FOUNDATION ENGINEERING DEEP FOUNDATION

1. 1
PILE FOUNDATION
MADE BY : MISS.DHARA DATTANI
(ME TRANSPORTATAION)
LECTURER AT ATMIYA INSTITUTE OF TECHNOLOGY AND SCIENCE FOR
DIPLOMA STUDIES,RAJKOT.GUJRAT,INDIA.

2. introduction
 The pile foundation is used to describe a construction for the
foundation of a wall or a pier, which is supported on the pile.
WHERE IT IS PLACED …?
 The piles may be placed separately or they may be placed in
the form of cluster throughout the length of the wall.
Where it is adopted …?
 Piles are adopted when the loose soil extended to a great depth.
 The load of the structure is transmitted by the piles to hard
stratum below or it is resisted by the friction developed on the sided of the piles.
2

3. Necessity of pile foundation
 Where the load coming from the structure is very high & the distribution of the load on soil is
uneven.
 The subsoil water level is likely to rise or fall appreciably.
 The pumping of subsoil water is too costly for keeping the foundation trench in dry condition.
 The construction of raft foundation is likely to be very expensive or it is likely to practically
impossible.
 The piles are considered to be long when their length exceeds 30 meters.
 The structure is situated on sea shore or river bed and the foundation is likely to adopted by the
scouring action of water.
 The piles are also used as anchors. They may be designed to give lateral support or to resist an
upward pressure of uplift pressure.
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4. Classification of piles based on
function
End bearing pile Friction pile
Compaction
pile
Tension /
uplift pile
Anchor pile
Fender pile /
Dolphin
Sheet pile Better pile
4
Civil Engineering Dept., MEFGI

5. End Bearing Piles & Friction Piles
END BEARING PILES
 These piles are used to transfer the load
through water or soft soil of ground to
asuitable hard bearing stratum.
FRICTION PILES
 These piles are used to transfer loads to a
depth of a friction load carrying material
by mean of a skin friction along the
length of piles
5

6. COMPACTIONPILES:
Compaction piles are used to
compact loose granular soil,
thus increasing their bearing
capacity.
The compaction piles
themselves don’t carry load.
The pile tube, driven to compact
the soil, is gradually taken out
and sand is filled in its place
thus forming a ‘sand pile’.
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7. Tension Pile or Uplift Pile
 These piles anchor down the structure subjected to uplift due to hydrostatic pressure or due
to over-turning moment.
ANCHOR PILE :
 These provide anchorage against the horizontal pull from sheet pulling or any other
pulling.
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8. Fender Pile
 These are used to protect water from structure against impact from ships or other floating
objects.
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9. Sheet Piles
 These pile are used as a impervious cut off sheet to reduce seepage and uplift under
hydraulic structure
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10. Batter Piles
 These piles are used to resist large horizontal or
inclined forces
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11.  BASED ON THE MATERIAL & COMPOSITION
1. Concrete Pile
2. Timber Pile
3. Steel Pile
4. Composite Pile: Concrete & Timber, Concrete & Steel
 BASED ON THE METHOD OF INSTALLATION
1. Driven Pile
2. Cast-in-situ Pile
3.Driven and cast- in- situ Pile
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CLASSIFICATION of piles

12. CONT…
 BASED ON THE LOAD CARRYING CHARECTERISTICS
1. End Bearing Piles.
2. Friction Piles.
3. Combined End Bearing and Friction Piles.
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13. DIFFERENT TYPES OF PILES BASED ON MATERIAL13

14. BASED ON THE MATERIAL &
COMPOSITION
CONCRETE PILE
1. precast piles
2. cast in situ piles and
3. prestressed concrete piles
Advantages:
 High capacity, relatively inexpensive, usually durable and corrosion resistant in
many environments (not marine).
Disadvantages:
 Handling, splicing, and transportation difficulties (for precast piles). Soil caving in
cast in situ piles.
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15. STEEL PILES:
Type of steel pile commonly used as:
1. H PILES 2. BOX PILES 3. TUBE PILES
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BASED ON THE MATERIAL & COMPOSITION

