Where do bridges begin? More than a few of the timber truss bridges of New South Wales (NSW) owe their existence to the energy and aspiration of local people, who lobbied their parliamentarians for a crossing over a river they saw as a barrier to transport and to the progress of their region.

Each particular location depended on the onsite surveyor who worked out the specifics of alignment, flood levels and foundations for the design engineer to assess the type of bridge to recommend for the Chief Bridge Engineer’s decision. Economy in spending from the public purse was always a prime factor for the design engineer, a factor revealed for instance where abutments were built close to a river bank to reduce the length of the span required. Without today’s knowledge of hydrology and river conservation and without useful flood records, economies like this could create new problems.1

From 1873, the timber truss bridges of NSW had their genesis in the Bridge Street headquarters of the Colony’s Department of Public Works (PWD) in Sydney (see Figure 6.1). This was where final decisions were made, where bridge plans were exhibited, specifications devised, construction contracts drafted and tenders received and assessed. The NSW Tender Board, the Public Works Minister’s office and those of the Chief Engineers and the Government Architect were all in this impressive Chief Secretary’s Building, an expression of the senior status of the PWD.

The Engineering Drawing Office where the truss designs were conceived and drafted was far less imposing, like all the other PWD branches’ drawing offices. The Government Architect’s Office architects and draftsmen worked in tin sheds opposite the Chief Secretary’s Building, while accommodation for the other Drawing Offices included make-do buildings in the yard of Hyde Park Barracks.

Figure 6.1

Figure 6.1: The Bridge Street entrance of the Chief Secretary’s Building was well known to building contractors viewing plans and specifications displayed in the offices of the Chief Engineer. Source: SARANSW

Figure 6.2

Figure 6.2: Contract copy of 1878 plan for a Bennett Truss bridge, signed by builder George Clarke (top right) with two bondsmen and witness below. Source: NSW Parliamentary Papers2

Calls for tenders were published in the NSW Government Gazette and the pages of the Sydney Morning Herald, with plans exhibited at the Chief Engineer’s Bridge Street office. Country contractors responding to the same notice in their local paper went to the courthouse or police station in the town nearest the proposed bridge site to view the plans. The bridge builders tendered to these plans with no variation of the design allowed. Unlike the covered timber truss bridges of the eastern United States where each builder added his unique and identifiable touch, the timber truss bridges of NSW are recognised by their designers, rather than their builders.

Winning tenders were published in both the NSW Government Gazette and the relevant local paper, providing a detailed though incomplete record of the bridge builders. The winning firms were required to sign a contract copy of the bridge plan along with two sureties (also known as ‘bondsmen’) who guaranteed the working capital (see Figure 6.2). Each document also had the signature of a PWD officer. As the builders contracted on individual projects, their financial backers might differ each time. Payment was not made until completion, so the swifter the build, the greater the profit for the builder and his surety investors.

Bridge Builder Families

Colonial timber bridge contractors were often father and sons, or brothers, with experience as bridge carpenters. With each contract the whole family was involved in the work; setting up camp at bridge sites and travelling between jobs by bullock or horse team, sometimes with as many as fifty horses. Though there were very few mechanical aids to construction, quite often the contract was executed in twelve months, with the whole family engaged in the construction.

Ten families were particularly prominent in building the timber truss bridges of NSW, each building five or more bridges. These were the Ahearns, the Taylors, the Murphys, the Farquharsons, the Fitzgeralds, the Oakes, the Jacksons, the McGills, the McPhillips and the Foords (see Figure 6.3). For bigger projects extra carpenters were taken on. Notable among these men is William Robert Maloney, foreman for three of these family firms on a total of 34 bridges built between 1901 and 1918.

Carpentry was the chief skill in executing the timber truss bridges of NSW, with the transition to composite truss designs opening the field to other skilled trades. The large blacksmithing business run by Cyril Foord and his brothers on New Canterbury Road in Sydney’s Dulwich Hill launched the family into building seven of the timber truss bridges of NSW, most of them to the Allan or Dare Truss designs.

The builders harvested any suitable timber growing locally, either on Crown land or by arrangement with landowners who were usually keen for help with land clearing. The trees were felled and pit saws set up nearby to saw the logs into planks for decking and the truss members.

