Fatigue Evaluation of Steel Box-Girder Pier Caps: Bridge 69832

Steel pier caps designed such that the longitudinal girders are continuous through the pier cap are subject to significant torsion due to differences in the girder end moments and may be susceptible to fatigue cracking. One such pier cap, part of Bridge 69832 on northbound Interstate 35 heading into the business district of Duluth, was instrumented, load tested, and modeled. Several similar pier caps had developed fatigue cracking at different details. The cracks are due to high stress ranges that occur in the corners of the box section. None of these cracks are presently a threat to the structural integrity of the pier caps. Most of the cracks are limited to the welds and will eventually arrest as they grow larger with minimal structural consequences. Therefore the recommendation for these cracks is to inspect them carefully every two years and not repair them. However, holes must be drilled at least at one location where the cracks are presently in the web plates of the pier caps. Recommendations are presented for inspection of similar integral pier caps and for design of new steel pier caps.

• Record URL:
  http://www.lrrb.org/pdf/200318.pdf
• 
• Corporate Authors:

  University of Minnesota, Twin Cities

  Department of Civil Engineering, 500 Pillsbury Drive, SE
  Minneapolis, MN  United States  55455

  Minnesota Department of Transportation

  Office of Research Services, 395 John Ireland Boulevard
  St Paul, MN  United States  55155
• Authors:
  • Youngberg, Clifford J
  • Dexter, Robert J
  • Bergson, Paul M
• Publication Date: 2004-3

Language

• English

Media Info

• Media Type: Web
• Edition: Final Report
• Features: Figures; References; Tables;
• Pagination: 68p

Subject/Index Terms

• TRT Terms: Box girder bridges; Bridge piers; Case studies; Cracking; Distortion (Structures); Fatigue (Mechanics); Fatigue tests; Highway bridges; Instrumentation; Load tests; Structural steel; Torsion
• Uncontrolled Terms: Pier caps
• Geographic Terms: Minnesota
• Subject Areas: Bridges and other structures; Design; Highways; I24: Design of Bridges and Retaining Walls;

Filing Info

• Accession Number: 01013316
• Record Type: Publication
• Report/Paper Numbers: MN/RC-2003-18
• Contract Numbers: (c)81655 (wo)13
• Files: TRIS, STATEDOT
• Created Date: Dec 22 2005 9:26AM