A novel TDR-based coaxial cable sensor for crack/strain sensing in reinforced concrete structures

Shishuang Sun*, David J. Pommerenke, James L. Drewniak, Genda Chen, Liang Xue, Michael A. Brower, Marina Y. Koledintseva

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


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.

Original languageEnglish
Pages (from-to)2714-2725
Number of pages12
JournalIEEE Transactions on Instrumentation and Measurement
Issue number8
Publication statusPublished - 3 Jul 2009
Externally publishedYes


  • Coaxial cable
  • Crack/strain sensor
  • Plasma spray
  • Sensitivity
  • Signal loss
  • Spatial resolution
  • Time-domain reflectometry (TDR)

ASJC Scopus subject areas

  • Instrumentation
  • Electrical and Electronic Engineering


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