Figure 6.3

Figure 6.3: The ‘top ten’ family firms and the timber truss bridge types they built in NSW. Source: Graphic by Jack Pulczynski, data from NSWGG3

The Colony’s timber export trade was underway by the 1870s when the Mann River Bridge was built, but its location on the colony’s northern rivers enabled harvesting from the still plentiful trees in the ‘Big Scrub’ (see Figure 6.4). Forested parts of the central and south coasts also afforded local timber for bridges, but in western regions both ironbark and tallowwood were scarce and milled timber was transported from the coast. A crucial part of tendering was close estimation of the cost of subcontracting to distant sawmills, as well as to foundries for metalwork.

Percy Allan reported that the contract let in 1893 for the bridge over the Murrumbidgee River at Wagga Wagga, meant timber ‘was brought from the northern rivers of the colony to Sydney, 100 miles by sea, and thence by rail, 310 miles to Wagga Wagga’.4 More than twice the distance, and presumably the cost, would have challenged tenderers for the bridge over the Murray River at Swan Hill in 1895, with the successful firm Farquharsons tackling the logistics. The whole of the timber, with the exception of a few piles, was obtained from the northern rivers of NSW, forwarded to Melbourne by sea, a distance of about 726 miles, thence to a site by rail a distance of 214 miles, for a total carriage of 940 miles.5

Figure 6.4

Figure 6.4: The newly-completed Bennett Truss bridge over the Mann River at Jackadgery, built in 1877 by D and F Ranken from timbers felled nearby. Source: DMR, Roads and Maritime copy

But even the most careful calculation could not accurately allow for accidents. In the early stages of constructing another Murray River bridge, at Albury, Farquharsons had to bear the losses when the coastal steamer Maitland was wrecked in May 1898 and its cargo lost, including their consignment of large timbers for the bridge. The works remained at a standstill while Farquharsons

have had to proceed to the mills on the northern rivers for the purpose of substituting the order for necessary timber, which can only be obtained in the district of Wyong.6

Despite generic references to ‘the northern rivers of NSW’, the Wyong region between Sydney and Newcastle was the source of both ironbark and tallowwood for these three 1890s bridges that ran over the Murrumbidgee River at Wagga Wagga (see Figure 6.6) and over the Murray River at Swan Hill and Albury.7

Figure 6.5

Figure 6.5: Among the dignitaries at the 1899 opening of the Dunmore Bridge over the Paterson River are the three McGill brothers (front row, R). Source: Woodville School of Arts

The bridge-building families necessarily led transient lives following the trail of government contracts and longer stays in a district must have been very welcome. When Samuel McGill and his brothers won the contract in 1896 to bridge the Hunter River at Morpeth, they were finishing the bridge over the Macintyre River at Inverell in the north of the Colony. The families made their own way 260 miles (420 km) from there to Morpeth where they were able to settle for five years, becoming valued members of that growing community. During that time some of the McGills’ team travelled south to build the 1897 Allan Truss bridge over the Wingecaribee River at Berrima. They completed the Morpeth Bridge in 1898 and won more bridge contracts in the area, including the Dunmore Bridge opened in 1899 (see Figure 6.5) and the Hinton Bridge, finished in 1901. For the latter bids, they had the considerable competitive advantage of established relations with local sawmills and foundries, as well as minimal transport and set up costs.8

The Oakes family had a long association with large timber constructions, spanning several generations. William Frank Oakes built bridges in New Zealand before emigrating to NSW where his first major project, the Smoky Cape lighthouse in 1889, was also his last. His death meant his two teenage sons, 19-year-old Walter Frank and 17-year-old Percy George, took over the work, completing the lighthouse in 1891. Walter then took on work as a surveyor and civil engineer on railway projects in Sydney, including the St Leonards to Milsons Point railway extension.

