Science Fair Project Encyclopedia
West Gate Bridge
The West Gate Bridge is a large cable-stayed bridge in Melbourne, Victoria, Australia. It spans the Yarra River, just north of its mouth into Port Phillip, and is a vital link between the inner city and Melbourne's eastern suburbs with the industrial suburbs in the west and with the city of Geelong, 80 km to the south-west.
Completed in 1978 after 10 years of construction, the bridge, a part of the larger West Gate Freeway, cost $202 million.
The main river span is 336 m in length, and the height above the water is 58 metres. The total length of the bridge is 2582 m. It is the second longest in Australia, and is twice as long as the Sydney Harbour Bridge. It carries four lanes of traffic in each direction. Cyclists are prohibited from using the bridge except for special bicycle events.
The West Gate Bridge was originally tolled but is now toll-free, unlike the Bolte Bridge much closer to the city centre, a part of the CityLink freeway system.
The collapse
Two years into construction of the bridge, on October 15, 1970, the 112 m span between piers 10 and 11, collapsed and fell 50 m to the ground and water below. 35 construction workers were killed.
There was a difference in camber of 4.5 inches between two half girders at the west end of the span which needed to be joined. It was proposed that the higher one be weighted down with 8, 10 tonne concrete blocks which were located on site. The weight of these blocks caused the span to buckle, which was a sign of structural failure. The longditinal joining of the half girders was partially complete when orders came through to remove the buckle. As the bolts were removed the bridge snapped back and the span collapsed.
A Royal Commission into the collapse was established, and concluded on July 14 1971. It attributed the failure of the bridge to two causes; the structural design by designers Freeman Fox and Partners and an unusual method of erection by World Services and Construction , the original contractors of the project.
External links
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