Frequently asked questions

Frequently asked questions

Timber Truss Road Bridges Strategy

  • Of the 407 built between about 1860 and 1936, 63 remain. 48 are managed by the RMS, with the remaining 15 bridges managed by local councils.
  • No. The RMS Timber Truss Bridge Strategy does not specify how local councils should manage their bridges.
  • The RMS has developed this strategy as a submission to the NSW Heritage Council. The strategy has been discussed with the Heritage Office of the Department of Planning and heritage groups represented on the RTA Heritage Committee.
    The Heritage Council has subsequently sought comment from the National Trust of Australia, Australia ICOMOS, Engineers Australia, the History Council of NSW, Royal Australian Historical Society and former (RMS) Chief Bridge engineers.
  • Not all timber truss bridges can be maintained into the future due to the increasing demands for heavier vehicles and the subsequent long term maintenance issues.
    Issues include bridges with poor load carrying capacity, narrow bridge width, poor access for large vehicles, potential exposure to structural damage and frequent and very expensive ongoing maintenance needs.
  • The RMS and heritage experts considered both operational and heritage criteria to identify which timber truss bridges provided the fewest operational constraints to heavy vehicles and which bridges have the highest level of heritage significance.
  • RMS is awaiting the outcome of this strategy. Any delisting has to be approved by the NSW Heritage Council.
    Further, site specific planning processes then take place. Each bridge replacement requires a review of environmental factors to be completed before final approval is provided.
    Only then can we proceed to replace and demolish a bridge.
  • The order of bridges to be replaced will be determined by the condition of the bridge and the road operation requirements.
    This order will be finalised by the RMS, if approval of the strategy is provided by the Heritage Council.
  • The retention of bridges outside normal use has operational and financial implications. These will need to be considered on a case by case basis.
    The RMS will consider requests and suggestions by the community. However, as the RMS would no longer need the truss bridge, it would look to transfer management to another body to take responsibility for its ongoing conservation.
  • 1. Respond to this strategy with your preferred action.
    2. Examine the proposals published by the Heritage Council for delisting and keep involved.
    3. Examine and be consulted on the RTA final proposals for your bridge of interest.
  • A bridge carrying only pedestrians or bicycles still requires maintenance. Although it will no longer have the wear and tear of vehicle use, timber still deteriorates over time.
    The bridge will require the same level of maintenance, including closing it to dismantle and replace truss components. As discussed above the RMS would look to transfer conversion of the timber truss bridge to another body.
  • Over the past decade the RTA has worked closely with the NSW Heritage Council to develop a number of ways to strengthen these timber truss bridges. While timber remains the primary bridge material, steel and concrete components can be incorporated into the design so that the timber truss bridge can carry loads of up to 42.5 tonnes - without affecting the appearance of the bridge.
    Loads above 42.5 tonnes require visible strengthening or the extensive replacement of timber components with other material. These both compromise the heritage values of the bridge and are not acceptable.
  • It is technically feasible to relocate intact trusses to use as a crossing elsewhere. However as the timbers are already deteriorating, it is likely that they would need to be replaced.
    Reusing the spans as footbridges has proved more successful than leaving them as sculptural items in parks, as their utility would appear to raise their status in the eyes of the community.
    Instead of the timber trusses, other bridge elements such as metal lift spans may prove to be more readily relocatable, robust and interpretable in new surroundings.
  • The RMS will archive/record all of those bridges prior to their closure. It will work with the Heritage Council and local communities to make information about the bridges available, their history and significance.
  • It is estimated to cost $480 million (2011 dollars) over the next 15 years to replace the 23 bridges and to upgrade or retain the 25 bridges.
  • There are many timber bridges on local roads managed by Councils. These are not timber truss bridges but timber beam bridges. Councils maintain these timber bridges.
  • The comment period runs for 6 weeks from 18 July to 26 August 2011.
  • Will the RMS really listen to the community’s comments or has it already made up its mind? Yes we will listen, The RMS has worked with the NSW Heritage Council and the independent members of the Heritage Committee for a considerable period to develop the Timber Truss Bridge Strategy. This group is also interested in community ideas, issues, concerns. This current consultation asks anyone in the community to identify what other issues should be considered by the RMS and the Heritage Council in making a final decision.
    To meet the requirements of the Heritage Act the RMS’s public consultation will be followed by a separate Heritage Council notification process for adding or removing individual bridges from the State Heritage Register.
  • At the end of the submission period all comments will be included in a submissions report. This report will be published and be part of the RMS submission to the Heritage Council.
    All questions from the community about the content of the Strategy will be responded to in a timely manner.
    RMS will endeavour to respond to phone and email enquiries within 24 - 48 hours. When enquiring by phone, it is essential to clearly state your name and a return (business hours) phone number.
    Otherwise there may be things raised that require more investigation – this will take time.
  • Email enquiries: timbertruss@rta.nsw.gov.au Community info line: 1800 633 332 Mail address: Timber Truss road bridges Locked Bag 928 North Sydney NSW 2059
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