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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



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


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


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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xii

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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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


47

4.15 Group D End Bearing capacity using Meyerhof, Vesic


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


50

4.18 Group C Skin Friction capacity using Meyerhof for


51

4.19 Group D Skin Friction capacity using Meyerhof for


51

4.20 Group A End bearing capacity factor (N'c) for silt study

case

55


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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


61

4.27 Group D End Bearing capacity using Meyerhof, Vesic


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


AV 5 study case

48


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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


for AV 5 study case

65


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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for Pt.1 study case

71


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


for Pt.2 study case

76


for P2 VP3 study case

76


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


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:


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


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


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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48

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


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



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



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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54

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


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


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


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


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.






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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.





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



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APPENDIX A 89



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APPENDIX A 90

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