16. CONT…
H-piles BOX PILES Tube Piles
 Wide flange section rectangle or octagonal shape driven in normal ground
 Small cross section area when H piles cannot drive in hard-strata
 Easily driven in soil
 Used as long pile
 High bearing capacity
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17. Advantages and Disadvantages of Steel Piles
 These piles can easily withstand the stresses due to driving.
 These piles can resist lateral forces in a better way
 These piles can be easily lengthened by welding and can also be cut off easily
 The bearing capacity of these piles is comparatively high
 These piles can take up impact stresses
Disadvantages:
 High cost, difficulty in delivery, relatively higher corrosion, noisy driving.
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18. Timber Piles
 It is made up from trunk trees.
 They may be square, circular or square.
 Diameter of circular is 30cm to 50cm and length not exceeding 20 times of
its width.
 At bottom cast iron shoe is provided, at top steel plate is provided.
 If group of piles are driven, then a concrete cap is provided to have a
uniform platform.
 They are not permanent , because its bearing capacity is low.
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19. 19

20. Advantages and disadvantages
 Easily available
 Length is adjusted by cutting.
 Can be remove easily
 No skilled person is required.
 Piles do not need heavy
equipment for driving
 Deteoriate due to soil, salty water
or insects.
 It cannot take heavy loads.
 It cannot drive into the hard
ground.
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21. Composite piles
 Combination of two different materials of piles are driven together.
 This piles are driven one over another.
 Advantage is taken of durability of concrete and the timber pile.
 Timber pile just at the lowest level.
Advantages
 They are economical
 Easy to construct
 This are suitable in ground conditions where other piles are unsuitable
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22. 22

23. SAND PILE
 For this piles they are driven by making holes in to ground and then filling
with sand
 It is placed up to 2 m to 3m.
 It is easy to construct and can be used for any position of water table.
 Not suitable for loose or wet soil or where there is danger of scour.
 Not suitable in the regions of earthquake.
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24. BASED ON METHOD OF INSTALATION
1. DRIVEN PILES :
 Applying load by applying blows with a heavy hammer on their tops.
 Timber, steel, concrete piles installed by driving.
 Position : inclined or vertical.
2. DRIVEN AND CAST IN SITU PILES :
 It is driven with a closed end in bottom.
 Casing is filled later with concrete.
 If casing is withdrawn called as uncased pile.
 If not withdrawn it is called as pile.
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25. 3. BORED AND CAST IN SITU PILES :
 Excavating a hole into ground and then filling with concrete
4. SCREW PILES :
This piles are screwed into the soil.
5. JACKED PILES :
Piles are Driven with Hydraulic Jack
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26. BASED ON LOAD CARRYING CAPACITY
1. End Bearing Piles.
2. Friction Piles.
3. Combined End Bearing and Friction Piles.
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27. BASED ON LOAD CARRYING CAPACITY
 Combined End Bearing and Friction Piles.
 At bottom end bearing pile and friction along the surface of pile shaft
 It depends on bearing capacity of soil below and skin friction along
surface of the pile.
 Total load carried by pile
= load carried by pile point + load carried by skin friction
(Qn= Qp+Qs)
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28. Factors Affecting Selection of Piles
 Nature of structure
 Loading conditions
 Availability of funds
 Avability of material and equipment's
 Type of soil and its properties
 Ground water table
 Self weight of pile
 Durability of pile
 Cost of pile
 Maintenance of pile
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29. Factors Affecting Selection of Piles
 Length of pile required
 Number of piles required
 Facilities available of driving the piles
 Erosion of soil near the structure
 Difficulties in pile driving
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30. PILE ACCESSORIES
 For wooden ,steel, timber, pre cast concrete piles to protect the top and
bottom of the pile while driving into ground and to facilitate easy pile
driving certain accessories required as under:
 PILE CAP
 PILE SHOE
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31. 31

32. FUNCTIONS OF PILE CAP
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33. PILE SHOE
 There for pile shoe is fitted at bottom end of pile to protect the pile and to
facilitate easy pile driving
 Pile shoe are made up of, cast iron, steel, wrought iron.
 While driving wooden or steel pile by hammer the bottom end of the pile
gets damaged and causing difficulty in driving.
 Therefore , a pile shoe is fitted at the bottom end of the pile to protect the
pile and also for ease of pile driving.
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34. Pile Cap and Pile Shoe
Square pile shoe Wedge-shaped pile shoe
Round pile shoe
Steel strap pile shoe for
timber piles
Closed-end shoe for
pipe piles
Socket type shoe for
timber piles
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35. PILE DRIVING
 OPERATION OF INSERTING PILE IS CALLED PILE DRIVING
 EQUIPMENT USED TO ALLOW HAMMER TO FALL ON THE HEAD OF
PILE IS CALLED PILE DRIVER.
VARIOUS METHODS OF PILE DRIVING:
HAMMER DRIVING
VIBRATORY PILE DRIVER
WATER JETTING AND HAMMERING
PARTIAL AUGERING METHOD
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36. Points considered for selection of pile driving method
 Type of soil at the site
 Cost of pile driving equipment's
 Avability of fluid pressure
 Material of pile
 Length of pile
 Ground water level
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37. Hammer driving
 Pile frame or pile driving rig
 Pile hammer
 Leads
 Winches
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38. Hammer Driving
38

