I'd like to share some excerpt from by blog here.
Foundations are horizontal or vertical members supporting the entire structure and transmitting the loads to the soil below. They are sub-structures supporting the super-structures of the columns, beams, walls, slabs and roofs.
Foundations mostly satisfy the following fundamental and independent requirements
The factor of safety against shear failure of the supporting soil must be adequate
The settlement should neither cause any unacceptable damage nor interfere with the function of the structure
Foundations can be classified as:
Shallow foundations
Deep foundations
The choice depends but not limited to these two elements:
Result of soil/geotechnical investigation- nature of the soil strata, type etc
Magnitude of the intended transmitted loads from the superstructure
Types Of Foundations
Shallow Foundations- Strip Foundations, Wide Strip Foundations, Pad Foundations Strap Foundations, Raft Foundations
Deep Foundations- Pile Foundations, Diaghragm Foundations, Displacement Foundations
Reference:
http://orccng.com/2016/05/16/141/