Things We Want To Keep

Until the 1970s, the focus of heritage preservation was mostly on elite places, grand buildings, and public and private landscapes that told a story of uncontested occupation of the land. Responsibility for heritage places was largely borne by the National Trust of Australia, a non-government organisation, based on the British body. Founded in New South Wales (NSW) in 1945, by 1976 the National Trust had chapters in each state and Territory, linked by a federal council. From the first, the Trust’s mission was to lobby for heritage protection, then almost impossible to achieve under state legislation. Its successes included protection of the suite of early colonial buildings on Sydney’s Macquarie Street and work on St Marys and St Andrews Cathedrals in the city. Between 1957 and 1967 the Trust managed to acquire historic buildings including the Tenterfield School of Arts and in Sydney, Old Government House in Parramatta, and Lindesay at Darling Point. Also notable was the Trust’s role in the introduction of the first NSW heritage legislation, the Heritage Act 1977 (NSW) (the Heritage Act).

Heritage conservation in NSW first made headlines with Sydney’s 1970s Green Bans, triggered by a coalition of union and resident action opposing redevelopment of the harbourside Kelly’s Bush and the city’s historic Rocks area. The Green Bans broadened recognition of what was worthy of preservation as heritage, introducing the novel idea that the community, through state-based legislation, had a collective stewardship for future generations.

This awareness was boosted by the reform agenda of the federal Labor government led by Gough Whitlam in 1972-1975, ensuring urban planning, community values and environmentalism entered state and local government agendas.

The government’s Inquiry into the National Estate, chaired by Justice RM Hope, built on this expanding awareness of heritage as the responsibility of government and established the Australian Heritage Commission and a Register of the National Estate, as well as comparable state and Territory cultural and natural heritage legislation throughout Australia.1 The Inquiry’s wide-ranging examination asked how environmental heritage – natural, Indigenous and settler – contributed to Australia’s national identity. This was likely to get interesting answers. Although Australia was already a largely urban, multicultural and globalised nation, its self-image resonated to stereotypes developed in the 19th century, captured for instance in Henry Lawson’s poems, stories and cartoons in The Bulletin. The imagined typical Australians had their heart, if not their home, in the bush, they were resourceful, and made do with materials at hand to build practical, no nonsense structures. Common man’s common sense won over the expert and the egghead every time.

Figure 8.1

Figure 8.1: Thirteen people, including three children and a baby, are posed for this photograph of the new bridge over Jugiong Creek, on the main southern road between Yass and Gundagai, in 1872. One of an estimated 150 Bennett Truss bridges built in 1858-86, the bridge was replaced in 1901. Source: WC Bennett Album

Among the many rural structures considered expressive of this desired identity were the timber truss bridges vital to the colonial road networks of NSW. Framing their meaning in terms of this assumed Australian identity introduced these workaday structures to a new generation. Just as the identity was misleading though, so were the qualifications of these bridges. Although built of locally sourced timber, these bridges were no more ad hoc, rustic and vernacular than the Sydney Opera House. Their complexity as engineering structures, fine-tuned through experience and increasingly through material science, was overlooked while fading paintwork, rusting lift-spans and rattling decks were hailed as hallmarks of age and authenticity. To the engineer these same marks of decay read as neglect, to be tolerated only if a replacement bridge was on the drawing board.

The incompatibility of these views shaped the story of timber truss bridges over the last half-century. To the engineers these were entirely purposeful structures and every stick of timber either had some function to perform, or it was eliminated from the design. As road freight demands increased, the bridges’ suitability declined, with the costs of frequent repairs beginning to outweigh the benefits of these bridges for freight purposes. Their replacement with more durable materials – concrete and steel – accelerated, with the western slopes and plains losing the most timber truss bridges as increasingly heavier trucks took to those roads. As earlier chapters show, once freight rail lines began to close, there was even greater pressure on the remaining road bridges, which now had to handle freight going cross-country to the nearest operating railhead.2

Figure 8.2

Figure 8. 2: The 1893 Crankies Plains Bridge over the Coolumbooka River near Bombala in 2013, one of the last of about 90 McDonald Truss bridges built between 1886 and 1893. Source: Amie Nicholas

This engineering and economic rationality was on a collision course with increasing understanding of environmental heritage values and the significance of history to us all. When constant change stopped meaning progress, the timber bridges began to signify not ‘battler’ localities – economically marginal, sparsely settled or remote places that didn’t rate a new steel or concrete bridge – but precious places protected from progress. The success of the Green Bans and developing environmental laws empowered people to challenge the inevitability of a progress that was feared both for what it brought and what could be lost. In this view, a new concrete bridge meant not better road access for a struggling country town, but the intrusion of an unwanted modernity and complexity into rural life. An ideological clash between urban perspectives and the realities of rural life began to be played out in the environmental assessments produced for new developments under the Environmental Planning and Assessment Act 1979 (NSW) (EP&A Act).

