Abstract

Info

Author(s):: WANG Yong-bao; ZHAO Ren-da; CHEN Lie; XU Yong; XIE Hai-qing; School of Civil Engineering, Southwest Jiaotong University

Keywords:: bridge engineering; vibrating wire sensor; experimental research; temperature correction; strain

Abstract:: In order to obtain reasonable temperature correction formula of vibrating wire strain sensor, temperature correction tests about the sensor in free state, the sensor embedded in concrete creep and shrinkage members, concrete filled steel tube (CFST) shrinkage and creep members in the outdoor sunshine temperature were carried out. Based on the experimental results, the temperature correction formulas of vibrating wire strain sensor under different conditions were fitted, and the results were analyzed based on the theoretical formula. The results show that the sensor strain in free state is positively correlated with the increase of temperature, and the slope is 2.8×10^-6℃^-1. The strain of sensor embedded in the concrete shrinkage and creep specimen presents negative correlation with temperature, and the slope is －2.15×10^-6℃^-1and －2.54×10^-6℃^-1respectively. The strains of the sensor embedded on surface of the CFST shrinkage and creep specimens show positive relationship with temperature. The strains of sensor embedded inside of the CFST shrinkage and creep specimens present negatively relationship with temperature, and the slope is －2.01×10^-6℃^-1and －1.70×10^-6℃^-1respectively. The difference between the linear expansion ratio of the steel wire and the expansion coefficient of the external test material is the main reason of the positive and negative correlation of the sensor strain and temperature.