Calibration of embedded fiber optic sensor in concrete under biaxial compression

Abstract This paper deals with the theoretical model for strain measurement of concrete under biaxial compression by embedded fiber optic sensor. Both the fiber core and the matrix concrete were supposed to be elastic, whereas the coating of the optical fiber was supposed to be ideal elasto-plasticity. And the bonding surfaces between the matrix concrete and the coating of the optical fiber and between the coating and the fiber core were supposed to be intact. The biaxial strains of the matrix concrete under biaxial compression can be decomposed to two independent strains at the two directions, and each of the independent strains can be employed to calibrate the difference between the strain of the matrix concrete and that sensed by the embedded fiber optic sensor. Based on these assumptions, a theoretical model was developed for strain measurement of concrete under biaxial compression. Some experiments were conducted to verify the validation of the theoretical model. And the comparison indicates a good agreement between the experimental and theoretical results.