Development of new fatigue design equations for railway bridges in New Zealand

ONTRACK (New Zealand Railway Corporation) has recently reviewed and updated its fatigue management process for steel bridges to enable improved risk management and predictive forecasting. The procedure for fatigue design of steel railway bridges has been updated to account for the increase in cumulative traffic tonnage over the last decades and the introduction of new rolling stock in the near future with potentially heavier axles. The methodology used to develop the fatigue design procedure is described. It involves the determination of variable amplitude stress cycles due to actual trains, the conversion of these cycles into an equivalent number of constant amplitude cycles and the determination of equations giving the number of equivalent constant amplitude stress cycles as a function of span length. Recently obtained data, describing current traffic on New Zealand railway lines in terms of tonnage and train profiles, was used to derive new equations for the fatigue design of steel bridges. Finally, the management of existing steel railway bridges is also described, as the same principles are used for deriving the safe fatigue life (SFL) of existing steel bridges. Revised equations are being developed on a regular basis to reflect the changes in traffic over the recent years. The provision and improved understanding of fatigue modelling in the design of steel bridges is a key tool for ONTRACK structures asset management processes. (a) For the covering entry of this conference, please see ITRD abstract no. E218118.


  • English

Media Info

  • Pagination: 12p
  • Monograph Title: Rail: the core of integrated transport: CORE 2008: conference on railway engineering, 7-10 September 2008, Perth, Western Australia

Subject/Index Terms

Filing Info

  • Accession Number: 01143932
  • Record Type: Publication
  • Source Agency: ARRB
  • Files: ITRD, ATRI
  • Created Date: Nov 16 2009 12:14PM