Title: The Manufacture of the Precast Concrete Floor Units for the Southern Cross Railway Station,Melbourne

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Publication: CIA

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Date: 2/13/2011

Abstract:
This paper deals with the manufacture and transport of about 205 high quality, complex shaped, thin walled precast concrete floor units for the Southern Cross Railway Station constructed by Leighton Contractors. It would have been impossible to cast these shapes in insitu concrete. These units now form the coffered ceiling and floor over three of the platforms and have been widely acclaimed for their finish and form. Two complex steel moulds were built at a cost of about $50,000 each. The units were poured using a 45 MPa concrete mix with 50% grey cement and 50% Brightonlite cement with a high quality off-form finish, struck from the steel moulds. Units were manufactured in two sizes, one being approximately 10.7 metres long x 2.0 metres wide x 1.4 metres high and the other varying only in length at 9.3 metres long. The units weighed about 14 and 12 tonnes respectively. Each type of units also varied by way of minor and major penetrations and incorporated varied connection details to allow them to be fixed to the finished structure. The off-form concrete mix provided an attractive offwhite/ grey colour that performs well as a ceiling in reflecting light for the open, airy effect sought by the designers. The reinforcing cages were prefabricated in special timber jigs to allow accurate placement of the reinforcing. Up to 10 units a week were produced and they were stored outside in the yard before being transported to site in Melbourne for erection.