Figure 6.6

Figure 6.6: This record of the visit of Chief Engineer Robert Hickson and Ernest de Burgh (second from right) to the Wagga Wagga bridge works in May 1895 shows some of the builders, including one atop the truss at left. Source: Fitzgerald Collection ML, SLNSW

Under the company name of WF Oakes, brothers Walter (see Figure 6.7) and Percy were engaged in 1894 as foremen to SF Stokes, contractor for the erection of Hampden Bridge at Wagga Wagga. The first example of Percy Allan’s new lightweight truss design, this was a major undertaking, with its longest span 110 feet (33.5 m) and deck area 3,165 square feet (294 m2). Under Chief Engineer for Roads and Bridges Robert Hickson’s 1891 reorganisation, the district road superintendents were now titled resident engineers. However, despite this onsite supervision, the bridge’s completion date of 5 April 1895 was not met. Fears grew that if the town’s 1862 ‘Company Bridge’ could not survive the winter, the Murrumbidgee would cut off traffic and commerce, with the electorate’s vociferous complaints aired in the Legislative Assembly.9

Hickson and Divisional Engineer Ernest de Burgh travelled to Wagga Wagga to assess the problems firsthand and find a way to accelerate the work (see Figure 6.6). The intervention worked and two months later the local press were able to anticipate an opening date and were quick to congratulate the contractor ‘on having been able to successfully overcome the difficulties of flood, stream and weather which he had to combat’. The actual opening ceremony was still four months away, celebrated with elation on 12 November 1895.10

Figure 6.7

Figure 6.7: Portrait of Walter Oakes c.1908, Parker Studios Lismore. Source: Frank Oakes

Ernest de Burgh’s inspections at Hampden Bridge gave him the opportunity to assess the skills of those involved and with characteristic generosity he provided the young Walter Oakes with the great asset of a glowing reference. With their early start in bridge building, the brothers’ firm of WF Oakes launched a long and productive career from a peak PWD year of recovery from economic depression. With staff of the Roads and Bridges branch increased from 238 to 1,791 in 1893-94 and Percy Allan promoted to Chief Design Engineer for bridges the following year, WF Oakes rose steadily up the ranks of successful contractors.

Specialising in public works heavy timber construction, the firm completed more than sixty works in thirty years from 1905, mostly in north-eastern NSW. This opus included small timber beam bridges built for local government councils after some 3,575 bridges and their roads were transferred from the PWD to local authorities under the Local Government Act 1906.11

The very long careers of the builder brothers grew with the timber truss bridge designs, as their PWD bridge contracts covered three of the five timber truss designs, the Allan Truss, the be Burgh Truss and the Dare Truss. The contemporary record of their bridges includes the watercolours Walter Oakes commissioned from landscape artist RM Ronald, now proud treasures held by the descendants of Walter and Percy Oakes.

WF Oakes built four Allan Truss bridges; on the north coast at Dyke Creek, Kempsey and on the south coast at Tantawangalo Creek, Kameruka in 1897, over the Styx River at Jeogla on the Kempsey to Armidale Road in 1900 (see Figures 6.8 & 6.11) and the last in 1920, over the Murrumbidgee River at Narrandera.

Figure 6.8

Figure 6.8: Completed by the Oakes’ family firm in 1900, the Allan Truss Styx River Bridge at Jeogla, captured by artist RM Ronald. Source: Frank Oakes, photo David Sciffer

The firm’s two de Burgh Truss bridges were built in 1902 in the Hunter River region, over Black Creek at Rothbury and over Webbers Creek on the Gresford to Singleton Road (see Figure 6.9).

Figure 6.9

Figure 6.9: In his 1902 watercolour of the newly completed de Burgh Truss bridge over Webbers Creek, RM Ronald included the crossing by ford in the foreground. Source: Frank Oakes, photo David Sciffer

Figure 6.10

Figure 6.10: Percy Oakes (L) supervising construction of the Dare Truss Bean Tree Bridge over the Richmond River near Wiangaree in 1927. Source: Peter Oakes

The families seem to have been based in the area at this time, with two of their Dare Truss bridges, over the Macdonald River at Bendemeer and over the Williams River at Dungog, completed in 1905.12 Among their other Dare Truss bridges were two on the Richmond River in the state’s northeast, Colemans Bridge over Leycester Creek at Lismore in 1908 and the Bean Tree Bridge near Wiangaree in 1927. These marked nearly forty years as builders for the Oakes brothers (see Figure 6.10).

WF Oakes’ Kempsey, Kameruka and Narrandera bridges have all been replaced, while the Bendemeer bridge, itself a replacement for an 1865 laminated timber arch bridge, was in use for eighty years before it was bypassed with a bridge on the New England Highway in 1985.

