FBG sensor-based monitoring of a reinforced concrete frame under pushover testing

This paper presents monitoring results of a two-story reinforcement concrete frame (RCF) under a pushover test by using various fiber Bragg grating (FBG) sensors, including the bare FBG strain sensors, long gage FBG strain sensors, and FBG displacement sensors. The long gage FBG strain sensors and the FBG displacement sensors are developed by the authors. The FBG sensors are either embedded in the structure or installed on the concrete surface of the frame structure to monitor the rebar strain, the concrete surface strain, or the crack width development. The testing results show that FBG sensors can measure rebar strain precisely and that the long gage strain FBG sensors can measure concrete surface average strain precisely. Destructive pushover test results show that the FBG strain sensors can detect the nonlinear strain development of the rebars. The yielding point was precisely monitored by the FBG sensors. Crack width development at certain location of the concrete structure is monitored by FBG displacement sensor, also with high precision.