Fiber Bragg Grating Sensor as the Most Effective Distributed Optical Fiber Sensor in Defense Applications of Civil Structures

Protection of civil structures such as towers, bridges, dams, refineries and other large structures against natural and unnatural disasters is one of the topics which should be addressed in the field of passive defense. One of the most important issues which should be regarded for massive structures is monitoring the status of their strength after the construction process. Cracks and fractures caused by subsidence, structural age, humidity, cold and warm air, corrosion, decay, as well as various disasters, are the problems that may occur after construction and can affect structure safety over time. Hence, many of structures in the world, besides being carefully monitored when constructed, are controlled by different systems after construction. One of the most popular types of these systems is distributed optical fiber sensors system. In this article, we first introduce and then compare different types of these sensors in the field of structural defense. After explaining the advantages and disadvantages of each of these distributed sensors and introducing their samples in different structures of the world, we will see that Fiber Bragg Grating sensor is more widely used than any other optical fiber distributed sensor, for monitoring the strength of civil structures.The main reason for the tendency to use Fiber Bragg Grating sensors is cost-effectiveness as they havehigh spatial resolutionand are easy to construct and install.