page_title: West Gate Bridge
section_title: Cause
hierarchical_section_title: West Gate Bridge / History / Collapse / Cause
caption_attribution_description: English: The West Gate Bridge as seen from the walkway near the West Gate Bridge Memorial Park in Melbourne, Victoria, Australia.
context_page_description: The West Gate Bridge is a steel box girder cable-stayed bridge in Melbourne, Victoria, Australia, spanning the Yarra River just north of its mouth into Port Phillip. It is a vital link between the inner city and Melbourne's western suburbs, with the industrial suburbs in the west, and with the city of Geelong 80 kilometres to the south-west. It is part of one of the busiest road corridors in Australia.
  The main river span is 336 metres in length, and the height above the water is 58 metres. The total length of the bridge is 2,582.6 metres. It is the fifth-longest in Australia, the longest being Melbourne's Bolte Bridge at 5 kilometres. The West Gate Bridge is twice as long as the Sydney Harbour Bridge and is one of the highest road decks in Australia, clearing the water at 58 metres, with the Sydney Harbour Bridge clearing the water at 49 metres.
  The bridge passes over Westgate Park, a large environmental and recreational reserve created during the bridge's construction, and carries up to 200,000 vehicles per day.
context_section_description: A Royal Commission into the collapse was established, which concluded on 14 July 1971. It attributed the failure of the bridge to two causes: the structural design by designers Freeman Fox & Partners, and an unusual method of construction by World Services and Construction, the original contractors of the project.
  On the day of the collapse, there was a difference in camber of 11.4 centimetres (4.5 in) 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 10 concrete blocks, each weighing 8 t (8.8 short tons), which were located on-site. The weight of these blocks caused the span to buckle, which was a sign of structural failure. The longitudinal 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.
caption: The West Gate Bridge as seen from the walkway near the West Gate Bridge Memorial Park
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