This document discusses shallow foundations. Shallow foundations are placed at a shallow depth and distribute structural loads over a wide area. The main types of shallow foundations are spread footings, combined footings, mat/raft foundations, and grillage footings. Spread footings support columns and walls and transmit loads to the soil. Common varieties include wall, reinforced concrete, inverted arch, and column footings. Combined and mat foundations are used when columns are close together or loads are large. Shallow foundations provide quick construction and resist water absorption but have limitations with point loads.

1. SHALLOW FOUNDATION
-: CREATED BY :-
ALAY MEHTA
SHIVANI PATEL
KAVIN RAVAL
KUNTAL SONI
AMIRAJ COLLEGE
OF
ENGINEERING AND TECHNOLOGY

2. FOUNDATION
 Foundation is the lowest
part of a structure which
provides a base for the
super‐structure and
transmit the loads (live
load, wing load) on the
structure including the
dead weight of the
structure itself to the soil
below.

3. TYPES OF FOUNDATION
 Types of Foundation:
 Foundation can be broadly classified into two types
:
1. Deep Foundations
2. Shallow Foundations

4. SHALLOW FOUNDATION
 Foundation is placed immediately lowest part of the
super structure, is termed as Shallow foundation:
 Why we use shallow foundation?
 To distribute the structural loads over a wide
horizontal area at a shallow depth below the ground
level.

5. TYPES OF SHALLOW FOUNDATIONS
 The various types of shallow foundations are :
 Spread footing
 Combined footing
 Mat or Raft foundation.
 Grillage footing
 Eccentrically loaded footing

6. SPREAD FOOTINGS
 Spread footings are
structural members used
to support columns and
walls and to transmit and
distribute their loads to
the soil.

7. SPREAD FOOTING
 Types of spread footing
 Wall footings
 Reinforced concrete footings
 Inverted arch footing
 Column footings

8. WALL FOOTING
 Why Wall Footing?
 Support walls that may be
either bearing or nonbearing
walls.
 Commonly required to
support direct concentric
loads.

9. WALL FOOTING
 Why Wall Footing?
 Footings carry relatively
light loads on well drained
cohesive soil.
 A wall footing under
concentric load behaves
similarly to a cantilever
beam.
 Used in low rise buildings.

10. REINFORCED CONCRETE FOOTING

11. REINFORCED CONCRETE FOOTING
 Why Reinforced
concrete footing?
 Relatively heavy
loading than wall
footing.
 Bearing capacity of the
soil is low.

12. REINFORCED CONCRETE FOOTING
 In a reinforced concrete
wall footing, the behavior is
identical to that of wall
footing.
 Reinforcing steel is placed
in the bottom of the footing
in a direction perpendicular
to the wall like a reinforced
concrete beam or slab.

13. INVERTED ARCH FOOTING

14. INVERTED ARCH FOOTING
 When a wall is
composed of isolated
piers, it is well to
combine all their
footings into one, and to
step the piers down .

15. COLUMN FOOTINGS

16. COLUMN FOOTINGS
 WHY COLUMN
FOOTINGS?
 This is one of the most
economical types of
footings.
 Used when columns are
spaced at relatively long
distances.

17. COLUMN FOOTINGS
 WHY COLUMN FOOTINGS?
 Low bending strength.
 When bearing capacity of soil is
good.
 Carry heavy loads.
 Used to support single columns.
 To distribute the load uniformly.

18. COLUMN FOOTINGS
 CHARACTERISTICS OF
COLUMN FOOTINGS
 Constructed with brick,
stone or plane concrete.
 Circular, rectangular or
square in plan.

19. COMBINED FOOTINGS
 Usually support two
columns, or three columns
not in a row.
 Combined footings are
used when tow columns are
so close that single footings
cannot be used or when
one column is located at or
near a property line.

20. COMBINED FOOTINGS
 WHY COMBINED
FOOTINGS?
 When two columns are
close together, causing
overlap of adjacent isolated
footings.
 When soil bearing capacity
is low, causing overlap of
adjacent isolated footings.

21. GRILLAGE FOUNDATIONS
 Grillage foundations consist of
a number of layers of beams
usually laid at right angles to
each other and used to
disperse heavy point loads
from the superstructure to an
acceptable ground bearing
pressure.

22. RAFT FOUNDATION
 Foundation which consists of thick reinforced concrete
slab covering the entire area of the bottom of the
structure like a floor. This foundation was invented by
John Root at Chicago in 19th century.

23. RAFT FOUNDATION
 Why Raft Foundation?
 Base soil has low bearing
capacity or the column loads
are so large that more than
50% of the area is covered
by conventional spread
footings.
 Resist unequal settlement
due to earthquake.
 Quickness of the
construction work

24. LIMITATIONS OF SHALLOW FOUNDATION
 A huge amount of earthwork is to be done in Mat
foundation.
 If the shoring system can not resist the pressure of
outside land, then the structure surrounding the
area may be damaged by deflection of soil.
 Ground water may come out when the earthwork is
done.
 Limited to dealing with point loads. foundation

25. ADVANTAGES OF SHALLOW FOUNDATION
 It is a quick process compared to others in the
construction work.
 This type of foundation is also economically
cheaper than any other foundations.
 Though there are some limitations in mat
foundation still it is economical in some cases.

26. ADVANTAGES OF SHALLOW FOUNDATION
 It can resist ground water absorption.
 The damage due to earthquake is lesser than any
other type of foundation.
 It consists of a reinforced concrete slab which is
more thicker than footing foundation.
 It prevents unequal settlements.