Types of foundation

1. FOUNDATIONS
“Building Construction and Materials “
Presented By
Ar. Avitesh

2. Introduction
 “The foundation of a building is that part of walls, piers and
columns in direct contact with the ground and transmitting
loads to the ground.”
Ground Level
Super-structure
foundation
Distribute building load to the ground
 The size and
depth of a
foundation is
determined by
the structure
and size of a
building it
supports and
the nature and
bearing
capacity of the
ground
supporting it.

3. Functions of Foundations
To distribute the load of the structure over a large bearing area so as to
bring the intensity of load within the safe bearing capacity of soil.
To load the bearing surface at a uniform rate to avoid differential
settlement.
To prevent the lateral movement of supporting material.
To attain a level and firm bed for building operations.
To increase the stability of the structure as a whole.
Even distribution of loads.

4. Types of Foundations
There are two basic types of foundations
1. SHALLOW FOUNDATION
2. DEEP FOUNDATION
Shallow foundation
The foundation provided immediately below the lowest part of the structure
near the ground level, transferring load directly to the supporting soil, is
known as shallow foundation.
Shallow foundation is provided when stable soil with adequate bearing
capacity occur near to the ground level.
Requirements
Suitable soil bearing capacity
Undisturbed soil or engineered fill

5. Types of Shallow foundation
a) Spread footing or open trench
foundation
A spread footing foundation, which is typical in
residential building, has a wider bottom
portion than the load-bearing foundation walls
it supports. This wider part "spreads" the
weight of the structure over more area for
greater stability.
Grillage foundation
A type of foundation often used at the base
of a column. It consists of one, two or more
tiers of steel beams superimposed on a
layer of concrete, adjacent tiers being
placed at right angles to each other, while
all tiers are encased in concrete.

6. Types of Shallow foundation
b) 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.
c) Strap footing
If the independent footings of two columns are
connected by a beam, it is called a strap
footing.
The strap beam does not remain in contact
with soil, and thus does not transfer any
pressure to the soil.

7. Types of Shallow foundation
d) Raft Foundation
Used to spread the load of the structure over a large base to reduce the
load per unit area being imposed on the ground
Particularly useful where low bearing capacity soils are encountered &
where individual column loads are heavy
Typical raft foundation:
 Solid slab raft
 Beam & slab raft

8. Types of Shallow foundation
e) Inverted arch footing
Provided for multi storyed buildings in old times.
However, with the advent of reinforced cement concrete construction practice,
inverted arch footing is rarely done these days.
One of the drawbacks in this type of construction is that the end piles have to be
specially strengthened by buttresses to avoid the arch thrust tending to rapture
the pier junction.
However, the advantage of inverted arch construction is that in soft soils the
depth of foundation is greatly reduced.

9. Deep foundation and its types
DEEP FOUNDATION
o transfer building loads deep into the earth
Deep foundation
1. Pile foundation
2. Pier foundation
3. Well foundation
Pile Foundations:-
• 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
Material
Steel; H- piles, Steel pipe
Concrete; Site cast or Precast
Wood; Timber

10. Pile Foundation
 Can be defined as a series of columns constructed or inserted into
the ground to transmit the loads of a structure to a lower level of
subsoil
 Can be used when suitable foundation conditions are not
presented at or near ground level
It can be:-
• End bearing piles
• Friction or floating piles

11. Pier Foundation
 A pier foundation consists of a cylindrical column of large diameter
to support and transfer large super-imposed loads to the firm
strata below.
 The difference between Pile foundation and pier foundation lies in
the method of construction.

12. Well Foundation
 Well foundations are hollow
from inside, which may be
filled with sand, and are
plugged at the bottom.
 The load is transferred
through the perimeter wall,
called seining.
 Well foundations are not
used for buildings.
 Used for:- Bridge piers and
abutment in rivers, lakes,
etc.