Context

The first crossing of the Murray River by white men occurred in November 1824 when Hamilton Hume and William Hovell led an expedition from Yass in search of an overland route to Westernport Bay. Their crossing point was some distance up river from Albury and an obelisk near the river commemorates this. Hume and Hovell came upon the river on 16 November 1824, naming it the Hume River, and inscribing a tree near the riverbank the next day before moving on to the south. In 1829, the explorer Charles Sturt discovered the Hume River downstream at its junction with the Murrumbidgee River. Not realising it was indeed the Hume, he named it the Murray River. Both names persisted for some time, Hume falling into disuse eventually in favour of Murray.^[1]

The explorers route was shortly followed by white squatters and their livestock, mainly sheep and cattle. Subsequently, many families took up parcels of grazing land on the rich river flatlands, among the first being William Wyse and Charles Ebden. The drovers track that developed along the line of the advancing squatters, and subsequently by their excess stock returning for sale at Melbourne and Sydney markets, led naturally to the same point Hume and Hovell first sighted the river. Although an easier crossing point could be found 10 miles upstream (where the Hume Dam now stands) the original site by Hume and Hovel's inscribed tree became the popular crossing place for people and stock on their way to new settlements in the south.^[1]

Crossing the river during the drier summer months could normally be achieved on foot. When the river was high after heavy rains or snow melting in the mountains crossing became difficult until a log punt was built in 1844. Stock, however, had to swim. The first bridge over the Murray was built in 1860 near the present crossing at Albury. People up and down stream had to find their own fords, or trek back to Albury.^[1]

The arrival of the railway from Melbourne in 1873 boosted the district and captured the Southern Riverina markets for Melbourne. The railway line from Sydney reached Albury in 1881, but the Albury-Wodonga Railway Bridge over the Murray was not opened until 1883.^[1]

The Bethanga-Talgarno gold and copper field became one of the top copper producers in Victoria although both minerals proved difficult to extract from the intractable ores. The alluvial field was first reported in 1852 and was visited by mining officials in 1854, but the field was not really opened up until the discovery of the New Year's Gift reef on 1 January 1876. This led to a number of highly capitalised mining ventures. Harris and Hollow, a mining partnership from Rutherglen, built a smelting works on the flats of lower Bethanga with a view to smelting copper for the public and opened the first furnace of their Great Eastern Copper Smelting works in January 1878. John Wallace MLC took an interest in the Bethanga mining scene and purchased mining leases and major mines at Bethanga, then built his own smelting works to treat the ore, completing three furnaces by June 1878. The Bethanga Goldfields Ltd company made a takeover in 1895 and both metals were mined and treated. Mining however, continued only sporadically into the 20th century, with further leads opened at Mount Corryong and Mount Talgarno. There was a brief revival in the 1930s and some mines struggled on to at least 1945, but in the latter half of the 20th century mining ceased and the town gradually diminished (Bannear).^[1]

The concept of damming Australian rivers for irrigation and flood mitigation was first investigated back in the days of the steamers. The Hume Dam was proposed under the River Murray Waters Agreement, which was signed on 9 September 1914, by the Prime Minister, Joseph Cook, and the Premiers of New South Wales, Victoria and South Australia. The first sod was turned by His Excellency, the Right Honourable Sir Ronald Crawford Munro-Ferguson, Governor-General of Australia, on 28 November 1919.^[1]

H. V. Beresford was construction engineer on the Hume Weir from about 1925, but died while still engaged on the project in 1927. At the height of construction, more than 1100 workers were employed at the site. These workers were housed in two fully serviced towns adjacent to the site, one on either side of the river.^[4][1]

Construction of the weir took seventeen years with the reservoir being completed and officially opened by the Right Honourable Lord Gowrie, Governor of NSW, on 21 November 1936 and a plaque on the northern pier of the dam commemorates the occasion. The Bethanga Bridge was evidently constructed in the middle of this period, probably when water backing-up behind the rising dam wall, began to reach the low level bridge at Bethanga.^[1]

