FOS = Allowable Pile Capacity / Design Load FOS for piles = 3 (for piles in clay) FOS for piles = 2.5 (for piles in sand) Higher FOS for piles in clay due to higher variability in strength compared to sand.

1. PILED FOUNDATION
DESIGN & CONSTRUCTION
By Ir. Dr. Gue See Sew
http://www.gnpgeo.com.my

2. Contents
Overview
Preliminary Study
Site Visit & SI Planning
Pile Design
Pile Installation Methods
Types of Piles

3. Contents (Cont’d)
Piling Supervision
Pile Damage
Piling Problems
Typical Design and Construction Issues
Myths in Piling
Case Histories
Conclusions

4. Overview

5. What is a Pile Foundation
It is a foundation system that
transfers loads to a deeper
and competent soil layer.

6. When To Use Pile Foundations
• Inadequate Bearing Capacity of Shallow
Foundations
• To Prevent Uplift Forces
• To Reduce Excessive Settlement

8. PILE CLASSIFICATION
Friction Pile
– Load Bearing Resistance derived mainly
from skin friction
End Bearing Pile
– Load Bearing Resistance derived mainly
from base

9. Friction Pile
Overburden Soil Layer

10. End Bearing Pile
Overburden Soil
Rock / Hard Layer

11. Preliminary Study

12. Preliminary Study
Type & Requirements of Superstructure
Proposed Platform Level (ie CUT or FILL)
Geology of Area
Previous Data or Case Histories
Subsurface Investigation Planning
Selection of Types & Size of Piles

13. Previous Data & Case
Histories
Existing
Existing Proposed Development
Development Development B
A
Only Need Minimal
Number of Boreholes
Bedrock
Profile

14. Challenge The Norm Thru
Innovation To Excel

15. SELECTION OF PILES
Factors Influencing Pile Selection
– Types of Piles Available in Market (see Fig. 1)
– Installation Method
– Contractual Requirements
– Ground Conditions (eg Limestone, etc)
– Site Conditions & Constraints (eg Accessibility)
– Type and Magnitude of Loading
– Development Program & Cost
– etc

16. TYPE OF PILES
DISPLACEMENT PILES NON-DISPLACEMENT PILES
TOTALLY PREFORMED PILES DRIVEN CAST IN-PLACE PILES Bored piles
(A ready-made pile is driven or jacked (a tube is driven into ground to Micro piles
into the ground) form void)
Hollow Solid Concrete Tube Steel Tube
Small displacement
Closed ended
tube concreted Closed ended tube Open ended tube
Steel Pipe Concrete Spun Piles with tube left in extracted while
position concreting (Franki)
Concrete Steel H-piles Bakau piles
(small displacement) Treated timber pile
Precast R.C. Precast prestressed
piles piles
FIG 1: CLASSIFICATION OF PILES

