Commonwealth Avenue Bridge

The Commonwealth Avenue Bridge are two parallel pre-stressed concrete box girder road bridges that carry Commonwealth Avenue across Lake Burley Griffin, and connect Parkes and City in Canberra, in the Australian Capital Territory, Australia.

Commonwealth Avenue Bridge
Commonwealth Avenue Bridge over Lake Burley Griffin, with Parliament House, Canberra in the background
Coordinates	35°17′30″S 149°07′37″E
Carries	Commonwealth Avenue (Motor vehicles, pedestrians, bicycles)
Crosses	Lake Burley Griffin
Locale	Canberra, Australian Capital Territory
Begins	Parkes (south end)
Ends	City (north end)
Other name(s)	Commonwealth Bridge
Owner	National Capital Authority
Preceded by	Kings Avenue Bridge
Followed by	Scrivener Dam
Characteristics
Material	Concrete
Trough construction	Steel
Total length	310 metres (1,017 ft)
Longest span	73 metres (240 ft)
No. of spans	5
Piers in water	4
No. of lanes	6 traffic (3 north / 3 southbound) Shared footway / bicycle path
History
Designer	Maunsell and Partners
Constructed by	Hornibrook
Construction start	March 1961
Opened	November 1963
Location

History

The current bridge is the fourth crossing over the Molonglo River. The first Commonwealth Avenue Bridge, completed 1916, was damaged in the 1922 flood. The second, using three Leychester-type trusses, was completed in 1924 and damaged in floods a year later. The third bridge, completed in 1927, was a modification of the 1924 bridge, by raising the bridge by one metre (three feet) and adding a fourth truss.[1] At that time, Molonglo River was not dammed to form Lake Burley Griffin.[2] Building on the plan developed by Walter Burley Griffin, in 1957 William Holford proposed to the Australian Government that the Molonglo be dammed near Yarralumla and that Canberra's 'two halves' should be joined via a lake.[3]

Construction of the Commonwealth Avenue Bridge began in March 1961 and the bridge was opened in November 1963. Concurrently, the Kings Avenue Bridge was opened in March 1962; and Scrivener Dam was completed in September 1963. Both bridges were built over a dry riverbed as Canberra was in the grip of drought. It took some time for the lake to fill; finally filled for the first time on 29 April 1964.[2]

Description

Designed by Maunsell and Partners and constructed by Hornibrook, the Commonwealth Avenue Bridge comprises five spans of continually pre-stressed concrete, totalling 310 metres (1,020 ft). The provide an entry and exit clover leaf layout, on the bridges southern approaches, operate structures were constructed totalling 49 metres (161 ft) each, in four approximately equal spans.[4] The main superstructure is of multi-web box section shape, continuous over the five spans, ranging from 56 to 73 metres (185 to 240 ft). The central piers, octagonal in shape, are carried on 2-metre (6 ft) diameter reinforced concrete cylinders. Each of the pre-cast concrete box girder sections are 3 metres (10 ft) each.[5][6]

In 2019 advanced plans were announced to widen the Commonwealth Avenue Bridge to allow for an expansion of the Canberra light rail network from Civic to Woden.[7][8]

References

1. Mildenhall, William James (1925). "Second Commonwealth Avenue Bridge" (image). ACT Heritage Library: ImagesACT. Government of the Australian Capital Territory. Retrieved 25 March 2020.
2. Ling, Ted, ed. (2013). "Expansion on a grand scale" (Part 1: Chapter 5). Government Records about the Australian Capital Territory. National Archives of Australia. Retrieved 25 March 2020.
3. Ling, Ted, ed. (2013). "The Holford Report" (Part 1: Chapter 5). Government Records about the Australian Capital Territory. National Archives of Australia. Retrieved 25 March 2020.
4. "Lake Burley Griffin Scheme, consisting of Lake impounded by Scrivener Dam, and Commonwealth and Kings Ave. bridges" (Chapter 6). The Institution of Engineers, Australia, Canberra Division. 22 February 2001. Retrieved 25 March 2020.
5. Birkett, E. M.; Fernie, G. M. (July 1964). "Bridges in the Canberra Central Lake Area - Design" (PDF). The Journal of the Institute of Engineers, Australia. The Institution of Engineers, Australia. 36: 139–147. Retrieved 25 March 2020.
6. Kelleher AO, Graeme (6 July 2019). "Commonwealth Avenue Bridge - Heritage". Lake Burley Griffin Guardians. Retrieved 25 March 2020.
7. Dingwell, Doug (3 April 2019). "Move to widen Commonwealth Ave Bridge, renew dam gets federal backing". WA Today. Retrieved 25 March 2020.
8. Bushnell, Ian (22 May 2019). "Light rail prompts NCA to look at replacing Commonwealth Avenue Bridge". RiotACT. Retrieved 25 March 2020.

Attribution

 This article incorporates text available under the CC BY 3.0 AU licence.

External links

• Clough, Richard (1963). Commonwealth Avenue Bridge under construction - detail, Canberra (photograph) – via Trove, National Library of Australia.
• Commonwealth Avenue Bridge, Canberra (photograph). National Archives of Australia. 1963.