A shallow foundation is a type of building foundation that transfers building loads to the earth very near to the surface, rather than to a subsurface layer or a range of depths as does a deep foundation. Shallow foundations include spread footing foundations, mat-slab foundations, slab-on-grade foundations, pad foundations, rubble trench foundations and earthbag foundations.

1. SHALLOW FOUNDATION
Presented By
A.Bharat kumar

2. FOUNDATION
 Lowest part of the Sub-structure.
 Provides a base for the super structure.
 Transmits the load on the structure
including the dead weight of the
structure itself to the soil below.

4. SHALLOW FOUNDATION
 Foundation placed immediately lowest
part of the super structure.
 Used to distribute the structural load
over a wide horizontal area at a shallow
depth below the ground level.
 According to Terzaghi, a foundation is
shallow if its depth is equal to or less
than its width.

6. TYPES OF SHALLOW
FOUNDTION
1. Isolated spread footing
2. Wall footing
3. Combined footing
4. Cantilever or Strap footing
5. Raft or Mat foundation

7. ISOLATED SPREAD FOOTING
 Structural members are used to support
columns and to transmit their loads to
their loads to the soil.

8. SPREAD FOOTING

10. TYPES OF ISOLATED SPREAD
FOOTING
 Wall footing
 Reinforced footing
 Inverted arch footing
 Column footing

11. Wall footing
 Supports wall that
may either be bearing
or non bearing walls.
 Required to support
direct concentric
loads.
 Used in low rise
buildings.

12. Reinforced concrete footing
 Relatively heavy
loading than wall
footing.
 Bearing capacity of
soil is low.
 Reinforcing steel is
placed in the bottom
of the footing in a
direction
perpendicular to the
wall.

13. Inverted arch footing
 Used to resist
sideways, in wards
loads.
 Used in conjunction
with retaining walls.

14. Column foundation
 Most economical type
of footing.
 Used when columns
are spaced at
relatively long
distance.
 Carries heavy loads.
 Used to support single
column.
 Distribute the load
uniformly.

15. Combined footing
 Usually supports two
or three columns not
in a row.
 Used when two
columns are so close
that single footings
cannot be used or
when one column is
located at or near a
property line.

16. Combined footing

17. Cantilever or strip footing
 A strap footing is used to connect an eccentrically
loaded column footing to an interior column.
 The strap is used to transmit the moment caused
from an eccentricity to the interior column footing
so that a uniform soil pressure is generated
beneath both footings.
 The strap footing may be used instead of a
rectangular or trapezoidal combined footing if the
distance between columns is large and / or the
allowable soil pressure is relatively large so that
the additional footing area is not needed.

18. Cantilever or Strip foundation

19. Raft / Mat Foundation
 Consist of a thick reinforced concrete
slab covering the entire area of the
bottom of the structure (like a floor).
 Base soil has low bearing capacity or
 Column load are so large that more than
50% of the area covered by
conventional spread footing.
 Resist unequal settlement due to
earthquake.
 Quickness of construction work.

20. Raft / Mat Foundation

21. Types of Mat Foundation
1. Flat plate mat
2. Plate thickened under columns
3. Two-way beam and slab
4. Rigid frame mat
5. Piled raft
6. Plate with pedestal

28. Advantages of shallow
foundation
 Quick process compared to others construction
work.
 Economically cheaper.
 Can resist ground water absorption.
 Damage due to earthquake is lesser than any
other type of foundation.
 Consist of reinforced concrete slab which is more
thicker than footing foundation.
 Prevents unequal settlements.

29. Disadvantages of shallow foundation
 Spread footers being installed is too shallow (2-3
feet below), which does not eliminate the effects
of expansive soil.
 Foundation repair will last longer than a week as
the excavations are made and the concrete will
have to be cured before the holes can be refilled.
 A huge amount of earthwork is to be done in mat
foundation.
 Ground water may come out when earthwork is
done.
 Limited to dealing with point loads.