The State’s Heritage Act and the EP&A Act gave comprehensive protection to the non-Aboriginal heritage of NSW, with even larger government agencies like the Department of Main Roads (DMR) subject to its provisions. But the battle to make planning legislation effective even for the most powerful construction agencies in NSW took another two decades.3 Without an effective mechanism for identifying places of heritage significance before the threat of development forced a potential protective order, the laws had limited effect. Evidence of the specific needs and benefits of replacement bridges still outweighed unspecified heritage benefits. Within the DMR, environmental compliance was gradual as entrenched attitudes took many years to dispel, just as in the wider society. There were exceptions of course and though the DMR had resisted the arrival and reality of environmental legislation, some of its projects were exemplars in this new field. The DMR produced its first comprehensive environmental assessments from the late 1970s.

Before the 1980s, a local Council or DMR engineer sentenced individual bridges to life or death. Since then, communities have become advocates for ‘the things we want to keep’. This motto of the new environmental heritage movement exemplified in the Hope report suggests the dramatically widened definition of heritage. It took longer for a popular vocabulary of heritage values to develop.

The 1931 Athens Charter for the restoration of historic monuments and its successor, the 1964 Venice Charter for the conservation and restoration of monuments and sites reflected the European focus on grand architecture and institutional buildings. But from the 1960s trends highlighted social history, an architecture that included vernacular building and working class environments, and engineering history, as all essential to an understanding of everyday life. From 1979 the Burra Charter drafted by Australia ICOMOS (the Australian chapter of the International Council on Monuments and Sites, representing professional heritage practitioners across all disciplines) provided a conservation charter specific to Australian conditions.

The Burra Charter initiated a consistent conservation language and methods to identify heritage items, assess their significance, and recommend the most appropriate methods for their conservation. It enabled recognition of what was distinctive in Australia, with comparatively recent colonisation of an ancient culture and land. The spectrum of Australian difference proved complex, from the often contrasting perspectives of Indigenous and other Australians, to the necessity-driven use of less durable materials in surviving colonial artefacts.

The Burra Charter approach determines cultural significance through rigorous cross-disciplinary research for identification, assessment, and conservation methods. For historic bridges, this extended the scope of potential value beyond technological evolution and changing engineering practice. A bridge could be important because it had founded a town, or shaped the aesthetics of a landscape, or told a story of tragedy or triumph. Future works thus had to acknowledge these deeper values embodied in the bridge’s fabric, setting and the way it memorialised historic events.

In October 1980 the NSW National Trust hosted Bridging the Past, an exhibition at its SH Ervin Gallery at Observatory Hill in Sydney. Jointly curated with the DMR, this innovative exhibition offered ‘an opportunity to view NSW bridges that have long disappeared in its display of original drawings and specifications, old photographs, paintings and watercolours’.4 Among the displays were scale models of the 1902 Pyrmont Bridge and the still innovative 1964 Gladesville Bridge, a focus perhaps influenced by the UK bicentenary celebration of the 1779 Coalbrookdale Iron Bridge, an icon of the Industrial Revolution. Bridging the Past did not feature the NSW timber truss bridges, despite the ongoing disappearance of hundreds, and the vulnerable status of the survivors.