17. PREFORMED PILES
LEGEND :
STEEL PIPE PILES
TYPE OF PILE
AUGERED PILES
INDICATES THAT THE PILE TYPE IS
STEEL H PILES
JACKED PILES
8
TIMPER PILES
BORED PILES
BAKAU PILES
MICROPILES
SUITABLE
SPUN PILES
PSC PILES
DESIGN
RC PILES
INDICATES THAT THE PILE TYPE IS
CONSIDERATIONS x
NOT SUITABLE
? ? ? ? x ? INDICATES THAT THE USE OF PILE
<100 KN a a a a a
? ? x ? TYPE IS DOUBTFUL OR NOT COST
100-300 a a a a a a a a
SCALE OF LOAD
EFFECTIVE UNLESS ADDITIONAL
(STRUCTURAL)
300-600 ? a a a a a a a a a a
600-1100 x ? a a a a a ? a a ? MEASURES TAKEN
COMPRESSIVE LOAD PER COLUMN
1100-2000 x ? a a a a a ? a a ?
2000-5000 x x a a a a a ? a a ?
5000-10000 x x a a a a a x a a x
>10000 x x ? a a a a x a ? x
<5m ? ? ? ? ? ? ? x a a ?
a a a a a a a ? a a a
BEARING TYPE
5-10m
MAINLY END -BEARING
10-20m ? ? a a a a a a a a a
(D=Anticipated depth of bearing)
20-30m x x a a a a a a a a a
30-60m x x a a a a a a a ? a
MAINLY FRICTION a a a a a ? a a a ? a
PARTLY FRICTION + PARTLY END BEARING a a a a a a a a a ? a
LIMESTON FORMATION ? ? ? ? ? a a a ? a a
BEARING
TYPE OF
LAYER
WEATHERED ROCK / SOFT ROCK x x a a a a a ? a a ?
ROCK (RQD > 70%) x x ? ? ? a a ? a a ?
x ?
GEOTECHNICAL
DENSE / VERY DENSE SAND a a a a a a a a a
SOFT SPT < 4 a a a a a a a a a ? a
M. STIFF SPT = 4 - 15 a a a a a a a a a a a
TYPE OF INTERMEDIATE LAYER
COHESIVE SOIL
V. STIFF SPT = 15 - 32 ? a a a a a a a a a a
HARD SPT > 32 x ? a a a a a a a a a
LOOSE SPT < 10 a a a a a a a a a a a
M. DENSE SPT = 10 - 30 ? a a a a a a a a a a
COHESIVELESS SOIL
DENSE SPT = 30 - 50 x ? a a a a a a a a a
V. DENSE SPT > 50 x x a a a a a ? a a ?
S < 100 mm x ? a a a a a a a a ?
SOIL WITH SOME BOULDERS / 100-1000mm x x ? ? ? a a ? a a x
COBBLES (S=SIZE) 1000-3000mm x x ? ? ? ? ? ? ? a x
>3000mm x x ? ? ? ? ? ? ? a x
GROUND ABOVE PILE CAP a a a a a a a a a a a
WATER BELOW PILE CAP x a a a a a a a a a a
NOISE + VIBRATION; COUNTER MEASURES ? ? ? ? ?
a a a a a a
ENVIRONME REQUIRED
NT
PREVENTION OF EFFECTS ON ADJOINING ? ? ? ? ? ? ? ?
a a a
STRUCTURES
UNIT COST (SUPPLY & INSTALL) RM/TON/M 0.5-2.5 0.3-2.0 1.0-3.5 1-2 0.5-2 1.5-3 1-2.5
FIG 2 : PILE SELECTION CHART

18. Pile Selection Based on Cost
Details: 250mm Spun Piles 300mm Spun Piles Micropile
Total Points 83 70 70
Average Length 9m 9m 9m
Average Rock Socket Length - - 2.5m
Indicative Rates :
Mob & Demob RM 50,000.00 RM 50,000.00 RM 20,000.00
Supply RM 33.00 / m RM 42.00 / m -
Drive RM 30.00 / m RM 32.00 / m -
Cut Excess, Dispose + Starter Bars RM 200.00 / Nos RM 200.00 / Nos -
Movement - - RM 200.00 / Nos
Drilling in Soil - - RM 110.00 / m
Drilling in Rock - - RM 240.00 / m
API Pipe - - RM 120.00 / m
Grouting - - RM 85.00 / m
Pile Head - - RM 150.00 / Nos
Est. Ave. Cost Per Point RM 967.00 / Nos RM 1,066.00 / Nos RM 4,297.50 / Nos
Est. Foundation Cost RM 190,261.00 RM 184,620.00 RM 380,825.00
√

19. Site Visit and SI Planning

20. Site Visit
Things To Look For …
Accessibility & Constraints of Site
Adjacent Structures/Slopes, Rivers,
Boulders, etc
Adjacent Activities (eg excavation)
Confirm Topography & Site Conditions
Any Other Observations that may affect
Design and Construction of Foundation

21. Subsurface Investigation (SI)
Planning
Provide Sufficient Boreholes to get Subsoil Profile
Collect Rock Samples for Strength Tests (eg UCT)
In-Situ Tests to get consistency of ground (eg SPT)
Classification Tests to Determine Soil Type
Profile
Soil Strength Tests (eg CIU)
Chemical Tests (eg Chlorine, Sulphate, etc)

22. Typical Cross-Section at Hill Site
Ground Level
Hard Material Level
Very Hard Material Level
Bedrock Level
Groundwater Level

23. EXISTING
CROSS SECTION GROUND
LEVEL
BH
BH C’1, ø’1
’
r C ’ 2, ø 2
edW
T
Laye
BH Perch Cla
y ey
Seepage C’3, ø’3
Water Table

24. Placing Boreholes in Limestone
Areas
Stage 1 : Preliminary S.I.
- Carry out geophysical survey (for large areas)
Stage 2: Detailed S.I.
- Boreholes at Critical Areas Interpreted from
Stage 1
Stage 3: During Construction
- Rock Probing at Selected Columns to
supplement Stage 2

