Load rating of timber bridges in Western Australia

Main Roads Western Australia (MRWA) inspects, load rates, and maintains (repairs, upgrades or replaces) all bridges for which it is responsible. In addition, MRWA also inspects, load rates and gives advice for other road bridges throughout the State as part of the statutory responsibility given under the Road Traffic Act 1974 to load post all bridges on public roads and through a long standing arrangement with Local Government Authorities. Many timber bridges were built in the past owing to the easy availability of hardwood trees. Although no new timber bridges have been built in the State by MRWA for the last 30 years the majority of Western Australia's road bridges are still timber. The condition assessment and maintenance of existing timber bridges will continue until their eventual replacement with non-timber bridges. The present MRWA policy is to inspect these bridges in detail once every five years. Last year approximately 300 timber bridges were inspected and 140 load rated. The load rating of this many bridges is a considerable task and has been greatly facilitated by use of a suite of in-house developed programs. This paper describes the suite of programs and their roles in strength assessment and load rating of key components of existing timber bridges. (a) For the covering entry of this conference, please see IRRD abstract no. E218160.


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  • Accession Number: 01144015
  • Record Type: Publication
  • Source Agency: TRL
  • Files: ITRD, ATRI
  • Created Date: Nov 16 2009 12:20PM