Among many other notable timber truss bridge builders in NSW was another pair of brothers, Scottish immigrants William and JB Farquharson. Self-taught bridge builders, they established a firm in Melbourne and built at least eight timber truss bridges, including five of the six great lift truss bridges over the Murray River.

Figure 6.11

Figure 6.11: The 1900 Allan Truss bridge over the Styx River, between Armidale and Kempsey, in 2013. Source: Amie Nicholas

Designed by Percy Allan, the bridge at Swan Hill was the first of its type, with a lift span and Allan Truss timber spans. The contract was let to the Farquharsons in 1895. They ordered the metal components from a Melbourne firm and all the timber from Wyong sawmills was shipped through Melbourne and sent from there by rail. The firm had just completed the Tocumwal Bridge and was able to use the same plant, but the major saving was the new design that halved the cost of both labour and materials with

the more economical design of lift, the substitution of timber for iron side spans, and the securing of foundations for the two river piers at Swan Hill at a lesser depth than at Tocumwal.13

Farquharsons built the Union Bridge at Albury in 1898 and the Cobram Bridge in 1902. The firm took just over twelve months to complete the Howlong Bridge in 1908 with the Dare Truss, ‘the latest type used by the PWD, with top chords and braces of Ironbark, the lower chords steel and the suspension rods wrought iron’.14

It was no accident that the bridge between Barham and Koondrook was the exception to Farquharsons’ Murray River full set of bridges. The very experienced Farquharsons’ bid of £12,000 was the second lowest of the six tenders submitted, making Monash & Anderson’s winning bid of £10,345 seem more risky than competitive, hinting at either desperation or determination to break the older firm’s dominance. Unlike the Farquharson brothers, John Monash and JT Noble Anderson were both graduate engineers. The firm had successfully completed the timber truss Tambo Bridge at Bruthen, Victoria in 1899, but their completion date of 30 April 1904 for the Murray bridge was overrun.

Their problems compounded, with difficulties in keeping a workforce together following prolonged delays in delivery of the 170 tonnes of ironwork ordered from Ballarat’s Eureka Ironworks. The subsequent loss on the contract might have been the reason Monash never tendered for bridge building again, though this was more likely due to the financial collapse of the business after other bridge losses, most dramatically the collapse of their Monier bridge at Bendigo and Anderson’s departure for New Zealand. John Monash went on to make his fortune with the firm’s possession of the Monier patent for reinforced concrete, and then had a distinguished military career. William Farquharson remained a bridge builder to the last. He died in 1925, aged 85 in the midst of building the new Allan Truss bridge over Goobang Creek that replaced Condobolin’s 1880 Bennett Truss bridge. His bridge was replaced in 2008, just short of the long lifespan of its builder.15

Bridge Building

Once numbered in their hundreds, timber truss bridges are now a rarity. The early bridges were built with hand tools, the broad axe, the adze, the hand auger and chalk line (see Figure 6.12). The broad axe made a hewn log ready, with the adze the primary tool for cutting and trimming a square edge on members so they would slot neatly into place to form the trusses. As these were hardwoods, blackbutt or ironbark, the bridge carpenter worked with a lot of effort and skill in making trusses.

A contractor’s first step was employing gangs either to fell and saw timber, or to shape the consignments of sawn timber delivered from a mill. Only occasionally would the PWD take on the role of employer of day labour, if the Tender Board deemed all tenders too high as with Tooleybuc Bridge in 1921, or if a contractor failed, or in the case of unemployment relief works during economic depression.16 The PWD would then source the materials and supply the equipment, and its Roads and Bridges officers supervised the work done by gangs of about ten men, each under a foreman.

