Foundation or Footings is defined as the lowest part of a structure which provides a base and stability for the super-structure . The term foundation or footing includes the portion of the structure which is below the ground level as well as the man-made arrangement of concrete blocks, piles, raft, grillage foundations, etc. provided to transfer the loads on the super-structure including the dead weight of the structure itself to the soil beneath.
Purpose of Foundation:
It is often mistaken that the foundation is provided to support the load of the super-structure. In fact it is used to transmit the load of the structure to the soil beneath.
Foundation is provided for the following purposes,
(i) To distribute the weight of the structure over wide area so as to prevent over-loading of the soil below.
(ii) To load the sub-stratum evenly and thus prevents unequal settlement.
(iii) To provide an even surface for building works.
(iv) To take the structure deep into the ground and thus increase its stability, preventing overturning.