Assessment methods for historic steel truss bridges

New Zealand has many historic and significant steel truss road and rail bridges, with the majority of these constructed between early 1900s to mid-1960s. Steel truss bridges are able to span long distances, and bridge members commonly include rivetted sections built up from plate, angles and channels, with lacing or battening between components. Currently, New Zealand design standards do not adequately cover the assessment of built-up steel members for truss bridges for a number of member types. Particular to built-up steel members, assessment outcomes are impacted by assumptions in member restraint, effective lengths, condition factors and strength reduction factors which are covered differently in design and assessment standards. Local refinements in modelling of members with realistic boundary conditions and nonlinear analysis can be applied to reduce conservatism in initial assessments for three significant bridges: Victoria Bridge in Cambridge, a grade 1 listed trussed arch bridge constructed in 1907; the Waikato River Bridge in Ngaruawahia, a steel truss bridge constructed in 1953; and the Auckland Harbour Bridge steel truss structures, the longest clear span bridge in New Zealand completed in 1959. The assessment of historic steel truss bridges is complex and a staged assessment approach is proposed, with level of assessment complexity increasing when required to optimise the load capacity of structure and provide the most value to asset owners.

Media Info

  • Pagination: 12p
  • Monograph Title: 11th Austroads Bridge Conference, Adelaide, 15th-18th November 2022

Subject/Index Terms

Filing Info

  • Accession Number: 01901634
  • Record Type: Publication
  • Source Agency: ARRB Group Limited
  • Files: ITRD, ATRI
  • Created Date: Dec 7 2023 2:53PM