October 22, 2009

Sydney Harbour Bridge

Sydney Harbour Bridge is the world's largest (but not longest as thats the New River Gorge in the USA) steel arch bridge, and, in its beautiful harbour location, has become a renowned international symbol of Australia.

The Sydney Harbour Bridge, also affectionately known as the 'Coathanger', was opened on March 19th 1932 by Premier Jack Lang, after six years of construction. Made of steel the bridge contains 6 million hand driven rivets. The surface area that requires painting is equal to about the surface area of 60 sports fields. The Bridge has huge hinges to absorb the expansion caused by the hot Sydney sun. You will see them on either side of the bridge at the footings of the Pylons.

Its total length including approach spans is 1149 metres and its arch span is 503 metres. The top of the arch is 134 metres above sea level and the clearance for shipping under the deck is a spacious 49 metres. The total steelwork weighs 52,800 tonnes, including 39,000 tonnes in the arch. The 49 metre wide deck makes Sydney Harbour Bridge the widest Longspan Bridge in the world.

After inviting worldwide tenders in 1922, the New South Wales Government received twenty proposals from six companies and on 24 March 1924; the contract was let to the English firm Dorman Long and Co of Middlesbrough.

You can have a close hand look while you are in Sydney by visiting the South Eastern Pylon. It is a walking trip and recommended for the fit only. It is a longish walk to get to the base of the Pylon and then there are 200 steps to the top.

The general design was prepared by Dr J.J.C Bradfield and officers of the NSW Department of Public Works, while the detailed design and crucial erection process were undertaken by the contractors consulting engineer Mr (later Sir) Ralph Freeman of Sir Douglas Fox and Partners and his associate Mr. G.C Imbault.

As Chief Engineer of Sydney Harbour Bridge and Metropolitan Railway Construction from 1912, Dr Bradfield is regarded as the "father" of the Bridge as it was his vision, enthusiasm, engineering expertise and detailed supervision of all aspects of its construction which brought Sydney's long held dream into reality.

The official opening day on Saturday 19 March 1932 was a momentous occasion, drawing remarkable crowds (estimated between 300,000 and one million people) to the city and around the harbour foreshores. The NSW Premier, the Hon. John T. Lang, officially declared the Bridge open. However, the Premier enlivened proceedings when Captain Francis De Groot of the para-military group, the New Guard, slashed the ribbon prematurely with his sword, prior to the official cutting. This incident caused both amusement and dismay on the day and has since become part of Australian folklore.

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