A COMPARISON BETWEEN STATIC LOAD TEST AND HIGH STRAIN

DYNAMIC TEST ON BORED PILES

MICHAEL ANGELO A/L MURUGAN @ AROKIASAMY

UNIVERSITI TEKNOLOGI MALAYSIA

PSZ 19:16 (Pind.1/97) UNIVERSITI TEKNOLOGI MALAYSIA

BORANG PENGESAHAN STATUS TESIS

JUDUL: A COMPARISON BETWEEN STATIC LOAD TEST AND HIGH

STRAIN DYNAMIC TEST ON BORED PILES

SESI PENGAJIAN: 2005/06

Saya MICHAEL ANGELO A/L MURUGAN @ AROKIASAMY __________________________________________________

(HURUF BESAR)

Mengaku membenarkan tesis (PSM/Sarjana/Doktor Falsafah)* ini disimpan di perpustakaan Universiti Teknologi Malaysia dengan syarat-syarat kegunaan seperti berikut:-

1. Tesis adalah hakmilik Universiti Teknologi Malaysia. 2. Perpustakaan Universiti Teknologi Malaysia dibenarkan membuat salinan untuk

tujuan pengajian sahaja. 3. Perpustakaan dibenarkan membuat salinan tesis ini sebagai bahan pertukaran antara

institusi pengajian tinggi. 4. **Sila tandakan ( )

SULIT (Mengandungi maklumat berdarjah keselamatan atau kepentingan Malaysia seperti yang termaktub di dalam AKTA RAHSIA RASMI 1972)

TERHAD (Mengandungi maklumat TERHAD yang telah ditentukan oleh organisasi/badan dimana penyelidikan dijalankan

TIDAK TERHAD Disahkan oleh

_____________________________ _____________________________ (TANDATANGAN PENULIS) (TANDATANGAN PENYELIA)

Alamat Tetap: No 35, E2/5A Lorong Ria, Dr. Nurly GofarTaman Timur,36000 Teluk Intan, Perak.Tarikh : 19 May 2006 Tarikh : 19 May 2006

CATATAN: * Potong yang tidak berkenaan. ** Jika tesis ini SULIT atau TERHAD, sila lampirkan surat daripada pihak berkuasa /organisasi berkenaan dengan menyatakan sekali sebab dan tempoh tesis ini perlu dikelaskan sebagai SULIT atau TERHAD.

A COMPARISON BETWEEN STATIC LOAD TEST AND HIGH STRAIN

DYNAMIC TEST ON BORED PILES

MICHAEL ANGELO A/L MURUGAN @ AROKIASAMY

A thesis submitted in fulfillment of the

Requirements for the award of the degree of

Master of Engineering (Civil – Geotechnic)

Faculty of Civil Engineering

University Technology Malaysia

MAY 2006

ii

“I declare that this project report is the result of my own research

except as cited in references. This report has not been accepted for

any degree and is not concurrently submitted in candidature of any

degree”.

Signature :_______________________________

Name of Candidate: MICHAEL ANGELO S/O MURUGAN @

AROKIASAMY

Date : 19 May 2006

iii

“I hereby declare that I have read this report and in my opinion

this report is sufficient in terms of scope and quality for the

award of Master of Engineering (Civil-Geotechnics)”.

Signature : ……………………………………….

Name of Supervisor : Dr. Nurly Gofar

Date : 19 May, 2006

iv

DEDICATION

For my dearest mother and dad

(Mariamah & Murugan @ Arokiasamy)

My success is your gift and prayers…

To my beloved brother, sister and relations

Everyone and friends whom are the best…

Success of mine is success of all of yours…

v

ACKNOWLEDGEMENT

I would like to thank God for giving me enough knowledge and time to

conclude this program. All the help rendered by the lecturers and friend are

appreciated. They have contributed towards the completion of this study. The time

spent in doing this program gives memories that would last for ages.

