Piled foundations for Eureka Tower, Melbourne, Australia

The Eureka Tower project in Melbourne is a 92 level (300 m high) residential development. The geology of the site is complex. Bored piled foundations were recommended, requiring socketing into very-high-strength basalt or high-strength siltstone. For the piles proposed to be socketed into the basalt, the successful piling contractor proposed the alternative of continuous flight auger (CFA) piles bearing directly on to the basalt rock. The design bearing stresses for both these CFA piles and the bored piles in siltstone exceeded previously adopted values in Melbourne. Statnamic and dynamic testing was performed on the CFA piles. For the bored piles an extensive investigation programme provided confidence in the socket design, with the assumed conditions verified during construction. This paper was first published in the BGA International Conference on Foundations, University of Dundee, 2003. It has been revised and expanded slightly to cover construction aspects of the project.