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A COMPARISON OF PILE CAPACITY OBTAINED BY STATIC FORMULAS
AND STATIC LOAD TEST
MASNORHADAFFI BIN MASUD
UNIVERSITI TEKNOLOGI MALAYSIA
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PSZ 19:16 (Pind. 1/07)
UNIVERSITI TEKNOLOGI MALAYSIA
DECLARATION OF THESIS / UNDERGRADUATE PROJECT PAPER AND COPYRIGHT
Authors full name : MASNORHADAFFI BIN MASUD
Date of birth : 19TH
APRIL 1979
Title : A COMPARISON OF PILE BEARING CAPACITY OBTAINED
BY STATIC FORMULAS AND STATIC LOAD TEST
Academic Session : 2010 / 2011
I dec lare that this thesis is classified as:
I acknowledged that Universiti Teknologi Ma laysia reserves the right as follows:
1. The thesis is the property of Universiti Teknologi Malaysia.2. The Library of Universiti Teknologi Malaysia has the right to make copies for the
purpose of research only.
3. The Library has the right to make copies of the thesis for ac ademic exchange.Certified by:
SIGNATURE SIGNATURE OF SUPERVISOR
790419-03-5659 DR. NAZRI BIN ALI
(NEW IC NO. /PASSPORT NO.) NAME OF SUPERVISOR
Date : 19TH
APRIL 2011 Date : 19TH
APRIL 2011
OPEN ACCESS I agree that my thesis to be published as online open access(full text)
RESTRICTED (Contains restricted information as spec ified by theorganization where research was done)*
CONFIDENTIAL (Contains confidential information under the Official SecretAct 1972)*
NOTES : * If the thesis is CONFIDENTAL or RESTRICTED, please attach with the letter from
the organization with period and reasons for confidentiality or restriction.
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I hereby declare that I have read this thesis and in my opinion this thesis is sufficient in
terms of scope and quality for the award of the degree of Bachelor of Civil
Engineering
Signature : ..
Name of Supervisor : DR. NAZRI BIN ALI
Date : 19TH
APRIL 2011
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i
A COMPARISON OF PILE CAPACITY OBTAINED BY STATIC FORMULAS
AND STATIC LOAD TEST
MASNORHADAFFI BIN MASUD
A report submitted in partial fulfillment of the
requirements for the award of the degree of
Bachelor of Civil Engineering
Faculty of Civil Engineering
Universiti Teknologi Malaysia
APRIL 2011
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I declare that this thesis entitled A Comparison of Pile Capacity Obtained by Static
Formulas and Static Load Test is the result of my own research except as cited in the
references. The thesis has not been accepted for any degree and is not concurrently
submitted in candidature of any other degree.
Signature : .
Name of Author : MASNORHADAFFI BIN MASUD
Date : 19TH
APRIL 2011
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For my dearest parents,
Masud Hj. Ahmadiah & Noorani Hj. Othman
Thank you for encouragement,
For my beloved wife,
Zainonarisma Mansuh who always by my side,
Thank you for sacrifice and understanding,
For my sister and brother,
Who always bring happiness to me
and also
For my great friends Ali, Ly and Rahmat
That always gives their hand
All of you inspire my effort and achievement
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ACKNOWLEDGEMENT
My most gratitude to Allah S.W.T, the Almighty for giving me this great chance
to enhance my knowledge and to complete this study. May the peace and blessings be
upon Prophet Muhammad S.A.W.
I would like to take this opportunity to express my deep and sincere gratitude to
my supervisor, Dr. Nazri bin Ali, a dedicate lecturer in Faculty of Civil Engineering for
his encouragement and expert advice regarding the planning, processing and editing me
in order to complete this final year project. The ideas and concepts have had a
remarkable influence on my entire project in this field.
During this work, I have collaborated with many persons for whom I have great
regard, and I wish to extend my warmest thanks to all those who have helped me with
my work. My friends were instrumental and played important roles in assisting me to
complete my project. They include my course mates, seniors who have graduated,
colleagues and my many other friends.
I owe my loving thanks to my parents, family and beloved wife who always
pray for my success yesterday, today and every tomorrow. Without their encouragement
and understanding, it would have been impossible for me to finish this work. With that,
I thank you.
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ABSTRACT
Since the early of pile static formula suggested by Terzaghi (1943) up until now,
several pile design methods is being proposed. Between one method and another, result
differences are still questionable. This study is conducted based on driven Spun Pile and
Reinforced Concrete Pile constructed in Malaysia in sand and cohesive soils. This is to
determine the different between several pile design methods by Meyerhof (1976), Janbu
(1976), Vesic (1975), Meyerhof (1981), method (1985) and method (1972) with the
End-bearing capacity and Skin Resistance capacity respectively value with static load
test using Maintain Load Test (MLT). All the design methods is analyzed by using soil
friction angle correlation by Schmertmann (1975), Peck, Hanson and Thornburn (1974),
Hatanaka and Uchida (1996) and Shioi and Fukui (1982). All soil friction angles iscalculated by using correctedN-value equation by Liao and Whitman (1986), Skempton
(1986), Peck (1974) and Seed (1974) except for Schmertmann (1975). From analysis it
can be found that Janbus method matching up with Shioi and Fukui soil friction angle
is the most conservative which its value excessively lower the MLT value. Then
followed by Meyerhofs method matching up with Hatanaka and Uchida soil friction
angle which its value almost near MLT or slightly above it. Vesics method is found to
be very not conservative which its value far above the MLT value. From this study it
can be concluded that it is recommended to use either Meyerhof or Janbu Method for
estimating end-bearing capacity in sand and silt. For skin friction in sand it
recommended using Meyerhof method. Finally for estimating skin friction in clayey
soil, it is recommended to use method.
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ABSTRAK
Sejak awal formula statik cerucuk dicadangkan oleh Terzaghi (1943), beberapa
formula rekabentuk cerucuk telah dicadangkan. Perbezaan rekabentuk antara beberapa
formula ini masih lagi menjadi tanda tanya. Kajian ini dijalankan berdasarkan cerucuk
kelompang dan cerucuk konkrit bertetulang yang telah ditanam di dalam tanah pasir dan
tanah jelekit di Malaysia. Kajian ini adalah untuk mengkaji perbezaan keupayaan galas
dan geseran kulit cerucuk antara beberapa kaedah rekabentuk oleh Meyerhof (1976),
Janbu (1976), Vesic (1975), Meyerhof (1981), kaedah (1985) dan kaedah (1972)
dengan keupayaan cerucuk yang diperolehi daripada ujian beban cerucuk menggunakan
Maintain Load Test (MLT). Kesemua kaedah rekabentuk dianalisa menggunakan
sekaitan sudut geseran tanah oleh Schmertmann (1975), Peck, Hanson dan Thornburn
(1974), Hatanaka dan Uchida (1996) dan Shioi dan Fukui (1982). Kesemua sudutgeseran tanah dihitung menggunakan persamaan pembetulan nilai N oleh Liao dan
Whitman (1986), Skempton (1986), Peck (1974) dan Seed (1974) kecuali Schmertmann
(1975). Daripada analisa, dirumuskan kaedah Janbu digandingkan dengan sudut geseran
tanah Shioi dan Fukui merupakan kaedah yang paling konsevatif kerana mempunyai
nilai keupayaan yang jauh lebih rendah dari nilai MLT. Ini diikuti oleh kaedah
Meyerhof digandingkan dengan sudut geseran tanah Hatanaka dan Uchida yang
mempunyai nilai hampir atau lebih sedikit daripada nilai MLT. Kaedah Vesic didapati
merupakan kaedah yang paling tidak konservatif kerana mempunyai nilai jauh lebih
tinggi berbanding nilai MLT. Daripada kajian ini dapat disimpulkan bahawa kaedah
Meyerhof dan Janbu dicadangkan keupayaan galas tanah pasir dan kelodak. Bagi
geseran kulit di tanah pasir, kaedah Meyerhof dicadangkan. Akhir sekali analisa
keupayaan geseran kulit cerucuk di tanah liat kaedah dicadangkan.
