Piling is a construction method that transfers the load of a building structure to a deep layer of soil or rock. It has been used for centuries to build structures on sloping land and protect against flooding.
The type of piling used depends on the ground conditions and the needs of the construction project. For example, a pile may be needed to support a bridge or provide extra strength to a concrete slab.
What is Piling?
Piling is a technique that sets deep foundations for construction work, such as buildings. It involves a lot of planning, measuring and hard labour and needs to be done by skilled engineers and workers.
Pile foundations are often used in construction projects, such as new homes, roads and infrastructure. They are particularly effective where the soil is too weak to support the weight of the structure.
They can also be used to carry uplift loads, such as those needed to support taller buildings.
There are two main types of piles: end-bearing and friction (or floating). The end bearing type transmits load directly to a deep strong soil or rock layer some way below the surface.
Friction (or floating) piles develop most of their capacity from shear stresses along the sides of the pile. They are suitable where harder layers are too deep, as they transmit load to surrounding soil by friction.
How Piling Works
Piling is a technique used to support buildings, roads or other structures above and underground. It can be particularly useful for projects that involve deep foundations where the ground is weak or cannot be removed easily.
In these situations, a pile driver is used to drive or bore piles into the ground. Once inserted, a pile cap is installed to protect the structure from damage.
The driving process requires the use of a hammer and can be noisy, which is why it’s sometimes not possible to use in sensitive locations. It also causes massive vibrations through the soil, which can cause damage to nearby buildings and other sensitive equipment.
Friction piles transfer load by friction between the surface of the pile and the surrounding soil over their full length. The deeper the pile is driven, the more friction develops until the pile “fetches up” and can no longer be driven any further.
Materials
Pile foundations are made of a variety of materials, including steel, concrete, and timber. They are installed in the ground to transfer load from a structure to a weak layer of soil at some significant depth below the base of the building.
They are used to support structures with heavy loads such as high rise buildings, bridges and water tanks. They also help reduce lateral pressure in the soil below the structure by transferring load to a firmer layer below the pile.
The most common type of piling is driven piling, which is created by drilling holes in the soil and filling them with concrete. The soil is then pushed sideways and compacted, which increases its strength.
Driven concrete piles come in a wide range of sizes and shapes. They are commonly precast before arrival on site and reinforced to withstand driving stresses.
Safety
Safety is important during any construction job, but it becomes even more critical when using piling. Modern piling rigs are large and can weigh hundreds of tonnes, have a high centre of gravity and must be operated over a site surface that has been prepared and maintained properly.
Incorrect ground conditions can lead to piling rigs topple and cause significant damage to property and claims for business interruption. This is often due to the presence of localised weak areas or deep obstructions that were not identified by load testing.
Whenever a piling rig is moved, it should be supervised by a qualified banksman who has visibility to both sides and the rear of the rig at all times. Only a supervisor, signalman or banksman should sign off the operator’s movements and hand signals must be used to indicate when to move, swing, pick up or lower loads.
