Foundation is the lowest portion of a structure which transmits the load into the supporting soil. The main purpose of the foundation is to distribute the total weight of the superstructure over a large area of soil.
TYPES OF FOUNDATION
A shallow foundation is a type of foundation in which the foundation is situated instantly below the lowest part of a structure. The depth of the foundation is equal or less than its width.
A deep foundation is a type of foundation in which the foundation is placed at a deeper depth below the ground level. the depth of foundation is much greater than its width.
The footing is one of the most important parts of a structure which transfers loads of a structure to the underlying soil. the selection of footing depends on the following factors.
TYPES OF FOOTINGS
A strip footing is a component of shallow foundation which distributes the weight of a load bearing wall across the area of the ground.it is also known as wall footings.
A spread is given the base of the foundation so that the load of the structure is distributed on a wide area of the soil in such a way that the safe bearing capacity of the soil is not exceeded.
It is a square, circular or individually rectangular slab of uniform thickness, provided under each column.
The main purpose using stepped footing is to keep the metal columns away from direct contact with soil to save them from corrosive effect .they are used to carry the load of metal columns and transmit this load to the below ground.
When two or more columns are supported by a footing it is called combined footing. This footing may be of rectangular or trapezoidal in plan.
The combined footing is provided under the following situations.
In this type of footing, the outer and inner column is connected by a strap beam, does not transfer any load to the soil.
This foundation covers the entire area under the structure. this foundation has only RCC slab covering the whole area or slab and beam together. raft foundation is adopted when heavy structures are to be constructed on soft made –up ground or marshy sites with uncertain behavior .raft foundation is also known as mat foundation.
The strapped footings having the sloping top or side faces are known as sloped footings. This type of footing is useful in the construction of formwork.
A pile foundation is a long cylinder of strong materials such as concrete that is pushed into the ground to act as a steady support for structures built on top of it.
PILE FOUNDATIONS ARE USED IN THE FOLLOWING SITUATIONS.