Engineers Australia

Design, Construction and Verification of CFA Piles for Infrastructure and Building Projects

Dr Ben Collingwood

September 8, 2021

Continuous Flight Auger (CFA) piling has become a common foundation type across both the infrastructure and building sectors in Victoria and nationally. Industry capability and practice in design and construction of this pile type has developed significantly over the past 20 years. While many specialist practitioners are highly skilled and experienced in CFA piling practice, this expertise is often not readily accessible to the broader profession.

In Australia, the use of CFA piling methodology developed initially in the commercial building sector, where it is typically used under a ‘design and construct’ contracting arrangement, where the contractor is responsible for the installation and certification of the foundation system. Design, construction monitoring, inspection, testing and verification processes have evolved in the building sector to suit this contracting environment.

More recently, CFA piling has become prevalent on infrastructure projects. In contrast to the building sector, for infrastructure projects the design is generally carried out by the engineering consultant and the piles are often installed under a ‘construct only’ contract. As construction equipment, methodology and practices significantly influence CFA pile performance, it is critical that appropriate construction monitoring, inspection, testing and verification processes are included in the project documentation and properly implemented. Deficiencies in such processes can lead to conflicts and practical difficulties during the piling works. Further, they can expose designers, contractors and project owners to significant risks with respect to cost, quality assurance and program outcomes.

The presenter’s experience suggests that important issues associated with the use of CFA piles are not broadly understood by many practitioners. Further, the available standards and specifications do not provide consistent guidance and are not always applied.

Dr Collingwood will discuss his view of best practice for the use of CFA piles in both the building and infrastructure sectors, highlighting some important technical, practical and commercial considerations.
A significant case study from a major road infrastructure project will be presented as an example of best practice for site investigation, design, construction and verification of CFA piles in the infrastructure space, along with some recent experience from major building projects in Melbourne.

Please note, a PDF of this presentation is also available for members via the event page.

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