In 1980 NSW still retained a large number of these bridges, though other states were replacing them as quickly as possible. Their outstanding engineering meant they remained serviceable and were maintained by specialist timber bridge crews. Even so, as they reached the time for major refurbishment, the relative costs of a new concrete beam bridge were less than re-building a timber bridge in both initial and projected maintenance costs measured in decades – or centuries. After the National Association of Australian State Road Authorities (now AustRoads) excluded timber bridges in its Bridge maintenance practice guideline, in 1987 DMR Chief Bridges Engineer Brian Pearson compiled a specialist bridge maintenance handbook for the 97 timber truss bridges then remaining (see Chapter 7 ‘Weighty matters’).5

Figure 8.3

Figure 8.3: The mix of truss lengths supported on stone piers which originally supported Bennett Trusses gives the 1919 bridge over the Abercrombie River at Tuena significance further enhanced by the attractive rural setting. Source: Amie Nicholas’

The impact of Pearson’s Timber Truss Bridge Maintenance Handbook cannot be overstated. It was not only the much-needed maintenance manual, but a very readable introduction to the history of these bridges. Its useful 5-type classification of timber truss bridge design showed how the quest for improved construction and serviceability had shaped the bridges. The historical overview made clear the intimate connection these bridges had with the expansion of occupation in NSW in the 19th and early 20th century. Pearson showed just how significant they were as historical artefacts, and in a series of maps and tables revealed what remained was less than one quarter of over 420 timber truss bridges built in NSW between 1855 and 1936.

An amendment to the Heritage Act in 1998 established a State Heritage Register (SHR) for listing items meeting the Burra Charter’s heritage significance criteria at a state level. Initially this was a list of items previously protected by permanent conservation orders, or those flagged in systematic studies as significant examples. The SHR established a two-tier heritage management system to be implemented by the State. Top tier items had to meet at least one of the five statutory criteria and one of the two other criteria. Any impact on these items was regulated by the Heritage Council of NSW, an independent advisory body supported and serviced by heritage specialists from a range of disciplines in the Heritage and Conservation Branch of the NSW Department of Planning. The SHR’s second tier protected items of local heritage significance, within the development approval roles of local government and different state agencies. This arrangement has held up well, despite many subsequent changes to both planning and heritage legislation and the responsible agencies.

Figure 8.4

Figure 8.4: The 1902 Tabulam Bridge over the Clarence River, the longest of the estimated 20 de Burgh Truss bridges built in 1900-05, was being replaced in 2018. Source: Amie Nicholas

Figure 8.5

Figure 8.5: An example of the longest spans among some 40 Dare Truss bridges built in 1905-36, the 1912 Bulga Bridge over Wollombi Brook has served for over a century. Source: Amie Nicholas

This amendment also added section 170 to the Act, requiring all state agencies to compile a heritage and conservation register of the assets they owned or managed which were of at least local heritage significance. This was intended to clarify the protection of heritage items owned by the state, as the focus of environmental and planning legislation was through local council approval processes. These ‘Section 170’ registers changed the way heritage was managed in NSW, ensuring agencies had better understanding of heritage values of assets and requiring annual condition reports.

Common Ground

Even after the Heritage Act was introduced, the National Trust had to lobby hard for heritage. Like many other state government agencies, the DMR did not consider itself bound by the National Trust’s advice and there were few opportunities for effective communication. Relations developed between 1969, when the DMR’s recognition of the Trust was as a recipient of vintage building materials from houses demolished for new roads, to 1975 when the DMR took considerable care in its planning to bypass the historic town of Carcoar in central western NSW.6

Among the Trust’s strategies for more effective liaison was establishing expert panels to guide assessment of heritage places for inclusion on its own register. Amongst the most active of these was its Industrial Archaeology Committee, chaired by the University of Sydney’s Judy Birmingham, one of the authors of the Burra Charter and a member of one of the specialist panels for the Hope Inquiry, along with Ian Jack, initiator of the University of Sydney’s first course in historical archaeology in 1974. During the 1970s this Committee regularly raised the issue of the significance of the timber truss bridges with the DMR’s Chief Bridge Engineer, Brian Pearson, concerns echoed by local communities who saw their bridges under active threat. As an archaeologist, Judy Birmingham recognised the engineering attributes of the bridges, but was especially interested in them in documenting the development of colonial industrial design, technological and craft skill transfer, adaptation of local materials and their place in a landscape of colonial and imperial occupation and exploitation.7 As Brian Pearson tells it in Chapter 7 ‘Weighty issues’, Judy Birmingham suggested he present the DMR’s plans to the Industrial Archaeology Committee, prompting a return invitation for the National Trust to meet Pearson at DMR headquarters to discuss their concerns more generally.8

