Pile Foundation - A foundation Technique for Building Foundation

1. Pile Foundation

2. Content
 Uses ,selection of pile and types of piles
 Pile spacing ,Group of piles and Efficiency of group of
piles
 Pile Cap and Pile shoe ,load tests on piles, pile driving
and pulling of piles
 Loads on piles, causes of failures of piles, pile driving
formulas.

3. introduction
3
 Foundations are structural components used to support
columns and transfer loads to the underlying Soil.
Foundation
s
Isolated Combined Strap wall
Raft
Shallow
footing footing footing footing
footing
Caissons
Piles
Deep

4.  When the depth of foundation is more then the width of foundation ,then it is
termed as deep foundation.
 If the desired soil bearing capacity is not available at shallow depth, the
foundation of the structure is to be taken to a more depth.
 The deep foundations are classified as below:
Pile foundation Cofferdams Caissons
 Pile foundations are used extensively for the support of buildings, bridges, and
other structures to safely transfer structural loads to the ground and to avoid
excess settlement or lateral movement. They are very effective in transferring
structural loads through weak or compressible soil layers into the more
competent soils and rocks below.

5. PILE FOUNDATION…
• 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.

6. Pile Foundation
6
 Our building is rested on a weak soil formation which can’t resist the loads coming
from our proposed building, so we have to choose pile foundation.
Pile cap
Piles
Weak soil
Bearing stratum
Piles are structural members that are made of steel, concrete or timber.

7. 7
Function of piles
As with other types of foundation, the purpose of a pile foundation is:
To transmit a foundation load to a solid ground
To resist vertical, lateral and uplift load
Piles can be
Timber
Concrete
Steel
Composite

8. Uses of piles
 The load of the superstructure is heavy and its distribution is
uneven.
 The top soil has poor bearing capacity.
 The subsoil water is high so that pumping of water from the open
trenches for the shallow foundations is difficult and uneconomical.
 There is a large fluctuation in subsoil water level.
 Where timbering to the trenches is difficult and costly.
 The structure is situated on the sea shore or river bed, where
there is danger of scouring action of water.
 canal or deep drainage lines exist near the foundations.
 The top soil is of expansive nature.
 Piles are used for the foundations of transmission towers, off-
shore platforms which are subjected to uplift forces.

10. Pile applications
Soft to
Firm Clay
Strong Rock

11. Factors affecting the selection of
type of piles
 Nature of structure
 Loading conditions
 Availability of funds
 Availability of materials and equipments
 Types of soil and its properties
 Ground water table
 Self weight of pile
 Durability of pile
 Cost of pile
 Maintenance cost
 Length of pile required
 Number of piles required
 Facilities available for pile driving
 Presence of acids and other materials in the soil that would injure the pile

12. Types of Piles Based on
Function
a) Classification based on Function or Use
1. Bearing Piles or End Bearing Piles
2. Friction Piles or Skin Friction Piles
3. Sheet Piles
4. Tension Piles or Uplift Piles
5. Anchor Piles
6. Batter Piles
7. Fender Piles
8. Compaction Piles

13. Types of Piles Based on
Materials
b) Classification based on Materials
1. Timber Piles
2. Concrete Piles
3. Composite Piles
4. Steel Piles
5. Sand Piles

14. Pile materials
SteelTimber
ConcreteTimber Steel H Composite
Pre-cast
Concrete
Concrete
Steel
Pipe

15. Types of Piles Based on
Method
c) Classification based on Method
1. Driven Piles
2. Driven and cast-in-situ Piles
3. Bored and cast-in-situ Piles
4. Screw Piles
5. Jacked Piles

16. Classification of piles (based on function or
use)
<1> END BEARING PILE
 These piles penetrate through the soft soil
and their bottoms or tips rest on a hard
stratum. These piles act as columns. The
soft material surrounding the pile provides
some lateral support. For end bearing pile
Qu = Qp.
<2> FRICTION PILE
 When loose Soil extends to a great depth,
piles are driven up to such a depth that
frictional resistance developed at the sides
of the piles equals the load coming on the
piles. Friction piles are used when a hard
stratum is available at a greater depth. For
friction pile
Qu = Qs where Qu = ultimate load &
Qs = skin friction

