‘West Gate Bridge’ is described as being a gigantic monitor lizard poised in an elongated ‘S’ astride the River Yarra linking Melbourne’s Western suburbs with Eastern Victorian suburbs between Central Business District as imagined by Carmel Egan, a fine journalist. (Brown, 2002)
1. An Analysis of the Project’s Structure and Management:
1.1 Project Structure:
The West Gate Bridge in Melbourne was going to be, undoubtedly, the largest bridge of Australia, with four lanes in each direction and a total span of 2.6 kilometres. The bridge consisted of two parts:
1) Approach Spans:
Spans in reinforced concrete of 67 metres each.
2) Centre part:
Total length of 848 metres, in steel.
This steel section was a continuous box-girder bridge divided in five spans out of which, three centre spans, suspended by stay-cables, were over the Lower Yarra River. The main span of 336 metres would be one of the largest spans for a bridge supported by stay cables. Cross-section of Bridge:
The cross-section of the Bride was a trapezoid, having four webs, two inclined and two vertical, forming a three celled box-girder. The vertical webs contributed to the load carrying capacity and acted as inner support for the crossbeams in the lower and upper flange. (Åkesson, 2008)
Western Industries Association – In 1951, formed by industries from Williamstown, Spotswood, Altona and Footscray and surrounding areas, this association was the most concerned that a crossing should be made across the River Yarra. Lower Yarra Crossing Company Inc. (LYCC) - Due to lack of funds with the government, in 1961, a private company ‘LYCC’ was formed which had negotiations with the government for establishment of a project for the crossing. Lower Yarra Crossing Authority (LYCA) - Due to voluntary liquidation of LYCC, in 1965, LYCA was formed by parliamentary act which had the powers for compulsory acquisition of land, managing finance, plans & engineering etc. Maunsell & Partners (MP) – Since 1964, MP provided consultancy to the LYCC and LYCA on the bridge project. Freeman, Fox & Partners (FF&P) – On recommendation by MP, FF&P were formally engaged in July 1967 to provide consultancy along with MP because of their successful Sydney Harbour Bridge. John Holland (Constructions) Pty. Ltd (JHC) – In January 1968, the responsibility of bridge foundation and concrete works was given to JHC. World Services & Construction Pty. Ltd (WSC) – Steel works for the bridge were given to WSC. (Commission, 1971)
1.3 Problems with Structure and Management:
JHC had been performing well in terms of foundation and concrete works but there was lack of co-ordination between FF&P and WSC as the latter was trying to create the designs made by the former. (Commission, 1971)The delays and mismanagement led the contractor chose an unusual method of bridge construction. Thus to save time, it was decided to build the girder spans in two halves which were then to be lifted up and fitted.
Due to delays, steel works of the bridge were given to JHC which had no experience for large scale steel works and construction. Due to miscalculations of the buckling stress, while on the ground, the free flange of the inner part had started to buckle due to self weight of the girder. On bringing the two half girders into close proximity, it was observed that there was a gap of approximately 4.5 inches (114 mm). (Works) Kent ledge to push down the north half span relative to its south counterpart was used and thus ten cube shaped blocks of concrete weighing eight tonnes each were placed on the bridge which further led to a buckle. To release this buckle, screws were removed. On removal of 16 bolts, the buckles were reduced but the other bolts were squeezed tight jamming them in position. It was then decided that the bolts should be tightened until they broke. On removal...
Bibliography: Åkesson, B. (2008). Understanding Bridge Collapses. The Netherlands: Taylor & Francis Group.
Brown, M. (2002). Australia 's Worst Disasters. Sydney: Hachette Australia.
Building, O. T. (n.d.). Retrieved from Old Treasury Building: http://www.oldtreasurybuilding.org.au/westgate-bridge-collapse-40-years
Commission, R. (1971). Report of Royal Commission into The Failure of West Gate Bridge. Melbourne: C. H. Rixon, Government Printer.
Victoria, S. G. (n.d.). Retrieved from Public Record Office Victoria: http://prov.vic.gov.au/whats-on/exhibitions/disaster-at-west-gate-the-west-gate-bridge-collapse-of-1970/the-disaster
Works, P. (n.d.). Retrieved from The West Gate Bridge Memorial: http://www.westgatebridge.org/
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