Foundation is one of the most important parts of the structure. It transfers the total loads from the structure to the soil and provides stability to the structure. Foundation can be primarily classified into two parts, such as Shallow Foundation and Deep Foundation. They are basically classified depending on the depth at which the foundation is provided.
Shallow Foundation vs Deep Foundation
Shallow foundation and deep foundation have several differences. Sources of main differences between deep and shallow footings are definition, depth of foundation, cost, feasibility, mechanism of load transfer, advantages, disadvantages, types, etc.
In the following table the main differences between shallow and deep foundations are given:
| Sources | Shallow Foundation | Deep Foundation | |
|---|---|---|---|
| 1 | Definition | A foundation that is placed near the surface of the earth or transfers the loads at a shallow depth is called the shallow foundation. | A foundation that is placed at a greater depth or transfers the loads to deep strata is called a deep foundation. |
| 2 | The depth of the foundation | The depth of a shallow foundation is generally about 3 meters or the depth of the foundation is less than the footing. | Greater than the shallow foundation. |
| 3 | Cost | A shallow foundation is cheaper. | Deep foundations are generally more expensive than shallow foundations. |
| 4 | Feasibility | Shallow foundations are easier to construct. | The construction process of a deep foundation is more complex. |
| 5 | Mechanism of load transfer | Shallow foundations transfer loads mostly by end bearing. | Deep foundations rely both on end bearing and skin friction, with few exceptions like end-bearing pile. |
| 6 | Advantages | Construction materials are available, less labor is needed, the construction procedure is simple at an affordable cost, etc. | Foundation can be provided at a greater depth, Provides lateral support and resists uplift, is effective when foundation at shallow depth is not possible, can carry a huge load, etc. |
| 7 | Disadvantages | Possibility of a settlement, usually applicable for lightweight structure, weak against lateral loads, etc. | More expensive, needs skilled labor, has complex construction procedures, can be time-consuming and some types of deep foundations are not very flexible, etc. |
| 8 | Types | Isolated foundation, strip foundation, mat foundation, combined foundation, etc. | Pier foundation, pile foundation, caissons, etc. |