Use of Fiber Optic Sensors for Monitoring Loads in Post-Tensioned Containment Tendons

Sontra Yim presented 'Use of Fiber Optic Sensors for Monitoring Loads in Post-Tensioned Tendon'. Fiber optic sensors were selected due to their expected stable performance over long time periods, accuracy, immunity to electromagnetic interferences as well as electrical noise, and environmental stability. The resulting fiber optic sensing system (FOSS) was installed in a NPP with a post-tensioned tendon systems and provides real time tendon monitoring in order to detected tendon wire breaks, wire relaxation, local concrete failure under tendon anchorage or loss of rock anchor. FOSS holds promise to be an alternative to lift-off testing. It has worked robustly for over two years, and is anticipated to perform over a long-time period (e.g. more than 10 years)