PRECAST PILE

Utilising off-site manufacture within large diameter pile construction

FROM CONSTRUCTION TO PRODUCTION

Eliminating the volume of concrete within Hollow piles reduces the weight per linear metre, which therefore offers the unique potential for off-site manufacturing processes. This redefines the entire construction method of traditional large diameter piles, embracing a design for manufacture and assembly (DfMA) approach for deep foundations. Why change? Our records show that site teams spend approximately 40% of their shift waiting for ready mix concrete. More importantly, challenges on site result in large diameter pile concrete pours taking place late in the afternoon, often overrunning beyond the allocated working hours. This nuisance impacts social communities and repeat occurrences can fatigue the site team. The precast pile construction method mitigates these risks.

METHOD OF CONSTRUCTION

Precast low-carbon concrete elements are delivered to site using just-in-time models. The elements are slightly undersized compared with the bored diameter and are stacked from the pile base. A bespoke system is utilised to guide each component into position and also provides the required structural capacity in the permanent condition. Once assembled to cut off level, the pile is capped and grout is placed between the precast outer face and the pile bore to provide the necessary skin friction.

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PRECAST PILE SEQUENCE

1. Pile drilled using conventional rotary bore techniques 2. Undersized precast pile elements are stacked within bore to the correct level 3. The hollow void is protected eliminating the need for pile breaking 4. Fresh grout forms the bond between the precast elements and the bored shaft

The Precast elements can be combined with the impression tool enhancements to pile shaft friction, providing increased surety for the quality of construction and thereafter affording greater confidence that the piles can be re-used in the future.

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Well controlled environments within off-site manufacturing facilities are well suited to low carbon concrete technologies. This further enhances the benefits of the overall HIPER® product as an environmentally friendly, high quality, low risk product.

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Captions: (1) Base unit installation and (2) Precast hollow units

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1. Precast caps designed to connect onto Precast piles to accelerate follow on works packages 2. Hollow precast segments of varying lengths and diameter to ensure pile is constructed to the required cut off level 3. Bespoke base unit with grout outlet ports

Unrecorded process waste accounts for 29% of all costs associated with errors across the construction industry.

Expedition Engineering, 2016 8

BENEFITS

Precast pile construction methods offers the following benefits by:

Eliminating the need for traditional fresh concrete and reinforcement deliveries

Improving productivity by reducing the time taken to concrete large diameter piles

Minimising construction waste as piles are built upwards, not broken down to cut off level

Improving health and safety by eliminating the need to break piles down

Improving quality through manufacture of the pile segments in a controlled environment

Reducing non-conformances relating to steel levels being out of tolerance