Optimized Fatigue Analysis of Steel Bridges Using Finite Element Method

Many steel bridges built prior to mid-1980s are affected by distortion induced fatigue cracks, caused by out of plane bending of girder web gaps. Welded connections between longitudinal girders and lateral cross beams or diaphragms are most susceptible to cyclic out-of-plane deformations, resulting in significant second order fatigue stresses. Existing design procedures do not provide recommendations on how to directly estimate the magnitude of these stresses. Research using finite element modeling along with experimental field monitoring was conducted at the University of Minnesota Twin Cities to develop formulas to estimate web gap stresses. This paper presents an efficient correlation-based approach to determining the magnitude of the distortion induced fatigue stresses with limited fatigue analysis of few connections, while accounting for all bridge geometric characteristics. Linear regression analysis was used to establish statistically based relationships between web gap distortions and fatigue stress ranges. This approach was successfully implemented in the IH-345 viaduct rehabilitation project in Dallas, Texas, and resulted in significant saving in computational time without sacrificing the level of accuracy in fatigue stress calculations.


  • English

Media Info

  • Media Type: Web
  • Pagination: pp 12-23
  • Monograph Title: Structures Congress 2018: Bridges, Transportation Structures, and Nonbuilding Structures

Subject/Index Terms

Filing Info

  • Accession Number: 01873208
  • Record Type: Publication
  • ISBN: 9780784481332
  • Files: TRIS, ASCE
  • Created Date: Feb 15 2023 5:15PM