Modeling of Supplemental Bar-Mounted Fiber Optic Strain Sensor for Structural Health Monitoring Applications

Abstract

Abstract Fiber optic sensors have been increasingly utilized in structural health monitoring of large-scale civil structures. Bare fiber sensors are quite brittle, and therefore, their installation and embedment in reinforced concrete elements can be challenging, particularly when using uncommon materials as internal reinforcements in concrete. In the present study, a fiber optic strain sensor is preinstalled on a supplemental bar of adequate length and appropriate diameter. The sensor is attached to a glass fiber-reinforced polymer (GFRP) reinforcing bar in concrete flexural element. Performance under static-loading conditions has been evaluated, and the results have shown potential toward applying the technique to large-scale structures. Another objective of the present study is to develop a numerical model that represents the interaction between the concrete, the reinforcement steel, and the supplemental GFRP rebar, which has the sensor mounted on. The model is calibrated using experimental results. The model can be used to investigate varying parameters including material properties (e.g., compressive strength of concrete), geometrical data (e.g., the length of the supplemental rebar), and loading and boundary conditions, consequently eliminating the need to perform a large number of full-scale costly experiments. The developed model exhibited nearly identical behavior to the experiments after calibration. The study shows that the performance of the present sensing system is primarily affected by the relative sizes of the main and supplemental bars.