An early result of this mutual interest and respect, and the expertise of the National Trust’s Industrial Archaeology Committee, was the jointly curated Bridging the Past exhibition at National Trust headquarters in 1980. The recognition of common ground was also the genesis of the DMR’s Historic Bridges Committee, now the Roads and Maritime Services Heritage Committee, in operation for more than 30 years, with current quarterly meetings. As they discuss in the previous Chapter, Brian Pearson remained a member of the joint committee until 2013. His successor as Chief Engineer, Ray Wedgwood, also succeeded to the Heritage Committee and both he and the present Principal Bridge Engineer, Wije Ariyaratne, are current members. Other original DMR members were Vince O’Grady, Peter Wolfe and Maree Humphrey, with National Trust members Judy Birmingham, Tony Brassil, Colin Crisp, Sue Clarke and Wal Whittaker. This co-operative committee was a first for the National Trust and for the DMR, its success prompting a Heritage Council recommendation that all government agencies follow the model.

The Historic Bridges Committee enabled the DMR, and then the Roads and Traffic Authority (RTA), to develop its internal management of heritage issues under the new era of environmental and heritage legislation. The benefit to public administration is evident in the successful amendment of procedures, and recognition that environmental protocols produced collateral benefits for the organisation, as well as minimising risk to operations, reputations, and governments.

Much of its routine business still focuses on the management of historic bridges, but the challenges are different. There is less debate about whether specific bridges should be replaced or not, and more about what factors best influence long-term decisionmaking about bridges. Attention is as likely to be on categories of bridges and how to ensure that the best conservation candidates within a group can be kept, as about the fate of individual bridges. The Heritage Committee became a close partner in the evolution of the current Timber Truss Bridge Conservation Strategy. Some of the key landmarks in this process were the preparation of thematic studies to assess different types of heritage assets, and using these to populate their Section 170 registers. The seven population studies of heritage bridges produced between 1998 and 2015 covered timber truss bridges (1998); timber beam bridges (2000); pre-1930 metal bridges (2001); masonry bridges (2005); pre-1948 concrete beam bridges (2005); pre-1948 concrete slab and arch bridges (2005); and moveable lift span bridges (2015).

Despite these achievements, an undeniable reality remained – timber truss bridges in particular were being demolished and modern replacements installed at a high rate, and the process appeared unstoppable. The RTA could marshal arguments to justify replacing individual bridges, and it knew there was no way of stopping it.

Surveying The State

Things began to change in 1998, when a technical study first mapped the significance of the resource and the pattern of attrition. That year, the RTA commissioned engineering firm McMillan Britten and Kell Pty Ltd (MBK) to prepare a study of the state’s surviving timber truss bridges.9 A key aim was to examine their heritage values and rank them from most to least significant, an unusual objective in heritage studies which normally identify items meeting the specific criteria for ranking as of national, state, or local significance. The purpose was to determine which bridges merited retention. As the authors noted ‘Increasingly, all bridges will approach the end of their service lives, and decisions about how to approach heritage management for the bridges will be required’.10 This was a debate that needed to take place within the RTA, with heritage authorities, and with local communities. Although the specific purpose was to acquire sentencing data, the importance of the study was much wider. Like Pearson’s Timber Truss Maintenance Handbook, which included a large number of bridges demolished in the interim, the 1998 MBK report was a landmark in valuing the state’s then surviving stock of 82 timber truss bridges, 58 of them the responsibility of the RTA and 24 managed by local government.

The MBK report identified sixteen timber truss bridges of national significance, rating them in order of importance:

Dunmore (see Figures 6.5, 7.12, 7.13, & 8.28)
Morpeth (see Figures 7.10 & 7.11)
Monkerai (see Figures 2.18, 2.19, 2.22, & 8.7)
Hampden (see Figures 6.6, 6.18 & 8.27)
Clarence Town (see Figures 6.19, 6.22, 7.6 & 8.6)
Tabulam (see Figure 8.4)
St Albans (see Figures 8.8 & 8.9)
Swan Hill (see Figures 5.1 & 8.12)
Bulga (see Figure 8.5)
Galston (see Figures 2.25 & 5.13)
Hinton (see Figures 5.3, 5.7 & 8.13)
Tooleybuc (see Figures 5.8, 5.9 & 8.15)
Rossi (see Figure 8.17)
Inverell (see Figure 2.39)
Junction (see Figure 8.10)
Colemans (see Figures 1.16 & 8.22).


