High Spatial Resolution Crack Monitoring in Concrete Structures Using a Distributed Fiber Optic Sensor

Abstract

A method to monitor the mechanical behavior and identify crack location and growth in a concrete structure element using a distributed fiber optic sensor (FOS) system is demonstrated experimentally by testing concrete specimens in four-point bending. The sensor system consisted of an optical frequency domain reflectometry (OFDR) interrogator unit paired with an all-grating sensing fiber that was bonded to the surface of the concrete test specimen. Strain measurements with high spatial resolution of <10 mm were obtained at various points along a single fiber cable. Large strain values at the crack locations indicated strain concentrations that could be used to assess the crack growth. The distributed sensing system demonstrated the capability to detect localized, early stage cracks, with crack width smaller than 0.1 mm, well before they become observable by visual inspection.

Instrumentación de edificios para la evaluación del estado estructural en tiempo real

“…Los grandes valores de deformación en las ubicaciones de las fisuras indicaron concentraciones de deformación que podrían usarse para evaluar el crecimiento de la misma. El sistema de detección distribuida demostró la capacidad de detectar fisuras localizadas en etapa temprana, con un ancho menor de 0,1 mm, mucho antes de que sean observables mediante inspección visual (Li and Gaudet, 2020).…”