Every structure is mainly divided into two parts – one is the superstructure and the other is the sub-structure or foundation. The lowest part of a structure, which is inside the ground, i.e. the lowest part of the structure is called the foundation. It acts as the base of the superstructure. In other words, the underground part of the structure is artificially constructed by combining concrete blocks, piles, rafts, grillages, etc., to transfer the weight of the structure above it to the solid layer of soil, called foundation.
Foundations are placed directly on solid subsoil or by lateral friction forces or both. All the mass of the structure is placed on solid ground through foundations or foundations. So hard ground has to be made with special care. So the bottom layer of specially made foundations is the foundation bed.
Foundation Engineering: Foundation engineering is a branch of civil engineering. It deals with the design, construction, repair and maintenance of footings, foundation walls, pile foundations, caissons etc. of buildings or any engineering structure.
Function of Foundation: It is generally considered that the foundation carries the weight of the structure. But in fact the foundation is only a means of spreading the weight of the structure on the foundation. So the main function of the foundation is the weight of the structure i.e. dead load, Temporary compressive loads on structures or transfer of live loads, wind loads etc. to the foundation through load foundations.
The basis is provided for the achievement of the following objectives or actions-
1. Reduction of Load Intensity: Foundations are provided to reduce load intensity i.e. to spread the weight of the structure over a larger area, so that the foundation avoids overloading. Hence the load imposed on the foundation shall never exceed the bearing capacity of the foundation soil.
2. Uniform distribution of load: The function of Foundation is to spread the uneven load of the superstructure evenly on the soil. So as to distribute the load evenly to the solid layer of the soil to prevent uneven settlement of the structure.
3. Providing flat surface: To obtain a hard and flat surface for the structure i.e. to obtain a flat surface to facilitate the construction of the structure.
4. Stability: To hold the superstructure as an anchor i.e. to increase the stability of the structure, resist sliding and overturning, resist horizontal forces (storms, earthquakes) etc.
5. Security from Undermining: To provide security to structures from flood waters and burrowing animals.
6. Prevention of Soil Movement: To prevent damage to the superstructure due to compression or expansion of the foundation soil or due to moisture.
