An investigation of the use of embedded FBG sensors to measure temperature and strain inside a concrete beam during the curing period and strain measurements under operational loading

An investigation of the use of embedded FBG sensors to measure temperature and strain inside a concrete beam during the curing period and strain measurements under operational loading

Infrastructure systems are critical for sustaining and maintaining a nation’s socioeconomic system. The critical
infrastructure is a term used by governments to describe assets that are essential for the functioning of a society
and economy. The critical infrastructure systems are complex systems that are dynamic. During a typical lifespan,
critical infrastructure is inevitably subjected to environmental effects, long-term loading effects, material
deterioration and/or extreme loading effects such as corrosion, fatigue, aging, earthquakes, hurricanes, extreme
temperature, etc. The increased use of critical infrastructure for load bearing structures has alarmed the related industries to immediate need of structural health monitoring (SHM) systems to ensure safe operation of the critical infrastructure. The SHM process is an important feature to achieve technological leaps in the design and operation of engineering infrastructures. Karbhari (2005) stated a generalize definition of SHM featuring non -destructive in-situ sensing. The SHM process involves analysis of structural characteristics and structural response for the purpose of estimating the severity of damage / deterioration. Then SHM evaluates the consequences thereof on the structure in terms of response, capacity and service life. Karbhari and Ansari (2009) described that a SHM
system includes main operations of acquisition, validation, analysis, prognosis and management. In SHM miniaturized sensors have been embedded in smart composite materials in order to mitigate t he risk of failure due to an overload or an unwanted inhomogeneity resulting from the fabrication process (Kinet et al 2014). Monitoring strain by measuring the wavelength shift of the light reflected from the FBG sensor has often been applied in conventional health monitoring. Epaarachchi et al. (2007, 2009), Kahandawa et al (2011) have successfully used embedded FBG sensors to measure internal strain and investigated the change of spectral shapes and change of strain in the vicinity of a damage. FBG sensors have attracted much attention for SHM applications due to their great advantages, such as high accuracy in measuring strain and/or temperature and multiplexing capability (Hill and Meltz 1997; Kersey et al. 1997).