The two main types of foundation are :

• Shallow foundation (spread foundation)
  • Isolated footing
  • Combined footing
• Deep foundation
  • Pile foundation
  • Pier foundation

Shallow foundation

Depth of foundation is less than or equal to its width.

Isolated footing

• In framed structures where several columns are to be constructed, isolated footings can be adopted.
• The columns involved can be provided with masonry or concrete footing.
• If masonry footing is provided, steps are given and the foundation area is thus increased so that the stresses developed at the base is within the limit.
• In case of masonry footing, the projection of each step must be ½ brick thick and each step is made of 1 or 2 bricks put together.

Combined footing:

• This type of footing is adopted when the space between two columns is so small that the foundation for individual columns will overlap.
• Combined footings are proportioned in such a way that the center of gravity of the loads coincides with the center of gravity of the foundation. Hence these footings have either a trapezoidal or a rectangular shape.

Pile foundation

• A slender, structural member consisting steel or concrete or timber.
• It is installed in the ground to transfer the structural loads to soils at some significant depth below the base of the structure.
• Pile is an element of construction used as foundation. It may be driven in the ground vertically or with some inclination to transfer the load safely.