17. Classification of piles (based on function
)
<3> COMPACTION
PILE
 When piles are driven in loose
granular soil with the aim of
increasing the bearing capacity of
soil, the piles are termed as
compaction piles. These piles
themselves do not carry any load.
<4> TENSION PILE
 These piles anchor down the
structures subjected to uplift due to
hydrostatic pressure or due to
overturning moment. It is also
called uplift pile.

18. Classification of piles (based on function
)
<5> FENDER PILE
 Fender piles are used to protect water structures against impact from ships or
other floating objects.

19. Classification of piles (based on material
)
19
Piles
Concret
e Pile
Steel
Pile
Timber
Pile
Composit
e Pile
Sand
Pile

20. Concrete Pile
20
Concrete
Piles
Pre
Cast
Pile
Cast-in-
situ
Pile
Prestressed
Concrete piles

21. 1. Pre Cast concrete pile
 Precast concrete piles are those which are
manufactured in a factory or at a place away from the
construction site and then driven into the ground at
the place required. These piles require heavy pile
driving machinery.
 Precast piles may be square, octagonal or circular in
cross section.
 The size of piles may vary from 30 cm to 50 cm in
cross sectional dimension, and up to 20 m or more in
length.
 The reinforcement may consist of longitudinal steel
bars of 20 mm to 40 mm in diameter, 4 to 8 nos. with
lateral ties of 6 to 10 mm diameter at 100 mm c/c
spacing.
 A concrete cover of at least 50 mm is provided. The
grade of concrete should be M20.

24. Procedure for forming precast concrete
piles
 The formwork for the pile is prepared and it is coated
with soap solution or oil to prevent adhesion.
 The cage of reinforcement is prepared as per design
and this cage is then placed in the formwork. A
concrete cover of at least 50mm is provided.
 A concrete of grade M20 is prepared with proportion
1:1.5:3. The size of coarse aggregate varies from 10
mm to 25 mm.
 The forms are removed after 3 days and the piles are
kept in the same position for about 7 days or so.
 The piles are then shifted to a curing tank and after a
period of about three or four weeks, they become
ready for use.

25. 2.Cast-in-situ Concrete Pile
25
Cast-in-situ
Concrete
Piles
Uncased
Simplex pile
Franki Pile
Vibro pile
Pedestal pile
Pressure Pile
Cased
Raymond pile
Mac Arthur Pile
Monotube Pile
BSP base driven
piles
Swage piles

26. RAYMOND PILE
 The Raymond standard pile is used primarily as a
friction pile. It is provided with uniform taper of 1 in
30 resulting in shorter piles.
 The lengths of piles vary from 6 to 12 m. The
diameter of piles vary from 40 to 60 cm at the top
and 20 to 30 cm at the bottom.
 Raymond piles have a high bearing capacity,
because of the corrugated surface of the pile shaft
and their conical pile shape. They are suitable for
high pile loads and difficult driving conditions.

28. Raymond Pile installation
 In Raymond Pile
installation shell is closed
at bottom. The shell is
driven in to ground with a
collapsible steel mandrel
or core in it having the
same taper. When the pile
is driven in to the desired
depth, the mandrel is
mechanically collapsed
and withdrawn, leaving the
shell inside the ground.
The shell is inspected
internally by using the light
from a mirror of flash light
or drop light. The shell is
gradually filled with
concrete up to the top.

29. Mac-Arthur piles
 These pile is a pile of uniform
diameter, using the corrugated
steel shell which remain in place.
However, the driving of the pile
uses an additional steel casing of
heavy gauge (thickness). The
heavy steel casing with a central
core is driven into the ground as
shown in the figure.
 After reaching the desired depth
the central core is withdrawn and
a corrugated shell is placed in the
casing.
 Finally concrete is placed in the
shell by gradually compacting it
and withdrawing the steel casing.
 The compacted pile contains
concrete core and the outer
corrugated shell.