Three engineers of note were involved in formulating the agreement, Ernest de Burgh, the Chief Engineer of the Water Supply Branch of the NSW Public Works Department, J. S. Detheridge the Commissioner, State Rivers and Water Supply of Victoria, and G. Stewart in South Australia. The initial designs for Hume Dam were prepared by de Burgh and Detheridge. NSW was responsible for construction of the concrete dam and the State Rivers and Water Supply Commission of Victoria was responsible for the southern earth embankments.^[1]

Another Victorian engineer, Ettore Checchi (1853-1946) was closely connected with the Hume Dam project in the 1920s and 30s. However, as his skills were with hydrographic work, it is unclear what contribution he had to the associated structures such as Bethanga Bridge. The State Rivers and Water supply Commission undertook at least some of the Hume Weir works in conjunction with the NSW Public Works Department. The River Murray Commission evidently had an overriding supervision of the works, but engineering and design details were left to the established public works engineers in the two states.^[1]

The heavy cost of Victoria's irrigation infrastructure lead to a parliamentary inquiry into the commission's finances in 1928, and recommendations against further irrigation investment in an era of low export returns from primary produce. However, the Hume scheme appears to have been immune to any cuts due to the State - Federal agreement and advanced stage of the project. The NSW Department of Public Works carried out modifications between 1950 and 1961 to enlarge the dam to about twice its original size to the present capacity of 3,038 gigalitres (668×10^⁹ imp gal; 803×10^⁹ US gal) to accommodate diverted water from the Snowy Mountains Scheme.^[1]

The place

As a result of the construction of the weir, the water level in the Murray River backed up behind the dam to permanently inundate the floodplain, which was up to several kilometres wide in many places.^[1] Although confirmation of the construction authority is yet to be found, there is later evidence in the form of lantern slides showing the construction of the bridge and clearly intended for public presentation, that the bridge was substantially the work of the SRWSC.^[5] The involvement of the NSW Public Works Department is also implied by photographs of components fabricated by Charles Ruwolt and Sons held by Museum Victoria. It is therefore very likely that the New South Wales Public Works Department and Victorian State Rivers and Water supply commission were jointly responsible for the design and construction, as was the case with the Hume Dam itself.^[1]

Bethanga Bridge is roughly contemporary with and is similar in design to the Yarrawonga Bridge at Lake Mulwala, which was designed by NSW Department of Main Roads Engineer Percy Allen and constructed in 1924, also as a result of the creation of an artificial lake on the Murray River. The other prominent engineers involved in the Hume Project, Ettore Checchi, Ernest deBurgh, and J. S. Detheridge, were water supply engineers or had ceased to be involved when the bridge was built.^[1]

There was a pattern in NSW/Victoria relationships over the Murray River border for NSW to design Murray River bridges, and Victoria to build them. Other examples of the arrangement can be found in the Swan Hill bridge and many timber bridges. Bethanga Bridge is similar to other large NSW bridges such as the Hawkesbury bridges, and uncharacteristic of Victorian bridge design practice.^[1]

The sequence of SRWSC lantern slides show the progressive construction of the Bethanga Bridge. Construction commenced in 1927 with clearance of the foundation sites and piling. By 1928 the piers were well under way and staging commenced from each bank. By 1929 all the piers were in place and waters had risen to the base of the piers. Erection of the trusses was underway. Falsework of underslung, divided Warren-type, metal trusses supported on three intermediate steel lattice towers, were used as staging for erecting the Pratt trusses. These were assembled in situ with the use of a travelling crane running across the falsework and hot riveting of preformed, punched and cut angle and flat section steel. As the permanent trusses were completed the staging was dismantled and moved on to the next span.^[5] Steel work for the bridge was fabricated at least in part, by Vickers Ruwolt of Burnley Melbourne. Photographs of components such as the truss members and bearings are in the collection of Museum Victoria. At least one of the main trusses was trial assembled at Vickers Ruwolt's Burnley works, probably one of the largest structures to be erected in this fashion.^[1]

The bridge was clearly seen as a landmark and complementary to the Hume Dam itself in terms of national pride and potential tourist value. The State Rivers documented the bridge's construction and produced a series of lantern slides showing progress. A number of hand coloured slides and images were produced of the finished bridge to show it at its most impressive. The Victorian Railways also produced its own series of photographs in the 1940s and 50s presenting the bridge as part of a dramatic landscape and engineering achievement, probably for promoting tourist visits(by train) to the region. The bridge has been included in several Postcard series of the natural and man-made features of Albury in the 1950s and 60s under titles such as A Souvenir of Beautiful Albury.^[1][5] The bridge was constructed at a cost of c. A£194,000 – 210,000.^[2]

