INVESTIGATION OF DELAYED CRACKING IN PIVOT STEEL GIRDERS

This report describes the results of an investigation to find the cause of the delayed cracking in the welds of the fracture-critical steel pivot box girders fabricated for the George P. Coleman Bridge. Through the use of different nondestructive methods, more than 200 transverse and longitudinal cracks were found. The possibility of unique, rare, and very long-term delayed cracking (cold or hydrogen-induced cracking) was supported by the results of the hydrogen content analysis, residual stress measurements, and macro-microstructural metallography and fractography. There was strong evidence that a susceptibility to hydrogen-induced cracking of the weld metal in the north girder developed during fabrication and that this susceptibility, the presence of hydrogen in the weld and base metal, and residual stresses combined to cause cracking to occur. The great number of cracks detected in the welds of the north girder, coupled with the very large total crack lengths, demonstrated that these welds have been and still are inordinately susceptible to cold cracking. Calculations showed that brittle fracture could occur in the partial penetration groove weld under the worst conditions, but this is not probable. Calculations also showed that there is little probability that the cracks will extend in any significant amount because of fatigue during the life of the bridge. The author recommends that the north box girder be inspected by magnetic particle testing or eddy current testing at least every 6 months for the next 3 years and that cracks be repaired when found.

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• Record URL:
  https://rosap.ntl.bts.gov/view/dot/19461
• Corporate Authors:

  Virginia Transportation Research Council

  530 Edgemont Road
  Charlottesville, VA  United States  22903

  Virginia Department of Transportation

  Office of Public Affairs, 1221 East Broad Street
  Richmond, VA  United States  23219
• Authors:
  • Lozev, M G
  • Washer, G A
  • Wright, W J
• Publication Date: 1997-6

Language

• English

Media Info

• Features: Appendices; Figures; Photos; References; Tables;
• Pagination: 113 p.

Subject/Index Terms

• TRT Terms: Box girders; Bridges; Cold weather; Cracking; Eddy currents; Fracture mechanics; Hydrogen; Inspection; Longitudinal cracking; Magnetic materials; Metallography; Nondestructive tests; Testing; Transverse cracking; Welds
• Uncontrolled Terms: Bridge inspection; Cold cracking; Magnetic particle testing
• Old TRIS Terms: Eddy current testing
• Subject Areas: Bridges and other structures; Design; Highways; I24: Design of Bridges and Retaining Walls;

Filing Info

• Accession Number: 00738999
• Record Type: Publication
• Report/Paper Numbers: VTRC 97-R18, Final Report, Proj No. 9133-010
• Files: NTL, TRIS, ATRI, STATEDOT
• Created Date: Jul 28 1997 12:00AM