31. Montube piles
 Montube piles use tapered
fluted steel shell without
mandrel, and are suitable
for wide variety of soil
conditions, from end
bearing to friction load
carrying soils.
 The shell provide rigidity,
and are watertight. The pile
shells are driven to the
required depth, and they are
inspected after driving .
 Shells may be driven with
hammer of comparable size
to those used for wood
piles.
 The shell, after inspection is
filled with concrete and the
excess length of shell is cut.

32. Swage piles
 A pipe pile, having a thin wall; the bottom of
the pipe is closed with a precast point. Swage
Piles are used with advantage in some soils
where the driving is very hard or where it is
designed to leave water tight shell for some
time before filling the concrete.
 The four stages of forming these piles are
shown i
 In the first stage (a), a thin steel pile (known
as Shell) is placed on a precast concrete plug,
and a steel core, which is not long enough to
reach the plug is inserted in the shell. In the
second stage (b), as the pipe is driven over
the plug until the core reaches the plug, the
pipe is swaged out by the taper of the plug,
thus forming a water tight joint.
 In the third stage (c), the pipe is driven to a
specified depth. The driving force is practically
all exerted by the core on the plug and the
pipe pulled down rather than driven.
 In the froth stage (d), after the pipe has
reached the desired depth, the core is
removed, and the pipe left open until it is
desired to fill it.
 In the final stage (e), the pipe is filled with
concrete.

33. Button-bottom Pile
 These piles are used in locations where
increase in the end bearing area is
desired. The pile uses a concreteplug,of
the shape of a button. this button forms an
enlarged hole in the soil during driving.
 The four stages in the pile driving are
shown.
 In the first stage a steel pipe with 12mm
thick walls and reinforced base of cast
steel, is set over the concrete button. the
concrete button has a diameter about
25mm larger than the pipe.
 In stage the pipe and button are driven to a
specified depth.
 In the third stage a corrugated steel shell is
inserted in the pipe, resting on the button.
A steel plate with a bolt hole in it is welded
on the bottom of the shell, before lowering
it, so that hole may fit over the central bolt
in button bottom.
 In the fourth stage the casing is withdrawn,
leaving the button in place and the shell is
filled with concrete.

34. Uncased cast in situ concrete
piles:
These piles are comparatively cheap, as no casing will
be left in the ground. But, great skill is required in this case to
achieve the desired results.
The common types of uncased cast in situ concrete piles are:
1. Simplex piles
2. Franki piles
3. Vibro piles
4. Pedestal piles
5. Pressure piles

35. Simplex pile
 In this type of pile, a steel tube
is fitted with cast-iron shoe is
driven in to the ground up to
the desired depth.
 The Reinforcement, if
necessary is placed in the
tube. The concrete is poured
into the tube and the tube is
slowly withdrawn, leaving the
shoe into the ground.
 The concrete is not tamped
and the pile is completed such
a pile is known as simplex
standard pile.
 If tampering of concrete is
done at regular intervals as
the tube is withdrawn, it is
known as simplex tamped pile.

36. Franki pile
 The Franki pile, known and used
world wide, It is a cast-in-situ
concrete pile with an enlarged
base and a cylindrical shaft
which, due to its powerful driving
method during installation, can
penetrate stiff soils and reach
large depths. By expulsion of a
dry concrete plug, the soil
surrounding the pile base is
improved and thus the initial soil
bearing capacity can be
increased significantly. Although
the application of the Franki
system has decreased due to
cost and environmental
considerations, this system is still
competitive and widely used
when site conditions are suitable.

