The Sydney Harbour Bridge
_The Sydney Harbour Bridge_At one stage of Australia`s history Sydney was two cities,on the south shore lived 600,000 people and on the north shore lived another 300,000 people.People would either travel to and fro by ferry or go via the Gladstone Bridge which would take several hours.The problem of linking the sides had seemed too expensive to resolve until 1922. In 1922 the New South Wales parliament got serious and passed the Sydney Harbour Bridge Act, world bridge builders were then invited to submit designs and approximate costs ,for what would become the Sydney Harbour Bridge.These designs had to meet requirement set down by government engineers. The building of the bridge would be closely supervised by J.J.C. Bradford. Dorman, Long and Company won the contract to build The Sydney Harbour Bridge one of the winning features was that the bridge was to be built using mainly Australian materials.Dorman, Long`s bridge was to be a two hinged steel arch bridge, with five approach spans on either side , the total lenght would be 1149meters and it would cost the government 4,217,722 pounds (250 million) The main span of the Sydney Harbour Bridge would be two steel arches 30 meters apart
The hinges are four huge steel rods held at each side of the bridge . The excavations for the Sydney Harbour Bridge began in January 1925,the first stone was laid on the 7 October 1925 ,although the stone surrounds were only to make the bridge look more attractive. The Sydney Harbour bridge is held together by 6 million rivets ,rivets were used because welding was to unreiliable and screws ,nuts ,and bolts were too expensive. In September 1928 all of the approach spans were completed , and work on the stone faced abutments began. These holes were then poured full of concrete in hexagonal shapes as this was to transfere the weight of the bridge evenly over the sandstone below. The footings were made by digging huge holes 27 meters wide ,12 meters front to back and 9 meters deep. De Groot belonged to a para-military group called"the guard" who were enraged that a member of royalty was not invited to open the bridge. The unfinished arch extending over the harbour was supported by steel cables ,thread through the steel and anchored in massives tunnels 40 meters long ,that was cut from the sandstone bedrock that the city of Sydney is built on. In October 1928 the building of the steel arch began ,the steelwork was installed using a creeper crane, which is five cranes of various sizes on one travelling base. The next step was to build the hinges that would allow the bridge to expand and shrink up to 180mm , due to weather changes. On the top of each abutment is two towers which are there for decoration and does not hold any of the bridges weight. The roadway is hung of the arches ,at the end of each arch is an abutment ,which stops the arches from spreading outwards. The bridge met in the middle after the tie-back cables were released to allow the two halves to tilt slowly together. The bridge officially opened !9 March 1932 ,the celebrations included the finish of a 550 kilometer relay of school children from Tottenham to Sydney, meetings ,sporting events, balls , dinners ,military shows, the huge party went on for two weeks. After the arch was completed it was time to hang the deck, on which the road would be constructed.
Common topics in this essay:
Moruya September,
Harbour Bridge,
Harbour BridgeThe,
South Wales,
Jack Lang,
Sydney Harbour,
Snowy Mountains,
Harbour Bridge_,
Bridge January,
De Groot,
sydney harbour,
harbour bridge,
sydney harbour bridge,
south wales,
approach spans,
march 1932,
steel arch,
jack lang,
arch completed,
total lenght,
bridge steel,
|
Acceptance Essays