I would like to also express and record my gratitude towards my lecturer cum

supervisor Dr. Nurly Gofar, for the time she allocated and all her guidance in

preparation of this thesis.

vi

ABSTRACT

Piles are both statically and dynamically tested to obtain the capacity and to

verify design. Both the test will provide results that may vary base on the method

applied in conducting the test. It is therefore, necessary to compare the results of a

static load test with dynamic load test. Many comparison studies are conducted

worldwide, but most of it is for displacement pile. Therefore, the results of the test

are compared for replacement piles. The piles are tested statically prior to dynamic

test. The test results shows that a good agreement have achieved between both the

test with plus minus 2mm at working load in terms of settlement. Comparatively the

settlement predicted in dynamic load test is smaller compared to static load test. In

terms of total capacity, the Davisson’s method gives the lowest value compared to

other methods. The Davisson’s method is used to compare the results because it is

more conservative. The comparison shows that the piles are within 20% relative to

the capacity obtained through Davisson’s method. Since the static test was

conducted prior to dynamic test, the capacity obtained from dynamic test is higher

due to the pile undergone elastic compression during static load test and also due to

soil setup. The shaft distribution show that large shaft distribution obtained on long

piles. They are comparable with the dynamic test taking into account the time factor.

vii

ABSTRAK

Cerucuk biasanya diuji secara static dan dinamik untuk menentukan beban

tanggungan dan juga untuk mengesahkan rekabentuk. Kedua-dua ujian akan

menghasilkan keputusan yang berlainan berdasarkan kaedah yang digunakan untuk

melaksanakan ujian. Oleh demikian, ia adalah penting untuk memperoleh suatu

hubungan diantara ujian static dan ujian dinamik beban cerucuk. Banyak kajian yang

dijalankan di merata dunia, tetapi kajian-kajian ini tertumpu pada ‘driven pile’. Oleh

yang demikian, kajian ini adalah tertumpu terhadap ‘bored pile’. Cerucuk-cerucuk

ini diuji secara static terdahulu sebelum menjalankan ujian dinamik. Keputusan

adalah memuaskan bagi bebanan kerja dengan ±2mm. Secara ringkas boleh

dikatakan bahawa keputusan yang diperolehi pada bebanan ujian adalah lebih rendah

bagi ujian dinamik berbanding ujian statik. Dari sudut bebanan muktamad pula,

kaedah Davisson memberi nilai yang paling minima berbanding kaedah-kaedah yang

lain. Nilai ini adalah pada had yang rendah, oleh itu ia digunakan bagi tujuan kajian.

Keputusan menggunakan kaedah ini memberikan keputusan bahawa nilai ujian

dinamik adalah dalam 20% nilai yang diperoleh. Ini adalah kerana ujian static

dijalankan dahulu sebelum ujian dinamik dan ini mengakibatan cerucuk mengalami

terikan mampatan dan jugan masa perantaran mengakibatkan tanah pulih semula

keadaan asalnya. Dari segi bebanan sisi cerucuk, didapati bebanan sisi menguasai

nisbah yang lebih banyak bagi cerucuk panjang. Keputusannya dapat dipersamakan

dengan ujian dinamik jika masa perantaraan diambil kira.

viii

TABLE OF CONTENTS

CHAPTER TITLE PAGE

DECLARATION ii

DEDICATION iv

ACKNOWLEDGEMENTS v

ABSTRACT vi

ABSTRAK vii

TABLE OF CONTENTS viii

LIST OF TABLES xi

LIST OF FIGURES xii

LIST OF SYMBOLS xiv

LIST OF APPENDICES xvi

1 INTRODUCTION 1

1.1 Background 1

ix

1.2 Problem Statement

1.3 Objectives

1.4 Scope

3

4

4

2 LITERATURE REVIEW 5

2.1 Bored Pile

2.1.1 Types of Bored Pile

2.1.2 Construction Procedures

2.1.2.1 Dry Method

2.1.2.2 Casing Method

2.1.2.3 Wet Method

2.1.3 Techniques and Equipment

2.1.3.1 Boring by Mechanical Auger

2.1.3.2 Boring by Percussion or Grab-type

Rig

2.1.3.3 Boring by Continuous Flight Auger

Drilling

2.1.3.4 Under-reammed Bored Piles

2.2 Load Test

2.2.1 Static Load Test (Maintain Load Test)

2.2.1.1 Test Equipment and Instruments

2.2.1.2 Test Procedures

2.2.2 High Strain Dynamic Test

2.2.3 Correlation Studies

5

7

7

7

8

11

12

13

15

16

17

19

20

20

24

25

28

3 METHODOLOGY 30

3.1 Introduction

3.2 Data Collection

3.3 Data Analysis and Results

3.4 Summary

31

31

32

33

4 DATA ANALYSIS AND DISCUSSION 35

4.1 Data Description 35

x

4.2 Analysis of field data

4.3 Analysis of Static Load Test Data

4.4 Analysis of PDA test data

4.5 Comparison between Static Load Test and Pile

Driving Analyzer

37

43

47

49

5 CONCLUSION AND RECOMMENDATION FOR

FUTURE STUDY 53

5.1 Conclusion

5.2 Recommendations for Future Study

53

54

REFERENCES 55

Appendices A-E 58 – 97

xi

LIST OF TABLES

TABLE NO. TITLE PAGE

4.1

4.2

4.3

4.4

4.5

4.6

4.7

4.8

4.9

Relationship between SPT, N value and weathering

grade

Subsoil classification (Komoo and Morgana, 1988)

