Performance of Embedded Fiber Optic Sensors in Composite Structures

The technology of fiber optic sensors, initially developed for use in aerospace industry, is currently investigated for its applicability in civil engineering. Advances in the structural application of this technology will facilitate the use of built-in monitoring capability in reinforced concrete members, and consequently enable the production of smart structures. This paper investigates the development of a Fiber Optic Bragg Grating Sensor (FOBGS) for embedding in concrete members to measure strain and monitor cracks. Tests were carried out on a steel plate subjected to flexural stress and reinforced concrete beams subjected to axial tensile stress and temperature change. The FOBGS was employed to track the behaviour of these members under loading conditions. A theoretical analysis was performed on the tested specimens to estimate strain values and cracking loads. Good agreement was found between the theoretical and the experimental results.