Intrinsic optical fiber temperature and strain sensor for structural health monitoring of concrete structure

Abstract

Structure failure in civil engineering has been a motivation behind the development of monitoring system where it provides analytical data for evaluating the performance of building's structure, highway bridge, tunnel, etc., in order to minimize the risk of engineering disaster that would endanger public’s safety and property. Fiber Optic Sensor (FOS) has been extensively studied and used since its first discoveries. However, erroneous in measurement due to cross-sensitivity of FBG is the main drawback for this sensing principle. Therefore, cascaded FBGs are developed to monitor temperature and strain. Another drawback of FBG toward temperature is it has poor thermal expansion properties. Thus, an analytical temperature model of FBG that able to enhance temperature sensitivity is developed and realized by coating the FBG with metal material that has good thermal expansion coefficient. The metal coating of FBG is done using electroless plating as this method is simpler and low cost.