Como (Georges River) Underbridge | NSW Environment & Heritage

Culture and heritage

Heritage

Como (Georges River) Underbridge

Item details

Name of item: Como (Georges River) Underbridge
Other name/s: Oately - Georges Rvr Undbr. Georges Rv Como Ub.
Type of item: Built
Group/Collection: Transport - Rail
Category: Railway Bridge/ Viaduct
Primary address: Railway location, Illawarra Line 19.925km Concrete Bridge 1.5Km Before Station, Como, NSW 2226
Parish: St George
County: Cumberland
Local govt. area: Sutherland

Boundary:

The curtilage is limited to the footprint of the Georges River Underbridge, its piers and abutments (adjacent iron lattice bridge is excluded).Northeast: Rear of abutmentsSouthwest: Rear of abutmentsSoutheast: Line along edge of concrete piersNorthwest: Line along edge of concrete piers
All addresses
Street AddressSuburb/townLGAParishCountyType
Railway location, Illawarra Line 19.925km Concrete Bridge 1.5Km Before StationComoSutherlandSt GeorgeCumberlandPrimary Address

Owner/s

Organisation NameOwner CategoryDate Ownership Updated
RailCorpState Government 
RailCorpState Government 
RailCorpState Government 

Statement of significance:

The Georges River Underbridge is of local significance as a highly visible landmark for users of the Georges River. The bridge is good representative example of prestressed concrete box girder design, using a rare form of prestressing during its construction.
Note: The State Heritage Inventory provides information about heritage items listed by local and State government agencies. The State Heritage Inventory is continually being updated by local and State agencies as new information becomes available. Read the OEH copyright and disclaimer.

Description

Designer/Maker: Donovan H Lee and Partners, London
Builder/Maker: John Holland (Australia)
Construction years: 1965-1972
Physical description: Two parallel, seven span, single track, prestressed concrete rectangular box girder railway bridges, with 48.49 m spans between skewed concrete piers and abutments, with cantilever reinforced concrete "wings" to form the track decks.

An earlier, iron lattice girder bridge is situated parallel and to the east of the underbridge.
Physical condition and/or
Archaeological potential:
The bridge is in good condition with the following defects: minor cracks and spalling concrete in all piers.
Date condition updated:20 Oct 09
Current use: Carries the double track Illawarra Line over the Georges River.
Former use: Nil

History

Historical notes: The Illawarra Line was opened in stages progressively southward from Sydney between 1884 and 1893. The line was opened between a junction with the Main Southern Line at Eveleigh (Illawarra Junction) and Hurstville on 15 October 1884. After the Railway Act of 1888 the Existing Lines became the New South Wales Government Railways under Commissioner Eddy. He began a programme of adding more tracks to the overcrowded lines through duplications and quadruplications, and upgrading infrastructure such as bridges. The line was extended to Wollongong in 1887 and reached its fullest extent of Bomaderry, across the Shoalhaven River from the town of Nowra, New South Wales in 1893. Consolidation of the line continued under successive Commissioners into the early 1920s. The original 1884 duplication was expanded in 1923.

The site was chosen in the 1880s by John Whitton for taking the new Illawarra Railway across the Georges River. Whitton favoured iron lattice girders for the bridge but was prevented by Government from building a 2-track structure and so a single track bridge was completed in 1885. It was a monumental blunder because traffic demand soon exceeded single line capacity and the bridge became a bottleneck for 85 years.

Reinforced concrete rail bridges had been tested earlier on the New South Wales rail network; however their low live load to self weight ratio meant that they were less economical than steel bridges. Prestressed concrete was introduced into Australia in the mid-1950s and its application to a wide range of structural uses grew rapidly. In bridge construction, the use of prestressing cancelled out the self weight of the girders, thereby increasing their efficiency to a competitive level. The first prestressed concrete girder railway bridge built in NSW was built in Dombarton (1962). IN the following decade the maximum span for prestressed bridges increased dramatically with the introduction of the box girder and segmental construction techniques.

Plans to eliminate the bottleneck began in the 1960s when it was decided to use the greater experience of prestressed concrete in England to design a new bridge for 2 track, and higher than the 1885 bridge in order to ease the original steep approach gradients. The box segments had been cast in a yard on the Hurstville side and transferred on to temporary falsework for stressing into the 160 foot girders.

The bridge was opened on 27 November 1972. The adjacent original iron lattice girder bridge remains, but is in ownership of Sydney Water.

