Glebe Island Bridge
The Glebe Island Bridge is a heritage-listed disused swing Allan truss road bridge that carried Victoria Road across Johnstons Bay, located in the inner city Sydney suburb of Pyrmont, New South Wales, Australia. The bridge, which connected Rozelle to Pyrmont by road, is one of the last remaining swing bridges of its type in Australia and in the world. It was designed by Percy Allan and built from 1899 to 1903 by Bridges Branch of NSW Public Works Department. It is also known as RMS Bridge No. 61. It was added to the New South Wales State Heritage Register on 29 November 2013 and was listed on the Register of the National Estate on 19 April 1989.
History
Sydney was declared a city in 1842 and was concentrated in the area currently occupied by the modern CBD. In the mid-1800s, it was a mix of commerce, retail, residences, manufacturing works and factories, with the Botanic Gardens and Domain to the east, port activities to the west and north and road outlets at its southern border leading to the inner western suburbs via the Parramatta Road, which was also the beginning of the Great Western Highway. By mid-century, it had become clear that a shorter route out of the city was available, across Johnstons Bay to the Glebe Island and on to Annandale.First bridge
The first Glebe Island Bridge was a private toll-bridge completed in 1862 and was a timber beam viaduct with a small, one arm, hand-cranked swing-span tucked into the Pyrmont shore. After 30 years, this bridge was in need of extensive repairs and the Colonial Government purchased the structure and the Public Works Department began planning a replacement bridge. Work on the new Pyrmont Bridge and the bridge across Black Wattle Swamp shortened the travel distance to the inner west suburbs making it easier for produce to be conveyed to the city. A previously un-used part of Johnstons Bay was promoted as the site for a larger abattoir than the others previously used around the closer areas of high water. The new abattoir, to be opened in January 1860, was provided a punt system to cross the short distance to Pyrmont. Work commenced on the first Glebe Island bridge in 1860; and the first bridge opened for traffic in 1861.Second bridge
The construction of the second bridge related also to a project commenced in the 1880s for the Five Bridges Route, to facilitate traffic flow from the city to the northern and western suburbs of the expanding city. Bridges were to be built or replaced at Pyrmont Bay, Glebe Island, Iron Cove, Gladesville and Fig Tree. For this project, the Pyrmont Bridge and the Glebe Island Bridge were purchased from their private owners and new bridges were built at Gladesville, Iron Cove and Fig Tree.These completed, attention turned to replacement of the Pyrmont and Glebe Island Bridges. The Sydney Morning Herald reported in September 1890:
"The Departmental Board appointed by the Minister for Public Works nearly a year ago to consider the desirability of constructing new bridges to replace the present Pyrmont and Glebe Island bridges... has now furnished the Minister with a lengthy report on the subject. The Board has decided in favour of the construction of a new bridge adjoining the present Pyrmont Bridge. The structure recommended is an iron or steel superstructure on cast-iron cylinders, with a roadway 12ft, in width, and two 12ft. footpaths....With regard to the Glebe Island Bridge, the Board recommended the construction of a bridge close to the present one, of a character similar to the proposed Pyrmont Bridge, at a cost of."
An international design competition for a new "Pyrmont Bridge" was called in 1891. The Department of Public Works submitted a non-conforming design based upon a much larger bridge than specified in the design brief.
Prizes were awarded but no designs were selected and the proposal was deferred, largely owing to the economic downturn of the early 1890s but also owing to different opinions regarding the best approach. The Chief Engineer for Harbour and Rivers, C. W. Darley, favoured the construction of a new bridge - the Chief Engineer for Roads and Bridges, Robert Hickson, favoured the reclamation of Darling Harbour as far north as Bathurst Street and no replacement for the Pyrmont Bridge at all.
In 1894 the proposal was referred to the Parliamentary Standing Committee for Public Works and, reporting in June, the Committee favoured no particular scheme but recommended that, when renewal of Pyrmont and Glebe Island bridges became advisable, they should be replaced by timber structures.
On 21 November 1894 the Public Works Committee recommended that Pyrmont Bridge be replaced by a timber bridge with steel swing-span, to cost, and that Glebe Island Bridge did not require renewal. No funds were allocated, though and no action resulted. By 1897, however, the Committee had reconsidered its stance and recommended the replacement of the old Glebe Island Bridge with a stone causeway and a bridge with a steel swing-span, at a cost of. Parliament voted the funding for these works in 1898 and detailed design work commenced in the Public Works Drawing Offices.
Design of the bridges was led by Percy Allan, who had been appointed Engineer-in-Chief for bridge design in 1896. His assistant engineer was Ernest de Burgh and the junior engineers were H. H. Dare, J. J. Bradfield and J. W. Roberts, all of whom went on to have distinguished careers in public works engineering. Bradfield had charge of the team responsible for the substructure, foundations, abutments and retaining walls for both bridges. Tenders for the construction of both bridges were invited in March 1899.