37. Franki pile
 This pile has an enlarged base of mush-
room shape, which gives the effect of a
spread footing. Also this type of pile is
best suited to granular soil.
 Figure shows various stages of pile.
 In the first stage a heavy removable pipe
shell is set vertically on the ground with
the help of leads and a charge of dry
concrete or gravel is formed.
 In the second stage a diesel operated
drop hammer of 20 to 30 kN weight is
driven on the concrete.
 In the third stage when the tube has
reached the desired depth, the tube is
held in position by cables and the
hammer is applied to the concrete,
forcing it down and outward.
 In the fourth stage the shaft is formed by
introducing successive charges of
concrete, ramming each in turn and
withdrawing gradually the casing. Finally
it shows formed pile which has

38. Vibro pile
 The Vibro piles are formed by driving a steel tube and a casi iron
shoe, filling with concrete and extracting the tube using upward
extracting and downward tamping blows alternatively.
 Vibro-piles are extremely suitable for a large variety of soil
conditions, for which the pile length can be adapted to the
supporting capacity of the subsoil. This avoids risks of having piles
too long or too short.
A Vibro-pile is a closed off casing that is vibrated into the ground
displacing and "densifying" all the material in its path. The casing is
then filled with concrete and reinforcement and then extracted (or
filled with concrete as it is extracted and the reinforcement is
installed later.
 Vibro-pile is used as an alternative to pre-cast piles or drilled cast-
in-situ piles in soft grounds especially when vibrating a can/probe is
faster than drilling and casing or when vertical tie downs are
necessary.

39. Pedestal piles
 This type of piles are used where the bearing stratum
is reached with reasonable depth. The pedestal of the
pile gives the effect of spread footing on this
comparatively thin bearing.
 The core and casing are driven together into the
ground, till they reach the desired level.
 The core is taken out and a charge of concrete is
placed in the tube.
 The core is again placed in the casing to rest on the
top of poured concrete. Pressure is applied on the
concrete through the core, and as the same time, the
casing is withdrawn. The process is repeated till the
casing is completely removed.

40. Pressure piles
 These are formed with the help of a casing tube, boring auger and
compressed air equipment. these piles are especially suitable for
those congested sites where heavy vibrations and noise are not
permissible.
 A hole is bored into the ground by means of an auger and as the
boring proceeds, the hole is lined by a steel tube.
 When the tube reaches the required depth, the boring tool is
withdrawn. the reinforcement, if any is then placed in the tube.
 In the second stage, a layer of concrete is laid and pressure cap
is provided at the top of the tube.
 Compressed air is then admitted through the air pipe and which is
applied to raise the tube.Thus,the pile is lifted slightly and at the
same time concrete is forced into the surrounding ground by
compressed air.
 The process is repeated till the pile is completed. care should
taken to see that some portion of concrete remains at the bottom
of tube when lifting of tube is stopped to receive a new layer of
concrete.

41. SHEET PILES
 Sheet piles are thin piles, made of plates of concrete, timber or steel, driven into
the ground for either separating members or for stopping seepage of water. They
are not meant for carrying any vertical load. Therefore, sheet piles are also
termed as non-load bearing piles.
 Sheet piles are used for the following purposes:
 (1) To isolate foundations from adjacent soils.
 (2) To prevent underground movement of water.
 (3) To prevent the transfer of machine vibrations to adjacent structures.
 (4) To construct retaining walls in docks, wharfs and other marine Structures.
 (5) To protect river banks.
 (6) To retain sides of foundations trenches.
 (7) To work as cutoff walls under dams.
 (8) To confine the soil and thereby increase the bearing capacity of soil.
 (9) To construct caissons for water-intake structures.

42. SHEET PILES
Based on the material, types of sheet piles are:
 1. Concrete sheet piles
 2. Steel sheet piles
 3. Timber sheet piles
1.Concrete sheet
piles :
Concrete sheet piles are reinforced, precast
units. The width of each unit may vary from 50 cm to
60 cm and thickness varies from 2 cm to 6 cm.
The rainforcement is in the form of vertical
bars and hoops. For important works, Pre-stressed
precast concrete piles are used.