39. Pile Frame Or Pile Driving Rig
 Pile drive with crawler mounted crane rig commonly used for pile driving.
 The hammer is guided between two parallel steel channel known
as leads.
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40. PILE HAMMER
 Types of hammer used for driving the pile are;
 Drop hammer
 Single acting hammer
 Double acting hammer
 Diesel hammer
 Vibratory hammer
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41. Winches
 Winches are used for lift hammer and pile.
 It should be light with single drum provision or
heavy with double drums.
 Winches may be fitted with reverse gear system.
 Winches are driven with diesel or
petrol engines or electrical power in case of drop
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42. Drop hammer
 The drop hammer is the oldest type of hammer used pile driving.
 A drop hammer is rise by a winch and Allowed to drop the top of the pile
under gravity from a certain height.
 During the driving operation a cap is fixed to the pile and cushion is
generally provided between the pile and the cap.
 Another cushion known as hammer cushion is placed on the pile cap on
which the hammer causes the impact.
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43. DROP HAMMER
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44. LOAD CARRYING CAPACITY OF PILES
 HOW CAN WE FIND LOAD CARRYING CAPACITY OF PILES?
 The ultimate load carrying capacity or ultimate bearing capacity or ultimate bearing
resistance of pile (Qu) is the maximum load which it can carry without failure or excessive
settlements of the ground.
 Allowable load (Qa) on a pile is the safe load which the pile can carry safely and I is
determined as,
 Allowable load =
𝒖𝒍𝒕𝒊𝒎𝒂𝒕𝒆 𝒍𝒐𝒂𝒅
𝑭𝑶𝑺
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45. METHODS TO DETERMINE LOAD CARRYING CAPACITY
 Methods to determine load carrying capacity:
 STATIC FORMULAE
 DYNAMIC FORMULAE
 PILE LOAD TESTS
 PENETRATION TESTS
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46. STATIC FORMULAE
 In static formula ultimate bearing capacity of pile is considered to the sum of end
bearing pile and resistance of skin friction.
 Qu=Qp +Qs
=qp*Ap +fs.As
Where,
 Qp=end bearing resistance
 Qp= unit end bearing resistance
 Ap =area at the base OR tip of the pile
 Qs= skin friction resistance
 fs= unit skin friction
 As= surface area
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47. ENGINEERING NEWS RECORD(ENR) FORMULA
Qa=
𝐖𝐇
F(S+C)
 Where,
 Qa= allowable load (kN)
 W= wt. of the hammer(kN)
 H= height of the fall in mm
 F= F.O.S, taken as “6”
 S= final set (penetration)
 C= empirical constant
 25mm for drop hammer,
 2.5mm for single and double acting
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48.  DROP HAMMER:
 Qa=
WH
6(S+25)
 SINGLE ACTING STEM HAMMER:
 Qa=
WH
6(S+2.5)
 DOUBLE ACTING HAMMER:
 Qa=
𝑊+𝑎𝑝 ℎ
6(S+2.5)
 Where,
 a = effective area of piston(mm2)
 p = mean effective steam pressure ( N/mm2)
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49. HILEY’S FORMULA :
 Qu=
𝑊ℎࣁ 𝑏
𝑆+
𝑐
2
 Where,
 Qu= ultimate load on pile
 W= weight of hammer
 H= height of fall of Hammer
 C= total elastic compression
= C1+C2+C3
= temporary elastic compression of dolly and packing, pile and soil
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50. 50