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TABLE OF CONTENTS
CHAPTER TITLE PAGE
TITLE i
DECLARATION ii
DEDICATION iii
ACKNOWLEDGEMENT iv
ABSTRACT v
ABSTRAK vi
TABLE OF CONTENTS vii
LIST OF TABLES xii
LIST OF FIGURES xv
LIST OF SYMBOLS xviii
LIST OF APPENDICES xix
1 INTRODUCTION 1
1.1 Background 1
1.2 Problem Statement 3
1.3 Objectives 3
1.4 Scope of Study 4
1.5 Importance of Study 5
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CHAPTER TITLE PAGE
2 LITERATURE REVIEW 6
2.1 General Overview of Pile Foundation Design 6
2.2 Pile Bearing Capacity Estimation Approaches 7
2.2.1 Interpretation of Data from Static Load
Test
8
2.2.2 Dynamic Analysis Methods Based On
Wave Equation Analysis
8
2.2.3 Dynamic Testing By Means of The Pile
Driving Analyzer (PDA)
9
2.2.4 Analysis By Using Static Formulas 9
2.2.5 Methods Using SPT N-Values 10
2.3 Review of Pile Bearing Capacity Equation 11
2.3.1 End Bearing Capacity 12
2.3.2 Skin Friction Capacity 13
2.3.2.1 The Method 14
2.3.2.2 The Method 15
2.3.2.3 The Method 16
3 METHODOLOGY 17
3.1 Phase One Research Data 19
3.1.1 Stage One Case Retrieval 19
3.1.2 Stage Two Data Interpretation 19
3.1.2.1 Data Acquiring From Soil
Investigation Report
19
3.1.2.2 Correlated Data From Soil
Investigation Report
20
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CHAPTER TITLE PAGE
3 METHODOLOGY (Contd)
3.1.2.3 Data Acquiring From Load Test
Report
23
3.1.3 Stage Three Analysis Preparation 23
3.2 Phase Two Pile Design 24
3.2.1 End Bearing Capacity (Qb) Design 25
3.2.1.1 Meyerhofs Method (1976) for
Estimating (Qb)
25
3.2.1.2 Vesics Method (1975) for
Estimating (Qb)
25
3.2.1.3 Janbus Method (1976) for
Estimating (Qb)
26
3.2.2 Skin Friction Capacity (Qs) Design in Sand 27
3.2.2.1 Meyerhofs Method for
Estimating (Qs)
27
3.2.2.2 Based on SPT Method for
Estimating (Qs)
28
3.2.3 Skin Friction Capacity (Qs) Design in Clay 28
3.2.3.1 Method (1977) for
Estimating (Qs)
29
3.2.3.2 Method (1972) for
Estimating (Qs)
30
3.3 Phase Three Research Analysis 31
3.3.1 Stage One Comparison Between
Redesign Bearing Capacity And Maintain
Load Test (MLT) Bearing Capacity
31
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CHAPTER TITLE PAGE
3 METHODOLOGY (Contd)
3.3.2 Stage Two Accuracy Analysis 32
3.4 Phase Four Pile Design 35
3.4.1 Stage One Accuracy Ratio Analysis 35
3.4.2 Final Stage Pile Design Method 35
4 RESULTS 36
4.1 Preparation of Design Parameter 37
4.1.1 Direct Design Parameter Values 37
4.1.2 Indirect Design Parameter Values 38
4.2 Sand Study Case 41
4.2.1 End Bearing Capacity Factor for Sand 41
4.2.2 Estimation of End Bearing Capacity for
Sand
45
4.2.3 Estimation of Skin Friction Capacity for
Sand
4.3 Cohesive Soils Study Case 54
4.3.1 End Bearing Capacity Factor for Silt 54
4.3.2 Estimation of End Bearing Capacity for
Silt
59
4.3.3 Estimation of Skin Friction Capacity for
Silt
59
5 ANALYSIS AND DISCUSSION 63
5.1 End Bearing Analysis for Sand Study Case 63
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CHAPTER TITLE PAGE
5 ANALYSIS AND DISCUSSION (Contd)
5.1.1 Comparison of Redesigned End Bearing
Capacity with Maintain Load Test (MLT)
End Bearing Capacity For Sand
63
5.1.2 Accuracy Analysis Ratio for Sand End
Bearing Estimation
66
5.2 End Bearing Analysis for Cohesive Soils Study
Case
70
5.2.1 Comparison of Redesigned End Bearing
Capacity with Maintain Load Test (MLT)
End Bearing Capacity for Silt
70
5.2.2 Accuracy Analysis Ratio for Silt End
Bearing Estimation
72
5.3 Skin Friction Analysis 75
5.3.1 Comparison of Redesigned Skin Friction
Capacity with Maintain Load Test (MLT)
Skin Friction Capacity
75
5.3.2 Accuracy Analysis Ratio for Skin Friction
Estimation
78
6 CONCLUSION 82
REFERENCES 85
APPENDICES 87
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LIST OF TABLES
TABLE NO. TITLE PAGE
2.1 Current methods for prediction of shaft resistance 13
3.1 Relationship between SPT N-value and Undrained Shear
Strength for clay
22
3.2 Group and classification for all analysis in all study cases 33
4.1 End Bearing design parameter taken directly from the
report
37
4.2 Skin Friction design parameter taken directly from thereport
38
4.3 - value correlated from SPT N-value for Schmertmann 39
4.4 - value correlated from SPT N-value for Peck, Hanson
and Thornburn
39
4.5 - value correlated from SPT N-value for Hatanaka and
Uchida
39
4.6 - value correlated from SPT N-value for Shioi and
Fukui
40
4.7 Pile design parameter calculated for overburden pressure 40
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TABLE NO. TITLE PAGE
4.8 Group A End bearing capacity factor (N'q) for sand
study case
41
4.9 Group B End bearing capacity factor (N'q) for sand
study case
42
4.10 Group C End bearing capacity factor (N'q) for sand
study case
43
4.11 Group D End bearing capacity factor (N'q) for sand
study case
44
4.12 Group A End Bearing capacity using Meyerhof, Vesicand Janbu for sand study case
46
4.13 Group B End Bearing capacity using Meyerhof, Vesic
and Janbu for sand study case
46
4.14 Group C End Bearing capacity using Meyerhof, Vesic
and Janbu for sand study case
47
4.15 Group D End Bearing capacity using Meyerhof, Vesic
and Janbu for sand study case
47
4.16 Group A Skin Friction capacity using Meyerhof for
length embedded in sand
50
4.17 Group B Skin Friction capacity using Meyerhof for
length embedded in sand
50
4.18 Group C Skin Friction capacity using Meyerhof for
length embedded in sand
51
4.19 Group D Skin Friction capacity using Meyerhof for
length embedded in sand
51
4.20 Group A End bearing capacity factor (N'c) for silt study
case
55
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TABLE NO. TITLE PAGE
4.21 Group B End bearing capacity factor (N'c) for silt study
case
56
4.22 Group C End bearing capacity factor (N'c) for silt study
case
57
4.23 Group D End bearing capacity factor (N'c) for silt study
case
58
4.24 Group A End Bearing capacity using Meyerhof, Vesic
and Janbu for silt study case
60
4.25 Group B End Bearing capacity using Meyerhof, Vesicand Janbu for silt study case
60
4.26 Group C End Bearing capacity using Meyerhof, Vesic
and Janbu for silt study case
61
4.27 Group D End Bearing capacity using Meyerhof, Vesic
and Janbu for silt study case
61
4.28 Skin friction capacity for cohesive soil study case 59
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LIST OF FIGURES
FIGURE NO. TITLE PAGE
2.1Bearing capacity factor,Nqfor piles penetrating into
sand 12
2.2 Relationship between the adhesion factor and
unconfined compressive strength, cu
14
2.3 Variation of coefficient with depth of pile
penetration
16
3.1 Study Methodology flowchart 18
3.2 Variation of with pile embedment length 31
3.3 The accuracy of method analysis for end bearing
capacity
34
3.4 The accuracy of method analysis for skin friction
capacity
34
4.1 Estimation of End Bearing capacity chart in sand for
P2 VP3 study case
48
4.2 Estimation of End Bearing capacity chart in sand for
AV 5 study case
48
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FIGURE NO. TITLE PAGE
4.3 Estimation of End Bearing capacity chart in sand for
SPT 7 study case
49
4.4 Estimation of Skin Friction capacity chart for Pt.1
study case
52
4.5 Estimation of Skin Friction capacity chart for Pt.2
study case
52
4.6 Estimation of Skin Friction capacity chart for P2 VP3
study case
53
4.7 Estimation of Skin Friction capacity chart for AV 5study case
53
4.8 Estimation of Skin Friction capacity chart for SPT 7
study case
54
4.9 Estimation of End Bearing capacity chart in silt for
Pt. 1 study case
62
4.10 Estimation of End Bearing capacity chart in silt for
Pt. 2 study case
62
5.1 Theory End Bearing and MLT capacity comparison
for P2 VP3 study case
65
5.2 Theory End Bearing and MLT capacity comparison
for AV 5 study case
65
5.3 Theory End Bearing and MLT capacity comparison
for SPT 7 study case
66
5.4 End Bearing / MLT Ratio for P2 VP3 study case 68
5.5 End Bearing / MLT Ratio for AV 5 study case 68
5.6 End Bearing / MLT Ratio for SPT 7 study case 69
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xvii
FIGURE NO. TITLE PAGE
5.7 Theory End Bearing and MLT capacity comparison
for Pt.1 study case
71
5.8 Theory End Bearing and MLT capacity comparison
for Pt.2 study case
72
5.9 End Bearing / MLT Ratio for Pt. 1 study case 74
5.10 End Bearing / MLT Ratio for Pt. 2 study case 74
5.11 Theory Skin Friction and MLT capacity comparison
for Pt.1 study case
75
5.12 Theory Skin Friction and MLT capacity comparison
for Pt.2 study case
76
5.13 Theory Skin Friction and MLT capacity comparison
for P2 VP3 study case
76
5.14 Theory Skin Friction and MLT capacity comparison
for AV 5 study case
77
5.15 Theory Skin Friction and MLT capacity comparisonfor SPT 7 study case
77
5.16 Skin Friction / MLT Ratio for Pt. 1 study case 79
5.17 Skin Friction / MLT Ratio for Pt. 2 study case 79
5.18 Skin Friction / MLT Ratio for P2 VP3 study case 80
5.19 Skin Friction / MLT Ratio for AV 5 study case 80
5.20 Skin Friction / MLT Ratio for SPT 7 study case 81
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LIST OF SYMBOLS
w - Soil moisture content
- Unit weight of soil
sat - Unit weight of saturated soil
w - Unit weight of water
cu - Undrained shear strength
L - Pile penetration length
D - Pile Depth
Dc - Pile critical depth (for skin resistance analysis)
Gs - Specified gravity of soil
v - Soil vertical effective stress / overburden pressure
Pa - Atmospheric pressure
Dr - Soil relative density
- Soil friction angle
- Soil-pile friction angle
Irr - Reduced rigidity index for the soil
fs - Unit skin friction / resistance
fb
- Unit end bearing / base resistance
Ncor - Corrected SPTN-value
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LIST OF APPENDICES
APPENDIX TITLE PAGE
A Soil Investigation Report for Pt.1 Study Case 87
Soil Investigation Report for Pt.2 Study Case 91
Soil Investigation Report for P2 VP3 Study Case 96
Soil Investigation Report for AV 5 Study Case 98
B Pile Driving Record for Pt.1 Study Case 100
Pile Driving Record for Pt.2 Study Case 101
Pile Driving Record for P2 VP3 Study Case 102
Pile Driving Record for AV 5 Study Case 103
Pile Driving Record for SPT 7 Study Case 104
C Load vs. Settlement Result for Pt.1 Study Case 105
Load vs. Settlement Result for Pt.2 Study Case 106
Load vs. Settlement Result for P2 VP3 Study Case 107
Load vs. Settlement Result for AV 5 Study Case 108
Load vs. Settlement Result for SPT 7 Study Case 109
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APPENDIX TITLE PAGE
D Sample Bearing Capacity calculation for Pt. 1 Study
Case
110
Sample Bearing Capacity calculation for Pt. 2 Study
Case
111
Sample Bearing Capacity calculation for P2 VP3
Study Case
112
Sample Bearing Capacity calculation for AV 5 Study
Case
113
Sample Bearing Capacity calculation for SPT 7 StudyCase
114
E Bearing Capacity Interpretation from MLT for All
Study Case
115
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CHAPTER 1
INTRODUCTION
1.1 Background
Piles are structural members commonly adopted to support structures when
suitable founding levels are generally deeper than 3m below the formation level. It also
adopted when shallow foundations are not suitable due to uneconomical or technically
not acceptable due to some stability problems or other peculiar site conditions.