At least two of each of the five truss types were included, generally the best preserved examples of the type. There was also a reasonable spread across the state, and the list includes long and short bridges, some in the middle of nowhere and others right next to a town. If anything, there is a higher number of bridges with lift spans, but no one could deny just how spectacular these could look with a fresh coat of paint.

Figure 8.6

Figure 8.6: The 1880 Bennett Truss Clarence Town Bridge over the Williams River, Australia’s oldest surviving timber truss bridge, in 2005. Source: Roads and Maritime

Figure 8.7

Figure 8.7: The 1882 Bennett Truss Monkerai Bridge over the Karuah River in 2005. Source: Roads and Maritime

Figure 8.8

Figure 8.8: The 1884 Bennett Truss St Albans bridge, before it was damaged by heavy flooding of the Macdonald River in 1889. Source: ML, SLNSW

Figure 8.9

Figure 8.9: The present St Albans Bridge in 2017, a de Burgh Truss completed in 1902 downstream of the 1884 bridge. Source: Houman Hatamian

Figure 8.10

Figure 8.10: The 1893 Junction Bridge over the Tumut River stands as an excellent example of a multi-span McDonald Truss bridge. Source: Roads and Maritime

Figure 8.11

Figure 8.11: The longest (90’) McDonald Truss spans are displayed in the 1893 McKanes Bridge over Cox’s River. Source: Roads and Maritime

Figure 8.12

Figure 8.12: The 1896 Allan Truss Swan Hill Bridge over the Murray River, seen here in 2001, is the oldest remaining timber truss lift bridge. Source: Roads and Maritime

Figure 8.13

Figure 8.13: A picturesque view in 2005 of Hinton Bridge over the Paterson River, an Allan Truss bridge completed in 1901. Source: Roads and Maritime

Figure 8.14

Figure 8.14: The timber Allan Truss approach and the bascule lift span of the Carrathool Bridge built over the Murrumbidgee River in 1922, a unique combination seen here in 2017. Source: Amie Nicholas

Figure 8.15

Figure 8.15: The 1925 Allan Truss Tooleybuc Bridge, with its lift span in action in 2017. Source: Roads and Maritime

Figure 8.16

Figure 8.16: The 1896 bridge over the Goodradigbeee River at Wee Jasper, one of the oldest Allan Truss bridges, in 2012. Source: Amie Nicholas

Figure 8.17

Figure 8.17: The 1898 Allan Truss Rossi Bridge over the Wollondilly River near Goulburn, remains a prime example of a 3-span Allan Truss bridge, 2013. Source: Amie Nicholas

Figure 8.18

Figure 8.18: The 1826 Allan Truss Paytens Bridge, named after a local soldier-settler who campaigned for the Lachlan River crossing on the Eugowra-Goologong-Grenfell road, still the district’s main transport route. Source: Amie Nicholas

Figure 8.19

Figure 8.19: Gulgong’s 1927 Beryl Bridge over Wyaldra Creek, like Paytens Bridge among the last Allan Truss bridges built, seen here in 2013. Source: Amie Nicholas

Figure 8.2

Figure 8.20: The 1902 de Burgh Truss lift bridge across the Murray River, now a relic with the new concrete bridge (behind) linking the border towns of Barooga in NSW and Cobram in Victoria. Source: Amie Nicholas

Figure 8.21

Figure 8.21: The 1904 Glennies Creek Bridge at Middle Falbrook, the only remaining de Burgh Truss bridge with the distinctive piers of Monier concrete pipe, seen here in 2005. Source: Roads and Maritime

Figure 8.22

Figure 8.22: Distinctive for its footway on each side, iron cylinder pier and long Dare Truss spans, and for surviving over a century of floods, the 1908 Colemans Bridge over Leycester Creek is seen here in 2003. Source: Amie Nicholas

Figure 8.23

Figure 8.23: The Dare Truss Briner Bridge over the Upper Coldstream River, seen here in 2013, has linked the Tucabia district with Ulmarra on the Clarence River since 1908, seen here in 2013. Source: Amie Nicholas

Figure 8.24

Figure 8.24: The 1909 Warroo Bridge over the Lachlan River between Forbes and Condobolin has the shortest of the standard Dare Truss spans, 2013. Source: Amie Nicholas

Figure 8.25

Figure 8.25: The Dare Truss Scabbing Flat Bridge built over the Macquarie River in 1911, linking the region southeast of Dubbo to the Mitchell Highway at Geurie, in 2013. Source: Amie Nicholas

Figure 8.26

Figure 8.26: West of Dubbo, this Dare Truss bridge over the Macquarie River, seen here in 2013, has linked the Rawsonville region to the Mitchell Highway and the Minore road since 1916. Source: Amie Nicholas

The Heritage Amendment Act 1998 (NSW) became law while the study was underway, introducing the State Heritage Register (SHR) and seven threshold significance criteria. These were different enough to the Burra Charter criteria that they were not directly comparable. To populate the SHR, 29 of the top ranked bridges in RTA ownership were added as a group without further individual assessment under the saving and transitional provisions of the Act.

