Contractor :  Grocon Constructors Pty Ltd
Geotechnical Consultant : Golder Associates Pty Ltd
Location: Melbourne, Australia.

Final completion 2005.

The project is a 300 m high residential development comprising 88 above-ground levels.  The overall site development also includes a hotel and multi-level car parking facility.  A single basement covers the entire site.
Extensive investigations revealed complex subsurface conditions.  The site lies in the upper reaches of the Yarra River delta area, where the typical subsurface sequence comprises Quaternary Age sediments overlying Silurian Age siltstone and sandstone bedrock.  This sequence is interrupted at the Eureka Tower site by a relatively shallow Quaternary Age basalt layer and at depth by very high strength Tertiary Age basalt.  Neither of these basalt flows extend across the entire site.
Based on the extensive investigations previously completed, a bored pile footing solution was proposed for the tower structure, with 1,200 mm diameter, rock socketed piles founding in either the lower basalt or siltstone.  Pile serviceability loads of up to 25 MN were accommodated.  Detailed studies were carried out to delineate the edge of the lower basalt flow.  The piling contractor proposed an alternative to the bored piles founding on the basalt, of 6.5 MN, 750 mm diameter continuous flight auger piles which were evaluated using Statnamic and dynamic testing.
The rock sockets in the siltstone were designed using Foundation QA rock-socket design program, ROCKET.

Special Features:

• Complex geology requiring extensive investigations and detailed analysis;
• Billed as world's tallest residential tower;
• High pile loads and associated foundation stresses justified by rigorous investigation and analysis; and
• Statnamic and dynamic testing program of contractor alternative.