In the complex world of piling construction, the choice of foundation method is paramount to a project's success. When shallow foundations aren't sufficient to support a structure, deep foundation solutions, collectively known as piling, come into play. But piling isn't a single technique; it encompasses a diverse range of methods, each designed to tackle specific ground conditions, structural loads, and site constraints. For piling companies and piling contractors, understanding the nuances of what are the piling types available is essential. This guide will explore the major types of piling and their applications.

What is Piling? A Quick Recap

Before diving into the types of piling, let's quickly define the core concept. Piling involves the installation of pilings (long, slender columns) deep into the ground. Their primary purpose is to transfer the weight of a building or structure through weak or unstable surface soils to stronger, more competent strata below, where the soil bearing capacity is adequate. This prevents issues like excessive settlement or visible signs of subsidence, ensuring the longevity and stability of the entire piled structure. Essentially, piling up refers to the process of installing these crucial supports.

The Main Piling Types: Bored, Driven, and Screw Piles

The various piling types can generally be categorized into three main families based on their installation method: Bored, Driven, and Screw Piles. Each category utilizes a specialized piling rig (or pile rig) and process.

Bored Piling Types

Bored piles are created by drilling a hole in the ground and then filling it with concrete and reinforcement. This method generally causes less vibration than driven piles.

• CFA Piling (Continuous Flight Auger Piles): One of the most common types of piling. A CFA piling rig uses a hollow-stemmed continuous flight auger to bore into the ground. As the auger is withdrawn, concrete is simultaneously pumped through its core, filling the void from the bottom up. This creates a solid CFA pile. These continuous auger piles (sometimes mistakenly called flighty auger piles or referred to as SFA piles in some contexts) are efficient and produce less noise and vibration, making continuous flight auger CFA piles ideal for urban environments.

• Mini Piling: A specialized form of bored piling using compact mini piling rig equipment. Mini piles (or Mini Pile) are small-diameter piles (typically 100-350mm) ideal for restricted access sites, low headroom areas, or when working close to existing structures where minimal disturbance is key. They are a crucial solution offered by mini piling contractors.

• Rotary Bored Piles: Similar to CFA but often used for larger diameters and greater depths, where casing may be used to support the bore before concrete is poured.

Driven Piling Types

Driven piling involves forcing pre-formed concrete piles, steel sections, or timber into the ground using a large pile driver (or pile piling equipment) that hammers or vibrates them. This method displaces soil rather than removing it.

• Driven Piles: A driven pile is a pre-manufactured element pushed into the ground. This technique, also known as driven piling, is fast to install and creates minimal spoil. However, it can generate significant noise and vibration, making it less suitable for sensitive locations. Piling contractors use this where soil conditions allow and environmental impact is less of a concern.

Screw Piling Types

Screw piling, or Helix piling, involves screwing large steel helical piles into the ground. They are a non-displacement, low-vibration method.

• Screw Piles / Ground Screws: A Screw pile (also known as a ground screw, ground screw anchor, or screw in ground) is essentially a large steel screw, often with one or more helical plates, which is rotated into the ground until the required torque (and thus bearing capacity) is achieved. This forms a ground screw foundation or screw pile foundation. These helical piles offer rapid installation, immediate load-bearing capacity, and minimal site disturbance. They are ideal for lighter structures, decks, solar arrays, and often used as helical pile foundation or helical screw piles, or screw pile footings. Ground screws foundations are gaining popularity for their efficiency and environmental benefits.

Essential Components & Considerations for All Piling Types

Regardless of the piling types selected, several common elements and considerations apply across all piling construction projects:

• Piling Rig: The essential machinery used to install the pilings. The type of pile rig varies significantly depending on the chosen method.

• Piling Mat: A temporary, stable working platform constructed to support the heavy piling rig and ensure safe operation.

• Pile Cap: Once the individual pilings are installed, a pile cap (a reinforced concrete block) is constructed on top of a group of piles (known as pile and pile caps). The pile cap acts as a connector, distributing the structural load evenly onto the supporting piles below.

• Soil Bearing Capacity: The strength of the soil at various depths, specifically the soil bearing capacity of soil or ground bearing capacity, dictates how deep piles need to go and what type is suitable.

In Conclusion

Understanding what are the piling types is crucial for anyone involved in deep foundation work. From the quiet efficiency of CFA piling and mini piling to the rapid installation of driven piling and the innovative simplicity of screw piling (helix piling), each method offers unique advantages. Piling companies and piling contractors expertly navigate these options, assessing site conditions, soil bearing capacity, and structural demands to select the optimal piled solution. By choosing the right types of piling, engineers ensure that the foundations of any building are robust, stable, and ready to stand the test of time, effectively preventing signs of subsidence and ensuring long-term structural integrity.