25. Pile Design

26. PILE DESIGN
Allowable Pile Capacity is the minimum of :
1) Allowable Structural Capacity
2) Allowable Geotechnical Capacity
a. Negative Skin Friction
b. Settlement Control

27. PILE DESIGN
Structural consideration
• Not overstressed during handling, installation & in
service for pile body, pile head, joint & shoe.
• Dimension & alignment tolerances (common
defects?)
• Compute the allowable load in soft soil (<10kPa)
over hard stratum
• Durability assessment

28. Pile Capacity Design
Structural Capacity
Qall = Allowable pile
capacity
Concrete Pile
fcu = characteristic strength
Qall = 0.25 x fcu x Ac of concrete
fs = yield strength of steel
Ac = cross sectional area of
Steel Pile concrete
Qall = 0.3 x fy x As As = cross sectional area of
steel
Prestressed Concrete Pile
Qall = 0.25 (fcu – Prestress after loss) x Ac

29. Pile Capacity Design
Geotechnical Capacity
Collection of SI Data
Depth Vs SPT-N Blow Count
0 50 100 150 200 250 300 350 400
0 0
2
4 2
6
Depth (m)
8 Upper Bound 4
10
12
6
14
16
8
18
20
Design Line
22 Lower 10
(Moderately
Bound Conservative)
24
26 12
0 50 100 150 200 250 300 350 400
SPT Blow Count per 300mm Penetration

30. Pile Capacity Design
Geotechnical Capacity
Collection of SI Data
Depth Vs SPT-N Blow Count Depth Vs SPT-N Blow Count
0 50 100 150 200 250 300 350 400 0 50 100 150 200 250 300 350 400
0 0 0 0
2 2
4 4 2
2
6 6
8
Depth (m)
8
Upper Bound
Depth (m)
4 4
10 10
12 12
6 6
14 14
16 16
8 8
18 Design Line 18
Upper Bound
Lower
20
20 Bound
22 10 22 Lower 10
Bound Design Line
24 24
26 12 26 12
0 50 100 150 200 250 300 350 400 0 50 100 150 200 250 300 350 400
SPT Blow Count per 300mm Penetration SPT Blow Count per 300mm Penetration

31. Pile Capacity Design
Geotechnical Capacity
• Piles installed in a group may fail:
• Individually
• As a block

32. Pile Capacity Design
Geotechnical Capacity
• Piles fail individually
• When installed at large spacing

33. Pile Capacity Design
Geotechnical Capacity
• Piles fail as a block
• When installed at close spacing

34. Pile Capacity Design
Single Pile Capacity

35. Pile Capacity Design
Factor of Safety (FOS)
Factor of Safety (FOS) is required
for
Natural variations in soil strength &
compressibility

36. Pile Capacity Design
Factor of Safety (FOS)
Factor of Safety is
(FOS) required for
Different degree of
Load
mobilisation for shaft
qsmob
& for tip
qbmob
≈ 5mm Settlement

37. Pile Capacity Design
Factor of Safety (FOS)
Partial factors of safety for shaft & base
capacities respectively
For shaft, use 1.5 (typical)
For base, use 3.0 (typical)
Qall = ΣQsu + Qbu
1.5 3.0

38. Pile Capacity Design
Factor of Safety (FOS)
Global factor of safety for total ultimate
capacity
Use 2.0 (typical)
Qall = ΣQsu + Qbu
2.0

39. Pile Capacity Design
Factor of Safety (FOS)
Calculate using BOTH approaches
(Partial & Global)
Choose the lower of the Qall values

40. Pile Capacity Design
Single Pile Capacity
Qu = ultimate bearing capacity
Qu = Qs + Qb
Qs = skin friction
Qb = end bearing
Overburden Soil Layer

41. Pile Capacity Design
Single Pile Capacity : In Cohesive Soil
Qsu Qbu
Qu = α.sus.As + sub.Nc.Ab
Qu = Ultimate bearing capacity of the pile
a = adhesion factor (see next slide)
sus = average undrained shear strength for shaft
As = surface area of shaft
sub = undrained shear strength at pile base
Nc = bearing capacity factor (taken as 9.0)
Ab = cross sectional area of pile base

42. Pile Capacity Design
Single Pile Capacity: In Cohesive Soil
Adhesion factor (α) – Shear strength (Su)
(McClelland, 1974)
1.0
Preferred
Design Line
0.8
0.6
Cα/Su
0.4
Adhesion
Factor
0.2
0
25 50 75 100 125 150 175
Su (kN/m2)

