Foundation & Types of Foundation

 

Foundation

 

types of foundation


Foundation is the lowest part of the building structure, which is directly in contact with the ground and provide the base for the superstructure and transmits the load to the sub-soil. The structure is not visible in a complete building because the portion of structure is below the ground level.
Sub-soil:-
The soil which is located just below the base of the foundations called the sub soil or foundation soil.
Footing:-
The lower portion of the foundation which is in direct contact with the sub-soil is called footing.

Function of Foundation

·         It transmits the dead load, live load & wind load from a building from a building to the soil without causing cracks in the superstructure.
·         It provides the level surface for building operation
·         It prevent from differential settlement of the structure
·         It also provides stability to the structure

Types of Foundation:-

There are two types of foundation. They are
(i)           Shallow Foundation
(ii)         Deep Foundation

(i) Shallow Foundation :- In this type of the foundations the depth is equal to or less than its width, it is called shallow foundation. In this type of the foundation the foundation is placed immediately below the lowest part of the structure.
shallow foundation
shallow foundation
Classification of Shallow Foundation
    (a)  Spread footing  : Spread footing consists of a wide base of foundation for transmitting the load to the soil over a wider area.

   (b) Combined footing : Combined footing consists of a common footing provided to two columns which may be either rectangular or trapezoidal


     (c)  Mat or Raft Foundation : Raft foundation consist of dense reinforced concrete slab which covers the total bottom area of the structure. It is provided in the soil with low bearing capacity where the structural loads are heavy.


(ii)  Deep foundation : 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.

deep foundation
Deep Foundation
Classification of the Deep Foundation :
(a)  Pile Foundation : Pile foundation is a type of foundation where a slender member of wood or concrete or steel is inserted into the ground for transferring the load of a structure. The load is transferred to a stronger stratum by friction.

Classification of Pile foundation :
On the basis of function :
1.    Bearing piles
2.    Friction piles
3.    Sheet piles
4.    Anchor piles
5.    Batter piles
6.    Fender piles

On the basis of Material
1.    Timber piles
2.    Concrete piles
3.    Steel piles

COFFERDAMS : A cofferdams is a temporary structure which excludes the water from a given site to enable the construction on a dry surface.

Classification Of Cofferdams on the basis of material :
1.    Earthen Cofferdam
2.    Rock-fill Cofferdam
3.    Single-walled Cofferdam
4.    Double – walled Cofferdam
5.    Crib Cofferdam
6.    Cellular Cofferdam

Caisson Foundation : Caisson is watertight structure made of wood, steel or reinforced concrete which excavates for the foundation of bridges, piers, etc

Types of Caissons :
1.Open Caisson
2. Box Caisson
3. Pneumatic Caisson







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