FATIGUE OF CURVED STEEL BRIDGE ELEMENTS--STRESS CONCENTRATION, STRESS RANGE GRADIENT, AND PRINCIPAL STRESS EFFECTS ON FATIGUE LIFE

Research on the fatigue behavior of horizontally curved, steel bridge elements was conducted at Lehigh University under the sponsorship of the Federal Highway Administration (FHWA) of the U.S. Department of Transportation. Among the various tasks of this project is the analytical prediction of fatigue life. Within the prediction process is the consideration of stress range gradient across the girder flanges. Also, attention is directed to the effect of principal stress in a flange as compared to normal stress due to bending and warping. Two specific details are investigated. The first is a transverse stiffener welded to a flange surface. The second is a gusset plate with circular transitions and groove-welded to a flange tip. For each detail stress concentration conditions are evaluated and the effect on fatigue crack growth is estimated. A procedure for calculating the effect of stress concentration for arbitrary detail geometry is established. The revised approach to fatigue life prediction yields cycle lives which are in reasonalbe agreement with the experimental test results. Stress range gradient is found to have less than 2 percent effect on fatigue life estimates for groove-welded details. For fillet-welded details the effect is even less noticeable. As in the case of straight girders, principal stress can usually be disregarded and life estimates based on nominal normal bending plus warping stress. (FHWA)

  • Corporate Authors:

    Lehigh University

    Fritz Engineering Laboratory
    Bethlehem, PA  United States  18015

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Zettlemoyer, N
    • Fisher, J W
    • Daniels, J H
  • Publication Date: 1980-4

Media Info

  • Pagination: 91 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00315050
  • Record Type: Publication
  • Report/Paper Numbers: FHWA-RD-79-132 Intrm Rpt., FCP 35F2-052
  • Contract Numbers: DOT-FH-11-8198
  • Files: TRIS, USDOT
  • Created Date: Aug 5 1980 12:00AM