Active Sensing for Online Highway Bridge Monitoring

This Innovations Deserving Exploratory Analysis (IDEA) project was aimed at developing and evaluating a sensor-based nondestructive testing (NDT) method for online monitoring of highway bridges without using any past baseline data. A theoretical framework of the proposed baseline-free NDT technique was developed along with a time reversal process (TRP), and a NDT methodology for detecting cracks in bridge steel girders was formulated. To prove the feasibility of the proposed concept, research addressed the following key questions: What is the practical sensing range of TRP for damage detection? Can different types of flaws be selectively detected and quantified? Do sensor conditions affect damage detection? Do undesirable operational and environmental conditions affect damage detection? Is the proposed TRP applicable to more complex structural geometries? The sensing range of TRP was found to be significantly larger than that achieved by conventional NDT methods, and the active sensing device was able to propagate up to 40 m. Results also indicated the feasibility of distinguishing between different types of defects, and adverse conditions such as debonding and cracking of the sensing device did not appear to severely affect the TRP used for structural damage detection. Laboratory experiments demonstrated that the proposed technique was not significantly affected by (i) ambient temperature variations, (ii) imperfect sizing and positioning of the active sensing device, (iii) ambient background vibration of the test specimens, (iv) changes in the test specimen's boundary conditions, and (v) surface debris or additional paint layer on steel girders. Field tests at a steel bridge near Pittsburgh further established the robustness of the proposed approach against operational and environmental variations of the bridge. Further field testing and refinement of the technique is needed to address issues with automating data collection and interpretation and with hardware and transducer devices for long term continuous monitoring.

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  • Supplemental Notes:
    • This NCHRP-IDEA investigation was conducted by the Carnegie Mellon University, Pittsburgh, Pennsylvania. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved
  • Authors:
    • Sohn, Hoon
  • Publication Date: 2007-5


  • English

Media Info

  • Media Type: Print
  • Edition: Final Report
  • Features: Figures; Photos; References; Tables;
  • Pagination: 44p
  • Serial:
  • Publication flags:

    Open Access (libre)

Subject/Index Terms

Filing Info

  • Accession Number: 01054251
  • Record Type: Publication
  • Report/Paper Numbers: TRB-NCHRP-120
  • Files: TRIS, TRB
  • Created Date: Jul 23 2007 10:56AM