A main girder of the Lafayette Street Bridge over the Mississippi River in St. Paul was discovered to be cracked on May 7, 1975. A detailed examination of the fracture is given in this paper. Fractographic examinations and analyses of crack growth showed that failure crack growth and brittle fracture both contributed to the members' failure. Fatigue cracks were found to originate at large lack of fusion areas in the lateral bracing gusset to transverse stiffener weld. After the crack had nearly penetrated the web thickness, it precipitated a brittle fracture. Subsequent intervals of fatigue crack growth and fracture were also observed. Recommendations are also provided on ways to retrofit the bridge details to prevent reoccurrence at other comparable details. In addition, a suggested detail configuration for this type of connection is recommended for future use. /Author/

  • Corporate Authors:

    American Society of Civil Engineers

    345 East 47th Street
    New York, NY  United States  10017-2398
  • Authors:
    • Fisher, J W
    • Pense, A W
    • Roberts, R
  • Publication Date: 1977-7

Media Info

  • Features: Appendices; Figures; References; Tables;
  • Pagination: p. 1339-57
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00165350
  • Record Type: Publication
  • Report/Paper Numbers: ASCE 13051 Proceeding
  • Files: TRIS
  • Created Date: Mar 7 1978 12:00AM