Basically, loads from structures are transmit to lower level in the soil mass by friction
developed along the pile shaft or a direct application of load to a lower stratum through
the pile base. Precast concrete piles, pre-stressed spun piles, bored piles, jacked piles,
etc., are commonly used in the design and construction of pile foundation in Malaysia.
Other than types of material and methods of installation, piles also may be
classified with respect to their load transfer mechanisms. There are two ways they resist
the applied load which are by end bearing and skin friction. End bearing is the capacity
derived from the assistance of dense or hard stratum where the pile base lays on and
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skin friction is the capacity develops between the surface area of the pile and the
surrounding soil. In most cases, piles work in a combination of the two principles and
this type of piles are called end bearing or pile to set. However, there is sometimes the
soil condition is too weak where no dense or hard stratum is found. Therefore, only the
skin friction consider in design, then the pile would be called as a friction or floating
pile.
Generally, pile design is a science, but piling practice is an art, which requires a
lot of practical experiences and judgments input. The design of piles has become
increasingly specialized and relies upon a detailed knowledge of ground conditions,
properties of the types of pile, effects produced by loading, possible imperfections in
the pile and the effect on the structure. It is certainly very unwise to design without
contingencies of pile capacity for some unforeseen uncertainties or undetected defects,
especially when no previous experience of piling on similar ground conditions.
In Malaysia, an estimation of geotechnical bearing capacity of driven piles is
usually based on data obtained from Standard Penetration Test (SPT), which is
extensively carried out at site. It is a universal test applicable to all types of granular soil
and has been extensively calibrated for skin friction and end-bearing correlation. There
are many methods are available to estimate the end bearing and skin friction capacity of
piles according to soil properties.
Normally, verification of the design bearing capacity of a pile by load tests it at
site. It can be categorized in static and dynamic load test. An example of static load test
is Maintain Load Test (MLT) while Pile Driving Analyzer (PDA) is an example of
dynamic load test.
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1.2 Problem Statement
In order to verify the design bearing capacity of a pile, load tests are performed
on site either by static load test or dynamic load test. Since numerous equations in the
dynamic load test are not consistently reliable, the most reliable method to verify the
actual bearing capacity of piles is by static load test.
Practically in most project constructed in Malaysia, the estimation of pile
bearing capacity are normally under estimated compared to actual performance of the
pile. It can be seen through the settlement of pile from Maintain Load Test results are
excessively lower than allowable settlements limited by specification.
It is proper and wise to have reasonable conservative pile foundation design with
adequate contingencies against some possible worst condition that cannot be assessed
with a high degree of certainty especially when detailed Soil Investigation and
knowledge of local geology are not available. However, an excessive conservative
design or even an overdesign will produce an uneconomical cost for foundation.
1.3 Objectives
This study aim is to give a guideline for pile designer to choose which method is
suitable for a certain type of soil properties and condition. There is four objective in this
study that need to be achieved in order to conclude which pile static formula suitable for
a given soil condition:
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Method (1985) and Method (1972). The selection of these analysis methods is base on
the most preferable design method use in Malaysia pile design practice.
1.5 Importance of Study
The importance of this study is to give a guideline for pile designer to come out
with economical pile design. A lower bearing capacity estimated means a larger pile
size or a deeper pile penetration is needed. This is laterally causes an unnecessary larger
piling cost.
By comparing the results from various methods, the different can be reduced to
optimize the ultimate pile bearing capacity and the cost for foundation is competitive
especially in a proposal for a tender project.
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CHAPTER 2
LITERATURE REVIEW
In this chapter, three main sub topics will be presented. These include literature
review on overview of pile foundation design, pile bearing capacity estimation
approaches and review of pile bearing capacity equation. Information for this chapter is
based on published literature on topics related to this study with the relevant
publications listed in the references.
2.1 General Overview of Pile Foundation Design
A comprehensive overview of pile foundation design focuses on site
investigation to produce sufficient information of the underground condition for design,
factors considered in selection of pile types for a project and miscellaneous piling issues
commonly encountered by engineers involved in piling works. Estimation of pile
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bearing capacity must take into consideration of the pile behavior and change of soil
properties due to method of installation.
Basically, pile design should comply with three basic requirements (Neoh,
1998):
i. Ultimate limit state, i.e., adequate geotechnical and structural capacity to resistthe design ultimate loads.
ii. Serviceability limit state, i.e., lateral deflection, vertical and differentialsettlement is within the tolerable limits at design loads.
iii. Durability aspects, i.e., pile should be durable and not suffer deterioration duringthe design life (>75 years) by aggressive chemicals.
2.2 Pile Bearing Capacity Estimation Approaches
Pile bearing capacity can be classified into structural capacity and geotechnical
capacity. The analysis and design of pile foundation should be based on both criteria
(Gofar N. and Kassim K.A., 2007). Geotechnical, the load is transferred into the soil
through piles by end bearing or by skin friction between the soils in contact with the
surface of pile. In most cases, piles work on a combination of the two principles.
Bearing capacity of piles can be estimated by five approaches as follows:
a) Interpretation of data from static load tests,b) Dynamic analysis methods based on wave equation analysis,c) Dynamic testing by means of the Pile Driving Analyzer (PDA),d) Analysis by using static formulas,e) Methods using SPT N-values.
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2.2.1 Interpretation of Data from Static Load Test
The most reliable method to determine the load capacity of a pile is to load test
it. This consists in driving the pile to the design depth and applying a series of loads. In
view of the uncertainties involved in the analysis and design of pile foundations, it has
become customary, and in many cases mandatory, to perform static load test.
In engineering practice, static load test will be carried out after the pile is driven
to ensure the settlement do not exceed allowable settlement as per specification
requirement. Due to limited time for design process, time consuming for this test is not
practicable for proposal of open tender design and build projects and ordinary or small
projects.
2.2.2 Dynamic Analysis Methods Based On Wave Equation Analysis
Dynamic analysis applied to piles while it is being driven into the ground at site
has resulted in numerous equations being presented to the engineering profession. This
method is based on wave mechanics for the hammer- pile-soil system. The uncertainty
in the hammer impact effect, as well as changes in soil strength from the conditions at
the time of pile driving, and also at the time of loading, causes uncertainties in bearing
capacity determination. Moreover, a wave equation analysis requires input assumptions
that can significantly bias the results.
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2.2.3 Dynamic Testing By Means Of the Pile Driving Analyzer (PDA)
Dynamic testing methods are based on monitoring acceleration and strain near
the pile head during driving. From these measurements, the pile capacity can be
estimated by means of the Pile Driving Analyzer (PDA) and numerical analysis of the
data. Unfortunately, the PDA can only be used by an experienced person, and the test
results apply essentially to the field-testing considerable situation. One considerable
limitation is that the capacity estimation is not available until the pile is driven.
In addition, general guideline for this test required hammer weight is about 1.5%
of the pile capacity (Hussein at el., 1996). As an example, 30 tonne hammer will be
required if a pile is designed to have capacity of 2000 tonne. It is difficult to lift up the
30 tonne hammer and strike it onto the pile.
2.2.4 Analysis By Using Static Formulas
For static analysis, one of the earliest equations was proposed by Terzaghi
(1943) and followed by different investigators such as Meyerhof (1956, 1976),
Berezantsev et al. (1961), Vesic (1963, 1972), Janbu (1976) and others. The angle of
internal friction, of the soils is needed for Nqvalues as well as the cohesion, Cof the
soils. Immediate controversy arises since some designers use undrained stress
parameters, whereas others use effective stress values (Bowles, J.E., 1996).
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Since all the theory involves a rather approximate -Nq relationship, the
difficulty of determining a reliable and representative in-situ value of the friction angle,
arises. This creates doubts about relying on the bearing capacity theory in pile
foundation design.
2.2.5 Methods Using SPT N-Values
The SPT is one of the earliest and still the most commonly used in-situ test.
However, the results from SPT are only applicable for pile capacity estimation
embedded in cohesionless soils which contradicts in most cases of soil profile with
different layers of soils. One of the reason is SPT does not give reliable estimation of
pile capacity in cohesive soils due to ignorance of excessive pore water pressure
generated during the test. Therefore, CPT must be conducted in cohesive soils with low
permeable properties such as clay and silt in order to get a reliable result for estimation
of pile capacity.