These 29 bridges were about a third of the total number of timber truss bridges surviving at the time. Another 21 bridges were identified as being regionally significant, a classification that has no statutory weight, and the remaining 24 were of local significance. None failed to reach this threshold.

Once a bridge is added to the SHR any modification, apart from minor maintenance and repairs, requires the approval of the (NSW) Heritage Council. Demolition of a listed item is difficult; it cannot be approved by the Heritage Council, but requires approval by the Minister. For the RTA, which had previously operated on the basis that the economic benefits of new bridges outweighed any counterargument, this was an extremely discomfiting position.

When the RTA began to approach the issue of replacing SHR-listed bridges, there was often an expectation that this did not necessarily mean removal of the old structure. Why couldn’t the older bridge simply be allowed to serve as a local traffic bypass, footway or fishing platform? Reality was a lot more complex. As its legislation made the RTA responsible for the bridge carrying the main road, maintenance of a retained timber truss bridge reverted to the local Council. Keeping an old bridge was not cheap, particularly timber truss bridges, as the timber continues to deteriorate with or without traffic. Even restricting the bridge to pedestrians means maintaining it, and that can require the capacity for service vehicles to cross it for inspection and to carry out repairs.

As well, a replacement bridge will not necessarily be located in the same position or on the original alignment, as the road geometry needed for modern motor vehicles is very different than for vehicles moving at lower speeds, or pulled by draught animals. Even so, RTA practice was to demolish replaced bridges. Where the old bridge was upstream it was considered a flood risk; if washed away it could jam against the new bridge and lateral flood pressure would then wash that away too. Even those downstream were replaced because they would, if not maintained, eventually collapse into the river and become a hazard to both navigation and river stability.

Figure 8.27

Figure 8.27: The former Allan Truss Hampden Bridge over the Murrumbidgee River at Wagga Wagga, in 2005. Source: Roads and Maritime

The RTA had divested itself of one significant bridge, the spectacular 1895 triple Allan Truss Hampden Bridge (see Figures 6.6 & 8.27), one of the main approaches to Wagga Wagga until a bypass bridge was opened in 1995. In agreement with the local Council, rather than demolishing it, RTA allocated funding so that Council could preserve it. Unfortunately the funds were inadequate and misdirected, and the Bridge deteriorated faster than many thought likely.

Eventually it was closed to pedestrians, and after further decay was demolished with explosives in August 2014.

The increase in the size of vehicles and quantum of road freight were other challenges to long established practice, developed since the postwar era when surplus haulage vehicles became available and escalated in the 1980s. Changes in farm technology and economy had meant the collection of larger crop loads with road transport from farm to railhead, so the closure of rural freight lines in the 1970s and 1980s added considerably to road freight movement. By the 1990s, vehicle weights were exceeding earlier regulated limits, prompting the introduction of higher mass limits across Australia.

The rate of bridge replacement from the mid-1980s to the adoption of the Timber Truss Bridge Strategy in 2012 was slightly more than one per annum.

The loss of each bridge placed more pressure on the RTA to demonstrate its commitment to preserving some of the timber truss bridges. With the establishment of the SHR, it seemed that retaining the 29 SHR listed bridges would allow nonperforming bridges to be replaced. This prospect vanished when it was realised that in many cases, it was the SHR-listed bridges that were under greatest pressure to meet transport and community needs, though they were precisely the ones that the Heritage Council would not allow to be adversely affected.