51. GROUP ACTION OF PILE
 Pile cannot act as a column
 It is difficult to drive pile absolute vertical and to place in foundation
 If eccentric loading occurs , pile may fail structurally due to bending stress
 What can we do to over come this problem?
 In actual structural loads are supported by several piles acting as a
group,there must be minimum three piles used under a column in a
triangular pattern.
 If we required more than three pile , it should be arrange symmetrically.
 It shall be arranged in symmetrically or staggered position
 We can also provide pile cap, which must be clealy above GL or beneath
of soil
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52. Pile spacing
 The center to center distance of successive piles is known as pile spacing.
 It has to be carefully designed by considering the following factors,
1) Types of piles
2) Material of piles
3) Length of piles
4) Grouping of piles
5) Load coming on piles
6) Obstruction during pile driving
7) Nature of soil through which piles are passing.
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53. PILE SPACING
 The spacing between piles in a group can be assumed based on the
following:
1-Friction piles need higher spacing than bearing piles.
2- Minimum spacing (S) between piles is 2.5.
3- Maximum spacing (S) between piles is 8.0.
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54. S
2 Piles 3 Piles S
4 Piles 5 Piles
S S
6 Piles
7 Piles
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55. S S
8 Piles
SS
S S
9 Piles
12/22/2017
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56. Efficiency of group of pile
 It is the average load per pile, when the failure of the group occurs to the load at the failure
of a comparable single pile.
 It depends on pile(length, diameter, material etc.), spacing of pile, total number of piles in a
row and number of rows,etc.
12/22/2017
56
Efficiency
=

57. FED’S RULE
 According to this rule, the value of each pile is reduced by one-sixteenth on account of the
effect of nearest pile in each diagonal or straight row of which the particular pile is a
member
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58. FED’S RULE
12/22/2017Civil Department, Mr.Mayank Parekh
58

59. Negative skin friction
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What is negative skin friction?
 Negative skin friction is a downward shear drag acting on the pile
surface due to relative downward movement of soil strata
surrounding the pile.
 The following are some of the causes of negative skin friction:
 Compressible layer
 Recently filled soil
 Effective stresses increases because water table goes down

60. Negative skin friction
60
Figure

61. Negative skin friction
 Lowering of ground water table causing the shrinkage of expansive soils.
 Under consolidated natural or compacted soils.
 If the pile tip is on a stiff or hard stratum, there will be a relative
downward movement of upper compressible layer of soil w.r.t. pile , due
to above causes, causing a downward drag force.
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62. Negative skin friction
Vesic stated that downward movement as little as 0.6 inch may be sufficient
to mobilize full negative skin friction.
 It will increase stresses on the pile and pile cap.
 The negative skin friction of a single pile is given by
 Negative skin friction load =
Unit frictional resistance (downward)* Length of the pile above bottom of
the compressible layer * Perimeter of the pile cross section
 And total downward load= negative skin friction load + live load+ dead
load
62

63. FOR COHESIVE SOIL:
 Qnf= P*C*Lf
 Where,
 Qnf= negative skin friction
 P= perimeter of pile
 C=cohesion of soil
 Lf= length of loose fill soil
63

64. FOR COHESIONLESS SOIL:
 Qnf= 0.5P *Lf2 * γ * K * tanδ
 Where,
 P=perimeter of pile
 Lf= length of losse fill soil
 γ = unit weight of soil
 K= co-efficient of earth pressure
 δ = angle of wall friction
64

65. UNDER-REAMED PILES
 Ideal solution to foundations in black cotton soil
 Diameter of an under-reamed piles: 20 cm. to 50 cm and diameter of
the bulb 2 to 3 times the diameter of pile
 Under-reamed piles: reinforced with 10 to 12 mm. dia. longitudinal
bars and 6 mm. dia. of rings
 Provide a clear cover of 4 cm.
 connected by a reinforced concrete beam, known as capping beam
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66. 66
Under-reamed
Pile Foundation

67. Under-rammer withBucket
67

68. BORED COMPACTION PILES
Civil Engineering Dept., MEFGI
68
BORED COMPACTION PILES

69. BORED COMPACTION PILES (continued..)
 Modification of under-reamed piles
 One type of cast-in-situ pile which combine the advantages of
both bored and driven pile
 Boring the piles and concreting the pile: both method same as
that for under-reamed pile, except that the reinforcement cage
is not placed in the bore hole before concreting
 Load-carrying capacity increased - 1.5 to 2 times over normal
under-reamed piles
 Suitable in loose to medium dense sandy and silty strata
69

70. Procedure:
 Prepare the bore hole with the help of spiral auger, using guides, and
then under-ream it with the help of under-reaming tool and then
Concrete the pile, without placing the reinforcement cage
 Place of reinforcement cage, enclosing a hollow driving pipe, on the
top of freshly laid concrete
 Drive the driving assembly through the freshly laid concrete to the full
depth by means of suitable drop weight (about 5kN), operated with
the help of mechanical winches
 After driving through the full depth of concrete, fill concrete in the
hollow drive pipe also
 Pipe - gradually withdrawn leaving the cage
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