43. SHEET PILES
 Pre-cast RCC sheet piles are used for permanent work such as bulk
Heads, cut-off wails, retaining walls, wharf walls, etc.
In order to make them water tight, they are placed in such a way that
Grooved are formed and these grooves are then filled by cement mortar
In proportion (1 : 3) under pressure. The feet of the piles are shaped
obliquely and beveled so as
To facilitate driving. Metal shoes are provided at the bottom of the piles,
If they have to pass through hard strata.
2. Steel sheet pile:
Steel sheet piles are most commonly used.
They are trough shaped and when the piles are interlocked with
alternate
once reversed.
They are generally made from steel sheets 20 to 30 cm wide and 4 to 5

44. SHEET PILES
 Steel sheet piles are strong and
durable and can be easily
driven without appreciable
distortion. They provide a fairly
water tight enclosure and
hence, they are widely used in
the construction of cofferdams.
 They are also used for
permanent works in marine
structures.

45. SHEET PILES
 Different types of steel sheet piles are:
1. Arch web steel sheet pile.
2. Built up steel sheet pile.
3. Z-type steel sheet pile.
4. Corrugated steel sheet pile.
5. Deep arch web steel sheet pile.
6. Universal joint steel sheet pile.
Universal joint steel sheet piles consists of I-beams
connected by standard clutches or lock bars. The clutch is also of I-beam.
But its flanges are curved so as to accommodate the flanges of I-beams.
3. Timber sheet piles:
Timber sheet piles are commonly y used for
temporary works Such as Cofferdams.

46. SHEET PILES
The width of the sheet may Vary from 225 to 280 mm,
while thickness should not be less than 50 mm.
They may be jointed by either butt or V-joints. Their feet
are beveled and sometimes Shod with sheet iron.

47. CLASSIFICATION OF SHEET
PILES
 Classification of piles based on method of
installation:
Based on the method of installation Piles may be classified as follows:
1. Driven piles:
These Piles are driven into the ground by applying blows with a heavy
hammer on their tops. Timber, steel and precast concrete Piles are installed by
driving. which may be driven into position either vertically or at an inclination.
2. Driven and cast in situ Piles:
These Piles are formed by driving a casing with a closed bottom end into
the soil. The casing is later filled with concrete. The casing may or may not
be withdrawn. 1f casing is withdrawn, it is called uncased Pile, and if casing is
withdrawn, it is called uncased pile, and if casing is not withdrawn, it is called
cased Pile.
3. Bored and cast in situ piles:
These piles are formed by excavating a hole into the ground and then
filling it with concrete.

48. 4. Screw piles:
These piles are screwed into the soil.
5. Jacked piles:
These piles are jacked into the ground by applying a downward force
with the help of hydraulic jack.
Under reamed piles:
These piles are successfully developed by C.B.R.I., Roorkee (U.P.) for
serving as foundations for black cotton soils, filled up ground and other types of
soils having poor bearing capacity.
An under reamed is bored cast-in-situ concrete pile having one or
more bulbs or under-reams in its lower portion. The bulbs or under-reams are
formed by under reaming tool. The diameter of under reamed pile varies from
20cm to 50cm and that of bulb varies from 2 to 3 times the diameter of pile.

49. Under reamed piles
The length of under reamed piles is
about 3m to 8m. The spacing of piles may vary
from 2m to 4m. The under reamed piles can be
used for sandy soils with high water table.
The load bearing capacity of under
reamed piles can be increased by adopting piles
or larger diameter or by extending the length of piles
or by making more bulbs at the base. A single under
reamed pile has only one bulb at the bottom. When
two or more bulbs are provided at the base, It is
known as multiple under reamed pile. The vertical
spacing between two bulbs varies from 1.25 to
1.50 times the diameter of bulb.

50. Under reamed piles
In case of black cotton soils, the bulbs,
not only increase the bearing capacity,
but also provide anchorage against
uplift.
 Figure Shows various stages in
the formation of a under reamed pile.
 The equipment required for the
construction of pile are
(i) auger boring guide,
(ii) spiral auger with extension rods,
(iii) under reamer with soil bucket,
(iv) concreting funnel.

