1. DEEP FOUNDATIONS
PREPARED BY:
SAQIB NAWAZ
B.ARCH. 3RD YR.

2. A foundation is the lowest and supporting layer of a structure.
Requirements (Functional)
A properly designed foundation is one that transfers the structural load
throughout the soil without overstressing of soil which can result in either
excessive settlement or shear failure,both of which can damage the
structure.
Based on their point of transfer of load, Foundations are generally divided
into two categories:
SHALLOW FOUNDATIONS
&
DEEP FOUNDATIONS.

3. a) Shallow Foundation System
A shallow foundation is a type of foundation which transfers building
loads to the earth very near the surface. Shallow foundations include
spread footing foundations, slab-on-grade foundations, rubble
trench foundations, and earth bag foundations.
b) Deep Foundation System
A deep foundation is used to transfer a
load from a structure through an upper
weak layer of soil to a stronger deeper
layer of soil. There are different types
of deep footings including impact
driven piles, caissons,helical piles,
and earth stabilized columns.
SHALLOW FOUNDATION
DEEP FOUNDATION

4. LOADS ON FOUNDATION
• Dead Load : Refers to the overall weight of the structure.
Includes weight of the materials permanently attached to the
structure (such as flooring) and fixed service equipment (such
as air conditioning)
• Live load : Refers to the weight of the applied bodied that are
not permanent parts of the structure. Applied to the structure
during part of its useful life (e.g. people, warehouse goods).
Specified by code.
• Wind loads : Acts on all exposed parts of the structure.
Calculated using building codes.
• Earthquake Forces : Building code is consulted.

5. DEEP FOUNDATIONS
“It is a foundation system that transfers loads to a deeper and
capable soil layer.”
Piers are foundations for carrying a heavy structural load which is constructed
insitu in a deep excavation.
Well foundations are commonly used for transferring heavy loads to deep
strata in river or sea bed for bridges, transmission towers and harbour
structures.
Piles are relatively long, slender members that transmit foundation loads
through soil strata of low bearing capacity to deeper soil or rock strata having a
high bearing capacity.
Caissons are a form of deep foundation which are constructed above ground
level, then sunk to the required level by excavating or dredging material from
within the caisson.

6. WELL FOUNDATIONS
• Well foundations are commonly used for transferring heavy loads to deep
strata in river or sea bed for bridges, transmission towers and harbour
structures.

7. PILE Foundations rely on driven piles, often have groups of piles connected by
a pile cap (a large concrete block into which the heads of the piles are embedded)
to distribute loads which are larger than one pile can bear.
PILES are relatively long, slender members that transmit foundation loads through
soil strata of low bearing capacity to deeper soil or rock strata having a high
bearing capacity.
PILES can be of timber, steel or of composite material(steel and concrete).

8. METHODS OF INSTALLATION
DROPPING WEIGHT
DIESEL HAMMER
VIBRATORY METHODS OF PILE DRIVING
JACKING METHODS OF INSERTION
DROPPING WEIGHT OR DROP HAMMER is the most commonly
used method of insertion of displacement piles.
DIESEL HAMMER produces controlled explosions which raises a ram
used to drive the pile into the ground.
VIBRATORY METHODS can prove to be very effective in driving piles
through non cohesive granular soils. The vibration of the pile excites the
soil grains adjacent to the pile making the soil almost free flowing thus
significantly reducing friction along the pile shaft.
JACKING PILES are the most commonly used methods in underpinning
existing structures. By excavating underneath a structure short lengths of
pile can be inserted and jacked into the ground using the underside of the
existing structure as a reaction.

9. Classification of Piles
Based on material
•Concrete
•Steel
•Timber
Based on size
• Micro piles dia. < 150 mm.
• Small piles dia. 151 to 600 mm.
• Large piles dia. > 600 mm.
Based on Load transfer mechanism
•End bearing piles
•Friction/Floating piles
•Bearing cum Friction piles

10. LOAD TRANSFER MECHANISM OF PILES

11. PRE CAST /PRE STRESS PILES(CONCRETE)
 Size :





150mm to
400mm
Lengths :
3m, 6m, 9m
and 12m
Structural Capacity : 25Ton to
185Ton
Material :
Grade M-35
Concrete
Joints:
Welded
Installation Method :
 Drop
Hammer
 Jack-In

13. Advantage of Pre Cast /Pre Stress Piles…..
•Better Bending Resistance
•Higher Axial Capacity
•Better Manufacturing Quality
•Able to maintain Higher Driving Stresses
•Higher Tensile Capacity
•Easier to Check Integrity of Pile
•Similar cost as RC Square Piles
Disadvantage:
•Difficult to transport
•Difficult to achieve desired cut-off.

14. Steel H Piles
Size :
200mm to 400mm
Lengths :
6m and 12m
Structural Capacity :
40Ton to
1,000Ton
Material :
250N/mm2 to
410N/mm2 Steel
Joints:
Welded
Installation Method :
Hydraulic
Hammer
Jack-In

15. Advantage:
1. Relatively less hassle during installation and easy
to achieve cut-off level.
2. High driving force may be used for fast
installation .
3. Good to penetrate hard strata Load carrying
capacity is high
Disadvantage:
1.
2.
3.
4.
Relatively expensive
Noise pollution during installation
Corrosion
Bend in piles while driving

16. Large Diameter Cast-In-Situ
Piles (Bored Piles)
Size :
450mm to 2m
Lengths :
Varies
Structural Capacity : 80Ton to 2,300Tons
Concrete Grade :
M-25,30,35 Grade (See IS-
456-2000)
Joints :
None
Installation Method : Drill then Cast-In-Situ

17. Advantages:
Fast method of pile installation
Economical, since reinforce-ment is installed after tube
installation, compared to precast piles, where reinforcement
must be designed with respect to transport and handling.

18. THANK YOU