Concrete Strain Monitoring with Fabry-Pérot Fiber-Optic Sensor

Abstract

The field of instrumentation is now going through new developments with the advent of fiber-optic strain gauges. Fabry-Pérot is one type of fiber-optic sensing technology that can be used for microstrain measurement of concrete. However, this new generation of strain gauges first needs laboratory investigation. The Fabry-Pérot type of sensor, specially designed for embedment in concrete, is evaluated. The sensor is protected by a steel sleeve that allows its installation in concrete elements. Laboratory experiments, including compressive and thermal loading, are performed on a high-performance concrete cylinder containing this new type of strain gauge. The fast response of these strain gauges allows monitoring of the dynamic load test up to 5 Hz. The strain gauge sleeve is made of steel, and numerical simulations using a finite-element method are performed to verify strain distribution in a concrete cylinder with an embedment fiber-optic strain gauge. Results show that this type of strain gauge performs well for strain measurement of concrete and seems not to be affected by temperature variations.