43. Meyerhof Fukuoka
su =
fsu=2.5N fsu=α.su
SPT N (0.1+0.15N)*50 α
(kPa) (kPa)
(kPa)
0 0 5 1 5
1 2.5 12.5 1 12.5
5 12.5 42.5 0.7 29.75
10 25 80 0.52 41.6
15 37.5 117.5 0.4 47
20 50 155 0.33 51.15
30 75 230 0.3 69
40 100 305 0.3 91.5

44. Pile Capacity Design
Single Pile Capacity: In Cohesive Soil
Correlation Between SPT N and fsu
fsu vs SPT N
110
100
90
80
70
60
(kPa)
fsu
50
40
30
20
10
0
0 5 10 15 20 25 30 35 40 45
SPT N
Meyerhof Fukuoka

45. Pile Capacity Design
Single Pile Capacity: In Cohesive Soil
Values of undrained shear strength, su can be
obtained from the following:
Unconfined compressive test
Field vane shear test
Deduce based on Fukuoka’s Plot (minimum su )
Deduce from SPT-N values based on Meyerhof
NOTE: Use only direct field data for shaft friction prediction
instead of Meyerhof

46. Pile Capacity Design
Single Pile Capacity: In Cohesive Soil
Modified Meyerhof (1976):
Ult. Shaft friction = Qsu ≅ 2.5N (kPa)
Ult. Toe capacity = Qbu ≅ 250N (kPa)
or 9 su (kPa)
(Beware of base cleaning for bored piles –
ignore base capacity if doubtful)

47. Pile Capacity Design
Single Pile Capacity: In Cohesionless Soil
Modified Meyerhof (1976):
Ult. Shaft Friction = Qsu ≅ 2.0N (kPa)
Ult. Toe Capacity= Qbu ≅ 250N – 400N
(kPa)

48. Pile Capacity Design
Load (kN)
0
0 100
100 200
200 300
300 400
400 500
500
0
0 0
0
4
4 4
4
ΣQsu
8
8
Qbu 8
8
Depth (m)
ΣQsu + Qbu
12
12 12
12
ΣQsu + Qbu ΣQsu + Qbu
1.5 3.0 2.0
16
16 16
16
20
20 20
20
0
0 200
200 400
400 600
600

49. Pile Capacity Design
Block Capacity

50. Pile Capacity Design
Block Capacity:In Cohesive Soil
Qu = 2D(B+L) s + 1.3(sb.Nc.B.L)
Where
Qu= ultimate bearing capacity of pile group
D = depth of pile below pile cap level
B = width of pile group
L = length of pile group
s = average cohesion of clay around group
sb = cohesion of clay beneath group
Nc= bearing capacity factor = 9.0
(Refer to Text by Tomlinson, 1995)

51. Pile Capacity Design
Block Capacity: In Cohesionless Soil
No risk of group failure
if FOS of individual pile is
adequate

52. Pile Capacity Design
Block Capacity: On Rock
No risk of block failure
if the piles are properly
seated in the rock
formation

53. Pile Capacity Design
Negative Skin Friction (NSF)

54. Pile Capacity Design
Negative Skin Friction
Compressible soil layer consolidates
with time due to:
Surcharge of fill
Lowering of groundwater table

55. Pile Capacity Design
Negative Skin Friction
Hf
Fill
OGL
0
1 2 3 Month
ρs
Clay

56. Pile Capacity Design
Negative Skin Friction
Pile to length (floating pile)
Pile settles with consolidating soil
NO NSF

57. Pile Capacity Design
Negative Skin Friction
Pile to set at hard stratum (end-
bearing pile)
Consolidation causes downdrag forces on
piles as soil settles more than the pile

58. Pile Capacity Design
Negative Skin Friction
WARNING:
No free fill by the contractor to avoid
NSF

59. Effect of NSF …
Reduction of Pile Carrying Capacity

60. Effect of NSF …

61. NSF Preventive Measures
Avoid Filling
Carry Out Surcharging
Sleeve the Pile Shaft
Slip Coating
Reserve Structural Capacity for NSF
Allow for Larger Settlements

62. Pile Capacity Design
Negative Skin Friction
Qall = (Qsu/1.5 + Qbu/3.0)
Qall = (Qsu/1.5 + Qbu/3.0) - Qneg
FL
OGL Sand OGL
Clay
Clay Qneg
Qsu
Qsu
Sand Sand
Qba
Qba

