Types of foundation

1. When we are thinking about any kind of construction like a small house to skyscraper,
foundation is base of the construction, foundation is the most important part of the structure,
which transferred whole load of structure to the soil safely and provide stability to the
structure.
Design of foundation is the most essential part when a structure is designed. After the study
of topography, geology, and size of structure and other factors consideration the type of
foundation is decided.
What Is Foundation?
 Foundation is the basic component of structure through which the whole load of structure
is transferred to the soil, the solid ground on which foundation is rested, is called foundation
bed.
 Stability is provided by Foundation to the structure, by distributing the load of
superstructure to the earth.
 Strong and well-designed foundation prevent settlement of structure and increase the
stability.

3. On the earth surface different kind of soil, sediment, stones are found. By
studying their characteristics, and so many factors geotechnical engineers
recognized how these factors affects the structure, and which type of
design of structural element should be done.
So there are two type of foundation
1. Shallow Foundation
2. Deep Foundation

4.  Shallow foundation is the foundation in which width of foundation is
greater than the depth of foundation.
 It is more economical than deep foundation because it requires less
digging.
 Shallow foundation is suitable where the soil can bear the weight of
structure at a shallow depth.

5.  Shallow foundation again divided into following types,
Types of Shallow Foundation
A. Individual foundation and isolated foundation
B. Combined foundation
C. Strip foundation
D. Raft or mat foundation

6.  Individual foundation or isolated foundation is the type of shallow
foundation, which is used for building construction.
 This foundation is constructed for single column.
 It is the most economical type of footing, because the column placed at
a particular distance.
 The shape of footing may be square or rectangular.
 Material used for it may be reinforced or non-reinforced.
 The size of footing is depending on the safe bearing capacity of soil and
load of superstructure come on column.
 Simply, the size of footing calculated by dividing the total load at the
column base by the allowable bearing capacity of soil.

7.  The combined footing is the combination of a different footing.
 It is not differing from the isolated footing, only difference is that one
base or footing is sharing weight of two columns.
 It happened because the two footing re come very close to each other.
 The shape of footing can be rectangular, square trapezoidal.
 The overall distribution of load is uniform.

8.  This type of footing is used in load bearing structure, in which wall
distributing the load of structure, not the column or pillars and beam.
 In this footing, the base of footing is wider than the load bearing wall
because the foundation runs the entire length of load bearing wall.
 This wider base of footing transferred load safely to soil and provide
better stability.
 It is made up of reinforced concrete, bricks, etc.

9.  This type of foundation is used when the bearing capacity of soil is
weak.
 The Mat foundation is spread across the entire area of building.
 This foundation is used where load of the structure coming from wall
and column is too high.
 To prevent settlement of structure this foundation is used.
 This is costly structure; this footing is constructed when there is no
other type of footing is suitable.
 The columns are placed closely to each other.
 It is suitable where ground water table is low.

10.  Deep foundation is used when building on the soft soil and sand which
cannot carry the load of structure safely.
 Up to getting hard strata, the foundation is deeper.
 The foundation is situated at the deep underground or underwater.
 For bridges, piers and dams such foundation is used.
 Deep foundation gain divided into following types:
Types of Deep Foundation
E. Pile foundation
F. Drilled shafts or caissons
G. Pier foundation

11.  Pile foundation is the most common type of deep foundation, which is used
where the hard strata of soil are deeper, and to carry load of structure the plies are
used.
 Pile length is more than its cross-sectional area.
 Pile transferred load to soil trough friction or bearing.
 They are helped to reduce cost of construction.
 The types of piles are as follows
a. Based on their function or use
1. Sheet piles
2. Load bearing piles
3. End bearing piles
4. Friction piles
5. Soil compactor piles
b. Based on the material and construction method.
1. Timber piles
2. Concrete piles
3. Steel piles
4. Composite piles.

12.  A drilled shafts also known as caissons, which is mostly used at the
construction of bridge, pier and mostly at the structure over water.
 They have the characteristics of floating at a desired location then sunk
into the place.
 By digging the loose land with an auger up to getting bedrock, sand
while digging, hollow steel casing is fixed to prevent the sand or soil
from caving, the reinforced mesh rebar is then centered inside the casing,
and then concrete poured. Concrete is filled from bottom to the top of
casing, so that all the groundwater out from the top. Caisson foundation
can be done by this way
 Also by using mesh grid of rebar filled with concrete, caisson can be
constructed on site.
Main types of caissons are as follows:
1) Open caissons
2) Pneumatic caissons
3) Monolithic caissons
4) Sump caissons
5) Box caissons

13.  The load which is not transmitted by the shallow foundation, for
transferring such massive load pier foundation is used.
 It is not as deep as piles; it is used in multistory structure.
 It transferred load to soil through end bearing.