Piles are structural elements that transfer loads of a building or structure to deeper, more stable layers of soil or rock. These are typically long, slender columns made of different materials such as steel, concrete, or timber. They are bored or driven into the ground to support the structure’s weight.
Pile foundations are commonly used in situations where the soil near the surface is not strong enough to support the structure’s weight or where the structure must be supported on soft, compressible soils or slopes.
This blog will discuss the brief history of piling along with its types and materials.
Evolution History of Piling
The use of pile foundations can be traced back to ancient times when wooden piles were used to support structures built on soft soil or marshy ground. In fact, the oldest known pile-supported structure is 6000 years old in Switzerland, where wooden piles were used to support buildings made of brick and stone.
In the Roman era, piles made of stone or timber were used to support bridges, aqueducts, and other structures. The Romans also used piles to support their famous Colosseum, which was built in the first century AD.
During the Middle Ages, pile foundations were commonly used in Europe to support structures such as cathedrals and castles. Wooden piles were used extensively and were often driven into the ground using a heavy hammer or a pile driver.
In the 19th Century, pile foundations became more common and sophisticated with the advent of new materials such as concrete and steel. The introduction of steam-powered pile drivers made it possible to drive piles deeper into the ground and to support much heavier loads.
In the 20th Century, the development of hydraulic pile drivers and other specialised equipment further improved the efficiency and effectiveness of pile foundations. Today, pile foundations are widely used in the construction of buildings, bridges, highways, and other structures that require a solid foundation on soft or unstable soil.
Types of Pile Foundations
These piles are designed to transfer the load of the structure to a hard layer of rock or very dense soil at the bottom of the pile. End-bearing piles are usually made of concrete or steel and are often used for structures with heavy loads, such as high-rise buildings, bridges, and transmission towers. The piles are usually driven into the ground by hammering them with a pile driver until they reach the hard layer.
These piles are designed to transfer the load of the structure to the surrounding soil by frictional forces between the soil and the surface of the pile. Friction piles are typically used in soft soils or where the soil layer is not thick enough to support the structure. They can be made of concrete or steel and are usually driven into the ground by a pile driver until the desired depth is reached.
These piles are designed to improve the load-bearing capacity of loose or weak soils by compacting the soil around the pile. Compaction piles are usually made of pre-cast concrete or steel and are driven into the ground by a pile driver until they reach the desired depth. After driving the pile, the soil around it is compacted using a vibrating hammer to increase its density.
These piles are designed to support structures subject to uplift forces, such as tall buildings or bridges. Anchor piles are typically made of steel and anchored to a solid rock or dense soil layer using a steel cable or rod. A pile driver drives the anchor pile into the ground, and the cable or rod is attached to the structure to provide additional support.
These piles are designed to provide lateral support to excavations, retaining walls, and cofferdams. Sheet piles are usually made of steel or concrete and are driven into the ground to form a continuous wall. They are often used in areas with limited space for excavation, and they can be installed quickly and efficiently.
These piles are created by drilling a hole in the soil and pouring concrete into it. Bored piles are often used in soils that are difficult to drive piles into or in areas with restricted headroom. They are typically made of reinforced concrete and can be used for both end-bearing and friction piles.
Different Materials for Piling
Some of the materials commonly used for pile foundations include:
These are made of reinforced concrete and are suitable for heavy structures and difficult soil conditions. They can be pre-cast or cast-in-situ and can be either driven or drilled into the ground.
These are made of steel and are used for both small and large structures. They are suitable for soils that are difficult to penetrate and offer high resistance to corrosion.
These are made of wood and are suitable for light structures and soft soil conditions. They are easy to handle and can be easily cut to any length.
These are made of a combination of materials, such as concrete and steel or steel and fibreglass. They offer the advantages of both materials, such as high strength and resistance to corrosion.
These are made of steel and screwed into the ground using a piling rig or other equipment. They are suitable for light structures and soils that are easy to penetrate.
Classification of Piles According to the British Standard Code of Practice for Foundations
Large Displacement Piles (Driven Types)
- Round or square timber Piles
- Pre-cast concrete piles with solid or tubular sections
- Prestressed concrete piles
- Steel tube Piles driven with closed end
- Fluted and tapered steel tube
- Steel box piles driven with closed end
- Jacked-down solid concrete cylinder
- Jacked-down steel tube with closed end
Large Displacement Piles (Driven and Cast-in-situ types)
- Pre-cast concrete shell filled with concrete
- Steel tube driven and withdrawn after placing concrete
- Thin-walled steel shell driven by the withdrawable mandrel and filled with concrete
Small Displacement Piles
- Prestressed concrete piles with tubular sections driven with open end
- Pre-cast concrete piles with tubular sections driven with open end
- Steel tube section driven with open end
- Steel H-Section
- Steel box section driven with open end