Swan Hill - Murray River Road Bridge

Item

Name of Item	Swan Hill - Murray River Road Bridge
Item Number	4301080
Type of Item	Built
Item Sub-Type	NSW Allan Truss Bridges
Roadloc
Address	**** McCallum Street (MR 67) Swan Hill 3585
Local Government Area	Wakool
Owner	Local Government
Current Use	Road bridge
Former Use	Road bridge

Statement of significance

Swan Hill Bridge, completed in 1896, is of State significance. The form and setting have high aesthetic and social significance. The superstructure construction - Allan timber Trusses and Allan Lift Span have very high significance in the detail and materials. The presence of the lift span is important. The bridge is the original of its type, and extremely rare. (There is one other example at Tooleybuc).

Date Significance Updated

14 May 2009

Description

Designer	****
Builder	****

Construction years	**** - 1896
Physical description	Swan Hill Bridge is a timber truss, steel lift span bridge across the Murray River at Swan Hill. The main axis of the bridge is East - West. There are three main spans including one lift span supported on cast iron cylindrical piers. On the northern side there are three approach spans, and on the southern side there is one. The two main truss spans are 27.9m Allan trusses, with timber cross girders. The main stringers have been replaced with steel I-sections. The deck is timber. The lift span (17.8m) superstructure is constructed with riveted lattice steel. The lifting layout was also developed by Percy Allan. The deck of the lift span is also timber, and traffic is restricted to one lane across the lift span. The approach spans (10.4m to 10.8m) timber girders supporting a timber deck. Piers are timber trestles, including the junctions with the main spans. There is a footway added on the upstream side, using steel beams. this has resulted n modification of the top chord stabilising angles to the Allan Trusses.
Physical Condition and/or Archaeological Potential	Original condition assessment: 'The bridge is described as being in fair condition as it has had major rehabilitation in recent years. One truss span is currently (May 1998) under repair.' (Last updated: 15/05/1998.) 2007-08 condition update: 'Poor.' (Last updated: 17/4/09.)
Modifications and dates	N/A
Date condition updated	17 April 2009

History

Historical notes

The 'beautiful notes' of the swans, on a lagoon 'incessantly hear during the night' prompted Sir Thomas Mitchell, the Surveyor General, to name Swan Hill when he camped there in 1836 on the wide Murray plain: Mitchell's head is today the crest of Swan Hill. This area was settled in the subsequent decade in very large stations: on the New South Wales side of the river, Murray Downs under Bell and Wilson covered 60,000 hectares and by the 1860s, under H S Officer, was carrying 6000 sheep. On the Victorian side, the principal runs were Tyntynder and Mercers Vale, established by the Beveridge family as cattle stations.

Because of this pastoral development a punt was installed at Swan Hill as early as 1846. In 1853, when the first two steamers on the river, the Lady Augusta and Mary Ann raced up the river, both stopped at Swan Hill and the Campbell family mounted a ball for the passengers and crew while their wool-clip was loaded. Swan Hill developed wharfage and in the 1860s had two hotels and three stores but only eleven houses. The town continued to develop as a crucial centre for the river trade, overlanding and interstate commerce, with hotels on both sides of the river adjacent to the punt.

The Victorian railway reached Swan Hill in 1889 and the need for a bridge was more and more recognised. A lift-span bridge, allowing the passage of the river-boats, which were still numerous in this area, was planned in 1895 and opened in 1896. The bridge is still in use: Swan Hill, with good road, rail and water links, reached a population of 4000 by 1948, remains the focus of a large area of diversified farming and attracts many tourists to its open-air museum.

Listings

Heritage Listing	Reference Number	Gazette Number	Gazette Page
National Trust of Australia register

