Pyrmont Bridge

Pyrmont Bridge
Pyrmont Bridge in 2014.
Carries	Pedestrian and bicycle traffic
Crosses	Cockle Bay
Locale	Darling Harbour, Sydney, New South Wales, Australia
Owner	Roads & Maritime Services
Maintained by	Sydney Harbour Foreshore Authority
Engineering design	Percy Allan
Design	Swing bridge
Material	Ironbark timber; Steel central spans
Total length	369 metres (1,211 ft)
Number of spans	14
Vertical clearance	6.5 metres (21 ft)
Construction begin	6 December 1899 (1899-12-06)
Construction cost	£112,500
Opened	28 June 1902 (1902-06-28)
Daily traffic	~14,000 pedestrians
Preceded by	Pyrmont Bridge (1858–1902)
Followed by	Western Distributor (1981–present)
Heritage status	Heritage Council of NSW; Engineers Australia (1992) National Engineering Landmark
References:

The Pyrmont Bridge, a swing bridge across Cockle Bay, is located in Darling Harbour, part of Port Jackson, west of the central business district in Sydney, New South Wales, Australia. Opened in 1902, the bridge initially carried motor vehicle traffic via the Pyrmont Bridge Road between the central business district and Pyrmont. Since 1981 the bridge has carried pedestrian and bicycle traffic only, as motor vehicles were diverted to adjacent freeway overpasses.

History

The first Pyrmont Bridge was opened on 17 March 1858, and was a wooden pile bridge with an iron centre 'swing panel' to allow ships to pass. In the first two weeks 20,000 pedestrians paid the one penny toll. It was also crossed by "932 carts and drays, 43 gigs, 17 carriages and 125 horse and rider." When the government bought the bridge for £52,500 from the Pyrmont Bridge Company in 1884, they abolished the toll. The wooden Pyrmont Bridge vanished with the construction in 1902 of a new steel bridge which took 33 months to build and was completed in time to accommodate Sydney's first cars.

Description

Pyrmont Bridge, circa 1902–1917.

The foundation stone for the new bridge was laid on 6 December 1899 by E. W. O'Sullivan and the bridge was opened for traffic on 28 June 1902 by the Governor of New South Wales, Harry Rawson. The bridge was designed under the engineering supervision of Percy Allan. The bridge had one of the largest swing spans in the world at the time of its construction and it was one of the first to be powered by electricity. Allen also designed the similar Glebe Island Swing Bridge, completed in 1903.

The Pyrmont Bridge is 369 metres (1,211 ft) long and cost £112,500 to build. The bridge is made up of 14 spans with Australian ironbark timber is used on 12 spans, while the two central spans, which swing, are constructed from steel. The swingspan weighs 1,000 tonnes (1,100 short tons) and is supported on a base made from concrete and Hawkesbury Sandstone. The base is filled with mass concrete and weighs 6,800 tonnes (7,500 short tons). The swingspan is 13 metres (43 ft) in diameter and 19 metres (62 ft) deep. The water is 6.5 metres (21 ft) deep and the base extends a further 10 metres (33 ft) below the sea floor.

Pyrmont Bridge takes approximately 60 seconds to open completely to 83 degrees. It has to be opened for vessels more than 7 metres (23 ft) high. Vessels/barges up to 21.5 metres (71 ft) wide can pass through the channel once the Bridge has been opened. Pyrmont Bridge is driven by the original two 50 horsepower (37 kW) 600 electronvolts (96 aJ) DC General Electric type 57 electric motors. Manual drum-type General Electric tramway controllers are used to drive the motors for the swingspan and gates. Power to operate the bridge was originally drawn from the Ultimo Power House (now the Powerhouse Museum). As a young engineer, J.J.C. Bradfield helped design the sandstone abutment walls at each end of Pyrmont Bridge.

In 1981 the Wran government ordered the bridge to be demolished, but later revoked this decision. The bridge was closed to vehicular traffic on 7 August 1981, the traffic having been diverted over the Western Distributor freeway structures built further south of Cockle Bay, and it was then re-opened as a pedestrian bridge as part of the re-development of Darling Harbour as a recreational pedestrian precinct. The swing bridge remains in operation, and opens to a schedule managed by the Sydney Harbour Foreshore Authority.

In 1992 Engineers Australia recognised the bridge as a National Engineering Landmark.

Modifications

Between 1988 and 2013, the bridge carried the elevated Sydney Monorail, which traveled between Darling Harbour and the Sydney central business district. The monorail track rested on a pivot that allowed the track to remain stationary while the bridge swung underneath. The pivot allowed the monorail to continue to cross the bridge even when the bridge was opened. Upon the closure of the Monorail in June 2013 the hydraulic lifting rams and support infrastructure were removed, and the control cab relocated to its original position in the middle of the bridge.

Gallery

• 

  The point at which the bridge turns

• 

  Pyrmont Bridge mid-swing.

• 

  The swinging operation is controlled from a tower in the centre of the bridge. Control Cabin relocation 2013

• 

  The arc-shaped split between bridge sections is shown here.

• 

  Pyrmont Bridge (with monorail)

• 

  Monorail travelling over Pyrmont Bridge while the bridge is open.

See also

• List of bridges in Sydney
• Historic bridges of New South Wales

Further reading

• "Pyrmont Electric Swing Bridge". The Engineer (London) 123: 75–8, 84, 103–6, 110, 124–6, 132, 150–3. 1917. 

External links

• Kass, Terry (February 2006). "RTA Thematic History: A component of the RTA Heritage and Conservation Register". NSW Roads & Maritime Services (PDF) (2nd ed.). Government of New South Wales. Retrieved 12 January 2015. 
• Pyrmont Bridge at Structurae
• Engineers Australia