1.Forces that Stabilize Foundation? 2.Burj Khalifia Construction 3. Bandra -Worli Sea Link Construction Process 4. Multi Storey Structure Construction Process 5. Pre-cast Reinforcement Structures Almost We Spend about 30-40% of Total Construction Cost So Designing a Foundation play a Crucial role Every Huge Masonry Foundation Construction Require Deep Foundation Bearing Capacity of the Soil is The Main factor That influence Every Foundation Every Soil Strength can be identified by Two Factors Angle of Friction Cohesion Factor

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Solution
How?
What?
Why?

4. Introduction4

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12. Types Of Piles
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19. Pile Driving
Piles may be of timber, steel or concrete. When the piles are of concrete,
they are to be precast at the Industries
They may be driven either vertically or at an angle to the vertical.
Piles are driven using a pile hammer.
Piles driven by using driving technique have higher bearing capacity
compared to bored piles.
Driving is usually done to soils which have medium Relative Density.
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24. Pile Driving
Axial Capacity
The fundamental equation for axial capacity of pile is
Q U = Q b + Q s
Where
Q U = Ultimate Load carrying capacity of pile
Q b =End bearing resistance= q b A b
Q s = Skin friction resistance= f s A s
Where
q b = Ultimate unit bearing capacity at base
A b = Bearing area of the pile base
f s = Unit skin friction
A s = Surface area of the portion of pile embedded in soil.
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25. Installation by Boring
These piles are distinguished from drilled piers as small diameter piles.
They are constructed by making holes in the ground to the required
depth and then filling the hole with concrete.
Straight bored piles or piles with one or more bulbs at intervals may
be cast at the site.
The latter type are called under-reamed piles.
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27. Load test on piles27
Forces
Vertical Load
Lateral Load
Pull out Load
Time
Initial
Routine