63. Pile Capacity Design
Negative Skin Friction
Increased Pile Axial Load
Check: maximum axial load < structural pile
SPT-N (Blows/300mm) Settlement (mm) Axial Compression Force (kN)
capacity 0
0 10 20 30 40 50
70 60 50 40 30 20 10
100 0 -100 -200 -300-400-500-600 -700 -800 -900-1000
0
5
10
15
Depth (m, bgl)
Settlement Curves &
20 Axial Compression Force
14 May 98
15 May 98
18 May 98
25 21 May 98
04 Jun 98
09 Jun 98
30 19 Jun 98
02 Jul 98
13 Jul 98
Maximum
Borehole
35
BH-1 Datum = 36.300m axial load
BH-2
40

64. Pile Capacity Design
Factor of Safety (FOS)
Without Negative Skin Friction:
Qult
Allowable working load
FOS
With Negative Skin Friction:
Allowable working load
Qult
(Qneg + etc)
FOS

65. Pile Capacity Design
Static Pile Load Test (Piles with NSF)
• Specified Working Load (SWL) = Specified foundation
load at pile head
• Design Verification Load (DVL) = SWL + 2 Qneg
• Proof Load: will not normally exceed
DVL + SWL

66. Pile Settlement Design

67. Pile Settlement Design
In Cohesive Soil
Design for total settlement &
differential settlement for design
tolerance
In certain cases, total settlement not an
cases
issue
Differential settlement can cause
damage to structures

68. Pile Settlement Design
In Cohesive Soil
Pile Group Settlement in Clay
=
Immediate / Consolidation
Elastic Settlement + Settlement

69. Pile Settlement Design
In Cohesive Soil
IMMEDIATE SETTLEMENT
μ1μ 0 qn B by Janbu, Bjerrum and
pi = Kjaernsli (1956)
Eu
Where
pi = average immediate settlement
qn= pressure at base of equivalent raft
B = width of the equivalent raft
Eu= deformation modulus
μ1, μ0= influence factors for pile group width, B at depth D
below ground surface

70. Pile Settlement Design
In Cohesive Soil
IMMEDIATE SETTLEMENT
μ1
μ0
Influence factors (after
Janbu, Bjerrum and
Kjaernsli, 1956)

71. Pile Settlement Design
In Cohesive Soil
CONSOLIDATION SETTLEMENT
As per footing (references given later)

72. Pile Settlement Design
On Rock
No risk of excessive
settlement

73. Pile Installation Methods

74. PILE INSTALLATION
METHODS
•Diesel / Hydraulic / Drop Hammer
Driving
•Jacked-In
•Prebore Then Drive
•Prebore Then Jacked In
•Cast-In-Situ Pile

75. Diesel Drop Hammer Hydraulic Hammer
Driving Driving

76. Jacked-In
Piling

77. Jacked-In Piling (Cont’d)

78. Cast-In-Situ
Cast-In-Situ
Piles
(Micropiles)
(Micropiles)

79. Types of Piles

80. TYPES OF PILES
•Treated Timber •Steel Piles
Piles
•Boredpiles
•Bakau Piles
•Micropiles
•R.C. Square Piles
•Caisson Piles
•Pre-Stressed
Concrete Spun
Piles

81. R.C. Square Piles
Size : 150mm to 400mm
Lengths : 3m, 6m, 9m and 12m
Structural Capacity : 25Ton to 185Ton
Material : Grade 40MPa Concrete
Joints: Welded
Installation Method :
–Drop Hammer
–Jack-In

82. RC
Square
Piles

83. Pile Marking

84. Pile Lifting

85. Pile Fitting to Piling Machine

86. Pile
Positioning

87. Pile Joining

88. Considerations in Using RC
Square Piles …
•Pile Quality
•Pile Handling Stresses
•Driving Stresses
•Tensile Stresses
•Lateral Loads
•Jointing

89. Pre-stressed Concrete Spun
Piles
Size : 250mm to 1000mm
Lengths : 6m, 9m and 12m (Typical)
Structural Capacity : 45Ton to 520Ton
Material : Grade 60MPa & 80MPa Concrete
Joints: Welded
Installation Method :
–Drop Hammer
–Jack-In

90. Spun Piles

91. Spun Piles vs RC Square Piles
Spun Piles have …
•Better Bending Resistance
•Higher Axial Capacity
•Better Manufacturing Quality
•Able to Sustain Higher Driving Stresses
•Higher Tensile Capacity
•Easier to Check Integrity of Pile
•Similar cost as RC Square Piles