N. Shariatmadari et al. (2008) believed some problems and limitations are
included with the SPT with respect to interpretation and repeatability. These are due to
the uncertainty of the energy delivered by various SPT hammers to the anvil system and
also with the test procedure.
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2.3 Review of Pile Bearing Capacity Equation
Methods for estimating the capacity of driven piles can be divided into two
broad categories, based on parameters obtained by laboratory tests (friction angle; ,
unit weight; , undrained shear strength; Suand unconfined compressive strength; Cu)
or on the results of in situ tests. In the latter approach, the most common test is the
Standard Penetration Test (SPT) N-Values. Estimation of end bearing and skin friction
capacity is done separately and differently in different types of soil.
The ultimate bearing capacity of a single pile (Qu) is derived from the
mechanism of end bearing capacity or base resistance (Qb) and friction capacity or shaft
resistance (Qs):
The end bearing derived from the bearing capacity of soil just below the pile tip
and is written as Qb= qbAb, where Abis the cross-sectional area of the pile base. The
term Qscan be evaluated based on the unit skin friction or adhesion between the pile
shaft and the soil which may vary with depth and the area of the pile shaft, thus the skin
friction capacity is written as Qs = fsAs, where Asis pile surface area in contact with
soil. Therefore, the ultimate bearing capacity of a single pile is rewritten as:
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2.3.1 End Bearing Capacity
One of the earliest end-bearing capacity equations was proposed by Terzaghi
(1943) with Nc, Nqand Nare bearing capacity factors. The Ncand Nqwere adjusted to
shape and depth factors while N term is often neglected when the pile base width Bis
not large. The end bearing capacity of the pile is written as:
However, the computed end bearing capacity varies widely because there is little
agreement on what numerical values to use for the bearing capacity factors Nq. Figure
2.1 shows the variation of Nq based on Terzaghi (1943), Berezantsev et al. (1961),
Hansen (1951) and Meyerhof (1976).
Figure 2.1:Bearing capacity factor, Nqfor piles penetrating into sand
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2.3.2 Skin Friction Capacity
The skin friction capacity is computed using both a combination of total and
effective, or only effective, stresses. Some evidence exists that use only effective
stresses gives a better correlation of prediction of load tests (Bowles J.E., 1996). Three
methods currently used for obtaining skin friction capacity of pile are methods using ,
and for the factors are presented in Table 2.1.
Table 2.1: Current methods for prediction of shaft resistance
In general, overburden pressure, voincreases as depth increases. For the case of
pile driven in sand, the overburden pressure assumed to remain constant at a certain
depth called a critical depth; Dc. McCarthy (1977) proposed the critical depth for loose
sand is about 10 times the diameter of pile while for dense sand is 20 times the diameter
of pile. However, the critical depth is an idealization that has neither theoretical nor
reliable experimental support, and contradicts physical laws.
The axial capacity of piles driven into sand is considerable uncertainty, and
design rules are generally not consistent with the physical processes involved. Designguidelines such as those published by the American Petroleum Institute (API, 1984,
1991) are generally not consistent with the physical processes that dictate actual pile
capacity. For example, the experimental observation of a gradual reduction in the rate of
increase of pile capacity with embedment depth is allowed for by imposing limiting
values of end-bearing and shaft friction beyond some critical depth.
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2.3.2.1The Method
The Method was initially proposed by Tomlinson (1971) which includes both
adhesion cand friction for piles embedded in clay. The average value of depends
upon the unconfined compressive strength is suggested by Peck et al. (1974) as shown
on Figure 2.2.
Figure 2.2:Relationship between the adhesion factor and unconfined compressive
strength, cu
With soft clays, there is a tendency for the clay to come in close contact with the
pile, in which case adhesion is assumed to be equal to cohesion (= 1.0). In the case of
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stiff clays, pile driving disturbs surrounding soil and may cause a small open space to
develop between the clay and the pile. Thus, adhesion is smaller than cohesion ( 300
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3.1.2.3Data Acquiring From Load Test Report
The information taken from Pile Load Test Report will be used later on in a pile
capacity comparison. The information taken from Pile Load Test Report is the location
of test pile on site, pile type and size, pile length and pile penetration depth. End
Bearing and Skin Friction capacity were interpreted by using Prof. Chin F. K.s method.
3.1.3 Stage Three Analysis Preparation
Practically there are many of pile and soil condition which the design differ
between one and another. Hence following through the scope of this study, the pile
design has to be limited to analyze case that only meets the two conditions or scope.
The first condition is driven type of pile either R.C square or Spun pile. And
secondly pile that driven in sand and cohesive soils condition. From the entire pile
construction case gather, only the pile cases meet the mention scope criteria will be
taken into account for this study.
The entire pile cases will be analyzed base on 2 types of soil condition, sand and
cohesive soils. Each pile cases will be sort out and group according to these 2
conditions based on information from soil borelog in Soil Investigation Report.
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The part should be look out for this purpose in the Soil Investigation Report is
the soil description. From the study, provided information in that part will help to
determine which part of condition the cases should be analyzed.
3.2 Phase Two Pile Design
After the entire cases information and data were organize and well group into
the designated analyze procedure in the phase one, now we can proceed to the back
bone of this study which is in phase two, the pile design.
Generally in this study, piles are design base on 2 groups which is sand and
cohesive soils. However technically, each group of cases can be divided onto 2 type of
analysis which is the end-bearing resistance and skin resistance because these two
analyses together are the main component in pile ultimate load carrying capacity.
In fine soil condition for this study, it can be detailed explain that there are 2
condition of soil which are silt and clay. By this, in total it will be 4 aspect of analyze in
each pile will later on give 4 conclusion of this study that are end-bearing of pile in sand
condition, skin resistance of pile in sand condition, end-bearing of pile in silt condition
and finally skin resistance of pile in clay condition.
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3.2.1 End Bearing Capacity (Qb) Design
The estimation of theoretical end-bearing capacity (Qb) for this study is
analyzed using three types of method which is Meyerhofs Method (1976), Vesics
Method (1975), and Janbus Method (1976).
3.2.1.1Meyerhofs Method (1976) for Estimating (Qb)
The load-carrying capacity of the pile point (Qb) suggested by Meyerhof (1976)
can be divided onto two condition, Sand and Clayey soil. For sandy soil, the equation
used for calculating the value ofNqis:
3.2.1.2Vesics Method (1975) for Estimating (Qb)
Vesic (1975) proposed a method for estimating the pile point bearing capacity
based on the theory of expansion of cavities. According to this theory, the equation used
for calculating the value ofNqis:
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According to Vesics Theory, Irr equal to reduce rigidity index for the soil.
When the volume does not change especially for dense sand, the reduced rigidity index
for the soil is same as the rigidity index for the soil,Ir =Irr.
The values of the Ir can be estimated from laboratory consolidation and triaxial
tests corresponding to the proper stress levels. For preliminaries use, it is recommended
to use Ir value range from 70 to 150 for sand and 50 to 100 for silts. However for
purpose of this study, the value of reduced rigidity index for soil is 80.
3.2.1.3Janbus Method (1976) for Estimating (Qb)
In Janbu (1976), computesNq(with angle in radians) as follows:
Angle is a failure surface at the pile tip which varies from 60ofor soft clay to
about 105ofor dense sand. For practical use, it is recommended to use value in a range
between 60 to 90. However for the purpose of this study, both sand and silt soil
condition are proposed to use 75 for value because the condition of soil considered
loose and soft respectively.
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3.2.2 Skin Friction Capacity (Qs) Design in Sand
The estimation of theoretical skin friction capacity (Qs) in sand for this study is
analyzed using two types of method which are Meyerhofs Method and Based on SPT
Method.
3.2.2.1Meyerhofs Method for Estimating (Qs)
Meyerhof proposed frictional resistance (Qs) for sand derived from the soil-pile
interface as:
It has been observed that the nature of variation offsincreases with depth more
or less linearly to a depth of Dc and remain constant thereafter due to overburden
pressure v effects. The magnitude of the critical depth Dc may be 10 to 20 pile
diameter . For the purpose of this study, the critical depth estimation is using a
conservative critical depth which isDc=20.
The unit frictionfs= Ksvtan is used for depth between 0 to Dc where Ksis
effective earth coefficient and is soil-pile friction angle.
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The value of from various investigation appear to be in the range from 0.5 to
0.8. For purpose of this study the value of is 0.6. The value of lateral earth
pressure coefficient, Ksfor this study is using Ko= 1 sin
3.2.2.2Based on SPT Method for Estimating (Qs)
The skin friction capacity of the pile depends on the type of piles. In this study,
all piles selected are close-ended pile which causes large displacement of soil.
Therefore the friction is estimated using fs= 2.0 Nwhere N is the average SPT value
along the embedded length of pile.
3.2.3 Skin Friction Capacity (Qs) Design in Clay
The estimation of theoretical skin friction capacity (Qs) in clay for this study is
analyzed using two types of method which are Method (1971) and Method (1972).
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3.2.3.1 Method (1977) for Estimating (Qs)
According to the Method, the average unit skin friction in clayey soils can
be represented by the equation:
fs= cu(kN/m2)
Where is the adhesion factor
cu is the undrained shear strength of soil.
The undrained shear strength for the different layers of soil strata is obtained
from the relationship between SPT N-value and Undrained Shear Strength for Clay
(Table 3.1).
