proposes a method for determination of the mechanical strain of stressed concrete beams. In the study, wireless electrical resistance strain gauges were used to measure the strain of concrete beams. This study first examined how temperature changes affected the strain gauge attached to concrete beams. Subsequently, a concrete beam experiencing changes in temperature and load was monitored for six consecutive days. The test results showed that the apparent strain response of the concrete beam was significantly affected by temperature changes. After adjusting for the temperature effect, the mechanical strain generated by a load could be obtained. However, temperature-induced drift was still observed in the mechanical strain response. Based on the assumption that temperature changes are slow and gradual, and mechanical strain changes are momentary, an adjacent data subtraction method can be used to eliminate the temperature-induced drift present in the mechanical strain data. The subtraction results show that the mechanical strain generated by a load was accurately obtained. The proposed data-processing method could also be used to find the residual strain of the nonelastic response of a beam subjected to substantial short-term forces.