Nowra Bridge, Shoalhaven River, Nowra NSW - Truss Bridges on Waymarking.com

The Nowra Bridge is the only example of a Whipple pin-jointed truss in service in New South Wales. The trusses were manufactured by Edge Moor Iron of Delaware, USA to the design of noted American bridge engineer C. Shaler Smith. It is unusual because at the time of its construction, colonial Australia was very attached to British engineering practice in contrast to American practice. The piers were manufactured locally by the Atlas Foundry.

This bridge is mentioned in several places as being originally for railway purposes, but there are some reasons to doubt this. The bridge was completed with a width suitable for two railway tracks or road carriageways and was in service 12 years before the railway reached the current southern terminus at Bomaderry in 1893. The railway was of single track from the outer Sydney suburbs and remains that way from Unanderra, some 70km north. The railway had a timber trestle bridge built across Bomaderry Creek (see waymark WM8WDZ "Bomaderry Creek Timber Trestle Bridge") but the railway on the south side of Bomaderry Creek curves eastward. An examination of maps would indicate that the railway would need to turn west after crossing Bomaderry Creek and turn very sharply south to cross the Shoalhaven River on the Nowra Bridge.

According to Don Fraser; "Bridges Down Under"; Australian Railways Historical Society 1995,
"
A particular feature of contemporary American bridges was the use of single large diameter pins at the joints rather than a group of small diameter rivets as was the British practice. The Americans were able to demonstrate that their bridges could be erected far more quickly using the pin-jointed construction. But the pins were a long-term problem for maintenance and strengthening. If the pins were withdrawn, the structural integrity of the joints was lost causing the bridge to collapse. Therefore expensive temporary supports would have to be used. Considerable international debate took place about the relative merits of the British-European riveted construction and the American pin-jointed construction for trusses. the former recognized the inherent safety of multiple small pins (rivets) and the ease of repairs and strengthening; the latter lacked these attributes but were 20 to 40% cheaper so could be over-designed to ensure safety and still be easier to construct. "

Amongst the challenges in constructing the Nowra Bridge included the depth of the piers which extend some 30m below the high water mark into a soft alluvium. Firm footing was difficult to achieve. The crossing of the Shoalhaven River was duplicated in 1980 with a concrete box-girder construction and similar difficulties in finding a firm foundation.

Parking Coordinates:: N 34° 51.915 W 150° 36.155 Date Built: 01/01/1881 Length of Span: 342m overall, end truss 56m, 7 trusses of 38.5m and an approach span of 15m. It is 5.8m wide between the kerbs and has a 1.3m wide footpath. www: http://www.rta.nsw.gov.au/cgi-bin/index.cgi?action=heritage.show&id=4301658

Visit Instructions:
Log your find with a picture of the bridge with yourself or your GPS in the foreground. This shot does not have to be taken "on" the bridge. The shot should show the "truss" structure of the bridge as well.

Recent Visits/Logs:

Date Logged Log User Rating   01/10/2016 Grahame Cookie visited it 02/23/2013 2BluFish visited it 07/28/2011 Tuena visited it 12/29/2010 Whitepaws9 visited it

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