QUASI DISTRIBUTED OTDR CRACK SENSOR FOR REINFORCED CONCRETE STRUCTURES

A quasi-distributed fiber optic sensor is developed for embedment in concrete structures. The sensor principles are simple, and therefore, practical for crack detection and deformation measurement in civil structural applications. The distributed sensor developed herein operates based on the intensity measurements of optical power. The sensor consists of a number of individual segments on one line, with gauge lengths designed according to the structural and materials requirements. An optical time domain reflectometers (OTDR) was employed for interrogation of the sensor signal. The study reported herein is aimed at demonstrating the applicability of this sensor in monitoring performance of concrete structures. Crack detection methodologies were established through experiments with plain concrete beams. Structural monitoring capability of the sensor was evaluated through experiments with reinforced concrete beams.

Chen, Z., Gu, X., and Ansari, F.
University of Illinois at Chicago, Dept. of Civil & Materials Engineering
Chicago, Illinois