Application of quasi-distributed fibre Bragg grating sensors in reinforced concrete structures

In this paper we report on our results for the applications of fibre Bragg gratings (FBGs) in structural health monitoring. Multiplexed FBG-based strain sensors were fixed onto the reinforced bars (rebars) in concrete structures to determine the strain changes at different locations within the structures during loading and unloading tests. A similar set of FBG-based strain sensor arrays was also mounted onto the surface of the structures for the purpose of comparison. At the same time an FBG-based sensor array optimized for temperature measurement was also distributed alongside the strain sensors to obtain the temperature information, as well as to compensate for the temperature-induced wavelength shifts on those FBG strain sensors. The results obtained followed the same trend as that expected from concrete structures subjected to loading tests.