6. Optical Time Domain Reflectometry (OTDR) Based Crack Sensing Technology For Full Scale Monitoring Of Structures

The most practical approach for distributed fiber optic sensing is based on ODTR, which is used for detection of transmission irregularities due to; splice losses, and local damage along the fiber length. An OTDR here is employed for determining the position, and degree of damage along the length of post tensioned cables in beams. It is also capable of one-port operation at the fiber input with no need to access the fiber output

Fig.1 Integrated Fiber Optic Time Domain Reflectometry for Monitoring the integrity of an FRP Rod and Anchorage System in a Post-Tensioned Concrete Beam

Fig.2 Integration of Sensors in the reinforcement cage prior to pouring of concrete.

Fig.3 Post-Tensioning of CFRP Rods prior to Structural Testing

Fig.4 Distributed Detection of Cracks and Measurement of Crack Widths in Reinforced Concrete Beams by Way of Embedded Fiber Optic Distributed Sensor