Development of new wireless sensors for concrete strain measurement and its correction for temperature effect

• Main Authors: Yu-Wen Chang, 張羽雯
• Other Authors: 林宜清
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/43sr9q

碩士 === 國立中興大學 === 土木工程學系所 === 106 === This study proposed a novel externally-implanted strain gauges for concrete strain measurement, which was integrated into a wireless system to form a wireless strain sensor. In the study, the new wireless strain semsor was applied to measure the strain of the concrete specimen and the possibility of replacing the conventional long strain gauge bonded on concrete surface was investigated. The experimental results illustrated that the linearly of the externally-implanted strain gauges is excellent although the implanted screw into the concrete could not completely tranfer mechanical deformation. A calibration coefficient must be applied to the externally-implanted strain gauges to have an accurate measuremeant of concrete strain. Furthermore, this thesis conducted temperature effect tests to determine the influence of temperature on the adhesive strain gauges commonly used in concrete structures. The effects of temperature on concrete strain measurement include the thermal expansion of the concrete and the change in electric resistance of the strain gauge itself. As a result, the mechanical strain can be obtained by deducting the free thermal strain of concrete and the temperature electric-resistance effect of the strain gauge itself from the measured strain in the test. Experimental results show that the mechanical strain can be obtained with an error of within 9 %.