Historic themes

Australian theme (abbrev)New South Wales themeLocal theme
3. Economy-Developing local, regional and national economies Transport-Activities associated with the moving of people and goods from one place to another, and systems for the provision of such movements Building the railway network-
8. Culture-Developing cultural institutions and ways of life Creative endeavour-Activities associated with the production and performance of literary, artistic, architectural and other imaginative, interpretive or inventive works; and/or associated with the production and expression of cultural phenomena; and/or environments that have inspired such creative activities. Evolution of design in railway engineering and architecture-
8. Culture-Developing cultural institutions and ways of life Creative endeavour-Activities associated with the production and performance of literary, artistic, architectural and other imaginative, interpretive or inventive works; and/or associated with the production and expression of cultural phenomena; and/or environments that have inspired such creative activities. Creating railway landscapes-

Assessment of significance

SHR Criteria c)
[Aesthetic significance]
The Georges River Underbridge is has aesthetic significance as the concrete bridge and the adjacent iron lattice girder bridge offer a significant landmark for users of the Georges River.

The Georges River Underbridge is technically significant as each box girder was cast in segments, which were assembled on site into full span girders using 'Macalloy' bars as the prestressing tendon, a rare example of this method in New South Wales.
SHR Criteria e)
[Research potential]
The Georges River Underbridge is has research significance as the location of the bridge adjacent to the John Whitton designed iron lattice girder bridge exhibits the evolution of rail bridge design during the 20th century.
SHR Criteria g)
[Representativeness]
The Georges River Underbridge is a good representative example of prestressed concrete box girder construction.
Integrity/Intactness: The Georges River Underbridge is of high integrity, retaining its original fabric in a good condition.
Assessment criteria: Items are assessed against the PDF State Heritage Register (SHR) Criteria to determine the level of significance. Refer to the Listings below for the level of statutory protection.

Recommended management:

1. Conservation principles: Conserve cultural heritage significance and minimise impacts on heritage values and fabric in accordance with the ‘Australia ICOMOS Charter for Places of Cultural Significance’. 2. Specialist advice: Seek advice from a qualified heritage specialist during all phases of a proposed project from feasibility, concept and option planning stage; detailed design; heritage approval and assessment; through to construction and finalisation. 3. Documentation: Prepare a Statement of Heritage Impact (SOHI) to assess, minimise and prevent heritage impacts as part of the assessment and approval phase of a project. Prepare a Conservation Management Plan (CMP) prior to proposing major works (such as new additions, change of use or proposed demolition) at all places of State significance and all complex sites of Local significance. 4. Maintenance and repair: Undertake annual inspections and proactive routine maintenance works to conserve heritage fabric in accordance with the ‘Minimum Standards of Maintenance & Repair’. 5. Movable heritage: Retain in situ and care for historic contents, fixtures, fittings, equipment and objects which contribute to cultural heritage significance. Return or reinstate missing features or relocated items where opportunities arise. 6. Aboriginal, archaeology and natural heritage: Consider all aspects of potential heritage significance as part of assessing and minimising potential impacts, including Aboriginal, archaeology and natural heritage. 7. Unidentified heritage items: Heritage inventory sheets do not describe or capture all contributory heritage items within an identified curtilage (such as minor buildings, structures, archaeology, landscape elements, movable heritage and significant interiors and finishes). Ensure heritage advice is sought on all proposed changes within a curtilage to conserve heritage significance. 8. Recording and register update: Record changes at heritage places through adequate project records and archival photography. Notify all changes to the Section 170 Heritage & Conservation Register administrator upon project completion.

Listings

Heritage ListingListing TitleListing NumberGazette DateGazette NumberGazette Page
Heritage Act - s.170 NSW State agency heritage register     

Study details

TitleYearNumberAuthorInspected byGuidelines used
State Rail Authority Heritage Register Study1999SRA834State Rail Authority  No
RailCorp Section 170 Register Update2009 Hughes Trueman Pty Ltd  Yes

References, internet links & images

TypeAuthorYearTitleInternet Links
WrittenDon Fraser1995Bridge Down Under, The History of Railway Underbridges in NSW
WrittenJohn Forsyth Historical Notes for the Illawarra Line. 1960s See "Bridges Down Under" pages 144 & 145.
WrittenOates, J2003Sydney’s Forgotten Illawarra Railways

Note: internet links may be to web pages, documents or images.

rez rez rez
(Click on thumbnail for full size image and image details)

Data source

The information for this entry comes from the following source:
Name: State Government
Database number: 4801834


Every effort has been made to ensure that information contained in the State Heritage Inventory is correct. If you find any errors or omissions please send your comments to the Database Manager.

All information and pictures on this page are the copyright of the Heritage Division or respective copyright owners.