Bored Piling: Deep Foundations for Heavy Load Structures

What are bored piles?

 

Bored piles are a type of reinforced-concrete foundation, that supports structures with heavy vertical loads.  Bored piling is commonly used for bridge abutments and piers, tall buildings, and typically industrial structures, all of which require a deep foundation to support the design loads specified by the engineers of the project.​

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Bored piles are used to transfer their load to layers of soil or bed rock. This is only possible where the soil layers have sufficient bearing capacity and suitable settlement characteristics that meet the design engineers requirements.

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Such piles are installed by first removing spoil to form a hole, where a reinforced concrete pile is poured in situ. Bored piles can be constructed as an open hole, if the supporting ground allows for it, or by using a temporary or permanent sleeve (casing).

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Bored piles are used primarily in cohesive subsoils for the formation of friction piles and when forming pile foundations close to existing buildings.

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How are bored piles installed?

 

Bored piles are drilled using buckets and/or augers driven by percussion boring (vibratory hammers) or through rotary boring (twisting in place).

In unstable soils or wet holes, due to perched or high water tables, specialised fluids are used to assists in stabilising the open hole, especially in large diameter, deeper piles. the technique also ensures the good integrity of the hole, allowing to place reinforcement before concrete is tremie poured.  

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What are Lattey’s capabilities in terms of bored piling?

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Lattey have the experience to install most types of bored piles used in the building industry. We do not shy from acquiring additional plants or equipment whenever needed so we can meet the specific needs of our clients and their projects.

Our drilling gear includes specialised equipments such as rock augers and clean-out buckets. We can pile to a depth of up to 35 meters in a range of 250mm to 1,800mm using our SR-40 Soilmec rig.

The plants and equipment we have procured over the past 40 years give Lattey the ability to procure successful solutions on some of the most challenging sites and environments. Here are a few of the equipment we use in bored piling:

- Three Hitachi 35 to 80 ton Crawler Cranes with up to 54m of Jib fitted, with a series of fly jibs available at hand
- Soilmec AR-4050 ton Rotary Drilling Rig with 35 mtrs of drilling depth available
- Five excavators, from 6.5 ton to 48 ton
- Fluid Mixing stations, Recirculating and Storage Plant
- Silt settlement tanks
- Muller MS7 Vibro Unit
- Monkeys and helmets (free falling hammers with leaders as required) 

 

Some interesting boring projects

 

Some of the recent projects using bored piling technology that we have seen to their successful outcome include:

 
- The Indian High Commission
- The Bupa Retirement Village in Wellington
- WDC wash out Retaining walls
- Queensgate shopping mall crane tower foundations.

 

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