51. Pile spacing
 The spacing of pile is the center to center
distance between two successive piles.
 The factors to be considered while
deciding
the pile spacing are as follows:
1. The nature of soil through which the pile
is
driven
2. The obstruction during pile driving
3. The type of pile
4. The depth of penetration
5. The area of cross section of the pile
6. The centre to centre distance of piles in
a
group

52. Group of piles
 Sometimes the piles are arranged in close-
spaced groups. When the piles are driven to
the required depth, their tops are cutoff a
same level and then the pile cap is provided.
 The piles forming the group of piles may
be arranged in square, rectangular, triangular
or circular as per the requirement.
 In case of single pile small pressure is developed
in the surrounding soil. And in case of group piles,
the pressure developed surrounding the individual
piles will overlap laterally and the pressure in the
overlapping zone will be sufficient to cause movement
of the soil and consequently the pile will settle down.

53. Pile Accessories
 In case of wooden piles, steel piles, pre-cast
concrete piles, to protect the top and bottom of
the pile while driving in to the ground and to
facilitate easy pile driving certain accessories
are required as under :
 1. Pile Cap
 2. Pile Shoe

54. 1. Pile Cap
 In case of driven pile, piles are driven in to the
ground by applying blows of a heavy hammer on
their tops. Thus, to protect the top of pile, pile cap
is provided.
 Normally, pile cap is made of steel. The thickness
and size of pile cap depends upon the shape and
size of the pile driving hammer.
 The pile should penetrate into the cap for at least
10 cm length.
 In case of group of piles, a common cap of R.C.C.
is provided for all the piles.

55. 2.Pile Shoe
 While driving wooden or steel pile by hammer
the bottom end of the pile gets damaged
causing difficulty in driving.
 Therefore, a pile shoe is fitted at the bottom
end of the pile to protect the pile and to
facilitate easy pile driving.
 Pile shoe are made of cast iron, steel iron.

56. Accessories of piles
 Various Types of Pile Shoe :
1. Square Pile Shoe
2. Wedge shape Shoe
3. Round Pile Shoe
4. Steel Trap shoe
5. Socket Type pile shoe
6.Closed end shoe for pipe pile.

57. Pile Driving
 The operation of inserting a pile into the
ground is known as pile driving.
 Points to be considered for selection of pile
driving method:
Various Methods of Pile driving :
 Hammer driving
 Vibratory pile driver
 Water jetting and hammering
 Partial augering method

58. Hammer driving
 Pile frame
 Pile hammer
 Leads
 Winches
 Miscellaneous
equipements.

59. Vibratory pile driver
 Drop hammer
 Single acting hammer
 Double acting hammer
 Diesel hammer

60. Single Acting Hammer
 Features
External compressor supplies
power
Stroke controlled by 1 or 2 slide bar
setting: 3 ft, 3 or 5 ft, 2 or 4 ft
 Comments
Air pressure, volume, and soil
resistance can influence actual
stroke by as much as 3 to 6 inches
Relatively heavy ram, short stroke

61. Drop Hammer
 Features
Ram raised by crane line
Efficiency of drop controlled
by operator and system
Comments
• Low equipment
cost
• Simple• Slow operation
• Inconsistent stroke

62. Diesel Hammer
Comments
Stroke depends on:
• fuel input
• pile stiffness
• soil resistance
Variable fuel settings
Potential energy = Wh
Most common hammer type
Relatively light ram, long stroke

63. Double Acting Hammer
Features
 Weight of hammer about 1000-
2500kg
 Can apply 90-240 blows per min
 Generally used for driving light to
moderate weight piles
Comments
 Skin friction between successive
blows is reduced due to number
of blows
 Reduction of time of driving piles

64. Water jetting and hammering
 The use of a water or air
jet to facilitate pile driving
by displacing parts of the
soil
 Jetting is useful in driving
piles through very dense
granular material

65. Loads on Piles
 Direct vertical load coming from super structure.
 Impact stresses developed during the process of pile
driving
 Stresses developed during handling operation.
 Bending stresses developed due to eccentricity of
loads coming on the pile.
 Lateral forces due to wind, waves , currents of water
etc.
 Impact forces due to the ice sheets or begs.
 Impact forces due to ships, in case of marine
structures.
 Forces due to uplift pressure.
 Earthquake forces etc.

