A Novel TDR-Based Coaxial Cable Sensor for Crack/Strain Sensing in Reinforced Concrete Structures


Novel coaxial cable sensors that feature high sensitivity and high spatial resolution are developed for health monitoring of concrete structures using a time-domain reflectometry (TDR). The new sensor was designed based on the topology change of its outer conductor, which was fabricated with tightly wrapped commercial tin-plated steel spiral covered with solder. The cracks that developed within concrete structures will lead to out-of-contact of local steel spirals. This topology change results in a large impedance discontinuity that can be measured with a TDR. A simplified equivalent transmission line model and numerical full-wave simulations using finite-difference time-domain techniques were used to optimize the sensor design. The sensors under test demonstrated high sensitivity and the capability of multiple-crack detection. A plasma-sprayed coating technique was employed to improve sensor uniformity. Engineering implementation issues, e.g., signal loss, signal postprocessing, and sensor design optimization, were also addressed. © 2009 IEEE.


Electrical and Computer Engineering

Second Department

Civil, Architectural and Environmental Engineering

Keywords and Phrases

Coaxial Cable; Crack/strain Sensor; Plasma Spray; Sensitivity; Signal Loss; Spatial Resolution; Time-Domain Reflectometry (TDR); Building Materials; Crack Detection; Electric Cables; Finite Difference Time Domain Method; Image Resolution; Optical Sensors; Plasma Jets; Protective Coatings; Reflection; Reflectometers; Reinforced Concrete; Sprayed Coatings; Steel; Structural Health Monitoring; Telecommunication Cables; Time Domain Analysis; Tin; Structural Design

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Article - Journal

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© 2009 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.