On the bonding performance of Distributed Optical Fiber Sensors (DOFS) in structural concrete

Distributed optical fiber sensors (DOFS) is one of the most promising and exciting technolo-gies under research to be applied in civil engineering infrastructures structural health monitoring (SHM). There-fore, in this paper, the authors present a laboratory experiment where a reinforced concrete beam was instru-mented with a 5-meter-long polyimide DOFS in a way that four equal segments were bonded to the bottom surface of the beam using for each segment a different type of adhesive. 3 strain gauges were also used to compare the results. The beamt was then loaded, generating expected equal levels of strain for each of the segments allowing for a direct comparison between them. In this exercise, additionally to the comparison with the other instrumented sensors it is also important the consideration and analysis of the associated Spectral Shift Quality (SSQ) values of the DOFS measurements. Since the applied load was both positive and negative, it was also possible to observe the performance of each combination of input and adhesive in measuring compressive strain