If you have ever wondered how building structures, such as homes, towers, bridges, roads and viaducts stand up, then you have come to the right place. Since the middle ages, we have driven deep foundations into the earth using a special technique that is known as piling. To answer all of your questions regarding foundations and, more specifically, foundation piling, we have put together a comprehensive guide – from how piles are used to how piling works. Piling is an essential part of any construction project, yet many of us struggle to wrap our heads around it. Read on to find out more.
What types of foundation are there?
The types of foundation are categorised into two different groups: shallow foundation and deep foundation. Factors that determine the type of foundation required for a building structure includes the load that the building needs to uphold, types of structure in your area, type of strata and climatic conditions. The pile foundation falls into the category of deep foundations.
Deep foundations are columns, typically made from steel or reinforced concrete, that are driven into the earth in order to spread the load of a building. They are used where the bearing capacity of surface soils are too little to support loads used to create building structures, and act as a steady support for building structures built on top. Piling is crucial to the stability of many building structures and significantly improves the life expectancy of a structure.
What exactly is the pile foundation?
The pile foundation is a common type of deep foundations that is used to transfer structural loads into deep layers of firm soil so that layers of rock and soil can sustain the load of a building structure. Pile foundations are one of the oldest methods – since the Middle Ages – used to ensure that a building stands on a strong foundation. It ensures that the foundation of a building is safe, sound and dependable.
A pile can either be driven into soil or, alternatively, it is formed on site by excavating a hole and then filling it with concrete. It is absolutely essential that the piling installation process is carried out professionally and correctly, using a heavy-duty pile driver.
When are pile foundations used?
As briefly discussed above, pile foundations are used when there are layers of low bearing capacity subsoils, such as wet clay or loose and unstable stand, on the surface. However, there are few other types of land conditions that also require piling to build a structurally sound building structure:
- Naturally formed and highly compressible subsoils, such as peat or limestone.
- Unconsolidated filled materials which have been artificially imported. These can be particularly difficult to compress.
- Subsoils with a tendency to volume change, such as shrinkable clay.
- Possibility of scouring (due to its location near a riverbed or seashore).
Piles work together with a foundation to perform two main functions:
- Sinking foundation repair: specialists install piles into the ground using hydraulic machinery. Once the piles are installed, they will surface, re-level and raise a building structure.
- Structural reinforcement: if a foundation is damaged, a pile still works to defend against potential future problems as they ensure that the foundation remains level.
What types of piles are there for foundation construction?
Various types of piles are used depending on a number of factors. These factors include such functions, the type of material used in their manufacture, their shape, load transfer mode, construction method and installation method.
Firstly, let’s take a look at different types of pile foundation designs based on their function or use:
End bearing piles
In end bearing piles, the loads pass through the lower tip of the pile; they penetrate through soft soil with poor supporting property and transfer the load to a hard stratum, such as rock. The pile effectively acts as a vertical column, safely transferring the load to a strong layer.
This type of pile uses adhesion or friction/resistance between the surface of the pile and the surrounding soil. Essentially, the load if transferred from the structure to the soil by frictional force. Depending on the length of the pile, friction can be developed for the length of the pile of a smaller section.
Sheet piles are mainly used to provide lateral support. They are watertight and therefore reduce seepage and uplift in case of hydraulic structure. Sheet piles are commonly used to protect river banks from erosion and to retain loose soil around foundation trenches. They are typically used for shore protection, trench sheeting and cofferdams. Sheet piles are most commonly made from steel, however, they can also be formed of timber or reinforced concrete.
Piles that are based on materials and construction method include:
Timber piles last for around 30 years and are either circular or rectangular in shape. They are placed under the water level and are designed for 15 to 20 tons. Timber piles are easy to install and economical, with a low possibility of damage being caused. They can also easily be pulled out.
Two different types of concrete piles include precast and cast-in-place concrete piles. Precast concrete piles are cast in pile bed in the horizontal form if they are rectangular, and vertical form if they are circular. Precast concrete piles require heavy duty pile driving machinery and are usually used for permanent and durable foundations. Cast-in-place concrete piles are constructed by boring of soil up to the required depth and placing mixed concrete in that place, letting it cure.
Steel piles are either an l-section or hollow pipe filled with concrete. They are very easy to drive and are most commonly used as end bearing piles. Compared to other types of piles, steel piles can reach great depths and can carry heavy loads, as well as easily penetrate through hard layers of soil – this is due to the reduced cross-sectional area.
118 Foundations: concrete foundations, grundomat piling and more
At 118 Foundations, our expert team can help with any project that requires piling, mini piling, driven piling up to 400kn, ground beams, underpinning, Grundomat Piling or structural calculations. Based in Whitworth, Rochdale, we serve customers across Greater Manchester and always complete every project to the highest Building Control standards.
If you have a piling project that requires the assistance of piling experts, or you simply want to discuss the cost of underpinning, you needn’t look further than us. At 118 Foundations, pride ourselves on our expert reliable and friendly service that is available throughout your entire project. Our team are all highly trained and skilled, ensuring that your project runs smoothly and is always completed to an excellent standard. We proudly offer a price that simply cannot be beaten, and offer free quotes and site surveys to all of our customers. In fact, if you manage to find a cheaper quote from another firm, we will guarantee to beat it.
We specialise in the design and construction of foundations for almost any type of building project – whether you are simply extending your current property or you are constructing a new housing development.