Value for adhesion factor is determined from API (1984) suggestion with the
assumption of soft clay, there is a tendency for the clay to come in close contact with
the pile, in which case adhesion is assumed to be equal to cohesion (= 1.0). In the
case of stiff clay, pile driving disturbs surrounding soil and may cause a small open
space to develop between the clay and the pile. Thus, adhesion is smaller than cohesion
(< 1.0). The above explanation is expressed and summarized as below:
For cu25 kN/m2:
= 1.0
For cu70 kN/m2:
= 0.5
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For 25 kN/m2 < cu < 70 kN/m
2:
3.2.3.2 Method (1972) for Estimating (Qs)
This method is proposed by Vijayvergiya and Focht (1972) based on theassumption that the displacement of soil caused by pile driving results in a passive
lateral pressure at any depth and that the average unit skin friction is:
fs= (v+ 2cu)
Where is a dimensionless coefficient
v is the average effective overburden pressure along the pile shaft
cu is the average undrained shear strength along the pile shaft.
The value of changes with the depth of penetration of the pile (Figure 3.2).
Thus, the total frictional resistance may be calculated as:
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3.3 Phase Three Research Analysis
3.3.1 Stage One Comparison Between Redesign Bearing Capacity AndMaintain Load Test (MLT) Bearing Capacity
In this phase, all the redesign bearing capacity result will be gather according to
its soil condition and group (Table 3.2). After that, each redesign result will be
compared to the bearing capacity value from Maintain Load Test (MLT) in load test
report.
Figure 3.2: Variation of with pile embedment length
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3.3.2 Stage Two Accuracy Analysis
For end bearing, a method used in this comparison is by plotting all the
redesigned capacity obtained by analysis methods and soil friction angle () obtained by
equations that explained earlier. Each depends on correctedN-value by four equations
except for Schmertmann where only one equation has been used.
A reference line is drawn horizontally representing Maintain Load Test (MLT)
end bearing capacity for each study case (Figure 3.3). This reference line will show
which method of design is more accurate based on the Maintain Load Test (MLT) end
bearing capacity.
For skin friction, a method used in this comparison is also by plotting all the
redesigned capacity obtained by three analysis methods which are - Method and
Method for piles embedded in cohesive soils whereas - Method and Based on SPT
Method for piles embedded in granular soils.
Same as end bearing, a reference line is drawn horizontally representing
Maintain Load Test (MLT) skin friction capacity for each study case (Figure 3.4). This
reference line will show which method of design is more accurate based on the
Maintain Load Test (MLT) skin friction capacity.
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Table 3.2: Group and classification for all analysis in all study cases
Study Case Soil TypeSoil Friction Angle
Correlation, (Group)
Bearing Capacity
Analysis
Schmertmann
(Group A)
Peck, Hanson and Thornburn
(Group B)
End Bearing
Capacity (Qb)
Hatanaka and Uchida
(Group C)
Cohesionless
SoilSand
Shioi and Fukui
(Group D)
Skin Friction
Capacity (Qs)
Schmertmann
(Group A)
Peck, Hanson and Thornburn
(Group B)
Hatanaka and Uchida
(Group C)
Silt
Shioi and Fukui
(Group D)
End Bearing
Capacity (Qb)Cohesive
Soil
Clay -Skin Friction
Capacity (Qs)
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Figure 3.3: The accuracy of method analysis for end bearing capacity
Figure 3.4: The accuracy of method analysis for skin friction capacity
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3.4 Phase Four Pile Design
3.4.1 Stage One Accuracy Ratio Analysis
In this stage, all the information from the analysis is gather and appropriately
presented in graph that have been mention before according to its cases and analysis.
Base on the information, the trend of each scatter chart will be studied.
The accuracy of each method analyzed in each group is studied and discussed it
in here, in details. The study of accuracy on each design method means the closest ratio
to value 1.0, play an importance role here as it will be the main criteria for the final
stage of study.
3.4.2 Final Stage Pile Design Method Recommendations
Pile design method recommendations part is the final step of this study in which
the conclusion will derive all 4 recommendations regarding on each pile analysis result.
This recommendation is based on the First Approach and Second Approach in
which later on will give a guideline which design method is more accurate or preferable
on each analysis as shown on Table 3.2. This guideline will also provide which
correlation for soil friction angle () and correctedN-value (Ncor) is suitable to be used
with which design method.
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CHAPTER 4
RESULTS
This study is conducted based on information taken from 3 locations in
Peninsular Malaysia. All the Soil Investigation Report and Load Test Report are based
on actual pile constructed at those 3 locations.
The total number of pile information that been used in this analysis is 5 which is
2 from Bertam, Penang, another 2 is from Kinrara, Kuala Lumpur, and finally 1 pile is
from Pekan, Pahang. Details report for each study case in Appendix A.
For sand study case, piles from 2 location which is Kinrara and Pekan sites are
been used for analysis. Whereas for silt study case, piles from Bertam is been used for
analysis.
For sand study case, 3 methods of analysis End-Bearing and 2 method of
analysis Skin Friction are been used. For silt study case, also 3 method of analysis End-
Bearing and 2 method of analysis Skin Friction are been used.
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4.1 Preparation of Design Parameter
Before all the redesign of the pile according to its length and soil condition
based from gather information in the report, first the design parameter value needs to be
provided base on Soil Investigation Report and Load Test Report either directly from
the report or indirectly which is some of the formula or correlation needs to be applied
to provide the needs design parameter value.
4.1.1 Direct Design Parameter Values
All the important design parameter that needs to be provided as been explaining
in methodology is gathering and groups it into its group of analysis. Below is the
summarize value that only needed for piles design analysis for End Bearing capacity
(Table 4.1) and Skin Friction capacity (Table 4.2). Pile embedment length for each
study case is according to pile driving record in Appendix B.
Table 4.1: End Bearing design parameter taken directly from the report
Pile
Ref. No.
Penetration
Depth, D(m)
SPT N-Value
(Ave 4B & 10B)
Undrained Shear
Strength, cu
(k )N/m2
Pt. 1 34.2 42 300
Pt. 2 24.9 12 118
P2 VP3 10.5 36 -
AV 5 16.8 34 -
SPT 7 42.0 37 -
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Table ric n p tak he
Ref. No.
P
B )
Length,
L L
Crit
D )
Average SPT
N-Value
4.2: Skin F
ile Size,
tion desig arameter
Length,
en directly from t
ical Depth,
report
Pile
(mm s(m) c(m) c(m
Pt. 1 300 21.0 13.5 6.0 6.9
Pt. 2 250 21.0 6.0 5.0 7.1
P2 VP3 600 10.5 - 12.0 25.1
AV 5 600 9.0 7.5 12.0 30.0
SPT 7 350 18.816.5 25.5 7.0
Note: Lsis friction length contact with sand
Lcis friction length contact with cohesive soils
.1.2 Indirect Design Parameter Values
son and Thornburn (1974), Hatanaka and Uchida
996) and Shioi and Fukui (1982).
and Group D need an
corwhereas Group A can use the correlation directly using Nf.
gn analysis for
nd-bearing capacity is in Table 4.3, Table 4.4, Table 4.5 and Table 4.6.
4
In this study Soil Friction Angle () value is derived using 4 types of correlation
by Schmertmann (1975), Peck, Han
(1
As explain on the methodology, the soil friction angle value is divided into 4
groups according to its correlation method. Group B, Group C
N
The summarized soil friction angle that only needed for piles desi
e
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Table 4.3 alue cor om SPT N-v r chmertmann
L r:- v related fr alue fo S
Pile ength - Nco
Ref. No. (m) 1Pt. 1 34.2 33.9
Pt. 2 24.9 25.4
P2 VP3 10.5 41.3
AV 5 16.8 37.9
SPT 7 42.0 30.9
Table 4. ue co from
L T a co Nc
4:- val rrelated SPT N-value for Peck, Hanson and Thornburn
Pile ength SP NcorrectedV lue (N r) - orR . Liao Skempton Peck Seedef. No (m) 1 2 3 4
Pt. 1 34.2 17 12 17 1 32.0 30.6 32.0 27.4
Pt. 2 24.9 5 4 6 2 28.7 28.4 28.8 27.7
P2 VP3 10.5 25 24 28 23 34.2 34.0 35.0 33.6
AV 5 16.8 20 17 22 14 32.7 32.2 33.4 31.3
SPT 7 42.0 13 9 12 4 30.9 29.6 30.6 28.2
Tabl valu ated f -value for Hatanaka and Uchida
L T a co Nc
e 4.5:- e correl rom SPT N
Pile ength SP NcorrectedV lue (N r) - orR . Liao Skempton Peck Seedef. No (m) 1 2 3 4
Pt. 1 34.2 17 12 17 1 38.3 35.4 38.3 24.3
Pt. 2 24.9 5 4 6 2 30.4 29.2 30.8 26.2
P2 VP3 10.5 25 24 28 23 42.3 41.9 43.6 41.2
AV 5 16.8 20 17 22 14 39.8 38.7 40.9 36.9
SPT 7 42.0 13 9 12 4 36.2 33.1 35.5 28.7
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Ta - value correlated from SPT N-value for Shioi and Fukui
L T a co Nc
ble 4.6:
Pile ength SP NcorrectedV lue (N r) - orR . Liao Skempton Peck Seedef. No (m) 1 2 3 4
Pt. 1 34.2 17 12 17 1 26.0 24.3 26.0 20.3
Pt. 2 24.9 5 4 6 2 21.9 21.5 22.1 20.7
P2 VP3 10.5 25 24 28 23 29.0 28.7 30.0 28.1
AV 5 16.8 20 17 22 14 27.0 26.3 27.9 25.1
SPT 7 42.0 13 9 12 4 24.7 23.1 24.3 21.4
Below is the summarized value that only
eeded for piles design analysis (Table 4.7).
Table 4.7: esign par ulated for overburden pressure
Ref. No.
