Fibre optic sensors for health monitoring of concrete structures

Abstract

After years in service, many concrete structures are showing severe deterioration. To ensure safety of these structures and to prioritize maintenance effort, there is a need to monitor the structural condition over time. Since concrete structures degrade through the formation and propagation of cracks, the monitoring of cracking and delamination (material separation parallel to the surface) is the most effective way to assess the 'health' of a structure. In this paper, we will focus on two novel fiber optic sensors for crack and delamination sensing in concrete structures. For each novel fiber optic sensor, the sensing principle is first described. Both theoretical and experimental results are then shown to verify their applicability to concrete structures. With these novel sensors, cracks and delaminations can be located and monitored without a-priori knowledge of their locations. This 'distributed' sensing capability of optical sensors is a big advantage over conventional gauges and transducers that can only obtain information at a single point