A meeting of the RTA Heritage Committee in 1997 noted ‘It is not an adequate approach to say there is one other’ in the State to justify the demolition of the bridge under discussion. After this, the RTA began to grapple with these problems differently considering whether these bridges could be strengthened if increased loads were the issue, rather than scheduling their replacement. The challenge was to achieve greatly increased strength and reliability of the timber truss and the bridge structure, which was just strips of timber and metal fixtures, with the least possible intervention. The given was that the truss would continue to be the main structural component of the bridge. Replacing it with a different functional element, even if concealed, would rob the structure of its significance. Changing the arrangement of truss timbers similarly would alter the outline, aesthetics and engineering logic of the truss and compromise its values. Substituting steel beams for timber ones would not necessarily work either. Timber and steel expand and contract at different rates, bolts passing through may not align properly, and bridge maintenance teams might not be able to replace components separately.

Figure 8.28

Figure 8.28: Dunmore Bridge over the Paterson River at work in 2013. Source: Amie Nicholas

Only by trial and error, proposal and counter-proposal could the ‘sweet spot’ be found – where the greatest load-bearing could be achieved without compromising the heritage significance of the truss bridge.

This dialogue took place between the Heritage Branch and the RTA, now Roads and Maritime. As loads increased, the compromise between heritage significance and authenticity became greater. Many bridge engineers, construction project managers and heritage specialists contributed to developing a suite of adaptations and strengthening techniques to resolve the operational problem of timber truss bridges required to take the heavier loads. These left the bridges looking unchanged from even a short distance, although certain close-up views, such as under the deck, betrayed the use of new materials. The changes were accompanied by renewed testing to understand better the capacity and performance of timber trusses, and this in turn provided new insights into the historical records of how and why particular bridges had failed and why the designers and builders had done things the way they had.

Applying these solutions enabled these timber truss bridges to carry 42.5 tonnes, meeting the load bearing component of the T44 General Access Limit standard that applied to all the heavy vehicles legally permitted to travel on NSW roads. It does not fully meet other elements of the standard, such as resistance to lateral flood pressures, so elements of risk remain even with strengthened bridges.

Achieving the goal of strengthening a number of bridges this way allowed the RTA to reconsider its approach to bridge heritage management. Although upgrades were very expensive, typically in the order of $3-5 million per span, they reduced subsequent cyclical maintenance expenditure. Upgrading also meant that the bridges now conformed to the general load limits applying to all NSW roads, other than those used by the heaviest freight vehicles.

Timber Futures

Timber, however well cared for, eventually decays, so building in timber forces long-term thinking, and planning across generations for continued use of infrastructure. Until the 1870s, Britain built naval ships of timber from millions of oaks and other trees planted several centuries before and cultivated for their eventual purpose. A small warship of Nelson’s fleet used about 2,000 mature oak trees in its construction, not to mention the large quantities of other trees supplying special purpose timbers to the shipwright.11 When foresters bent trees to specific shape for a vessel of the future, they knew that their great-grandchildren’s generation would be the ones to fell the forest and harvest the timber. Building in timber requires the maker to think ahead on a timescale few others contemplate.

Few timber structures of any kind survive intact for more than a century, except in unusual conditions, none of which applies to the timber bridges of NSW. A cold climate inhibiting wood-eating micro-organisms helps, as does burial in anaerobic mud. Faith helps too – not the hopefulness of heritage fans, but the sort that builds and fills places of worship and veneration, where the very fabric engenders respect. Most of Europe’s oldest timber buildings are large mediaeval and Reformation churches and cathedrals that retain their original roof and structural timbers. As part of the world’s heritage, these religious and national monuments are protected by intricate fire systems and conserved with constant maintenance and care, sometimes even to the exclusion of the congregation. In contrast, much fewer of the modest timber homes most people occupy survive.

The great Buddhist and Shinto temples of Japan offer an interesting contrast to the European understanding of the significance of original fabric as heritage. Shikinen sengū-sai is the Japanese ceremony of ritualised rebuilding; every twenty years an exact duplicate of many Shinto temples is built next to the existing one. Veneration passes from the old to the new as a mark of this re-birth. Specialist carpenters learn their trade knowing they may only take part two or three times in their lifetime. The 680AD temples at Ise Grand Shrine in Honshu marked their 62nd re-building in 2013, with each re-building the culmination of a decade-long series of preliminary rituals. Each re-building is done on the former sites, using timber from the sacred cypress forest surrounding the Grand Shrine. The shrine, the temple sites and the faith and traditions that underpin them are ancient, but the two temple buildings are never more than twenty years old.