66. Causes of Failure of piles
 Absence of statistical data regarding the nature of
soil strata through which the piles are to be driven.
 Actual load coming on the pile being more than
the design load.
 Bad workmanship in case of the cast-in-situ
cement concrete piles.
 Attack by insets, etc. on wooden piles.
 Breakage due to over driving especially in case of
the timber piles.
 Buckling of piles due to removal of side support,
inadequate lateral support, etc.

67. Causes of failure of pile
 Lateral forces (wind, waves, currents etc.) not
being taken into the design of the pile.
 Improper choice of the type of pile.
 Improper choice of the method of driving the
pile.
 Improper classification of pile.
 Insufficient reinforcement or misplacement of
reinforcement in case of the R.C.C. piles.
 Wrongful use of pile formula for determining its
load bearing capacity.

68. Pile load Test
 Preliminary pile design
is first carried out on
the basis of site
investigations,
laboratory soil testing,
and office study.
 Pile load tests are
then carried out to
refine and finalize the
design. For these
conditions, the test
piles are generally
tested to failure.

69. Construction
 Bearing plate
 Anchor piles
 Anchor girder
 Hydraulic jack
 Reference beam
 Dial gauge

70. Method
 Load the pile in eight equal increments (Le., 25 percent, 50 percent, 75
percent, 100 percent, 125 percent, 150 percent, 175 percent, and 200
percent) to 200 percent of the design load.
 Maintain each load increment until the rate of settlement has
decreased to 0.01 in./h (0.25 mm/h) but not longer than 2 h.
 Maintain 200 percent load for 24 h.
 After the required holding time, remove the load in decrements of 25
percent with 1 h between decrements.
 After the load has been applied and removed, as above, reload the
pile to the test load in increments of 50 percent of the design load,
allowing 20min between load increments.

71. Graph
 Sn = St – Se,
Where, Sn=net settlement
St=total settlement
Se=elastic settlement.

72. Pulling of Piles
Features:
 To replace damage
pile during driving
operation
 To change design and
arrangement of piles.
 To prepare data of
strata of pile driving.
 Removal of piles.

73. Methods Commonly Adopted
 Use of double acting
hammer:-
worked in reversed way,
steady pull of 4Nmm2
is applied
 Use of pile extractors:-
Easily put up in to use ,
does not require any
special fitting.

74.  Use of tongs:-
Suspended from frame
and a pull of 50
N/mm2 is applied
 Use of electricity:-
Apply of direct current
voltage leads to
attraction of water
causing lubrication of
steel pipe, hence skin
friction reduces.

75. Pile Driving Formulae
 Dynamic formulae
1. Engineering news record formula
2. Hiley’s formula
3. Danish formula
 Static formulae

76. Dynamic Formulae
Kinetic energy delivered=work done in penetration
Whηh = R X S + energy losses
Where,
W= weight of hammer (KN)
h= height of fall of hammer
ηh =efficiency of hammer
R= pile resistance
S= penetration of pile per blow

77. Engineering news record(ENR)
Formulae
Qa =
 Qa= allowable load
 W= weight of hammer
 h= height of fall of hammer
 F= factor of safety=6
 S= penetration per blow
 C= emperical constant
 = 25 mm for drop hammer
 = 2.5 mm for single acting and double acting steam
hammer
Wh
F( S + c )

78. Engineering news record(ENR)
 For drop hammer
 Single acting steam
hammer
 Double acting steam
hammers
a= effective area of piston
p= mean effective steam
pressure
Qa =
Qa =
Qa =

