Structural health monitoring of composite poles using fiber optic sensors

The development of a fiber optic sensor system for the long-term monitoring of composite glass fiber-reinforced polymer (GFRP) poles is presented Due to aging and substantial usage of these structures, there is a growing interest in developing techniques which evaluate and monitor structural integrity. In the past few years, fiber optic sensor technology has emerged as a promising alternative to conventional methods. Fiber optic sensors can be attached to or embedded in civil structures such as bridges, dams and buildings. They operate by responding to changes in temperature and strain on the structure. One type is called a long gauge fiber optic sensor and it measures the average strain between two points on a structure. Long gauges are interferometric sensors which involve phase matching two optical paths to create a maximum interference pattern at the photodetector. The strain is calculated using the distance in which the reference arm of the interferometer is moved in order to match the optical path lengths.