The most complicated construction stages were building the piers and fabricating the trusses. Most of the over 420 timber truss bridges of NSW had piers made up of timber logs, the piles supported in a trestle arrangement. Using the initial onsite survey information, the PWD provided the contractors with concept drawings showing the depth of the waterway and provisions to drive the piles to ensure the stability of the bridge (see Figure 6.13). This seems generally to have been sound practice, though of course there were exceptions such as the unpleasant surprise of the Farquharsons at Cobram, when they found the solid rock shown on the plan turned out to be unstable sand at just eight feet (2.4m).17

Figure 6.12

Figure 6.12: Hewing a log with a broad axe. Source: VicRoads, Roads and Maritime copy

Figure 6.13

Figure 6.13: Drawing with pile depths required for a Sydney suburban bridge at Mona Street, Auburn, built in 1891 and replaced in 1949. Source: Roads and Maritime

The piling derrick (or pile driver) was the most substantial piece of equipment in the bridge builder’s kit (see Figure 6.14). The iron ram (also known as a ‘monkey’ or ‘drop hammer’) was raised by a rope running over the top of the framework and attached to a winch. A log was stood upright beside the derrick and the operator (mounted at the top of the derrick) released a clutch that let the ram drop to drive the pile (see Figure 6.15). Steam-driven winches typically operated the pile driver, though horses were also used.

Pile-driving was particularly dangerous. A fatal accident at WF Oakes’ Narrandera bridge works in 1919 was closely reported by the local press:

At about 5 o’clock on Thursday afternoon an accident occurred at the new bridge construction works which resulted in a pile driver named George Daniel Knight (aged 45) losing his life.

It appears the deceased was bolting the monkey on the frame at the top of the pile driver, about 30 feet from the ground. He was standing on one of the landings of the pile driver. He had been screwing up a bolt with a spanner and he called out to witness to look out, and soon after fell to the ground (a distance of some 30 feet and died the following evening). Witness’ opinion was that deceased dropped the spanner, and in trying to catch it, over balanced. He had been employed on the pile driver about seven weeks.18

Figure 6.14

Figure 6.14: Large piling derrick stabilised by ropes, with ladder ready for operator, 1955. Source: Roads and Maritime

Figure 6.15

Figure 6.15: ‘Monkey’ and pile-driver operator. Source: Roads and Maritime

Figure 6.16

Figure 6.16: Pile being drawn onto derrick, with platform under construction at bridgeworks over the Avon River in Victoria in 1925. Source: VicRoads, Roads and Maritime copy

Once the timber piles were driven to the required depth, a platform was built and the rest of the structure erected on top to the specified height (see Figure 6.16). But pile-driving could also be celebrated, with Koondrook and Barham en fête for the occasion of driving the first pile of the bridge on 9 April 1903, with a half-holiday for schools and the banks of the river lined with an audience for the dignitaries who were towed out to the midstream barge. There the shire president’s ceremonial release of the monkey of the pile driver sunk the first pile three inches into the riverbed and set in train lengthy speeches. The absence of bridge contractor John Monash was regretted, but perhaps not by him.19

Where flooding was a major problem, once iron was available new timber truss road bridges had cast iron cylinder piers instead of the timber trestle piers with inadequate resistance to the combined force of flood water and its destructive cargo of tangled debris. Cast iron cylinder segments about a metre deep were delivered on site and built up one on top of the other via a simple tongue and groove feature (see Figure 6.17). The wrought iron webbing and any other large iron components required riveting on site.

Figure 6.17a

Figure 6.17: At Eureka Iron Works in Ballarat in 1903 Scottish iron was used to fabricate these paired iron cylinders, as specified in the design drawing (R) which also shows the caissons at the base. The cylinders were then separated into segments for transport to the Barham construction site on the Murray River. Source: University of Melbourne Archives

Piling derricks could not be used to place the cylinders, which instead were connected using internal stiffened flanges then progressively lowered onto the riverbed, with a cutting edge bolted to the base. Once in place the cylinders were filled with concrete for anchorage. Cylinder piers were sunk either by open excavation, or under air pressure where compressed air balanced the external water pressure. This meant work could be done inside the caissons to remove riverbed material until gravity caused the caissons to settle to a solid foundation. This work varied with the bridge, and the river, but was in every case hard and hazardous. On the Murray River, Farquharsons had to sink the four iron cylinders carrying the lift section of the Tocumwal Bridge 35ft (10.7m) below the river bed and with the Union Bridge at Albury, a solid foundation for the centre pier midstream was not reached until 48 feet (14.6 m) below the riverbed.20