92. Steel H Piles
Size : 200mm to 400m
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

93. Steel H
Piles

94. Steel H Piles (Cont’d)

95. Steel H Piles Notes…
•Corrosion Rate
•Fatigue
•OverDriving

96. OverDriving
of Steel Piles

97. Large Diameter Cast-In-Situ
Piles (Bored Piles)
Size : 450mm to 2m
Lengths : Varies
Structural Capacity : 80Ton to 2,300Tons
Concrete Grade : 20MPa to 30MPa (Tremie)
Joints : None
Installation Method : Drill then Cast-In-Situ

98. Drilling
Borepile Construction
Overburden Soil Layer
Bedrock

99. Advance Drilling
Borepile Construction
Overburden Soil Layer
Bedrock

100. Drilling & Advance
Borepile Construction
Casing
Overburden Soil Layer
Bedrock

101. Drill to Bedrock
Borepile Construction
Overburden Soil Layer
Bedrock

102. Lower
Borepile Construction
Reinforcement
Cage
Overburden Soil Layer
Bedrock

103. Lower Tremie
Borepile Construction
Chute
Overburden Soil Layer
Bedrock

104. Pour Tremie
Borepile Construction
Concrete
Overburden Soil Layer
Bedrock

105. Completed
Borepile Construction
Borepile
Overburden Soil Layer
Bedrock

106. Bored Pile Construction
BORED PILING MACHINE
BG22

107. Rock Reamer Rock Auger
Cleaning Bucket

108. Rock Chisel
Harden Steel

109. Bored Pile Construction
DRILLING EQUIPMENT
Coring
bucket Soil auger
Cleaning
bucket

110. Bored Pile Construction
BENTONITE PLANT
Desanding
Machine
Water
Tank Mixer Slurry
Tank

111. Drilling

112. Lower
Reinforcement

113. Place
Tremie
Concrete

114. Completed Boredpile

115. Borepile Cosiderations…
•Borepile Base Difficult to Clean
•Bulging / Necking
•Collapse of Sidewall
•Dispute on Level of Weathered Rock

116. Micropiles
Size : 100mm to 350mm Diameter
Lengths : Varies
Structural Capacity : 20Ton to 250Ton
Material : Grade 25MPa to 35MPa Grout
N80 API Pipe as Reinforcement
Joints: None
Installation Method :
–Drill then Cast-In-Situ
–Percussion Then Cast-In-Situ

117. Cast-In-Situ
Piles
(Micropiles)

118. TYPES OF PILE SHOES
•Flat Ended Shoe
•Oslo Point
•Cast-Iron Pointed Tip
•Cross Fin Shoe
•H-Section

119. Cross Fin Shoe

120. Oslo Point Shoe

121. Cast Iron Tip Shoe

122. H-Section Shoe

123. Piling Supervision

124. Uniform Building By
Law (UBBL)1984

125. PILING SUPERVISION
•Ensure That Piles Are Stacked Properly
•Ensure that Piles are Vertical During Driving
•Keep Proper Piling Records
•Ensure Correct Pile Types and Sizes are Used
•Ensure that Pile Joints are Properly Welded with
NO GAPS
•Ensure Use of Correct Hammer Weights and Drop
Heights

126. PILING SUPERVISION
(Cont’d)
•Ensure that Proper Types of Pile Shoes are Used.
•Check Pile Quality
•Ensure that the Piles are Driven to the Required
Lengths
•Monitor Pile Driving

129. FAILURE OF PILING
SUPERVISION
Failing to Provide Proper Supervision
WILL Result in
Higher Instances of Pile Damage
& Wastage

130. Pile Damage

131. Driven concrete piles are vulnerable
to damages by overdriving.

132. Damage to Timber Pile

133. Weak
Timber
Joint

134. Damage To RC Pile Toe

135. Damage to
RC Pile
Head

136. Damage to
RC Piles

137. Damage to RC Piles – cont’d

138. Tilted RC
Piles

139. Damage to Steel Piles

140. Damaged Steel Pipe Piles

142. Detection of Pile Damage
Through Piling Records

143. Piling Problems

144. Piling Problems – Soft Ground

145. Piling Problems – Soft Ground
Ground heave due to
pressure relief at base &
surcharge near
excavation
Pile tilts & moves/walks