For both sites, Allan designed an electrically-operated swing bridge, the earliest use of electrical power for this purpose in Australia. The bridges were considered very innovative at the time of their construction and attracted international attention. For the Glebe Island Bridge, the large pivot pier was founded on a nest of timber piles capped by concrete, whereas the Pyrmont pivot pier was founded on rock.
Third and current bridge
Construction commenced on the Glebe Island Bridge and Pyrmont Bridge at the same time but Glebe Island involved more extensive land resumptions, extensive waterfront reclamation and the construction of an elevated causeway across Glebe Island. Over of mud was dredged to establish the causeway and the fill was obtained by cutting down what was left of the hillock of Glebe Island, producing of flat land for railway yards and of deepwater frontage for wharfage. In August 1899 a large load of ballast being placed for the causeway to the new bridge slipped sideways and crushed the piles of the old bridge, rendering it unfit for anything but pedestrian traffic for the following two weeks.Construction of the trussed swing spans at each site was by simple cantilevering out from the steel pivot ring. Where timber trusses were used for the approaches of the Pyrmont Bridge, the Glebe Island Bridge used two steel deck trusses, then stone-faced embankments to reach each shore. The use of steel trusses for the approach spans had been part of Allan's original design for the Pyrmont Bridge but the Parliamentary Standing Committee on Public Works directed that this material be replaced with timber, presumably as a cost-cutting measure. When Glebe Island Bridge was built, Allan's original specification was reinstated.
The contractor for construction was H. McKenzie and Sons and the bridge was opened on 1 July 1903 by Miss Lily See, daughter of Premier, Sir John See. It was opened the year after the opening of the new Pyrmont Bridge over Darling Harbour, which has a similar design. The bridge was designed by Percy Allan of the New South Wales Public Works Department who also designed the Pyrmont Bridge. During normal operation the two swing spans rotated about a central vertical axis.
The Glebe Island Bridge operated from 1903 to 1995 with little interruption and few major works, apart from maintenance, being undertaken. In 1933, the bridge underwent an underwater upgrade, with underpinning to replace decayed piles around the central pier. In 1961, the DC electricity supply from the Tramways system was shut down, as was the tramway system in Sydney. A new AC supply was obtained from the local reticulated network and a set of rectifiers was installed in a small kiosk erected on the north east side of the bridge. In the 1980s, the Control Cabin was burnt out and was subsequently rebuilt to the original design.
In 1995 the bridge was decommissioned being made redundant with opening of the adjacent Anzac Bridge, and remains in a permanently open position with no access to pedestrians or vehicular traffic. The bridge was operated and used for access by cyclists in the annual Spring Cycle in October until 2008.
On 18 April 1989 the bridge was listed on the Register of the National Estate.
A 2009 structural assessment found the bridge in "very poor condition" and in April 2013 a new report found that it had deteriorated further. City of Sydney Council and the community groups lobbied the state government to restore the structure and reopen the bridge for pedestrian and cyclists. A cost–benefit report by ACIL Allen consultants for Transport for NSW on options for the bridge was released in September 2013. In 2015, it was suggested the bridge could be reused to extend the Inner West Light Rail as part of the White Bay redevelopment.
Description
The Glebe Island Bridge over Johnstons Bay is an electrically-operated, low-level, steel, central-swing-span road bridge. The central swing span is supported by a massive pivot pier, founded on a nest of timber piles capped by concrete, on which it can rotate through ninety degrees to allow passage of maritime traffic. The approach spans are two steel deck on stone-faced piers and stone-lined abutments. The bridge includes constructed embankments on both sides of its western approach.The bridge has an approach span at each end of, two main spans of and an overall length of. The roadway is wide between kerbs and has a wide footway on each side. The central pivot in the waterway is protected by an extensive ring of timber piles. The swing span is mounted on a steel roller track on the cylindrical stone masonry and concrete pivot pier and is swung by means of a 600 volt motor.
Traffic was controlled by lights and a pair of timber swing-gates on either end which were electronically interlocked to ensure that the bridge cannot open until the gates are closed.
The bridge includes a rare surviving operable mercury-arc rectifier, as well as some early silicon rectifiers, installed in 1960 when the reticulated DC supply was discontinued.
Both Pyrmont and Glebe Island Bridges were electrically operated and could swing in 44 seconds, much faster than contemporary bridges in the world. Pyrmont Bridge, also designed by Percy Allan, has more numerous fixed spans of timber than Glebe Island Bridge where they are of steel supplemented by stone causeways. The swing-span of Glebe Island Bridge is smaller than that of Pyrmont.
High quality Pyrmont yellowblock sandstone is thought to be used for dimension stone and Pyrmont coloured sandstone on the abutment facing and causeway fill.