Harbor Bridge

The Harbor Bridge is a metal Bridge arch located in the town of Sydney, in Australia. It is the principal point of crossing of bay of Sydney, allowing the passage of the trains, cars and pedestrians between the district of the businesses and northern bank of bay. The sight of the bridge and the very close opera is emblematic city and of whole Australia. The 75ème birthday of the bridge was celebrated on March 18th, 2007.

The bridge remained the highest structure of the city until in 1967 with 134 meters with the top of the sea level. According to the Guinness Book of the records, it is the broadest bridge in the world (48,8 meters) and having the highest steel arch with the top of the bridge located at 134 meter with the top of water. It is also the fourth longer bridge in the world (1149 meters in all, 503 meters in range) for the bridges in arch.

Situation

The two ends of the bridge are located on the one hand at " Dawes Point" , in the district of " The Rocks" in the south and in addition with " Milsons Point" , in the district of " North Shore" in north.

Description

It has six ways for the traffic of the cars on the central part of its apron, two ways for the cars (which, formerly, were useful for the Tramway S) and a pedestrian passage on the part is, two ways of railroad and a way for the cyclists on the western part, the 30,5 centimetres western part being broader than the part is.

The road which crosses the bridge is known under the name of " Bradfield Highway" of Sydney and measurement 2,4 kilometers length what does one of the shortest Australian highways of them. (Shortest being the " Bradfield Highway" of Brisbane which borrows the Story Bridge). The coating for the fitted part is made plates of concrete resting on steel cross-pieces which rest they same on steel rails of the width of the bridge.

The arches are reinforced by 28 pairs of posts of which the height varies from 18 meters in the center with 57 meters near the pylons.

At each end of the central arch a pair of pylons out of concrete and 89 height meters is stone. The thrusts, which support the ends of the bridge are located in the base of the pylons. They make it possible the bridge to dilate or narrow according to the temperature variations. These pylons do not have utility in themselves and were used only for esthetic balance of the bridge. It should be known that at present they have each one a utility;: the south-eastern pylon shelters the museum and a center for tourists with sight on the port; the south-western pylon shelters the New South Wales Roads and Traffic Authority (RTA) with the televisual monitoring system of the bridge and its surroundings; the two pylons of north are used as chimneys to evacuate smoke of the tunnel which passes under the port.

History of the bridge

The first construction projects date from the beginning of 1815, when Francis Greenway proposed the creation of a bridge to cross the port but this idea did not emerge.

One can consider that the decision of the construction of the current bridge started in 1890, when a royal commission estimated that the best means of decreasing rotation continues ferries to connect two banks of the port was the construction of a bridge. There were well some small bridges which connected two banks upstream but they were not large enough.

The first preliminary drafts were required in 1900 but none of them was accepted until 1911. In 1912, John Bradfield was named chief engineer of the mixed project of bridge (road and railway). After having travelled in the whole world to see the principal bridges of the world, it retained the models of the Hell Gate Bridge with New York or that very near to the Tyne Bridge with Newcastle Upon the Tyne in England. Bradfield completed its plans in 1916 but the beginning of construction was deferred to 1922 mainly because of the First World War.

In November 1922, the government of News-Wales of the South voted the laws allowing the construction of the bridge. An invitation to tender was launched the same year and the British firm " Long Dorman and Co Ltd" , with Middlesbrough the ermporta. To calm concerns to see a foreign company directing the project, Bradfield gave the insurance that all the workmen building the bridge would be Australian.

The construction of the bridge coincided with the construction of a subway known under the name of " City Circle" and the bridge was conceived by taking account of this other construction. At the beginning the bridge was to receive a road with six ways in the center, two ways of railroad and a way pedestrian on each side. The two pairs of railways were connected by a symmetrical system of slopes and tunnels to the underground station of Wynyard. The way east was designed to connect by rail the northern station of Wynyard to the beaches of Sydney.

The construction of the bridge started in 1923 with the demolition of 800 houses. The owners were compensated but not the tenants.

Bradfield directed construction helped by three other people: Laurence Ennis, the chief engineer of " Long Dorman and Co" which directly supervised the building site, Edward Judge which was the person in charge of the engineering services and Sir Ralph Freeman which was charged by its company with regulating the least details.

The official ceremony of the installation of the first stone took place the July 28th 1923. In January 1925, the first foundations started. In October 1925, began the construction of the points of anchoring and the ways initially which were completed in September 1928. The construction of the bridge itself began in December 1928 with the assembly of parts in the buildings contiguous to the future bridge. The construction of the central arch started in 1929 with a team at each end of the bridge which assembled the parts and stabilized them with floating cranes. The southern portion of the bridge was completed voluntarily a month before that of north to be able in the event of error on the southern portion, to correct it on the northern portion.

During the construction of the bridge, the two half-arches had been maintained balances some by many cables which were slackened trè slowly to be able to bring closer and join together the two halves what took place the August 19th 1930.

The road and the railways were completed in 1931. The electric lines, telephone, the waste water, gas, water pipelines were installed the same year. The January 19th 1932, a first engine with vapor crossed the bridge at low speed to test its solidity.

The bridge was inaugurated odfficiellemnt the March 19th 1932 by the Prime Minister of News-Wales of the South, Jack Lang.

External bonds

Card on the governmental cultural gate
sydneyharbourbridge.info
Card Structurae

Simple: Sydney Harbor Bridge

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