Studies on Embeddable Type Packaged Strain-Temperature FBG Sensor for Concrete Structures

Abstract

Fiber Bragg Grating (FBG) sensors are the most current type of fibre optic sensors, which are gaining importance in the field of structural strength observing for civil structures. These are confirmed to be more useful due to their distinctive advantages such as high sensitivity, resistance to electromagnetic meddling, and ease of multiplexing and remote sensing. Embedded FBG sensors are relatively suitable for non-destructive assessment and long term observing of concrete structures. Bare fibre optic sensors are fragile and not suitable for directly embedding in concrete. Suitable packaging to the bare sensor is needed to protect the sensor and to ensure proper strain transfer from concrete to sensor. The FBG sensors are found to be effective in strain and temperature sensing. The total strain obtained using FBG sensor is the sum of the strain stimulated due to mechanical load and the superficial strain stimulated due to temperature. In this paper, performance evaluation of newly developed packaged embeddable type FBG sensor which can simultaneously measure strain and temperature has been carried out experimentally. This paper also includes numerical studies carried out to compare the experimental results.