Register of the National Estate	16074	115	0004

Heritage Act - s.170 NSW State agency heritage register

Heritage Act - State Heritage Register	01481

Assessment of Significance

Historical Significance	The Swan Hill Bridge is historically very significant. It is hard to differentiate between Historical and Technical Significance in this instance as they are closely intertwined. This bridge has great importance for its association with Percy Allan, who is respected as the outstanding bridge engineer in NSW. In his 46 yeas in the Public Service he designed over 550 bridges, including several outstanding structures. Swan Hill Bridge was one of his major works, and a significant advancement in technology. He was extremely proud of this bridge and prepared a technical paper on it. The bridge demonstrates a major step in the evolving pattern of our moveable bridge history.
Historical Association	****
Aesthetic/Technical Significance	The Swan Hill Bridge has aesthetic significance due to its outstanding setting and landmark qualities. The bridge provides a gateway to NSW from the major urban area of Swan Hill. It is a focus of the town to the river, which it dominates by its size and mass. The setting within the town of a lift bridge is rare, being only duplicated (with Roads and Maritime Services (replacing Roads and Traffic Authority) bridges) at Tooleybuc.
Social Significance	The Swan Hill Bridge has high significance in the Swan Hill / Wakool District as the main urban link across the river and the focus of movements across the river, controlling access of people and commerce. The river is the centre of social and recreational region, and the Swan Hill Bridge is the centre of this area. It is considered an important element in the Region by the local people, although there is concern at its perceived traffic inadequacies.
Research Significance	The bridge is the earliest example of an Allan Truss and Allan Lift Span on the Murray, and one of only two remaining (the other being Tooleybuc). It is also the first Allan Lift Span constructed, and served as a pattern for all subsequent lift bridges. This form of truss was designed by Percy Allan MICE, MAM, Soc. CE. In 1893 Allan produced the design of the truss which now bears his name. These were originally of two standard spans, 70ft and 90ft but the system was eventually adopted for all spans, and also used in railway construction. It probably represents the highest point in the development of timber trusses. America had changed to steel long before this time, and Australia was soon to follow. Although the truss type is often referred to as a �Modified Howe� truss, it is as different from the original Howe as each of the American types were from one another. The features of the design were: * the omission of counter braces, i.e. the use of single diagonal webs in lieu of crossed members. * the placing of all webs on the same angle so that any shrinkage could be taken up by the tightening of suspension rods * the use of swan flitches for all braces, bowed to prevent warping and twisting * the introduction of cast iron shoes at the top and bottom of braces * the adoption of open top and bottom chords, for easier painting and obviating the decay due to the entrance of water between the members in a built up chord Floor beams were placed at panel points to eliminate bending in the bottom chord. The cast iron butting blocks at the ends of the webs served two purposes. Firstly, they eliminated the worst features of previous types which was lodgement of water in re-entrant corners. Secondly, they allowed easy removal and renewal of the webs. The whole system was designed with maintenance in mind, as any member can be renewed without staging room below. the trusses were designed for a live load of 18.8 cwt per lineal foot of span, or a 16 on traction engine. Factor of safety in timber was 7. The economy of the system was quoted by Allan: �In the superstructure of one 90ft span carrying a 15ft deck, there is a 500cub ft. less timber than in the 1886 type of truss, which, in conjunction with the greater ease in framing together (notably in the bottom chord, where no fitting is required) the fewer bolt holes to be bored, and the short length of timber employed, effects a large saving in cost of each span. The economy is more marked when it is considered that the old trusses were designed to carry a 15ft carriageway, whereas the Allan Trusses are designed to carry two 5ft footways in addition to a 15ft carriageway. Thus it will be seen that the later design of truss bridge offers greater facilities for traffic at a much reduced cost.� Allan was aware of the problems found in splices in bottom chords, and developed a testing machine for those at Pyrmont. Nevertheless, he appears to have not properly solved the problem, as these joints are the major causes of problems in the trusses. Allan reported that his splice details was adopted in America. Longer spans (over 90ft) required overhead bracing to stabilise the to chord. This required trusses to be 21ft deep �to allow clearance under the bracing from a loaded wool wagon.� Several important bridges were built by Allan using his truss. The Hampden Bridge at Wagga Wagga was built in 1895 and at the time was the largest timber structure in the colony. The Pyrmont Bridge (1902) was larger in deck area than any in the UK at the time, and its electrically opened spans were considered marvellous and daring by the English Engineers of the time. The Allan Truss remains a fine example of timber truss technology. The bridge is a fine example of its type and one of only two remaining. It was the first of its type and a significant variation to a class.
Rarity	****
Representativenes	****
Integrity/Intactness	****
Assessed Significance	State

References

Type	Author	Year	Title
Written	R.P. Whitworth	1866	Baillieres New South Wales Gazetteer and Road Guide

Written	W.C. Foster	1985	Sir Thomas Livingston Mitchell and his World, 1792-1855

Written	R.B. Ronald	1960	The Riverina: People and Properties

Study details

Title	Year	Author	Inspected by	Guidelines used
Murray Crossings Heritage Study	1998	Hughes Trueman Reinhold		Yes

Custom fields

Roads and Maritime Services (replacing Roads and Traffic Authority) Region	South West
Bridge Number	3215
CARMS File Number	469.1339
Property Number	Bridge
Conservation Management Plan	****

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