146. Piling Problems – Soft Ground

147. Piling in Kuala Lumpur Limestone
Important Points to Note:
• Highly Irregular Bedrock Profile
• Presence of Cavities & Solution Channels
• Very Soft Soil Immediately Above Limestone
Bedrock
Results in …
• High Rates of Pile Damage
• High Bending Stresses

148. Piling Problems in Typical Limestone
Bedrock

149. Piling Problems – Undetected
Problems

150. Piling Problems – Coastal Alluvium

151. Piling Problems – Defective Piles
Defect due to poor
Seriously damaged workmanship of pile
pile due to severe casting
driving stress in soft
ground (tension)

152. Piling Problems – Defective Piles
Problems of
defective pile head
Defective pile shoe & overdriving!

153. Piling Problems – Defective Piles
Non-
chamfered
corners
Cracks&
fractured

154. Piling Problems – Defective Piles
Pile head defect due to
hard driving or and poor
workmanship

155. Piling Problem - Micropiles
Sinkholes caused by
installation method-
dewatering?

156. Piling in Fill Ground
Important Points to Note:
•High Consolidation Settlements If Original Ground is
Soft
•Uneven Settlement Due to Uneven Fill Thickness
•Collapse Settlement of Fill Layer If Not Compacted
Properly
Results in …
•Negative Skin Friction (NSF) & Crushing of Pile Due
to High Compressive Stresses
•Uneven Settlements

157. Typical Design and
Construction Issues #1
Issue #1
Pile Toe Slippage Due to Steep Incline Bedrock
Solution #1
Use Oslo Point Shoe To Minimize Pile Damage

158. Pile Breakage on Inclined
Rock Surface
No Proper Pile
Shoe

159. Extension Pile
Pile
Joint

160. First Contact
B/W Toe and
Inclined Rock

161. Pile Joint Breaks
Pile Body Bends
Toe “Kicked Off”
on Driving

162. Pile Breakage on Inclined
Rock Surface
Continue
“Sliding” of
Toe

163. Use Oslo Point Shoe to Minimize
Damage

164. Design and Construction
Issues #2
Issue #2
Presence of Cavity
Solution #2
Detect Cavities through Cavity Probing then
perform Compaction Grouting

165. Presence of Cavity
Pile Sitting on
Limestone
with Cavity

166. Application of
Building Load

167. Application of
Building Load
Roof of Cavity
starts to Crack …

168. Building Collapse
Pile Plunges !
Collapse of
Cavity Roof

169. Design and Construction
Issues #3
Issue #3
Differential Settlement
Solution #3
Carry out analyses to check the settlement
compatibility if different piling system is adopted

170. Differential Settlement of Foundation
Link House of
SAFETY
Original Building
Construction Cracks!!
Not Compromised
Original House Renovation:
on Piles Construct
Extensions
Piling in Progress
No Settlement
Settlement
Soft Piles No
transfer pile
Layer Load to
Hard
Layer
Hard Layer
SPT>50

171. Eliminate Differential Settlement
Construct
Extension with
Suitable Piles
Piling in Progress
Soft
Layer
Hard Layer
All Load transferred to Hard
Layer – No Cracks! SPT>50

172. Problem of Short Piles
Cracks!!
Construct
Extensions
with Short
Piling in Progress Piles
Load
transferred to
Soft Soft! Soft Layer,
Layer Extension
still Settles
Hard Layer
Load from Original House
transferred to Hard Layer SPT>50

173. Cracks at Extension

177. Typical Design and
Construction Issues #4
Issue #4
Costly conventional piling design – piled to set to
deep layer in soft ground
Solution #4
-Strip footings / Raft
-Floating Piles

179. “Conventional” Foundation for
Low Rise Buildings

180. Foundation for
Low Rise Buildings (Soil Settlement)

181. Settling Platform Detached from Building
Settlement
Exposed Pile

182. Conceptual Design of
FOUNDATION SYSTEM
1. Low Rise Buildings :-
(Double-Storey Houses)
= Strip Footings or Raft or
Combination.
2. Medium Rise Buildings :-
= Floating Piles System.

183. Low Rise Buildings on
Piled Raft/Strips
Fill
Strip / Raft
System
25-30m
Soft Clay
Stiff
Stratum
Hard Layer

184. Comparison
Building on Piles Building on Piled Strips
Fill
25-30m
Soft Clay
Strip
System
Stiff
Stratum
Hard Layer

185. Comparison (after settlement)
Building on Piles Building on Piled Strips
Fill
25-30m
Soft Clay
Strip
System
Stiff
Stratum
Hard Layer

186. Advantages of
Floating Piles System
1. Cost Effective.
2. No Downdrag problems on the
Piles.
3. Insignificant Differential
Settlement between Buildings and
Platform.

