Investigation of Cause of Cracked Stringer on the Blanchette Bridge

The Blanchette Bridge carries Interstate 70 across the Missouri River, connecting St. Louis and St. Charles counties in eastern Missouri. The westbound bridge was constructed in 1958. In 1979, the original reinforced concrete roadway deck on the bridge was replaced with a steel grid deck system, welded to supporting girders and stringers. In 1999 and 2005, cracks were discovered in stringers on the bridge approach spans. The members cracked in a counter-intuitive fashion—from top to bottom at midspan between supports, where positive bending would be expected. The stringers were repaired with bolted splices. The Missouri Department of Transportation (MoDOT) worked with the University of Missouri, Rolla (UMR) to investigate the cause of these cracks. The investigative effort included site visits, review of bridge documents, preliminary fatigue analyses, review of material property information, detailed analyses, and field testing.

  • Supplemental Notes:
    • This research was funded by the U.S. Department of Transportation, University Transportation Centers Program.
  • Corporate Authors:

    University of Missouri, Rolla

    Center for Infrastructure Engineering Studies
    1870 Miner Circle Drive
    Rolla, MO  United States  65409

    Research and Special Programs Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Marianos Jr, Ward
  • Publication Date: 2006-11


  • English

Media Info

  • Media Type: Print
  • Edition: Final Report
  • Features: Figures; Photos;
  • Pagination: 5p

Subject/Index Terms

Filing Info

  • Accession Number: 01044269
  • Record Type: Publication
  • Report/Paper Numbers: UTC R163, 00001406/0008404
  • Contract Numbers: DTRS98-G-0021 (Grant)
  • Files: UTC, TRIS, USDOT
  • Created Date: Feb 28 2007 9:26PM