Figure 6.17b

Pile-driving was dangerous but work inside the pressurised caissons was even more so, with the only safety measure a signalman or ‘banksman’ posted at the top of the caisson to alert the engine-driver to any problem for those inside. At many sites contractors worked men night and day, especially if there had been delays. Only when workers at the SF Stokes’ bridge site at Wagga Wagga complained of the danger in winter 1894 was a banksman posted, and then only for the night time shift. When the local MLA visited the site he explained to a reporter:

Some locks are made with the exhaust taps on the outside (a very objectionable practice), and in these it is absolutely necessary to have a man outside, for those working in the lock cannot help themselves, or get out without his assistance. In such locks, the men inside give the signal, and the banksman allows the air to escape, when the door can be opened. As those outside cannot know the effect the reduction of the pressure is having upon those in the lock, and as a careless foreman may insist upon the taps being turned full, to shorten the time occupied in lowering the pressure, this is dangerous to the men.

In other locks the taps are inside, and are controlled by the men themselves, who if anything goes wrong have it in their power to open the lock and come out, and also can regulate the pressure to suit themselves; they are thus absolutely independent of a signalman.

The airlock in use at the Wagga Wagga bridge works was the latter type and by summer when the men had won their case for a banksman on the night shift – and increased wages for these hours – they agreed the extra man was not necessary in daytime.21 Four years later, builder Samuel McGill devised an improved airlock for the caissons used in construction of Dunmore Bridge on the Paterson River, patenting the design in Victoria as well as NSW.22

Work inside the caissons held other dangers too. A new recruit at the Farquharsons’ Cobram bridge site was struck by a bucket falling from the top; the same labourer some weeks later used his shovel to shield his head when a pick plummeted down the cylinder he was working inside. As he had no serious injury and such incidents were not uncommon, the only reason for this record was that just four days after the second incident, the same young man drowned in the Murray River, struck by the barrow of sand that fell with him from a temporary bridge.23

Figure 6.18

Figure 6.18: Cast iron cylinder segments ready for assembly at the Hampden Bridge site beside the Murrumbidgee River at Wagga Wagga, 1894. Source: Fitzgerald Collection, ML, SLNSW

Figure 6.19a

Figure 6.19a: Cast iron piers of Clarence Town Bridge over the Williams River, built in 1880. Source: Ian Berger

Figure 6.19b

Figure 6.19b: Cast iron piers of the 1922 Carrathool Bridge over the Murrumbidgee River. Source: Ian Berger

Bracing between the piers usually was a plate diaphragm with an oval ‘window’ (see Figure 6.17 above) and while bracing with iron stiffeners was less common, several examples exist (See Figure 6.19).

The approach spans of the bridges were relatively straightforward constructions over land. ‘Gin’ (engine) poles were used for erection because of the ease of rigging, moving and operating. They comprised a strong pole with four ropes and hoisting tackle fastened at the top end and were used for raising or moving heavy weights up to 50 feet in the air. Gin poles helped put in place a headstock on top of piles (see Figure 6.20) and girder logs on top of headstocks (see Figure 6.21) to build up the bridge deck. For smaller jobs, piling derricks could double as cranes.

Ironwork needed for the bridges included cast-iron shoes (also known as ‘chairs’) and rods, bolts, washers and angle blocks. These were generally ordered through a foundry which fabricated the items to patterns provided by Public Works. Large complex structures needed more elaborate planning for the quantities of ironwork required. For the Hampden Bridge at Wagga Wagga, Allan recorded that:

all the wrought iron bars are rolled from scrap at the Lithgow Ironworks, 97 miles distant by rail from the Atlas Company’s works in Sydney, where all the ironwork was manufactured, being then forwarded by rail to Wagga Wagga, a distance of 310 miles.24

Much like home assembly of modern flat-pack furniture, the first step in assembling the trusses was checking off the list of timber and iron parts. The skilled crews next framed the trusses on the ground for trial assembly to ensure timber sizing and tightness of fit. The arrangement of connections on the Bennett and McDonald trusses meant these were built in situ, on the bridge over the water. Grey ironbark has a weight of 75 pounds per cubic foot when green, reducing to 70 pounds per cubic foot when seasoned (from 1200 to 1100 kilograms per cubic metre, so a single top chord member for a 90 feet (27.4 m) Bennett Truss weighed over 3 tonnes. The lifting of these top chord timbers (yet to take place in Figure 6.22) was obviously a difficult and skilled procedure.