De D
(
The value of overburden pressure (v) is calculated by multiply the soil unit
weight () with level depth. Base from the ground water level information, the soil is
considered as saturated at level of analysis.
n
Pile d ameter calc
Pile pth,
(m)
vat DkN/m
2)
Pt. 1 34.2 606.0
Pt. 2 24.9 471.0
P2 VP3 10.5 199.5
AV 5 16.8 291.0
SPT 7 42.0 760.5
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Table 4.9:Group B End bearing capacity factor (N'q) for sand study case (contd
Peck, Hanson and Thornburn N'q - 1PileRef. No. 1 2 Meyer Vesic Janbu MP2 VP3 34.2 34.0 30.46 68.01 21.29 2
AV 5 32.7 32.2 25.41 48.72 18.11 2
SPT 7 30.9 29.6 20.58 41.13 15.01 1
Table 4.9:Group B End bearing capacity factor (N'q) for sand study case (contd
Pile Peck, Hanson and Thornburn N'q - 3Ref. No. 3 4 Meyer Vesic Janbu MP2 VP3 35.0 33.6 33.47 73.11 23.15 2
AV 5 33.4 31.3 27.54 51.84 19.46 2
SPT 7 30.6 28.2 19.80 39.85 14.50 1
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Table 4.10:Group C End bearing capacity factor (N'q) for sand study case (cont
Hatanaka and Uchida N'q - 1PileRef. No. 1 2 Meyer Vesic Janbu MP2 VP3 42.3 41.9 90.16 143.46 55.83 8
AV 5 39.8 38.7 62.32 91.93 40.23 5
SPT 7 36.2 33.1 38.92 66.93 26.48 2
Table 4.10:Group C End bearing capacity factor (N'q) for sand study case (cont
Hatanaka and Uchida N'q - 3PileRef. No. 3 4 Meyer Vesic Janbu MP2 VP3 43.6 41.2 108.36 160.13 65.71 7
AV 5 40.9 36.9 73.60 102.08 46.64 4
SPT 7 35.5 28.7 35.45 62.60 24.37 1
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Table 4.11:Group D End bearing capacity factor (N'q) for sand study case (cont
Shioi and Fukui N'q - 1PileRef. No. 1 2 Meyer Vesic Janbu MP2 VP3 29.0 28.7 16.46 40.64 12.30 1
AV 5 27.0 26.3 13.27 28.13 10.15 1
SPT 7 24.7 23.1 10.39 22.35 8.15
Table 4.11:Group D End bearing capacity factor (N'q) for sand study case (cont
Shioi and Fukui N'q - 3PileRef. No. 3 4 Meyer Vesic Janbu MP2 VP3 30.0 28.1 18.45 44.97 13.61 1
AV 5 27.9 25.1 14.59 30.64 11.04 1
SPT 7 24.3 21.4 9.94 21.41 7.84
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4.2.2 Estimation of End Bearing Capacity for Sand
The End Bearing capacity (Qb) in sand is analyzed using the value of Nq
obtained from the above. The result is shown on Table 4.12 for analysis on Group A,
Table 4.13 for analysis on Group B, Table 4.14 for analysis on Group C and finally
Table 4.15 is for analysis on Group D. All of these data are presented in graph as shown
in Figure 4.1, Figure 4.2 and Figure 4.3 for each sand case study.
4.2.3 Estimation of Skin Friction Capacity for Sand
The Skin Friction capacity (Qs) in sand is redesigned using Meyerhofs Method
(1976). The result is shown on Table 4.16 for analysis on Group A, Table 4.17 for
analysis on Group B, Table 4.18 for analysis on Group C and finally Table 4.19 for
analysis on Group D. All of these data are presented in scatter chart with combination of
and method as shown in Figure 4.4, Figure 4.5, Figure 4.6, Figure 4.7 and Figure
4.8 for each study case.
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Table 4.12:Group A End Bearing capacity using Meyerhof, Vesic and Janbu for san
End Bearing- 1 (kN)PileRef. No. Meyer Vesic Janbu
P2 VP3 4364 7362 2746
AV 5 3967 6389 2632
SPT 7 1504 3007 1096
Table 4.13:Group B End Bearing capacity using Meyerhof, Vesic and Janbu for san
End Bearing- 1 (kN) End Bearing - 2 (kN) End Bearing - 3 (kN) PileRef. No. Meyer Vesic Janbu Meyer Vesic Janbu Meyer Vesic Janbu
P2 VP3 1719 3838 1201 1668 3749 1170 1889 4126 1307
AV 5 2092 4010 1491 1950 3794 1401 2266 4267 1602
SPT 7 1506 3011 1098 1298 2658 962 1449 2917 1061
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Table 4.14:Group C End Bearing capacity using Meyerhof, Vesic and Janbu for san
End Bearing- 1 (kN) End Bearing - 2 (kN) End Bearing - 3 (kN) PileRef. No. Meyer Vesic Janbu Meyer Vesic Janbu Meyer Vesic Janbu
P2 VP3 5088 8096 3151 4792 7804 2988 6115 9036 3708
AV 5 5130 7567 3312 4414 6862 2898 6058 8403 3839
SPT 7 2849 4899 1938 1944 3690 1379 2595 4582 1784
Table 4.15:Group D End Bearing capacity using Meyerhof, Vesic and Janbu for san
End Bearing- 1 (kN) End Bearing - 2 (kN) End Bearing - 3 (kN) PileRef. No. Meyer Vesic Janbu Meyer Vesic Janbu Meyer Vesic Janbu
P2 VP3 929 2294 694 896 2220 672 1041 2537 768
AV 5 749 1587 573 690 1472 532 823 1729 623
SPT 7 586 1261 460 495 1066 395 561 1208 442
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Figure 4.1: Estimation of End Bearing capacity chart in sand for P2 VP3 study case
Figure 4.2:Estimation of End Bearing capacity chart in sand for AV 5 study case
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Figure 4.3:Estimation of End Bearing capacity chart in sand for SPT 7 study case
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Table 4.16: Group A Skin Friction capacity using Meyerhof for length embedded
Skin Friction (kN)Pile
Ref. No.Meyerhof - 1
P2 VP3 594
AV 5 884
SPT 7 864
Table 4.17: Group B Skin Friction capacity using Meyerhof for length embedded
Skin Friction (kN)Pile
Ref. No.Meyerhof - 1 Meyerhof - 2 Meyerhof - 3 Meye
P2 VP3 642 634 630
AV 5 924 919 912
SPT 7 863 862 864
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Table 4.18: Group C Skin Friction capacity using Meyerhof for length embedded
Skin Friction (kN)Pile
Ref. No.Meyerhof - 1 Meyerhof - 2 Meyerhof - 3 Meye
P2 VP3 576 542 532
AV 5 856 827 745
SPT 7 846 850 825
Table 4.19: Group D Skin Friction capacity using Meyerhof for length embedded
Skin Friction (kN)Pile
Ref. No.Meyerhof - 1 Meyerhof - 2 Meyerhof - 3 Meye
P2 VP3 647 646 644
AV 5 919 925 926
SPT 7 830 825 846
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Figure 4.4: Estimation of Skin Friction capacity chart for Pt.1 study case
Figure 4.5: Estimation of Skin Friction capacity chart for Pt.2 study case
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Figure 4.6: Estimation of Skin Friction capacity chart for P2 VP3 study case
Figure 4.7: Estimation of Skin Friction capacity chart for AV 5 study case
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Figure 4.8: Estimation of Skin Friction capacity chart for SPT 7 study case
4.3 Cohesive Soils Study Case
4.3.1 End Bearing Capacity Factor for Silt
The End bearing capacity factor in cohesive soils (Nc) is calculated using three
types of methods which are Meyerhofs Method (1976), Vesics Method (1975), and
Janbus Method (1976) for all 4 groups of soil friction angle. The result is shown on
Table 4.20 for analysis on Group A, Table 4.21 for analysis on Group B, Table 4.22 for
analysis on Group C and finally Table 4.23 is for analysis on Group D.
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Table 4.20:Group A End bearing capacity factor (N'c) for silt study case
N'c - 1PileRef. No.
Schmertmann
1 Meyer Vesic JanbuPt. 1 33.9 41.9 79.1 29.0
Pt. 2 25.4 21.3 48.1 16.1
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Table 4.21:Group B End bearing capacity factor (N'c) for silt study case (contd
Peck, Hanson and Thornburn N'c - 1PileRef. No. 1 2 Meyer Vesic Janbu
Pt. 1 32.0 30.6 35.49 70.90 25.11
Pt. 2 28.7 28.4 27.32 58.74 20.02
Table 4.21:Group B End bearing capacity factor (N'c) for silt study case (contd
Peck, Hanson and Thornburn N'c - 3PileRef. No. 3 4 Meyer Vesic Janbu
Pt. 1 32.0 27.4 35.55 70.99 25.14
Pt. 2 28.8 27.7 27.57 59.14 20.17
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Table 4.22:Group C End bearing capacity factor (N'c) for silt study case (cont'd
Hatanaka and Uchida N'c - 1PileRef. No. 1 2 Meyer Vesic Janbu
Pt. 1 38.3 35.4 63.31 100.85 41.37
Pt. 2 30.4 29.2 31.23 64.84 22.48
Table 4.22:Group C End bearing capacity factor (N'c) for silt study case (cont'd
Hatanaka and Uchida N'c - 3PileRef. No. 3 4 Meyer Vesic Janbu
Pt. 1 38.3 24.3 63.57 101.08 41.52
Pt. 2 30.8 26.2 32.18 66.24 23.07
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Table 4.23:Group D End bearing capacity factor (N'c) for silt study case (cont'd
Shioi and Fukui N'c - 1PileRef. No. 1 2 Meyer Vesic Janbu
Pt. 1 26.0 24.3 22.34 50.06 16.81
Pt. 2 21.9 21.5 16.87 39.07 13.17
Table 4.23:Group D End bearing capacity factor (N'c) for silt study case (cont'd
Shioi and Fukui N'c - 3PileRef. No. 3 4 Meyer Vesic Janbu
Pt. 1 26.0 20.3 22.38 50.14 16.84
Pt. 2 22.1 20.7 17.03 39.42 13.27
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4.3.2 Estimation of End Bearing Capacity for Silt
The End Bearing capacity (Qb) in silt is analyzed using the value of Nc
obtained from the above. The result is shown on Table 4.24 for analysis on Group A,
Table 4.25 for analysis on Group B, Table 4.26 for analysis on Group C and finally
Table 4.27 is for analysis on Group D. All of these data are presented in graph as shown
in Figure: 4.9 and Figure 4.10 for each silt case study.
