Continuous Coaxial Cable Sensors for Monitoring of RC Structures with Electrical Time Domain Reflectometry


This study was aimed at developing and validating a new type of coaxial cable sensors that can be used to detect cracks or measure strains in reinforced concrete (RC) structures. The new sensors were designed based on the change in outer conductor configuration under strain effects in contrast to the geometry-based design in conventional coaxial cable sensors. Both numerical simulations and calibration tests with strain gauges of a specific design of the proposed cables were conducted to study the cables' sensitivity. Four designs of the proposed type of sensors were then respectively mounted near the surface of six 3-foot-long RC beams. They were tested in bending to further validate the cables' sensitivity in concrete members. The calibration test results generally agree with the numerical simulations. They showed that the proposed sensors are over 10~50 times more sensitive than conventional cable sensors. The test results of the beams not only validate the sensitivity of the new sensors but also indicate a good correlation with the measured crack width.

Meeting Name

Smart Structures and Materials 2003: Smart Systems and Nondestructive Evaluation for Civil Infrastructures (2003: Mar. 3-6, San Diego, CA)


Civil, Architectural and Environmental Engineering

Second Department

Electrical and Computer Engineering

Keywords and Phrases

Coaxial Cables; Computer Simulation; Cracks; Reflectometers; Sensors; Strain; Time Domain Analysis; Strain Sensors; Reinforced Concrete; Continuous Sensors; Crack Sensors; Electrical Time Domain Reflectometry; Reflection Coefficient

International Standard Serial Number (ISSN)


Document Type

Article - Conference proceedings

Document Version


File Type





© 2003 SPIE -- The International Society for Optical Engineering, All rights reserved.

Publication Date

01 Sep 2003