This summary of the state-of-the-art in nondestructive inspection methods, evaluates their reliability and adaptability for the detection of fatigue cracks in welded highway bridges. Emphasis is placed on in-situ testing and on the capability of techniques to define cracks accurately in terms of length and depth. The underlying concept of fatigue failure prevention in explained, and five testing techniques are described. Details of X-ray examination are briefly outlined. The X-ray image on film provides a permanent record of the size and shape of the defect in two dimensions; it does not show its position in depth in the part. In ultrasonic examination, instrumentation includes a sound wave generator and pick-up device and a display screen on which the initial and reflected pulse is displayed. The display instrumentation permits estimation of the position, nature and size of the defect. The details (modifications, advantages and disadvantages) of the dye penetrant examination, the magnetic particle examination and the eddy current examination are discussed. The general features of these five methods are summarized in a chart. The study indicates that the best methods for surface crack detection are magnetic particle and dye penetrant examination. The opinion is also expressed that the ultrasonic examination would be the most effective for fatigue crack detection if only one nondestructive examination system could be used. The current capabilities of nondestructive examination methods are reviewed, and practical field crack detection is discussed.

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  • Supplemental Notes:
    • An NCHRP staff digest of the essential findings from an interim report on NCHRP Project 12-15, "Detection and Repair of Fatigue Cracking in Highway Bridges," by Alan W. Pense, Lehigh University, Bethlehem, 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.
  • Corporate Authors:

    Transportation Research Board

    500 Fifth Street, NW
    Washington, DC  United States  20001
  • Publication Date: 1975-1

Media Info

  • Media Type: Digital/other
  • Features: References;
  • Pagination: 14 p.
  • Serial:
  • Publication flags:

    Open Access (libre)

Subject/Index Terms

Filing Info

  • Accession Number: 00081856
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Mar 26 1975 12:00AM