28. Test pile
It is used in load test and doesn't carry the load of superstructure.
Working pile
Pile which is driven along with other piles to carry load from the
superstructure.
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29. Procedure
The test shall be carried out by applying a series of vertical loads on a r.c.c cap over the
pile.
Load shall be applied by means of a remote controlled hydraulic jack.
The test load shall be applied in increments of about 20 percent of assumed safe load.
Settlement shall be recorded with at least three dial gauges.
Each stage of loading shall be maintained till the rate of movement of pile top is not
more than 0.1 mm per hours.
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30. The allowable load on a single pile shall be lesser of the following:
• Two-thirds the final load at which the total settlement attains a
value of 12mm.
• Five percent of the final load at which total settlement equals
10percent of the pile diameter in case of uniform diameter
piles and 7.5 per cent of bulb diameter in case of undrreamed
piles.
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31. The allowable load on group of piles shall be lesser of the
following:
• Final load at which settlement attains a value of 25mm.
• Two-thirds the final load at which the total settlement attains a
value of 40mm.
the procedure for routine test should be same as for an initial
test with maximum loading and settlement requirements as
mentioned earlier.
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34. Group Action Of Piles
Pile is not used as singularly, beneath a column or a wall , it is used as a group of piles because, eccentric loading pile
my fail due to bending stresses.
In an actual practice, structural loads are supported by several piles acting as a group.
For a column, minimum of three piles are installed in a triangular pattern.
For walls, piles are installed in staggered arrangement on both sides of it’s center line.
The loads are usually transferred to the pile group through reinforced concrete slab, structurally tied to pile tops such
that, the piles act as a unit.
Such slabs are called as PILE CAPS.
The load carrying capacity of a pile group is not necessarily equal to the sum of load capacity of the individual piles.
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37. Estimation of load carrying capacity of the pile group is very complicated problem.
Because when piles are spaced in a sufficient distance, a group capacity may approach equal to the sum of individual
capacities of each pile .
On the other hands, if the piles are closely spaced, stresses transmitted by the piles to the soil my overlap, this may
reduce the load carrying capacity of the pile group.
The efficiency (Ƞ) of a group of piles is defined as the ratio of the ultimate load of the group to the sum of individual
ultimate loads.
Ƞg =
𝑸 𝒈𝒖 × 𝟏𝟎𝟎
𝒏 𝑸 𝒖
N=Number of piles in a group Qg(u) =Ultimate load of group of piles.
Qu =ultimate load of individual pile
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38. Ƞg =
𝑸 𝒈𝒖
𝒏 𝑸 𝒖
Thus the group efficiency is equal to the average load per pile to the ultimate load in individual
pile.
The group efficiency depends on the spacing between the piles .
The ideal spacing gives us 100% efficiency.
Generally center to center spacing kept between the piles is 2.5B to 3.5B
Where B is the diameter of the pile.
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39. For the piles driven in loose and medium dense cohesion less soils, group efficiency Is
high.
The soil around and between the piles is compacted due to vibration caused during the
driving operation.
For better result, it is essential to start driving the piles at centre and then work outward.
(A) End bearing piles : For driven piles bearing on dense ,compact sand with a spacing
equal or greater than 3B , the group capacity is generally taken equal to the sum of
individual capacities.
Qg = N Qu .
(B) Friction piles : The group action of piles in sand is obtained from following expression.
Ƞg =
Qu
𝑁𝑄 𝑢
×100
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41. C) Bored Piles : For the bored piles in sand at conventional
spacing of 3B, the group capacity is taken as 2/3 to 3/4 times
equal to sum of the individual capacities for both, end
bearing and the friction piles.
Q q( u) =( 2/3 to3/4 )(NQ u)
In bored piles, there is limited densification of the sand
surrounding the pile group . Consequently, the efficiency is
low.
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43. MEYERHOF METHOD ; Meyerhof suggested the following
empirical relation for the elastic settlement of a pile group in
sand.
Sand:
S g =
9.4 q √BI
𝑵
S g=settlement of group q=load
B g=width of group I=influence factor
N= standard penetration number
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45. CLAYEY SOILS
Due to consolidation of pile group , sometimes load assumed to spread outward from the edge of the block
at an angle 300 to the vertical.
settlement of each layer is given by
Hi =∆s(i)=
𝑪 𝒄
1 + e0 (i)
log
ϭ0 + ∆ ϭi
ϭ0
Hi =Thickness of i layer
eo (i)=initial void ratio of i layer
ϭ0 = initial Effective stress
∆ϭi =change in effective stress
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46. Settlement of Pile groups
1.settlement in sand cannot be estimated.
2.Equivalevt raft approach is widely used for calculating the settlement of a pile group in clay.
Assumptions to identify the equivalent raft:
1.comman practice is to assume the equivalent raft at a depth of two-third the pile length over an area
enclosed by the pile.
2.For bored piles the equivalent raft is assumed at the base of the pile.
Pile group in sand:
For estimating the settlement of a pile group in sand, the common practice is to
extrapolate this form the settlement of an individual test pile measured in a load test.
𝑆 𝑔
𝑆 𝑖
=(
4𝐵+2.7
𝐵+3.6
)2
Where,𝑆 𝑔-settlement of a pile group
𝑆𝑖-settlement of an individual pile
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49. Negative skin friction
Magnitude of negative skin friction
for cohesive soils
𝑭 𝒏 = P𝑳 𝒄 𝒄 𝒂
Where, P = perimeter of pile
𝐿 𝑐 = length of pile
𝑐 𝑎 = unit adhesion = ∝ 𝑐 𝑢
∝ = adhesion factor
𝑐 𝑢 = un drained cohesion of the compressible layer.
for cohesion less soils
𝑭 𝒏 =
𝟏
𝟐
P𝑳 𝒄
𝟐 𝜸𝑲𝒕𝒂𝒏𝜹
Where, K = lateral earth pressure coefficient
𝛿 = angle of friction between pile and soil.
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50. When a pile group passes through a soft, unconsolidated stratum, the magnitude of
negative skin friction on the group
𝑭 𝒏𝒈 = n𝑭 𝒏
𝑭 𝒏 = 𝒄 𝒖 𝑳 𝒄 𝑷 𝒈 + 𝜸𝑳 𝒄 𝑨 𝒈
Where, n = number of piles in the group
𝑷 𝒈 = perimeter of the group
𝜸 = unit weight of the soil within the pile group upto a depth 𝐿 𝑐
𝑨 𝒈 = area of pile group within the perimeter 𝑃𝑔
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52. Laterally Loaded Piles
INTRODUCTION
Pile foundation are subjected to laterally loaded and moments which under goes wind loads and seismic
forces in building.
Where as in water earth pressure in retaining wall is water front structure.
Piles are assume to resist load and moment in axial compression or tensile only.
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55. Plastic theory
This theory has been developed for short rigid piles where it has been assumed that the
limiting or maximum soil resistance is acting against along the pile length develops.
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57. Laterally Loaded Piles
Elastic theory
This theory assume the soil to be replaced by a series of closely spaced
independent elastic springs.
The equation for a beam on elastic foundation , utilizing the concept of
sub grade modulus , hence been solved for different conditions and non
dimensional solutions have been given for laterally loaded vertical piles
to determine the variation of deflection Bending Moment , soil reaction ,
shear etc. along entire pile length.
The methods based on elastic theory based on the concept of Reese
and Matlock Approach for a laterally loaded vertical pile with the soil
modulus assumed to increase with depth.
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59. REESE AND MATLOCK APPROACH
Non – dimensional solutions for a laterally loaded piles in a soil deposit in which the sub
grade modulus increases linearly with depth. The solutions have been developed for
long piles when
L/T>5
L is length of the pile and
T is the relative stiffness factor
T=
𝑬𝑰
𝜼 𝒉
𝟏
𝟓
E and I are the modulus of elasticity and moment of inertia of pile material
𝜼 𝒉 = unit modulus of sub grade reaction or constant of soil modulus
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