Monitoring of Fatigue Crack Growth in Steel Structures Using Intensity-Based Optical Fiber Sensors

In this study we evaluated the potentiality of the application of intensity-based optical fiber sensors (IOFS) to the monitoring of crack growth behavior of steel structures subjected to fatigue loading. This evaluation was performed based on the sensing principle of IOFS and the fracture mechanics theory of cracked structures by the use of IOFS attached to center-cracked-tension steel specimens and a model bridge. Experimental results showed that the attached IOFS could detect the stiffness changes caused by the crack growth of steel structures. We also studied the characteristic advantages of the IOFS, such as durability to fatigue and immunity to elecromagnetic interference, compared to the strain gage. From this experimental study it can be said that the potentiality of the IOFS for practical application has been confirmed.