Abstract
This article describes a continuous monitoring system based on fibre optic sensors that can identify changes in optical characteristics caused by mechanical deformations in concrete structures. The principle of operation is based on analysing the pattern of the light spot at the fibre output, the shape and intensity of which change depending on the stress applied to the structure. A mathematical model linking the effective refractive index and deformation is presented. An experimental prototype with a multi-channel configuration and a closed loop has been assembled, providing distributed and highly sensitive monitoring. The experimental results confirm the system's ability to detect deformations, confirming its potential for use in the structural diagnostics of reinforced concrete elements.