4.3.3 Estimation of Skin Friction Capacity for Silt
The Skin Friction capacity (Qs) in silt is redesigned using 2 types of methods
which are Method (1971) and Method (1972). The result is shown on Table 4.28
below. All of these data are presented in scatter chart with combination of Meyerhofs
Method as shown in Figure 4.4, Figure 4.5, Figure 4.6, Figure 4.7 and Figure 4.8 foreach study case.
Table 4.28:Skin friction capacity for cohesive soil study case
Skin Friction (kN)Pile
Ref. No.
Length, Lc
(m) - Method - MethodPt. 1 13.5 1542 1126Pt. 2 6.0 115 209
AV 5 7.5 643 1543
SPT 7 25.5 1508 1397
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Table 4.24:Group A End Bearing capacity using Meyerhof, Vesic and Janbu for sil
End Bearing- 1 (kN)PileRef. No. Meyer Vesic Janbu
Pt. 1 1131 2136 782
Pt. 2 226 511 171
Table 4.25:Group B End Bearing capacity using Meyerhof, Vesic and Janbu for sil
End Bearing- 1 (kN) End Bearing - 2 (kN) End Bearing - 3 (kN) PileRef. No. Meyer Vesic Janbu Meyer Vesic Janbu Meyer Vesic Janbu
Pt. 1 958 1914 678 856 1770 615 960 1917 679
Pt. 2 738 1586 541 718 1553 528 744 1597 545
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Table 4.26:Group C End Bearing capacity using Meyerhof, Vesic and Janbu for sil
End Bearing- 1 (kN) End Bearing - 2 (kN) End Bearing - 3 (kN) PileRef. No. Meyer Vesic Janbu Meyer Vesic Janbu Meyer Vesic Janbu
Pt. 1 1709 2723 1117 1300 2328 882 1716 2729 1121
Pt. 2 843 1751 607 765 1629 558 869 1788 623
Table 4.27:Group D End Bearing capacity using Meyerhof, Vesic and Janbu for sil
End Bearing- 1 (kN) End Bearing - 2 (kN) End Bearing - 3 (kN) PileRef. No. Meyer Vesic Janbu Meyer Vesic Janbu Meyer Vesic Janbu
Pt. 1 603 1352 454 534 1218 408 604 1354 455
Pt. 2 456 1055 355 443 1027 347 460 1064 358
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Figure 4.9:Estimation of End Bearing capacity chart in silt for Pt. 1 study case
Figure 4.10:Estimation of End Bearing capacity chart in silt for Pt. 2 study case
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CHAPTER 5
ANALYSIS AND DISCUSSION
In this chapter, the capacity obtained by both End Bearing and Skin Friction
estimation using the selected methods is analyzed and studied. Subsequently, analysis
was carried out on all of these data in order to obtain the accuracy of each method.
Analyzed data was only from the all of case studies.
5.1 End Bearing Analysis for Sand Study Case
5.1.1 Comparison of Redesigned End Bearing Capacity with Maintain Load Test(MLT) End Bearing Capacity For Sand
Based on the end-bearing capacity analysis conducted for Group A, Group B,
Group C and Group D using the mentioned three methods as shown in Table 4.12,
Table 4.13, Table 4.14 and Table 4.15, the accuracy in each method can be studied.
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Based on the scatter chart plotted for all group soil friction angles in each study
case (Figure 5.1, Figure 5.2 and Figure 5.3) shown that the value of estimated end-
bearing is scattered but still maintaining its trend in group. From this chart it is seen that
some of the analysis method in certain soil friction group has a huge different value
because it shown in plotted much higher than the reference line. Detail calculation is
shown in Appendix D.
This difference is mainly because of the main component in each end-bearing
analysis method, the soil friction angle. As can be seen in Table 4.3, Table 4.4, Table
4.5 and Table 4.6 in previous chapter, it can be show that there is a range of soil friction
angle as low as 20 up to as high as 44.
The variation of this value, contribute to the variation of estimated end-bearing
value. The high soil friction angle value gave high end-bearing value and vice versa,
low soil friction angle value gave low end-bearing value.
From this study it can be shown that the calculation of estimated end-bearing
capacity is more likely to accurate when using Meyerhofs Method compares than other
methods as it is near to the reference line (Figure 5.1, Figure 5.2 and Figure 5.3) in
dense sand study case. The reference line shown that if the plot higher than the
reference line, means the estimated value is more than the MLT end-bearing value and
also vice versa for the lower value then the reference line. MLT end-bearing calculation
is shown in Appendix E.
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Figure 5.1: Theory End Bearing and MLT capacity comparison for P2 VP3 study case
Figure 5.2: Theory End Bearing and MLT capacity comparison for AV 5 study case
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Figure 5.3: Theory End Bearing and MLT capacity comparison for SPT 7 study case
5.1.2 Accuracy Analysis for Sand End-Bearing Estimation
Based on the end-bearing capacity value from Group A, Group B, Group C and
Group D using the mentioned three methods as shown in Table 4.12, Table 4.13, Table
4.14 and Table 4.15 in previous chapter, the calculated value is divided by the MLT
end-bearing value to get the accuracy ratio.
The closer the ratio values of 1.0, means the closer value of estimated value with
MLT value. The lower the ratio value than 1.0 means the estimated value is much lesser
then the MLT value. However the higher the ratio values than 1.0 means the estimated
value is much higher than the MLT value.
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For the analysis, End-bearing / MLT Ratio scatter chart is plotted to study the
trend of the plotted. Horizontal lines at value 1.0 also drawn on the chart just as
reference line, which plot is more accurate.
Group A gives a reliable plot for both Meyerhofs and Janbus Method, in which
the plot is lower compared to MLT for low overburden pressure. However, the plot is
higher compared to MLT when using Vesics Method either for low or high overburden
pressure.
Group B gives a reliable plot for all method, in which the plots have a lower
value compared to MLT for lower overburden pressure. However, the plot is high
compared to MLT when using Meyerhofs and Vesics Method for high overburden
pressure.
Group C gives a less reliable plot, in which the plots are much higher compared
to MLT for low overburden pressure (Figure 5.1 and Figure 5.2) except the analysis
using Janbus Method. For high overburden pressure, all methods give a less reliable
value which the plots is higher compared to MLT value.
Group D gives a reliable plot for all methods, in which the plots have a lower
value compared to MLT for low overburden pressure group (Figure 5.1 and Figure 5.2)
and almost the same value with MLT for higher overburden pressure group (Figure
5.3).
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Figure 5.4: End Bearing / MLT Ratio for P2 VP3 study case
Figure 5.5: End Bearing / MLT Ratio for AV 5 study case
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Figure 5.6: End Bearing / MLT Ratio for SPT 7 study case
Based on the same Redesigned End-Bearing data, the relationship with
overburden pressure is also been studied because the overburden pressure is also one of
the component in design method of estimating end-bearing capacity.
As can be seen from previous plotted scatter chart of redesign end-bearing and
MLT capacity comparison, it is clearly plotted that there is a trend of a group plotted in
the scatter chart. The groups are actually related to the effective overburden pressure.
From Figure 5.1, Figure 5.2 and Figure 5.3, it can be shown that there is 2 range
of plot which is high overburden pressure and another one is low overburden pressure
that affects the end-bearing capacity plotted.
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Based on the same scatter chart, it can be shown that for low overburden
pressure, the utilization of Group B and D correlation with any method of end-bearing
analysis is the most suitable. Group A and Group C is suitable but with Janbu method of
end-bearing analysis. For high overburden pressure, only Group D with any method of
end-bearing analysis is suitable (Figure 5.3).
5.2 End Bearing Analysis for Cohesive Soils Study Case
5.2.1 Comparison of Redesigned End Bearing Capacity with Maintain Load Test(MLT) End Bearing Capacity for Silt
Based on the end-bearing capacity analysis conducted for Group A, Group B,
Group C and Group D using the mentioned three methods as shown in Table 4.24,
Table 4.25, Table 4.26 and Table 4.27, the degree of accuracy in each method can be
studied.
Based on the scatter chart plotted for all group soil friction angles in each study
case (Figure 5.4 and Figure 5.5) shown that the value of estimated end-bearing is
scattered but still maintaining its trend in group. From this chart it is seen that some of
the analysis method in certain soil friction group has a huge different value because it
shown in plotted much higher than the reference line.
This difference is mainly because of the main component in each end-bearing analysis
method, the soil friction angle. As can be seen in Table 4.3, Table 4.4, Table 4.5 and
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Table 4.6 in previous chapter, it can be show that there is a range of soil friction angle
as low as 20 up to as high as 39.
The variation of this value, contribute to the variation of estimated end-bearing
value. The high soil friction angle value gave high end-bearing value and vice versa,
low soil friction angle value gave low end-bearing value.
