Types Of Foundation Footings Explained: Selecting the Best Option for Stability

 

Types of Foundation Footings    

Foundations are very important in construction. They help to sustain the entire structure and make it stable. There are two broad groups onto which they can be classified: deep foundations and shallow foundations. The selection of the correct foundation depends on three main factors, which include soil type, load bearing capacity and the weight of the structure. This source discusses all types of foundations, their uses, and at what points to be implemented.

 

Shallow Foundations

The shallow foundations will be effective when the soil is near the surface and is capable of supporting weight of the building. They commonly fit into 3 meters of the ground and are appropriate at minor construction works or at sites with favorable soils.

Below are the common options:

Spread Footing (Pad Footing)

Spread footing distributes a column's load over a large area of soil. It is used in buildings where the requirements are light to moderate load and the soil is stable. It supports columns or concentrated loads.

Strip Footing (Continuous Footing)

Weight is distributed, along an extended continuous line, in supporting walls. This type of footing is ideal for low-rise buildings with load bearing. Strip footing is suitable to wall that supports the weight of the building along its length.

Mat Foundation

A concrete slab is used to form the whole building area evenly that carries the weight. Ideal use is on structures that have massive loads or those found on low bearing soil.

Slab‑on‑Grade:

The slab rests on the ground that is why it does not need any reinforcement hence construction is less expensive and easier. It is also useful in firm soils and structures that have a lightweight up to heavyweight of constructions. It is able to handle light to medium weight on hard soils.

Combined Footing:

Purpose is to divide the load of two or more adjacent columns which have a common footing. It suits well when there are columns which are closely spaced that can share a common footing. Intended to be used in the multiple columns loads that are in proximity.

Isolated Footing

With The help of a single column, the heaviness loads on the soil. Isolated Footing are used when the columns are spacing but are not interconnected with the walls. It deals with single columns with either light or medium loads.

Raft Foundation

The whole construct is dependent on a massive concrete slab. It is normally applied in cases where the bearing capacity of the soil is low, or the weight of the building is too weighty to support other types of foundations. It is used when bearing capacity of soil is low or weight of the building is too much to support other foundations. This type of load supports large buildings with heavy loads and poor soils.

Deep Foundations

In cases where the load of the structure is not supported by the surface soil, deep foundations are required. They are used where tall buildings have weak and deep soils. Such foundations go way down beneath the surface.

The main types are:

Pile Foundation

In pile foundations, long narrow piles are driven deep into soil to counter the weight on to stable soil or bedrock. They are suited on weak surface soil or any place that is subject to extreme conditions, and also the ones that are used in heavy buildings or where the soil may be unsteady.

Well (Caisson) Foundation

It is a considerable cylindrical building embedded in the ground and usually located in the water-logged places or on the rivers. The application of underwater welding is often typical to underwater structures or in cases where the underwater excavation must be carried out. This type of foundation is used for large and heavy structures like bridges or piers in water bodies.

Types of Caissons

Mainly three types of Caissons are there:

Open Caissons:

These are hollow constructions that are employed at shallow water and on soft soils.

Closed Caissons:

Sealed units which are best used in deep water or dry excavation.

Pneumatic Caissons:

Compressed air is used to ensure that the working environment is dry; it is relevant in underwater construction works that are deep.

Drilled Piers

Vertical holes of great size are drilled, and concrete is poured in giving deep support. It is applicable where the topsoil is not very firm but the ones below that are firmer. It is used in large buildings that need deep foundation.

Socketed Piles

Socketed piles are drilled into bedrock or stable soil to enhance foundation support. It is used in cases when it is necessary to have a strong support and where there is a solid ground available at a distance. Suited to heavy structures which require great stability.

Barrette Piles

Why choose Barrette piles? These are massive pods that are constructed in the form of rectangles to secure heavy constructions that require deep foundations. When should you use them? Barrette piles are ideal for heavy loads or construction on poor soil.

This type fits best when used on large structures that require a heavy load support.

Selecting the right foundation is crucial for ensuring stability and longevity. Deep foundations are needed in unstable or weak soils whereas the shallow underpinning can be used in the buildings set on soils of light magnitude. All types have their own purpose and are selected depending on soil conditions, requirements in terms of load, and general size.

For light buildings on stable ground, spread footings, isolated footings, or slab-on-grade foundations are suitable. In large heavy structure or weak soils, Raft Foundation, Pile Foundation or Caisson Foundation should be considered. Always seek the advice of a structural engineer to know the best type of the foundation to use in your construction work.