I imagine there were quite a lot of significant timber bridges in the UK approx 80-100 years ago - Australian bridge engineering would have borrowed significantly from UK practice as most of our engineers were ex-pat Britons.
There was a substantial hardwood export industry from Western Australia in the period 1870s-1930s and I imagine some of this would have ended up in bridges in the UK? Significant volumes of Jarrah and Karri were used for block paving streets in the UK.
There are still many timber bridges on minor country roads in Australia. They were cheap and easy to build in the first place, they are not difficult to maintain
, and there is no need to spend scarce road funds on an expensive concrete replacement.
Here is an example at Morpeth, about 100 miles north of Sydney. http://g.co/maps/hgdru
That's not exactly true - they cost substantially more to maintain, particularly in recent years as timber is more expensive and the expertise to maintain bridges is not readily available.
Generally once they require major overhauls they are replaced by concrete structures. The Morpeth example is heritage listed and is being maintained as a heritage item. Others with less significance simply get demolished.
The NSW State Government has actually funded a special timber bridge replacement programme over the past 3 years to help Councils renew their dilapidated timber bridges.
While driving between Sydney and Brisbane a couple of years back, the GPS diverted me off the Pacific Highway to cut out a few KM near Ballina in north NSW.
There are two wooden bridges on this road, this was the more spectacular of the two.http://maps.google.com.au/maps?hl=en&ll ... 61,,1,2.34
Both replaced by concrete structures now.