Low Cost Sensing System For Long-Term Monitoring of Cracks in Concrete Structures

Plastic optical fibre sensing of active cracks in a concrete tunnel is presented in this work. The characteristics features of plastic optical fibres in sensing applications, such as large deformation range, ruggedness and easiness of handling are exploited to enable an optical fibre sensing system for long-term crack monitoring, with the aim of assessing the deterioration of the structure. The strain exerted on the fibre is interrogated by means of a low cost commercially available interrogator capable of measuring the cumulated deformation induced on the plastic optical fibre by the crack opening. Practical issues, like fibre anchoring, temperature compensation and system network integration are addressed and data collected on the field are presented.