The 13.7-metre (45 ft) approach span on the New South Wales side was constructed in 1963 as part of the upgrading of the Hume Dam.^[1]

The town of Bellbridge at the southern end of the bridge, was created to replace facilities inundated by the reservoir. The bridge is currently managed by River Murray Water, although it is understood that the Roads & Traffic Authority, VicRoads and River Murray Water are negotiating on the future management responsibility for the bridge. A current 33-tonne (36-short-ton; 32-long-ton) load limit applies and recent tenders have been advertised for the cleaning and repainting of the bridge.^[6][1]

Condition

The road deck was initially timber but was replaced in 1961 with a concrete waffle slab deck. In 1961 the bridge deck and truss structure was also raised by 300 millimetres (12 in) in response to the upgrading of Hume Dam and works to increase the storage capacity of the dam. In 2005 the waffle slab decking was replaced to raise the load capacity, new guard rails were installed and the NSW approach to the bridge was widened for safety reasons. These 2005 works were undertaken with the joint advice and approval of Heritage Victoria and the NSW Heritage Office.^[1]

The Pratt truss was an American style bridge truss that began the tide of change from British to American bridge technology in the nineteenth century. The Bethanga example comes from a period when Pratt trusses were an established design alternative, favoured by railways but generally shunned in Victorian road bridge design. It is a type of truss in which vertical web members are in compression and diagonal web members in tension. Many possible configurations include pitched, flat, or camelback top chords. It may be recognised by diagonal members which appear to form a "V" shape toward the centre of the truss when viewed in profile. Variations include the Baltimore truss and Pennsylvania truss. Elaboration in the form of variable depth from sloping upper chords as in the Camel-back arrangement, reduced the amount of steel required, and also dead weight for a similar strength. The Pratt truss compares to Warren truss and Howe designs in the different compression and tension arrangements of diagonal and vertical members. It was named for Thomas W. and Caleb Pratt (Boston railway engineers), who were issued a patent for a truss bearing their name in April 1844.^[7][8]

The overall length is given in VicRoads inventory as 733 metres (2,405 ft) although a deck length of 752.4 metres (2,469 ft) and total length of 750 metres (2,461 ft) in their inspection system appears more probable. The nine truss spans are each 82 metres (269 ft) with the NSW approach span being 12.5 metres (41 ft); clear height is 25 metres (82 ft) and width 7.7 metres (25 ft). Concrete endposts frame the entry to the bridge. The construction date is cast in the one end post.^[1]

The original wooden road surface has been raised once and twice replaced, the railings replaced and the NSW approach modified. Nevertheless, Bethanga Bridge remains substantially the same structure erected in the 1920s.^[1]

Engineering heritage

The bridge received an Engineering Heritage Marker from Engineers Australia as part of its Engineering Heritage Recognition Program.^[9]

Bibliography

• "Bethanga Bridge over the Murray River". New South Wales Heritage Database. Office of Environment & Heritage.
• Cridlebaugh, Bruce S. "Bridge Basics". Bridges and Tunnels of Allegheny County, Pennsylvania.
• East, Ronald (1979). Checchi, Ettore (1853-1946), engineer.
• Hughes Trueman Reinhold (1998). Murray River Crossing Study.
• Philipp, June (1982). Poor Man's Diggings: Mining and Community at Bethanga, Victoria, 1875-1912.
• Philipp, June, ed. (1993). The making of a mining community : Bethanga, Victoria, 1875-1885.
• River Murray Commission (Australia) (1928). Hume Reservoir, Australia.
• VicRoads Bridge Design Files (1993). Drawing No 478282, 25/06/1993.
• Waddell, J. A. L. (1891). The Designing of Ordinary Iron Highway Bridges.

Attribution

This Wikipedia article contains material from Bethanga Bridge, entry number 01750 in the New South Wales State Heritage Register published by the State of New South Wales (Department of Planning and Environment) 2018 under CC-BY 4.0 licence, accessed on 28 May 2018.