All our old timber truss bridges are also new in that none of the survivors entirely comprises original fabric; just as grandfather’s axe which has had two new heads and six new handles, is still grandfather’s axe. Any bridge refurbishment affirms continuity, that the future will not break with but build on past and present, that change will be manageable. Bridges that are part of our everyday life are taken for granted, until work starts and suddenly all is chaos for a few months while roads are blocked and trucks and equipment take up every spare spot and fill every view. Seeing the bridge being pulled apart emphasises its fragility and suddenly we are wondering how it had lasted so long and carried such loads. Then it is all over, the barriers come down and we are on the bridge again – the same bridge? Sometimes not a single stick of old timber remains, with shiny new wood under the shiny white paint.

The re-opening is rarely celebrated like the opening of the original bridge was – none of the parades, speeches by the mayor or local Member, arches of flowers nor symbolic ceremonial crossings by the town’s youngest and oldest together that Chapter 5 ‘People, places and their bridges’ so entertainingly parades. The bridge is back and life settles down again. Despite the extent of its rebuild, the bridge is treated as if it were just the same, a better same, a sturdy safe crossing made once more without a thought.

To heritage practitioners taught not to give up authentic, original fabric without a fight, the thought of completely renewing or removing an old bridge and rebuilding it meant betraying the fundamentals of their profession. At the very least they must press for some part to be retained. It was as if timber bridge engineers and heritage specialists were conducting a dialogue in different languages.

But the timber conservation dilemma is recognised internationally by ICOMOS, with the fragility and impermanence of timber requiring cyclical replacement of fabric so that the intangible values of the place endure, rather than decay along with the old timber.12

Renewed thinking of the principles of heritage conservation reveal how ideas about material heritage are culturally conditioned and invite constant questioning. In the quarter century since adoption of the first Burra Charter, the emphasis on material authenticity shifted, enabling for instance Indigenous concepts of intangible heritage to be included in the current Charter.13 In turn, this invites us to see how building in timber might be considered more important than the timber; that this highly significant form of traditional craft knowledge and practice is worthy of conservation.

Stewardship of any heritage item gambles on the future and with its strategy for the timber truss bridges of NSW, the Roads and Maritime has sought to guarantee the survival of a rare form. If left to the pressures of increasing road traffic, material deterioration and cost, extinction would be assured, one bridge at a time. The Timber Truss Bridge Strategy works by keeping the bridges operable and fulfilling their designed purpose.

The real achievement will be apparent only to future generations who have the opportunity to use and appreciate a representative set of sustainable and well-managed historic timber truss bridges to tell of a place and of their part in the history of NSW.


  1. Australian Government (1974), Report of the Committee of Inquiry into the National Estate, Canberra, Government Printer
  2. Australia n Government Productivity Commission (1999), Impact of Competition Policy Reforms on Rural and Regional Australia, Report C3-5
  3. B Boer and G Wiffen (2006), Heritage Law in Australia, Melbourne, Oxford University Press
  4. National Trust Magazine, September 1980, pp. 5-6; Main Roads March 1981, pp. 20-21.
  5. Brian Pearson (1987), Timber Truss Bridge Maintenance Handbook; the previous guide for timber truss bridges was Manual No. 6 – Bridge Maintenance- instructions for bridge maintenance foremen, Department of Main Roads 1962
  6. JS Endean (1969),‘Clearing the right of way’ Main Roads, 34, 3, pp.80-83
  7. J Birmingham, RI Jack and DN Jeans (1979), Australian pioneer technology: sites and relics, Melbourne, Heinemann; J Birmingham, RI Jack and DN Jeans (1983) Industrial archaeology in Australia: rural technology , Melbourne, Heinemann
  8. Brian Pearson’s reminiscences at Roads and Maritime Heritage Committee farewell, December 2013; see also Main Roads 47, 4, 1982, p.116
  9. The MBK study team comprised Jim Verco as project director, Richard Hitch as project manager, project engineers Michael Ludvik and Bernard Quinlan, engineer and bridge historian Dr Don Fraser and heritage consultant Siobhan Lavelle.
  10. MBK (1998), Study of relative heritage significance of all timber truss road bridges in New South Wales, p.6
  11. RG Albion (1926), Forests and Sea Power, Cambridge University Press
  12. ICOMOS Principles for the protection of historic timber structures, adopted in 1999
  13. Australia ICOMOS (2013), Charter for Places of Cultural Significance, The Burra Charter