79. Hiley’s Formulae
Qu= ultimate load on pile
W = weight of hammer
h= height of fall of hamer
C= total elastic
compression
=C1+C2+C3
ηh= efficiency of hammer
S = average settlement per
blow
Qu =
Drop hammer (ηh=100%)
Single acting hammer ( ηh=75-
85%)
Double acting hammer (ηh= 85%)

80. Danish Formulae
 Where,
 S0= elastic
compression of piles
 S = Penetration per
blow
 L=length of pile
 A= cross sectional area
of pile
 E= modulus of
elasticity
 F= factor of safety=3
Qu =
So=
Qa=

81. Static Formula
 Qu=ultimate bearing load
 Qp=end bearing resistance
 Qs=skin friction resistance
 qp= unit end bearing
resistance =ultimate bearing
capicity
 Ap =area at base
 Fs= unit skin friction
 As=surface area of pile in
contact of soil
 Qu=Qp +Qs
Qp=qp
Qs= fs . As

82. Micro Piles

83. Micro Piles construction
Sequence
 Drilling or installation of temporary casing
 Remove inner drilling bit and rod
 Placing reinforcement and grouting it
 Remove temporary casing, inject further grout
under pressure
 Complete pile

85. Classification of Micro Piles
1.Design Behaviour (Case 1 and Case 2)
2. Method of Grouting (Type A, B, C, D, E )

86. Classification of Micro Piles
1.According to Design Application (Case - 1)
 Each Micro pile is Loaded Directly
 Primary Resistance is Provided by Steel
Reinforcement and Side Resistance over Bond
Zone
 Each Micro pile Designed to Act Individually, Even
When in Groups

88. Classification of Micro Piles
1.According to Design Application (Case – 2 )
 Network of Micro piles
 Act As Group to Reinforce The Soil Mass
 Each Micro pile is Lightly Reinforced
 Design Procedures Not Fully Developed

90. 2.According to Method of
Grouting

92. Drilling Techniques of Micro
Piles
 Single Tube Advancement
 Rotary Duplex
 Rotary Percussion Concentric Duplex
 Rotary Percussion Eccentric Duplex
 Double Head Duplex
 Hollow Stem Auger

93. Duplex Casing and Roller Bit Rotary Eccentric Percussive Duplex

94. Grouting
Purpose :
 Transfer of load from reinforcement to surrounding
ground
 Part of micro pile load-bearing cross section
 Protect steel reinforcement
 Extend the limits of the drill hole by permeation,
densification

95. Grouting
General Characteristics :
 High strength and stability
 Use potable water to reduce potential for
corrosion;
 Neat water-cement grout mix most common;
 Design compressive strengths
 Admixtures/additives used, must be compatible,
one supplier only;

96. Grouting
Most Important Considerations:
 Water/cement (w/c) ratio 0.40 to 0.50;Pre-construction
testing, specifications , construction monitoring
 After completion of grouting, no significant loss of grout in
load bearing zone, Monitor grout take, grout to refusal, pre-
grout, re-grout
 For Type B micro piles, consider possibility that target
pressure may not be fully obtained during installation include
verification load test program and proof testing of suspect
piles in specifications

97. Grouting

98. questions
Q-1 Explain the situations in which pile foundations are used?
Q-2 Discuss the main factors affecting selection of type of pile.
Q-3 Explain with sketches the method of forming button bottom
pile & simplex pile.
Q-4 Describe precast concrete pile with sketches, process of
casting advantages & disadvantages.
Q-5 What are the factors considered while deciding the pile
spacing?
Q-6 Explain the behaviour of a single pile & piles in group under
the load.
Q-7 Describe in brief, various type of pile driving equipments with
sketches of each.
Q-8 Explain the dynamic formulae adopted for determining load
carrying capacity of a pile.
Q-9 Make a comparison between Cast-in-situ piles & Pre-cast

99. Thank
you