On September 26, 1996, the Michigan Department of Transportation visually detected fatigue cracks at the end of horizontal gusset plates on cantilever sign structures. A technical investigation was conducted to: determine the cause of the cracking; develop an ultrasonic inspection method of detecting the cracks; develop a repair procedure for cracks at this location; and recommend changes to the connection detail. This paper describes the techniques used to detect and repair fatigue cracks found at the end of horizontal gusset plate connections on cantilever sign structures. In addition, this paper describes and shows the detail used to reduce the potential for fatigue cracks at this location. Between April 1997 and July 1998, approximately 1,100 cantilever sign structures had the end of the horizontal gusset plate to the vertical pole connection visually examined for signs of fatigue cracking. After visual examination, 209 ends of horizontal gusset plate connections were ultrasonically inspected to determine fatigue crack severity. In 1998, several cantilever sign structures were removed from service as a result of fatigue cracks at the end of the horizontal gusset plate to vertical pole connection confirmed by ultrasonic testing. A routine inspection program and better connection details will help prevent fatigue cracking at this location and catastrophic collapse of the cantilever sign structure arm.

  • Availability:
  • Supplemental Notes:
    • This entry in the TRIS database is made from the hardback copy of the conference proceedings, which are also available on CD-ROM.
  • Corporate Authors:

    Technomic Publishing Company, Incorporated

    851 New Holland Avenue, Box 3535
    Lancaster, PA  United States  17604
  • Authors:
    • Cook, S J
    • Till, R D
    • Pearson, L
  • Conference:
  • Publication Date: 2000


  • English

Media Info

  • Features: Figures; Photos;
  • Pagination: p. 419-427

Subject/Index Terms

Filing Info

  • Accession Number: 00793156
  • Record Type: Publication
  • ISBN: 1566769493
  • Files: TRIS
  • Created Date: May 9 2000 12:00AM