187. Bandar Botanic

188. Bandar Botanic at Night

190. Soft Ground Engineering

191. Myths in Piling

192. MYTHS IN PILING #1
Myth:
Dynamic Formulae such as Hiley’s Formula
Tells us the Capacity of the Pile
Truth:
Pile Capacity can only be verified by using:
(i) Maintained (Static) Load Tests
(ii)Pile Dynamic Analyser (PDA) Tests

193. MYTHS IN PILING #2
Myth:
Pile Achieves Capacity When It is Set.
Truth:
Pile May Only “Set” on Intermediate Hard
Layer BUT May Still Not Achieve Required
Capacity within Allowable Settlement.

194. CASE HISTORIES
Case 1: Structural distortion & distresses
Case 2: Distresses at houses

195. CASE HISTORY 1
Distortion & Distresses on 40
Single/ 70 Double Storey Houses
Max. 20m Bouldery Fill on
Undulating Terrain
Platform Settlement
Short Piling Problems
Downdrag on Piles

196. Distresses on Structures

197. Void

198. 70
Piling Contractor A
Offset 36.2m Offset 13.1m Building
Offset 13.1m Platform
60 Offset 13.1m
Original
R e d u c e d L e v e l (m )
Ground Profile
50
N=34
? ?
N=30
40 ? ?
N=5
N=40
?
? ? ? Filled ground
N=25 ? Original Ground
? ?
30 N=29
? Hard Stratum
Borehole
Pile Toe
Profile with SPT 'N'≅30 Pile Toe of Additional
Profile with SPT 'N'>50
Piles
20
0 40000 80000 120000 160000 200000
Coordinate-X (mm)

199. 80 Piling
Contractor A Piling Contractor B
70
Offset 9.1m
Offset 9.1m
R e d u c e d L e v e l (m )
60
N=34
Profile with SPT 'N'≅30
Building Platform
N=28
50 ?
N=41
?
N=30 Original Ground Profile Filled ground
Original Ground
? ?
40 N=5 Hard Stratum
Borehole
N=29 Pile Toe
Pile Toe of Additional
? Piles
Profile with SPT 'N'>50
30
0 40000 80000 120000 160000 200000
Coordinate-X (mm)

201. Prevention Measures
Design:
– Consider downdrag in foundation design
– Alternative strip system
Construction:
– Proper QA/QC
– Supervision

202. CASE HISTORY 2
Distresses on 12 Double Storey
Houses & 42 Townhouses
Filled ground: platform settlement
Design problem: non-suspended floor
with semi-suspended detailing
Bad earthwork & layout design
Short piling problem

203. Diagonal cracks due
to differential
settlement between
columns
Larger column
settlement

204. Sagging
Ground
Floor Slab

205. SAGGING PROFILE OF NON- NON-SUSPENDED GROUND FLOOR
SUSPENDED GROUND FLOOR SLAB SLAB BEFORE SETTLEMENT
V ρs V <V
e > Vc V
c c e
PILE PILECAP
BUILDING PLATFORM PROFILE AFTER
SETTLEMENT
ρs ACTUAL FILLED PLATFORM SETTLEMENT

206. Distorted Car Porch Roof

207. Poor Earthwork Layout
Silt trap
BLOCK 2
Temporary
earth drain
BLOCK 1

208. Prevention Measures
Planning:
– Proper building layout planning to suit terrain
(eg. uniform fill thickness)
– Sufficient SI
Design:
– Consider filled platform settlement
– Earthwork layout
Construction:
– Supervision on earthwork & piling

209. SUMMARY
Importance of Preliminary Study
Understanding the Site Geology
Carry out Proper Subsurface Investigation
that Suits the Terrain & Subsoil
Selection of Suitable Pile
Pile Design Concepts

210. SUMMARY
Importance of Piling Supervision
Typical Piling Problems Encountered
Present Some Case Histories

212. 54 PEOPLE TOOK PART IN THIS
CONCERTED ACROBATIC JUMP.
FERRARI ‘S PITSTOP WAS COMPLETED BY
15 MECHANICS (FUEL AND TYRES) IN 6.0
SECONDS FLAT.