Creative Solution for Sydney Data Centre-Paper

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The Equinix SY5 data centre in Sydney required a foundation solution for variable ground conditions: fill and alluvial sands, including loose layers and soft clay near the surface, over stiff to hard clay and bedrock at about 27 m. A raft-only foundation risked excessive settlement, while conventional piles would have increased construction time and cost.<br /><br />Keller developed a piled-raft solution combining Rapid Impact Compaction (RIC) with Atlas drilled displacement piles. RIC improved the upper soils to a maximum depth of approximately 4–4.5 m, increasing stiffness and providing a stable platform. Site trials and post-treatment tests confirmed improved ground consistency and stiffness. The reinforced concrete raft carried much of the building load, while strategically positioned Atlas piles acted as settlement-control elements beneath heavily loaded areas. The displacement piles offered high capacity, low spoil generation and installation without harmful vibration.<br /><br />Geotechnical assessment and PLAXIS 3D analyses were used to refine pile locations and evaluate raft stiffness, dimensions and load sharing. The design targeted piles carrying about 60% of service loads. For the whole building, analysis predicted maximum total settlement below 30 mm and differential settlement between columns within 10 mm. Approximately 349 piles were included in the model, with their combined reaction representing about 60% of the building’s working load.<br /><br />The case study demonstrates how ground improvement and a carefully designed piled raft can accommodate variable soils, control settlement and reduce pile numbers compared with a conventional piled foundation, delivering potential savings in construction cost and programme.

Keywords

Equinix SY5

Sydney data centre

piled raft foundation

Rapid Impact Compaction

Atlas drilled displacement piles

ground improvement

settlement control

alluvial sands

PLAXIS 3D analysis

geotechnical design