05.Driven Piles:

High-Capacity, Prefabricated Foundations

Driven piles are a deep foundation system where prefabricated pile elements are inserted into the ground using specialized impact or vibratory hammers.1 Unlike bored piles, driven piles are non-displacement piles, meaning they physically displace the soil as they are installed, leading to significant densification of the surrounding ground.

Installation and Types

The pile elements, which can be made of precast concrete, steel (H-piles or pipe piles), or timber, are hoisted and positioned vertically under the leads of a piling rig.2 The hammer then delivers repeated blows or high-frequency vibrations until the pile reaches the required depth or achieves a specific load-bearing resistance, often measured by the 'set' (the penetration distance per hammer blow).

This method is highly favored due to its inherent qualities:

• • Quality Control: Since the piles are manufactured off-site, their quality, material strength, and dimensions are strictly controlled before they arrive at the construction site.
• • High Load Capacity: The displacement of soil during driving increases the density and confining stress in the adjacent soil. This action significantly enhances the skin friction (side resistance) and end bearing, resulting in very high load-carrying capacity.

Advantages on Site

• • Speed of Installation: Once the rig is set up, the installation rate is very fast, making them ideal for large-scale infrastructure projects like marine jetties, bridges, and industrial plants.
• • Immediate Use: Driven piles can carry the structural load immediately upon installation, as no curing time for concrete is required.
• • In-situ Load Test: The driving criteria itself acts as a full-scale load test, offering immediate verification of the pile's capacity.

Driven piles offer a proven, powerful, and rapid solution for deep foundation requirements in various soil and environmental conditions.