Pyrmont Bridge

The original timber Pyrmont Bridge was built in 1857. It provided quicker access to the city markets for meat from the new Glebe Island abattoir and produce from Parramatta. However, by 1893 the bridge and its later companion at Glebe Island were in danger of collapse having been eaten ‘by white ant from the top and cobra borer from the bottom’.

Replacement bridges were designed by Percy Allan of the Public Works with assistance from young engineers, J J C Bradfield and Gordon Edgell.

During his career Allan designed nearly 600 bridges and revolutionised the design of timber bridges, in particular, with his invention of the "Allan" type timber truss bridge. Allan's design focused on using marketable lengths of timber, and maximising durability and maintainability. Tension connections in timber are notoriously difficult and so Allan's successful bottom chord splice plates were used also by rail bridge designers and even in the USA.

The new Pyrmont Bridge was completed in 1902 and the Glebe Island Bridge in 1903.

Pyrmont Bridge has 12 timber truss spans and a central swing span of steel. It was the widest of all Allan’s bridges having four traffic lanes and two footways; the six trusses are beneath (and thus carry) the roadway, instead of, as in other bridges of the time, the roadway passing between two side trusses with the deck being supported off the bottom chords of the trusses.

The swing span was among the largest in the world and one of the earliest to be powered by electricity. The power came from the nearby Ultimo (tramways) Power House and the motors were of the tramway type.

The bridge was added to the New South Wales State Heritage Register on 28 June 2002, the centenary of its opening.

The opening span of the bridge soon after construction.
Source: Public Works Department print.

The bridge in its modern use as a pedestrian way.
Source: Unknown

The Engineers Australia plaque on the western abutment wall.
Source: Unknown

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Engineering Heritage Recognition Program

Marker Type	National Engineering Landmark (NEL)
Award Date	28 June 1992
Heritage Significance	The swing span was considered one of the largest and most innovative in the world at the time, and was powered by electricity before Sydney had street lighting. The timber approach spans represented the highest level of development of the timber truss. It was designed by Percy Allan with assistance from J J C Bradfield and Gordon Edgell.
Nomination Document	Available here.
Ceremony Booklet Ceremony Report	Available here.
Plaque/Interpretation Panel	Not Available.