Types of Building Foundation
Types of Building Foundations: Foundations are basically of two (02) types and the types of Building Foundation are as follows:
1) Shallow Foundation
2) Deep Foundation.
1) Shallow Foundation:
According to Terzaghi, if the depth of foundation is less than or equal to its width, then it is called a Shallow Foundation. This type of foundation transfer building load to the earth very near to the surface.
Shallow Foundation are:
i) Isolated Footing:
This is the most common type of foundation used for building construction and also most economical one. They are most commonly square and rectangular is size.
ii) Combined Footing:
Combined footing support more than one column in a row. Combined footings are constructed when two or more columns are close enough and their isolated footing overlaps one-another.
iii) Strap Footing:
A strap footing consists of two isolated footings connected with a structural strap or a lever. The strap connects the two footing such that they behave as one unit.The strap simply act as a connected beam and does not take any soil reaction.
iv) Mat or Raft Foundation:
A mat or a raft is a large slab supporting a number of columns and wall under the entire or large part of a structure. Mat foundation required when the allowable soil pressure is low or where the columns or walls are so closed that individual footings overlap or touch each-other.
v) Wall Footing:
This type of foundation runs along the direction of the wall and helps to transmit the load of the wall into the ground.
2) Deep Foundation:
According to Tarzaghi, if the depth of foundation is greater than its width. then it is called Deep Foundation. A deep foundation is generally much more expensive than a shallow foundation.
Deep Foundations are:
i) Pile Foundation :
A pile is a slender structural member made of steel, concrete or wood.A pile is either driven into the soil or formed in-situ by excavating a hole a filling it with concrete.
ii) Pier Foundation:
A pier is a large diameter concrete cylinder build in the ground. The difference between a drilled pier and a bored pile is basically of size.
iii) Well Foundation:
A well foundation is similar to an open caisson. Well foundation can be constructed on a dry bed or after making a sand island.
