Bridge Fatigue Evaluation per AASHTO Specifications

Provisions for bridge fatigue design and/or evaluation are currently available in four different AASHTO specification documents: (1) Standard Specifications for Highway Bridges; (2) Guide Specifications for Fatigue Evaluation of Existing Steel Bridges; (3) LRFD Bridge Design Specifications; and (4) Guide Manual for Condition Evaluation and Load Resistance Factor Rating (LRFR) of Highway Bridges. Although all these specifications are based on the same fatigue resistance S-N curves, analysis procedures and reliability factors vary thus different fatigue lives can be predicted as a result. Confusion exists among bridge engineers on which specification, or procedure, being most suitable for their applications. This paper reviews the background and compares the procedures of all available AASHTO specifications and methods for bridge fatigue design and evaluation. The total safety margin over the statistical S-N curves is characterized for each of the specifications. For fatigue life evaluation of existing steel bridges, a generalized procedure per AASHTO specifications is recommended that begins with the simplified approach using the specification load distribution factor and then determines the need for refined analysis and/or field strain measurement.


  • English

Media Info

  • Media Type: CD-ROM
  • Features: Figures; References; Tables;
  • Pagination: 36p
  • Monograph Title: First International Conference on Fatigue and Fracture in the Infrastructure: Bridges and Structures of the 21st Century

Subject/Index Terms

Filing Info

  • Accession Number: 01091730
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Apr 14 2008 1:56PM