Allan Truss Bridges

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The third type of timber truss bridges are the Allan truss bridges.  Percy Allan joined Public Works Department of NSW and in 1890, he designed a completely new truss based on the American Howe truss.  It had many improvements over the McDonald truss, could carry heavier loads and used less timber. The main advantage was the use of many smaller pieces of timber spliced together for the top and bottom chords.  This did away with the huge single beam of earlier truss designs.  Also, the top and bottom chords had the timber beams arranged in pairs with a gap between them. This allowed the iron rods to be placed in the gaps instead of drilling holes in the timber.  The gaps also helped prevent water collecting and rotting the timbers. Another significant advantage was that any piece of timber could be replaced without taking the bridge out of service.
Allan truss bridges were built from 1894 to 1929 and 105 were constructed in this period.

*!  LONG PAGE LOAD TIME !*

Statistics
Number built:    105
Number remaining:    25 (20 under state government, 5 under local council)
Number to be preserved:    11

Bridges Remaining:

Bridge Name
Date Built
# of Spans
Location
Waterway Name
Status
To be preserved?
Abercrombie
1919
3
South of Blayney
Abercrombie River
Rebuilt
Yes, for now
Barrington
1920
2
Barrington
Barrington River
Not rebuilt
No
Beryl
1927
2
West of Gulgong
Wyaldra Creek
Not rebuilt
Yes, for now
Carrathool
1922
2 + bascule
Carrathool
Murumbidgee River
Under rebuild
Yes
Charleyong
1901
1
Nerriga Road
Mongarlowe River
Not rebuilt
No
Dunmore
1899
3 + lift
Woodville
Paterson River
Rebuilt
Yes
Foxlow
1896
1
Hoskinstown Road
Molonglo River
Not rebuilt
Not sure - this is a council bridge
Gundaroo
1920
1
Gundaroo
Yass River
Demolished
Demolished March 2014
Hampden
1895
3
Wagga Wagga
Murumbidgee River
Demolished
Demolished July 2014
Hinton
1901
2 + lift
Hinton
Paterson River
Rebuilt
Yes
Mill Creek
1929
1
East of Wisemans Ferry
Mill Creek
Bypassed
Yes
Morpeth
1898
3
Morpeth
Hunter River
Partially rebuilt
Yes
Paytens
1926
2
Grenfell-Eugowra Road
Lachlan River
Not rebuilt
Yes, for now
Pretty Point
?
1
New Buildings Road
Mataganah River
Demolished
Cosmetic only
Pyrmont
?
n/a
Sydney
Sydney Cove
Rebuilt
Yes
Rossi
1899
3
Goulburn
Wollondilly River
Original
Yes, without modern materials
Swan Hill
1896
2 + lift
Swan Hill
Murray River
Rebuilt
Yes, but not as vehicle bridge
Tharwa
1895
4
Tharwa
Murumbidgee River
Rebuilt
Yes
Tooleybuc
1925
2 + lift
Tooleybuc
Murray River
Partially rebuilt
No
Vacy
1898
2
Vacy
Paterson River
Under rebuild
No
Victoria
1879
3
Picton
unknown
Original
Yes, without modern materials
Wallaby Rocks
1897
3
West of Sofala
Turon River
Rebuilt
No
Wee Jasper
1896
1
Wee Jasper
Goodradigbee River
Partially Rebuilt
Yes



Abercrombie Bridge

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This bridge is located on Abercrombie Road about 55km south of Blayney and 112km north of Goulburn. It is a three span bridge over the Abercrombie River.  It is built in 1919 on the masonry piers of a former Old PWD bridge.  It is unique in that it has two different truss span sizes.  The centre span is a 90 foot span while the outer two are 70 foot spans. The bridge has been rebuilt and strengthened and unfortunately, painted white.  It would be nice if some of the timber truss bridges were left in the old colours - brown in this bridge's case.

Abercrombie1

View of the bridge from a convenient hill.

Abercrombie2

View of the bridge showing the different truss heights and the steel railing.

Abercrombie3

View of the bridge showing the stressed laminated deck and the maintenance gantry.

Abercrombie4

Closer view of the centre truss.

Abercrombie5

View of the bridge from the nearby hill.

Abercrombie6

Closer view of the bridge.