The small numbers of timber truss bridges constructed by the NSW Railways were also built by trial assembly before raising the pieces into position:

Staging was erected between the piers, consisting of 14’ x 14” Oregon, stiffened by struts from piers reaching to one-third the span on each side. The trusses were first assembled on the ground alongside the southern approach, and put together on the flat, properly fitted and cambered. They were then dismembered, and the individual pieces lifted on to the approach by a jib crane, and run out on the staging to place. The floor beams were first laid in position, properly spaced, and the lower beams laid upon them, the rest of the truss then being built up on top.25

Figure 6.20

Figure 6.20: Example of gin poles in use in erecting lattice iron truss bridge over Peel River, Tamworth, c1882. Source: Roads and Maritime

Figure 6.21

Figure 6.21: Gin pole is at rear centre with ropes extended to place a girder log, with piling derrick at rear (R). Source: Roads and Maritime

Figure 6.22

Figure 6.22: Clarence Town Bridge in 1880, with the end principals in place on one truss supported by gin poles. Source: Ford (1993) 26

Figure 6.23

Figure 6.23: At Ross Hill bridge works near Inverell, the top chord is being raised by pulleys on an overhead-braced Allan Truss, dwarfing the 1876 Bennett Truss bridge (L) it is replacing. Source: Roads and Maritime copy

It is easy to see the advantage of the Allan Truss with connections arranged so the truss could be assembled first and then launched into position. Sometimes though, the depth of the trusses dictated the in situ method even with the Allan Truss, as at the McGills’ bridgeworks on the Macintyre River (see Figure 6.23).

Another example was with timber truss spans as components of lift span bridges. The lift span, comprising cast iron piers, a tower and movable deck, was built first and the connecting spans second (see Figure 6.24).

Figure 6.24

Figure 6.24: At Monash’s Barham- Koondrook bridge works in 1904 the right hand side de Burgh Truss (R) is complete, though the top chord and diagonals are yet to be fixed into position at left. Source: University of Melbourne Archives

Figure 6.25

Figure 6.25: Pyrmont Bridge in 1901, drilling holes in the bottom chord for hanger rods with a steam powered augur. Source: Roads and Maritime copy

Figure 6.26

Figure 6.26: Upside down top chord (left) and bottom chord fitted with shoes (right) for Pyrmont Bridge, September 1901. Source: Roads and Maritime copy

As the fabrication and assembly of the Pyrmont Bridge over Sydney’s Darling Harbour in 1902 was well documented, it is a guide to many of the steps involved. Each of the ironbark Allan trusses spanned 82 feet and weighed 15 tonnes and these were assembled on the wharf, close to the bridge site and to the designer’s attention (see Figures 6.25 & 6.26).

At Pyrmont, after fabrication the trusses were hoisted about thirty feet by pile-driving machines mounted on trolleys or barges, then towed to their sites and placed on the piers. All the trusses were lifted and placed in position in seven hours, with half a pier and two spans with roadway gates completed for traffic in just eight days (see Figure 6.27).

This process was also used with the Dare Truss, for example in building the first Commonwealth Avenue Bridge over the Molonglo River in Canberra in 1925 (see Figure 6.28).

In the more direct method allowed by Allan’s design, trusses were erected on the approaches, then each truss was launched individually using a ‘gin’ pole in the centre of the span, and a second pole on the far abutment, moved with hand-operated winches. Figures 6.29 & 6.30 demonstrate two stages of this method of launching a truss.

Figure 6.27

Figure 6.27: A top chord suspended by braced gin poles, with the last timber diagonal (R) ready for insertion at Pyrmont Bridge works. Source: Roads and Maritime copy

Figure 6.28

Figure 6.28: Assembly of a Dare Truss for Canberra’s Commonwealth Avenue Bridge in 1926, inundated in 1961 with the construction of Lake Burley Griffin. Source: NAA: A3560, 2016

Figure 6.29

Figure 6.29: Bridgeworks on the Dungog-Chichester road with truss secured on two gin poles for lifting onto the abutments, 1890s. Source: Newcastle Region Library

Figure 6.30

Figure 6.30: Launching a truss with a gin pole (out of sight at right) at Osbornes Bridge in Victoria in 1922. Source: VicRoads, Roads and Maritime copy

Figure 6.31

Figure 6.31: Lengths of timber cut for the hand railing are ready on the deck of the Allan Truss bridge over Palmers Channel, under construction in 1926 alongside the 1882 laminated arch spandrel bridge on the Yamba – Maclean road. Source: Maclean Historical Society

As each pair of trusses was installed, the cross girders were placed to carry the deck and the work of installing the deck planks, kerbs, tar coating, and fencing carried on (see Figure 6.31).

