The Windsor Bridge over the Hawkesbury River was officially opened on the 20 August 1874. The town celebrated in great style with about 7000 attendees and the day was observed as a general holiday. The Australian Town & Country Journal published the interesting sketch below, as well as an informative article about the construction of the newly opened Windsor Bridge on the 22 August 1874.
The New Bridge over the Hawkesbury at Windsor. Australian Town & Country Journal, 22 August 1874, p. 20. |
This want of a bridge over the
Hawkesbury River at Windsor has been felt for many years. In 1864, [politician James Augustine Cunneen 1826-1899] presented a
petition from the inhabitants of the district for the erection of a bridge at
Windsor, but it was not until June, 1871, that the Legislative Assembly voted
the necessary funds for the construction of a low level bridge.
There was much diversity of
opinion as to the advisability of constructing a low level bridge at the site
proposed, as the floods rise there to a height of more than 50 feet above low
water. The Commissioner and Engineer for Roads was however, instructed by the
Government to prepare designs for a low level bridge, and to invite tenders for
its construction. Mr. Andrew Turnbull's tender was accepted in December 1871 and
the work began on the 15 January 1872.
According to the original
design, the total length of the bridge was to be 406 feet, composed of eight
main spans of 44 feet each, and of two approaches 32 feet and 22 feet respectively.
The abutments were to be of timber; and the nine intermediate piers of cast
iron cylinders and screw piles braced with strong wrought iron beams. The screw
piles and cylinders to be sunk to the rock, and lewised thereto by heavy
wrought iron bolts, previous to being filled up with cement concrete.
In October 1872, three of the
iron piers had been sunk 4 feet into the rock to the depth of 25 feet below
river bed; each column was lewised with four inch bolt and filled up with
strong cement and concrete, supporting a ring of 9-inch radiating bricks;
enclosing a cone of concrete to the top of the pier. From the nature of the
strata found in sinking those piers, it became doubtful whether screw piles
could be used, as the bed of the river to the rock consisted of drift timber,
silt, and boulders deposited by floods.
A test screw-pile, 2 foot 6
inches in diameter, was, however, put down in the middle of the stream; but
the rock could not be reached, owing to the difficulty of removing the drift
timber. Mr. Bennett, the Commissioner and Engineer for Roads, then decided to
give up the screw-piles and to use cylinders for all the piers.
Many freshes and several heavy
floods retarded operations; and the
sinking of all the piers could not be completed until December, 1873. Although
a few feet only of the iron columns appear above water, the cylinders reach to
an average depth of 40 feet below summer level. By the use of the sand-pump and
air-lochs, boulders, drift-wood, and logs, several feet in thickness, were
removed at considerable depths, and each pillar firmly bedded and lewised four
feet into the solid rock. The bracing beams were also
fixed below water by divers, before the erection of the superstructure.
The extraordinary floods at
Windsor which reach to a height of 51 foot above low water, or 36 feet above
the decks of the bridge, made it necessary to have the superstructure unusually
strong; and much ingenuity is shown in tho design for securely fastening it to
the piers. The deck is 21 feet 6 inches
wide; and is composed of planks five inches thick, securely fixed to five
ironbark girders 17 and 18 inches by 16 inches and 44 feet long, strongly
bolted to corbels and capsilla firmly secured to-the iron piers. The whole of
the timber is ironbark, which has little buoyancy under water, and the girders
are fine specimens of our colonial wood.
All the joints are covered
with iron fish-plates, bolted with inch bolts, and it is evident from the
massive fastenings throughout, and the great strength of the structure in every
detail, that the engineer has taken every precaution to prevent the floods from
making a breach in any part of the bridge. The handrail is also
ingeniously contrived to protect it from the large quantity of drift timber
brought down by the floods. The foot of every rail post swings on a stout bolt
secured to the girders, and the top is jointed to a two-inch wrought iron pipe,
provided with sockets and collars at every 44 feet; the total length being held
in place by two iron couplings in such a manner that one man can lower the
whole alongside the girders in ten minutes.
The amount of Messrs. Turnbull
and Dixon's contract was £8287; but an additional expenditure of about £2000
was rendered necessary by the substitution of cylinders for screw piles in the
piers, and by the addition of two spans to the bridge to prevent future encroachment
on the approaches. It was observed that moderate floods bring large deposits of
sand and drift; but that heavy floods scour the river bed to a considerable
extent.
The total length of the bridge
as completed is 480 feet. The abutment on the Windsor side is built of iron
backed with masonry in cement; and that on the opposite bank is protected by
sheet piling reaching below summer level. A new cutting has also been
made on the Wilberforce side for the approach, which is covered with ironstone
gravel. The number of cast-iron
cylinders used in the piers is 130. They are six feet long, and 3 feet 6 inches
in diameter, and their weight exceeds 150 tons. They were cast at the Mort's
Dock and Engineering Works at Balmain; and are another instance of the facility
afforded for such works by colonial establishments.
The inhabitants of the
district may well be pleased at the completion of this fine bridge; and it will
be satisfactory for them to know that it has been ascertained by the officers
of the Department of Roads and Bridges, in reference to the traffic and the
disastrous floods of the Hawkesbury River, that, while the deck of the Windsor
bridge is free from flood, the Richmond bridge is covered with three feet eight
inches of water, and that the Windsor bridge is crossable twenty-two hours
after the stoppage of the traffic at the Richmond bridge.
Great credit is due to the
contractors, Messrs, Turnbull and Dixon, for their energy and perseverance in
carrying out, without any accident, such an important and difficult work, to
the satisfaction of the Commissioner and Engineer for Roads.
More about the official
opening of the bridge will follow.