Barrington Bridge

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Barrington Bridge is located just to the north of the small town of the same name and crosses the Barrington River.  The bridge is a two span bridge built in 1920. It has not been rebuilt and is not going to be preserved. It is noticeably narrower than most timber truss bridges.

Barrington1

View of the bridge from.

Barrington2

View from the north side showing how narrow this bridge is.

Barrington3

Side view of the north truss.

Barrington4

Closer view of the truss.

Barrington5

The rounded posts at the end of the railing is a feature on nearly every timber bridge in NSW.

Barrington6

View showing the uneven lengths of the cross beams.  On rebuilt bridges these are all exactly the same length.

Barrington7

View from the north side.


Beryl Bridge

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Beryl Bridge is a small two span bridge crossing Wyaldra Creek about 8km west of Gulgong on Beryl Road. It uses the smaller 70 foot trusses. It has recently had substantial maintenance carried out, but has not been upgraded or rebuilt. The bridge was built in 1927.

Beryl1

View of the whole bridge.

Beryl2

View of the bridge from the west side.

Beryl3

View of the underside.

Beryl4

View of the bridge from the east side.

Beryl5

View showing the cross beams.

Beryl6

View of the bridge from the creek bed.

Beryl7

View of the bridge deck.


Carrathool Bridge

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This bridge is a two span Allan truss with a bascule lift span. It is one of only two remaining bridges with this type of lift span and the only one left with timber trusses.  The bridge was built in 1922 and crosses the Murumbidgee River.  The lift span has not been operated since the 1930s and cannot lift now as the deck has been laid continuously over the joins.  As of mid 2014, the bridge is undergoing restoration.  This will not include making the lift span operational again. The truss spans have been restored and work is underway on the ironwork of the lift span.  New steel railings have been installed on the lift span and southern approach. This bridge is going to be preserved, but I've heard that the local council would rather see it replaced and have the original stuffed and mounted somewhere else.

Carrathool1

View of the bridge.

Carrathool2

View of the deck and lift span tower..

Carrathool3

View of the two truss spans.

Carrathool4

View of the lift structure.

Carrathool5

View of the trusses.

Carrathool6

Detail of the lift mechanism. It was operated by hand and the weights rolled down the slopes as the lift span was raised.

Carrathool7

View of the lift span.

Carrathool8

Information plaque.

Carrathool9

View of the bridge sign.


Charleyong Bridge

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This bridge is a single span bridge built in 1901 over the Mongarlowe River.  It is located on Nerriga Road about 30km north of Braidwood. The bridge has had its piers reinforced with steel.  The truss span, however, is pretty much original.  This bridge is not going to be preserved.

Charleyong1

View of the bridge.

Charleyong2

Side on view of the bridge. This view shows the steel pier reinforcements.

Charleyong3

View of the bridge trusses and deck.

Charleyong4

Charleyong Bridge is in a quiet, peaceful location.

Charleyong5

View of the approaches with reinforced piers..

Charleyong6

View of the bridge.



Dunmore Bridge

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Dunmore Bridge was built in 1899 over the Paterson River. It is a three span overhead braced truss with a lift span.  The lift span has not operated since the 1940s. The bridge has recently been fully rebuilt. This involved building completely new trusses. The old trusses were lifted out and the new ones in by a 300 ton crane.  The only thing that I think could improve it would be to use timber railing rather than the steel railing used for truss bridge rebuilds. This bridge is difficult to photograph as there is no access to get side views and there is a lot of traffic.

Dunmore1

Distant side view of the bridge.

Dunmore2

View from the south end.

Dunmore3

View of the bridge trusses and deck.



Foxlow Bridge

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This bridge is a single span truss over the Molonglo River. It is located on Hoskinstown Road just off Captains Flat Road about 12km north of Captains Flat. Built in 1896, it is still pretty much original.  It has a 5 ton load limit and a 3 metre height limit.  Unlike nearly every other timber truss bridge, it has a single layer of deck planking.

Foxlow1

General view of the bridge.

Foxlow2

Side view of the bridge and Molonglo River..

Foxlow3

I'm not sure why the row of white posts was there.

Foxlow4

Close angle view of the bridge.

Foxlow5

Underside of the bridge showing the single layer of deck planking.

Foxlow6

End view of the bridge.

Foxlow7

View of the deck..

Foxlow8

Detail of the bottom chord and diagonal member mounting points.



Gundaroo Bridge

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Gundaroo Bridge is a single span truss built in 1920 over the Yass River. The bridge was replaced in 2009 and the old bridge was demolished in March 2014. These photos were taken in February 2014. The bridge was located on Sutton Road just south of the community of Gundaroo.

Gundaroo1

General view of the bridge.

Gundaroo2

End view of the bridge.

Gundaroo3

View from the north side.

Gundaroo4

Close angle view of the bridge.

Gundaroo5

View of the whole bridge.

Gundaroo6

View of the bottom chord in very poor condition.

Gundaroo7

View of the top chord.

Gundaroo8

The new and the old.


Hampden Bridge

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Hampden Bridge was built in 1895 over the Murumbidgee River in Wagga Wagga and was the first overhead braced Allan truss. It was a three span bridge with a long approach on the northern side.  The bridge remained in use till 1985, when a new bridge was opened a short distance downstream.  The original bridge was retained as a pedestrian bridge until 2006, when one of the trusses sagged alarmingly.  The span was supported with a temporary steel truss.  Hampden Bridge was demolished in July 2014 after the Wagga Wagga council decided it would be too expensive to restore the bridge.

Hampden1

View of the bridge from the south side. The bottom chord of the first truss can be seen sagging in this view.

Hampden2

View of the bridge and Murumbidgee River.

Hampden3

Mirror shot.

Hampden4

View of the trusses.

Hampden5

View of the bridge from the south end showing the support truss and the date stone on the left.

Hampden6

View from the south side.

Hampden7

View from the approaches on the north side.

Hampden8

View from the north bank of the river.

Hampden9

The approach spans.



Hinton Bridge

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This bridge crosses the Paterson River near the community of Hinton and was built in 1901. The lift span has not been used since the 1940s. Hinton Bridge was been fully restored and upgraded.  This was the first of the bridges to receive the "modernizing" treatment. This includes replacing the cross girders with steel, installing steel plating on the insides of the bottom chord timbers, replacing the deck with stress laminated timber and replacing the railing with steel railing.  The result is a much stronger bridge that still looks like the original bridge.

Hinton1

View of the bridge from the south side.

Hinton2

Closer view of the bridge.

Hinton3

View of the underside showing the stress laminated deck. Aso just visible are the steel plates on the insides of the bottom chords.

Hinton4

View of the lift span.

Hinton5

Close up view of the south truss.

Hinton6

View of the deck from the north end.

Hinton7

View of the bridge from another angle.



Mill Creek Bridge

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Mill Creek Bridge is a unique type of Allan truss. The standard from of the truss was modified to suit this particular crossing.  The bridge crosses Mill Creek about 4km east of Wisemans Ferry on the road to Gosford.  The main differences are the use of timber, rather than iron footings for the diagonals and steel, instead of timber for the cross beams.  The cross beams are also mounted below the bottom chord, rather than above it.  The bridge was built in 1929 and is currently out of use, a new bridge being constructed beside the old a few years ago.

MillCreek1

View of the bridge from the side.

MillCreek2

Information board.

MillCreek3

View from the west end.

MillCreek4

View of the steel cross beams and timber sway bars.

MillCreek5

Close up view of the timber footings.

MillCreek6

Timber end footing.

MillCreek7

View of the bridge from the east side.

MillCreek8

View of the bridge from the new road.



Morpeth Bridge

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This bridge was built in 1898 and crosses the Hunter River at the historic town of Morpeth. It is a three span overhead braced truss, one of only two remaining. This bridge will be preserved and has already been partially restored and upgraded.  The approach spans have all been replaced with concrete spans.

Morpeth1

View of the bridge from the north bank.

Morpeth2

View of the new approach spans.

Morpeth3

View of the trusses and approach spans.

Morpeth4

View of the bridge from the south bank of the river.

Morpeth5

Close up view of the centre span.

Morpeth6

View of the truss spans and approaches.



Paytens Bridge

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Paytens Bridge is located on Grenfell-Eugowra Road just off the Lachlan Valley Way, about 30km east of Forbes. It is a two span bridge and crosses the Lachlan River.  It is mostly original with the exception of the steel central pier. This bridge is going to be preserved for now.  It is difficult to get good side angle photos of this bridge.

Paytens1

View of the bridge from the south bank of the river.

Paytens2

View of the bridge from the south end.

Paytens3

View of the trusses.

Paytens4

Detail view of the end diagonal footing..

Paytens5

The central pier was replaced with this steel structure several years ago.

Paytens6

View of the truss.

Paytens7

View of the approaches with the original decking.

Paytens8

View of the bridge from the north end.



Pretty Point Bridge

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This bridge is located on New Buildings Road, a few km south of Mount Darragh Road, about 30km west of Pambula.  It is a single span truss and is in very poor condition. Pretty Point Bridge is a council maintained bridge and is not likely to be preserved.  The bottom chord has been reinforced with steel in several places. It crosses Mataganah Creek.
Update August 2016:  This bridge has been heavily modified.  The trusses have been removed and the main span is now supported by large steel beams.  The bridge will be eventually rebuilt and the timber trusses will be replaced. They will carry no load and be there for cosmetic and historic value only. This work is ongoing.

PrettyPoint1

View of the bridge from the north end.

PrettyPoint2

View of the bridge from the south side.

PrettyPoint3

View of the trusses. This bridge has only four sway bars on each side, the usual number for unrestored bridges.

PrettyPoint4

View from below. The steel reinforcement of the bottom chord is visible in this view.

PrettyPoint5

View of the deck.

PrettyPoint6

View from the south end.

PrettyPoint7

View of the bottom chord.

PrettyPoint8

View of the bottom chord.



Rossi Bridge

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Rossi Bridge is a three span bridge built on the masonry piers of a former Old PWD bridge built in 1867 The current trusses were built in 1899. It crosses the Wollondilly River on Range Road just west of Goulburn.  This road has a load limit of 15 tons.  Because of this, the bridge does not need to be strengthened and will be preserved without upgrading with modern materials.

Rossi1

View of the bridge from the south side.

Rossi2

View of the bridge from the south end.

Rossi3

View of the trusses.

Rossi4

View from the other south side.

Rossi5

View of the deck.

Rossi6

View from the north end.

Rossi7

Side view of the truss.

Rossi8

View from the south end.



Swan Hill Bridge

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This bridge was constructed in 1896 and crosses the Murray River at the town of Swan Hill. It is a two span bridge with a lift span. The bridge has had a lot of strengthening and upgrading work done, including on the lift span, which is still operational. This bridge is probably going to be preserved, but likely as a bridge for pedestrians or light traffic only.  Planning is underway for a new bridge.

SwanHill1

View of the bridge from the north side.

SwanHill2

View of the bridge from the south end.

SwanHill3

Close view of the bridge.

SwanHill4

View showing the pedestrian walkway that is not original. If the bridge is preserved, this will probably be removed.

SwanHill5

View of the deck.

SwanHill6

View from the north side.

SwanHill7

View of the bridge.

SwanHill8

View of the underside of the approach spans..

SwanHill9

View from the north end.

SwanHill10

View from the south end. These bridges are quite a bottleneck for heavy trucks and are the a big reason why there are no big trucks in NSW.

SwanHill11

View of the lift span.

SwanHill12

View of the lift span.



Tharwa Bridge

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Tharwa Bridge crosses the Murumbidgee River about 35km south of Canberra at the community of Tharwa.  It was constructed in 1895 and is the only remaining four span timber truss bridge. The original bridge was closed in 2006 due to severe deterioration of the timbers. A new bridge was almost built, but the ACT government then decided to restore the original bridge (the local community was also strongly opposed to the idea of a new bridge. The bridge was completely rebuilt and the concrete piers strengthened and the bridge was reopened in 2010.

Tharwa1

View of the bridge from the east side.

Tharwa2

View of the bridge from the east end.

Tharwa3

View of the bridge deck and trusses.

Tharwa4

View of the underside showing the maintenance gantry and stress laminated deck.

Tharwa5

Closer view of the bridge. The steel reinforcements of the concrete piers are visible in this view.

Tharwa6

Detail of the truss showing steel footings and splice plates.

Tharwa7

There are a few pedestrian alcoves.

Tharwa8

View of the original bridge from the west side in December 2005.

Tharwa9

View from the west side in December 2005.

Tharwa10

View from the west side of the original bridge in December 2005.  Note the timber railing.

Tharwa11

Close up of one of the trusses.



Tooleybuc Bridge

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Tooleybuc bridge was built in 1925 and crosses the Murray River at the tiny town of Tooleybuc. It is a two span bridge with lift span and is quite similar to Swan Hill Bridge, differing in having, shorter, low profile trusses. As of May 2014, it was undergoing maintenance with one truss supported by a Bailey truss. This bridge is not going to be preserved. It has already had a lot of strengthening work done such as replacing the cross beams with steel and installing new sway bars. The lift span is still operational.

Tooleybuc1

View of the bridge from the south side.

Tooleybuc2

View of the bridge from the south end.

Tooleybuc3

View of the bridge from the south river bank.

Tooleybuc4

View of the lift span.

Tooleybuc5

View of the truss showing the steel cross beams and new sway bars.

Tooleybuc6

View from the north side.

Tooleybuc7

View of the deck.

Tooleybuc8

View from the north side with signage.



Vacy Bridge

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Vacy Bridge is a two span truss built in 1898. It crosses the Paterson River about 20km north of Maitland on Gresford Road. In November 2013, it had Bailey trusses in place. This was due to another bridge nearby being partly closed for upgrade works. The Bailey trusses were installed on Vacy Bridge to cater for the increase in traffic.  As of May 2014, Vacy Bridge is undergoing a complete reconstruction with new trusses being installed.  This is unexpected as this bridge is not on the list to b e preserved.

Vacy1

View of the bridge from the south side.

Vacy2

View of the bridge from the north side.

Vacy3

View of the bridge from the north end.

Vacy4

Another view from the north end.

Vacy5

View of the bridge in the countryside.

Vacy6

View showing the tall timber pier.

Vacy7

View of the truss in November 2013.

Vacy8

Same view in May 2014 with the new trusses going in.

Vacy9

View of the huge crane in use.

Vacy10

View from the north side. The old trusses have been removed, but the new ones are not yet in place on this side of the bridge


Wallaby Rocks Bridge

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This bridge is a three span truss built in 1897 crossing the Turon River on Hill End Road, 4km west of the historic town of Sofala, north of Bathurst. It has been fully restored and upgraded.  It is not, however, ont he list of bridges to be preserved, but it will be around for a while yet.  It is located in a beautiful, peaceful setting.

WallabyRocks1

View of the bridge from the north side.

WallabyRocks2

View of the bridge from up a tree on the south side.

WallabyRocks3

Detail of the truss showing the steel cross beams and new sway bars.

WallabyRocks4

Underside view showing the iron piers and the dry riverbed as it was in February 2014.

WallabyRocks5

Close angle of the bridge from the north side.

WallabyRocks6

View showing bottom chords and the stress laminated deck..

WallabyRocks7

View of the bridge from a distance in the dry river bed.

WallabyRocks8

View of the deck and trusses.

WallabyRocks9

View from the south end.


Wee Jasper Bridge

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Wee Jasper Bridge is located at the west side of the locality of Wee Jasper. It crosses the Goodradigbee River on Wee Jasper Road about 50km south west of Yass and was built in 1896. The river is on the edge of the Burrinjuck Reservoir. This bridge has been partially restored and will be preserved.  It is in a very picturesque and peaceful setting at the end of a very curly road!

WeeJasper1

View of the bridge from the west side.

WeeJasper2

View of the bridge from the west end.

WeeJasper3

View from the east side.

WeeJasper4

View from the bank on the east side.

WeeJasper5

Detail of the truss. Unlike most other truss bridges, this one is painted black below the road deck.

WeeJasper6

View showing the cross beams and deck..

WeeJasper7

View of the deck and hill on the east side.

WeeJasper8

View of the whole bridge from the west side.

WeeJasper9

View from underneath.


Victoria Bridge

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This three span bridge is located on Prince Street in Picton, about 80km south west of Sydney. It crosses a steep valley and has the tallest timber trestles in NSW. The bridge is limited to light traffic only and is going to be preserved without being upgraded. It has a pedestrian walkway within the trusses, unlike any other truss bridge.  Due to the terrain, it is difficult to get side photos of this bridge. It also has a height limit of 2.4m, which prevented the Google Streeview car from crossing it.

Victoria1

View of the bridge from the east side.

Victoria2

View of the bridge showing the pedestrian walkway.

Victoria3

View of the tall trestles.

Victoria4

As best a side view as I could get.

Victoria5

View from the east end.

Victoria6

View from the west end showing the height limiter.

Victoria7

View of the truss.

Victoria8

View of the height limiter on the east end.

Victoria9

View of the deck.

Bridge Videos

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Driving views of Allan timber truss bridges.