However from this study it can be shown that the calculation of estimated end-
bearing capacity is more likely to accurate when using soil friction angle Group B and
Group C compares than other soil friction angle group correlation as it is near to the
reference line (Figure 5.7 and Figure 5.8) in stiff silt study case. The reference line
shown that if the plot higher than the reference line, means the estimated value is more
than the MLT end-bearing value and also vice versa for the lower value then the
reference line.
Figure 5.7: Theory End Bearing and MLT capacity comparison for Pt.1 study case
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Figure 5.8: Theory End Bearing and MLT capacity comparison for Pt.2 study case
5.2.2 Accuracy Analysis Ratio for Silt End-Bearing Estimation
Based on the end-bearing capacity value from Group A, Group B, Group C and
Group D using the mentioned three methods as shown in Table 4.24, Table 4.25, Table
4.26 and Table 4.27 in previous chapter, the calculated value is divided by the MLT
end-bearing value to get the accuracy ratio.
The closer the ratio values of 1.0, means the closer value of estimated value with
MLT value. The lower the ratio value than 1.0 means the estimated value is much lesser
then the MLT value. However the higher the ratio values than 1.0 means the estimated
value is much higher than the MLT value.
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For the analysis, End-bearing / MLT Ratio scatter chart is plotted to study the
trend of the plotted. Horizontal lines at value 1.0 also drawn on the chart just as
reference line, which plot is more accurate.
Group A gives a reliable plot for both Meyerhofs and Janbus Method, in which
the plot is lower compared to MLT. However, the plot is higher compared to MLT
when using Vesics Method except for soil friction correlation with Skempton (1986)
and Seed (1974) corrected N-value.
Group B gives a reliable plot for both Meyerhofs and Janbus Method, in which
the plots have a lower value compared to MLT. However, the plot is almost the same
value with MLT when using Vesics Method.
Group C also gives a reliable plot for both Meyerhofs and Janbus Method, in
which the plot is lower compared to MLT. However, the plot is higher compared to
MLT when using Vesics Method except for soil friction correlation with Seed (1974)
corrected N-value.
Group D gives a reliable plot for all methods, in which the plots have a lower
value compared to MLT (Figure 5.9 and Figure 5.10). However, the most suitable
method is Vesics Method in which the plots have the closest value with MLT.
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Figure 5.9: End Bearing / MLT Ratio for Pt. 1 study case
Figure 5.10: End Bearing / MLT Ratio for Pt. 2 study case
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5.3 Skin Friction Analysis
5.3.1 Comparison of Redesigned Skin Friction Capacity with Maintain Load Test(MLT) Skin Friction Capacity
Based on the skin resistance analysis conducted using the mentioned methods,
the degree of accuracy in each method can be studied when scatter chart Theory Skin
Friction is plotted.
Figure 5.11: Theory Skin Friction and MLT capacity comparison for Pt.1 study case
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Figure 5.12: Theory Skin Friction and MLT capacity comparison for Pt.2 study case
Figure 5.13: Theory Skin Friction and MLT capacity comparison for P2VP3 study case
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Based on the scatter chart plotted, value of estimated skin friction shown a
maintain trend. From the plot it is clear that both have the over-estimate value because
the entire plot is excessively higher from the reference line.
5.3.2 Accuracy Analysis Ratio for Skin Friction Estimation
Based on the skin friction value using the mentioned methods, the calculated
value is divided by the MLT skin friction value to get the accuracy ratio.
The closer the ratio values of 1.0, means the closer value of estimated value with
MLT value. The lower the ratio value than 1.0 means the estimated value is much lesser
then the MLT value. However the higher the ratio values than 1.0 means the estimated
value is much higher than the MLT value.
For the analysis, Skin-Friction / MLT Ratio scatter chart is plotted to study the
trend of the plot. Horizontal lines at value 1.0 also drawn on the chart just as reference
line, which plot is more accurate.
For high overburden pressure (Figure 5.16), it can be shown that method value
is higher than method value in which method gives an excessively higher value
compared to MLT skin friction value. For low overburden pressure (Figure 5.17, Figure
5.19 and Figure 5.20), the results are different where the method value is higher than
method value.
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Figure 5.16: Skin Friction / MLT Ratio for Pt. 1 study case
Figure 5.17: Skin Friction / MLT Ratio for Pt. 2 study case
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Figure 5.18: Skin Friction / MLT Ratio for P2 VP3 study case
Figure 5.19: Skin Friction / MLT Ratio for AV 5 study case
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Figure 5.20: Skin Friction / MLT Ratio for SPT 7 study case
For pile totally embedded in sand (Figure 5.18), it can be shown the result has
slightly better accuracy in which the values are closer to the ratio value of 1.0 compared
to pile embedded in soil consist of sand, clay and silt layer.
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CHAPTER 6
CONCLUSION
From the two analyses conducted on the end-bearing capacity and skin friction
for each study cases, sand and cohesive soils, 4 conclusions which can be used as a
guideline for pile design can be proposed.
From the analysis conducted for pile end-bearing capacity or skin resistance in
any condition of soil, it can be shown that each method, Meyerhof (1976), Janbu (1976)
and Vesic (1975) will give a reliable result for any overburden condition. In a simple
word a reliable result at any depth of pile penetration.
However this reliability only subjected in term of each method of analysis,
means it has a predictable trend of end-bearing capacity or skin resistance, the deeper
pile penetration the higher end-bearing capacity or skin resistance if analyze using the
same analysis method. The main issue is how much the safety factor needs to be
applying if using any method.
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However as a guideline for pile end-bearing capacity design, it is more
concerned on an accuracy of the analysis result, means a lower factor of safety applied
in pile design.
It can be concluded that for pile end-bearing analysis in sand, it is recommended
to use Meyerhof (1976) method matching up with Hatanaka and Uchida (1996) soil
friction angle correlation and Skempton (1986) corrected N-value for soil in condition
of low overburden pressure. For high overburden pressure, it is recommended to use
either Meyerhofs (1976) or Vesics (1975) method for the analysis. If using
Meyerhofs method, it is recommended to matching up with Peck, Hanson and
Thornburn (1974) soil friction angle correlation and Skempton (1986) corrected N-
value. If using Vesic (1975) method, it is recommended to matching up with Shioi and
Fukui (1982) soil friction angle correlation and either Liao and Whitman (1986) or Peck
(1974) corrected N-value.
For pile skin friction analysis in sand, it is recommended to use Meyerhof
(1976) method combining with either one of any four soil friction angle correlation.
There is only slightly different if compared this method with the MLT skin friction
value. Noted that Schmertmann (1975) soil friction angle correlation will give a high
value of soil friction angle compared to Peck, Hanson and Thornburn (1974), Hatanaka
and Uchida (1996) and Shioi and Fukui (1982) correlation.
In cohesive soils study case, the end-bearing capacity focusing on silt type of
soil, it is recommended to use either Meyerhofs (1976) or Vesics (1975) method for
the analysis. If using Meyerhofs method it is recommended to matching up with
Hatanaka and Uchida (1996) soil friction angle correlation and either Liao and Whitman
(1986) or Peck (1974) corrected N-value. If using Vesics method, it is recommended to
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matching up with Peck, Hanson and Thornburn (1974) soil friction angle correlation
and Skempton (1986) corrected N-value.
In cohesive soils study case, the skin friction capacity focusing on clayey and
silty soils, it is recommended to use method (1972). Noted this recommendation is
taken based on more conservative analysis result approach because method (1985)
gives a higher skin friction value if compared with method skin friction value.
However, overall skin friction values are over-estimated for cohesive soils study
case. This is because the SPT N-value used for design parameter correlation is not
applicable for skin friction embedded in cohesive soils. Therefore, it is recommended to
conduct Cone Penetration Test (CPT) in order to obtain a reliable design parameter for
pile embedded in cohesive soils.
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REFERENCES
1. Shim, W. C. and Wong, W. S. Practical Problems & Solutions for RC & Spun PilesDesign. Petaling Jaya, Selangor: Wawasan Professional Training Centre. 2008.
2. Bowles, J. E. Foundation Analysis and Design. 5th edition. New York: TheMcGraw-Hill Companies, Inc. 1997.
3. Mirasa, A. K. et al.Design Guide for Piles Using Locally Produced Steel H-Section.Skudai, Johor: Penerbit Universiti Teknologi Malaysia. 2001.
4. Gofar, N and Kassim, K. A.Introduction to Geotechnical Engineering Part II.Revised edition. Jurong, Singapore: Prentice Hall. 2007.
5. British Standard Institution.British Standard Code of Practice for Foundations.London, BS 8004. 1986.
6. Braja M. Das. Principles of Foundation Engineering.5th edition. United States.Thomson Brooks Cole. 2004.
7. Bujang B. K Huat. Organic and Peat Soils Engineering.Kuala Lumpur: UniversitiPutra Malaysia Press. 2004.
8. Neoh, C. A.Loading Tests on Piles.JKR Journal. 1984.
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9. Carl, J.F. Clausen. Capacity of Driven Piles in Clays and Sands on the Basis ofLoad Tests. Stavanger, Norway: The International Society of Offshore and Polar
Engineers. 2001.
10.Shariatmadari, N.Bearing Capacity of Driven Piles in Sands from SPT-Applied to60 Case Histories. Iran: Iranian Journal of Science and Technology. 2008.
11.Poulos, H. G. Pile Behaviour Theory and Application. 29thRankine Lecture. UK:British Geotechnical Society. 1989.
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APPENDIX A 87
Soil Investigation Report for Pt.1 Study Case
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APPENDIX A 88
Soil Investigation Report for Pt.1 Study Case
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APPENDIX A 89
Soil Investigation Report for Pt.1 Study Case
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APPENDIX A 90
So
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