The bridge over Palmers Channel on the north coast of NSW (see Figure 6.31) was welcomed as ‘sister’ to the 1911 Dare Truss Sportsmans Creek bridge upstream at Lawrence. Locals cared less about the design distinction than the utility of their new bridge and the historic touch given its rubble abutments, topped with dressed stone from ‘the old Ramornie dancing hall [that] did duty for some fifty years.’27

The timber truss bridges can be read as a record of their builders, as well as of their designers, as novelist Kate Grenville suggested in The Idea of Perfection:

the men who had built this bridge had even gone to the trouble of countersinking the bolt-heads, pecking out a tidy hole to get it all as tight as a piece of cabinetwork. It was tricky, working hardwood like that, but they had thought it worth doing. “True” was the word carpenters used. It was as if they had thought there was something moral about it.28


  1. Mike Mort (2008), A Bridge Worth Saving: a community guide to historic bridge conservation Michigan State University Press, p.53
  2. ‘Bridge over Meryla Creek’, 9 August 1878, NSWLA V. & Proc. XXIV, 1878
  3. NSW Government Gazette 1870-1930
  4. Percy Allan (1895), ‘Timber bridge construction in New South Wales’, J. & Proc. RSNSW, 29
  5. Australian Town and Country Journal 12 December 1896
  6. Albury Banner & Wodonga Express 22 July & 5 August 1898
  7. Sydney Morning Herald 12 November 1895
  8. Sydney Morning Herald 18 January 1895 & 22 July 1896 & 6 February 1932; Australian Town & Country Journal 25 July 1896
  9. NSWGG 9 May 1893; Sydney Morning Herald 21 September 1893; Wagga Wagga Express 11 April 1895; Wagga Wagga Advertiser 16 May 1895; PWDAR 1891, p.145 & 1893, p.72
  10. Wagga Wagga Express 11 July 1895; The Age 12 November 1895
  11. Lenore Coltheart (1991), Research Guide to the History of the Public Works Department NSW, Sydney, The Department, p.51
  12. Don Fraser (2005), ‘Centenary ceremony report for the Bendemeer Bridge Historic Engineering Marker’, IEA; Dungog Chronicle 18 August 1905
  13. Australian Town and Country Journal 12 December 1896; Sydney Morning Herald 29 December 1925
  14. Albury Banner & Wodonga Express 22 July & 23 December 1898 & 6 November 1908; Cobram Courier 8 November 1900; Border Morning Mail 2 November 1908
  15. Geoffrey Serle (1986), ‘Monash, Sir John (1865–1931)’, Australian Dictionary of Biography, 10, Melbourne, MUP; The Age 16 December 1902; Kerang New Times 23 September 1904; Sydney Morning Herald 29 December 1925
  16. Riverina Recorder 23 February 1921
  17. The Age 22 May 1901
  18. Narrandera Argus 27 February 1919
  19. Kerang New Times 10 April 1903
  20. Australian Town and Country Journal 14 September 1895; Wodonga and Towong Sentinel 6 January 1899
  21. Wagga Wagga Advertiser 27 November 1894
  22. Government Gazette Victoria, 17 November 1899
  23. The Age 24 August 1901
  24. Percy Allan (1897), ‘The Wagga Wagga timber bridge’, Min. & Proc. ICE, 128, pp.222-25
  25. JW Roberts (1897), ‘Pioneer Railways in New South Wales’, J. & Proc. SUES, November
  26. RL Ford (1995), Williams River: the land and its people 1800-1900, Clarence Town NSW, author publ.
  27. Daily Examiner 20 October 1925
  28. Kate Grenville (2000), The Idea of Perfection, Melbourne, Text Publishing, p.66