The Timber Truss Bridge Strategy

Background

Transport for NSW manages the remaining timber truss road bridges in NSW, as well as those on non-operational, former rail lines throughout the regional rail network. ​

Over time, many timber truss bridges have been replaced by more modern designs to meet increasing road network demands. However, the remaining bridges have significant heritage value, both individually and as a historical collection. They are nationally unique in their technological development and serve as a tangible record of NSW's non-Aboriginal settlement history.​

In 1999, the then Roads and Traffic Authority commissioned an overview of the 82 remaining timber truss road bridges. The resulting report identified the bridges with the highest heritage significance, which were subsequently added to the NSW State Heritage Register. 

Retaining these heritage-listed bridges presented challenges, particularly as some struggled to meet modern operational demands from heavy freight traffic. However, for select bridges like Dunmore, Morpeth, and Junction Bridge near Tumut, necessary repairs and capacity upgrades were undertaken. These efforts revitalised the bridges, allowing them to continue serving while fostering renewed appreciation for their beauty and intricacy.

Need for a strategy

Recognising the need to balance heritage conservation and safe operation, we introduced The Timber Truss Bridge Conservation Strategy (the Strategy) in 2010. We identified 26 out of the 48 existing timber truss bridges for retention and conservation due to their heritage significance and importance to the state. The selected bridges represent the variety of former bridge types, spanning different ages, sizes and configurations. Additionally, they were located on roads forecast not to have a freight demand beyond the capacity of the bridges.​

In 2011, with the support of the Heritage Council of NSW, Transport consulted with the NSW community and stakeholders. The feedback led to amendments to the Strategy which was subsequently endorsed by the Heritage Council in 2012. The revisions are detailed in the Timber Truss Bridge Conservation Strategy – Submissions Report and revised conservation Strategy - August 2012. 

The endorsement of the Strategy provided improved certainty for the Heritage Council about our commitment to their conservation, and also directed our bridge maintenance program how to best spend limited resources. The Strategy was considered a landmark in progressive heritage conservation approaches at the time.

Review of the strategy

About six years after the launch of the Strategy, new insights into structural truss types and strengthening methods which conserve heritage values while providing adequate capacity to keep bridges operational prompted the need for updates. A revised Strategy was subsequently developed. Out of the 26 bridges selected for preservation under the 2012 Timber Truss Bridges Conservation Strategy, seven could not be modified to meet community and network needs while preserving heritage value and were thus removed from the list. To balance them, eight other bridges were reassessed and were suitable for preservation, bringing the updated total number to 27 bridges to be retained.​

This included some bridges that had been owned by local government which had previously not been included in the first strategy, but as it had become clear that their survival was uncertain due to limited funding, including them in the Strategy went some way to ensuring the survival of several better examples.

Where we are today

The Heritage Council endorsed the revised list of bridges designated for preservation under the Strategy in June 2019. This list safeguards a representative sample of 27 timber truss bridges across the operational road network. By including them in regular maintenance schedules and ensuring consistent management, we aim to protect their significant heritage values. ​

We’re currently in the process of planning a similar approach for developing a conservation strategy for the timber truss bridges on railways.

These are the 27 road bridges to be retained under the Strategy: