Development of a Non-Destructive Imaging Tool to Identify Deficiencies in External Tendons Containing Flexible Fillers

Details

• Creators:
  Alexander, Christopher L. ; Sagüés, Alberto A. ; Karki, Mahesh ; Kandel, Laxmi
• Corporate Creators:
  University of South Florida. Department of Civil and Environmental Engineering
• Corporate Contributors:
  Florida. Department of Transportation
• Subject/TRT Terms:
  Bridges Configuration Management Convolution Flexible Structures Image Reconstruction Laboratory Tests Magnetic Sensor Magnets Mechanical Impedance Monitoring Reconstruction Sensors

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• Publication/ Report Number:
  BED25-977-20
• Resource Type:
  Tech Report
• Geographical Coverage:
  United States ; Florida
• Edition:
  Draft Final Report: 03/15/2024-07/31/2026
• Corporate Publisher:
  Florida Department of Transportation
• Abstract:
  The University of South Florida's Corrosion Research Laboratory previously developed a tendon imaging unit (TIU) capable of providing representative cross-section images of external tendons that show strand envelope position and the likelihood of grouting deficiencies. The objective of this work was to adapt the grout-based TIU for application to wax-filled external tendons. After characterization of the electrical properties of FDOT approved waxes, it became apparent that adaptation to wax-filled tendons would require sophisticated signal analysis to account for the limited difference between the dielectric constant for wax and air. An analysis approach was developed in which the magnetic signal is converted to a representative impedance signal considering a flaw-free, completely wax-filled condition. Comparison between the magnetic-signal recovered impedance and the measured impedance facilitates deficiency detection. Air void and water pocket deficiency detection with cross-section image recovery was demonstrated for a series of strand configurations and fill conditions. In a parallel thrust, an initial design for a rotation-free TIU was developed, and preliminary testing confirmed the capability of recovering strand position. This is a particularly promising advancement that with further development could result in increased ability to rapidly scan external tendons to facilitate bridge-scale testing or monitoring systems.
• Format:
  PDF
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:2e580694b9493b832dbe1166c52cf7edcd75063b33e44259d57d3ca9d97a7bbe1eb379ee877d43523ac18a34d74cdb95426627a740469abc8278857191c852c8
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/92986/dot_92986_DS1.pdf
• File Type:
  [PDF - 4.64 MB ]