Pile details

Date and time interval between tests

Maximum load implied during static load test

Pile settlement

Pile capacity for static load test using various

methods

Pile capacity

Shaft and end bearing contributions

38

40

41

42

42

43

45

50

51

xii

LIST OF FIGURES

FIGURE NO. TITLE PAGE

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

2.9

2.10

2.11

Bore hole created by dry method of construction

Process of dry method

Bore hole created by casing method

Process of casing method

Bore hole created by wet method

Process of wet method

Auger a) spiral auger b) bucket auger c) rock

auger d) earth auger

Percussion drilling equipment

Continuous flight auger machinery

Belling tool

Under reamed bored pile

8

9

9

10

11

12

14

15

17

18

19

xiii

2.12

2.13

3.1

4.1

4.2

4.3

4.4

Static load test in progress

Test equipments a) 30 tonne steel ram with

hydraulic release b) pile driving analyzer

c) accelerometer d) transducer

Flow chart of the study

Instrumented bore pile schematic diagram

Typical comparison of methods for Pile 3

Pile – soil model

CAPWAP method – iteration program

21

27

32

36

46

48

49

xiv

LIST OF SYMBOLS

A

c

E

Fm

Fc

c

L

L

Q

Qra

-

-

-

-

-

-

-

-

-

-

Cross section Area of the pile

Wavespeed

Modulus of Elasticity of the pile material or strain

gauge reading

Force measured

Force calculated

Empirical correlation factor (Case method

damping factor)

Distance along the pile between two telltale

anchor plates

Difference in movement between two telltale rods

Quake

Load in the pile midway between two anchor

plates or load in the pile at the location of the

strain gauge

xv

Rshaft

Rtoe

Ru

t

vm

Z

-

-

-

-

-

-

-

Shaft Resistance

Toe Resistance

Ultimate resistance in the soil ‘springs’

Travel time

Velocity measured

Pile impedance

Mass density

xvi

LIST OF APPENDICES

APPENDIX TITLE PAGE

A

B

C

D

E

Results of Analysis Pile 1

Results of Analysis Pile 2

Results of Analysis Pile 3

Results of Analysis Pile 4

Results of Analysis Pile 5

58

66

74

82

90

CHAPTER 1

INTRODUCTION

1.1 Background

Foundation is an essential part of a structure because it transmit load from the

structure to the soil below it. The foundation can be classified into shallow

foundation and deep foundation. Shallow foundations such as individual footings,

combined footings, and raft foundation are used when the supporting soil is found at

shallow depth. While, deep foundations such as caissons and piles are required when

the depth of supporting soil is significant or building is placed on soft compressible

soil. Deep foundation is also required if construction is subjected to horizontal load

or moment.

Piles are mainly classified into two categories; displacement piles and

replacement piles. Displacement piles consist of reinforced piles, pre-stressed piles,

steel-H piles, whereas replacement piles consist of bored piles, and cast in-place-

piles. All these piles are designated to a particular situation or site based on location

and type of structure, ground condition and durability.

2

Piles are designed based on the load that is transferred from the structure to

the piles; thus the type, size and length of piles are determined accordingly.

However, load test should be conducted to verify the design capacity. Piles that are

not properly designed, would pose danger to the structure. Inadequate load or large

settlement would cause severe damage to the structure and its occupants.

There are several alternatives to load test, i.e.: maintained load test (MLT),

high strain dynamic test (PDA), statnamic test and Osterberg Cell load testing. All

the mentioned tests are rigorously being carried out in Malaysia. These tests would

provide the engineer with the load and the corresponding settlement. It actually

enables the engineer in decision making as to resume work or to make changes to the

selected design criteria. Of the four, the most viable and the most common as being

practiced in the industry are the Static Load Test and the High Strain Dynamic

Testing.

Maintained load test or static load test is commonly known in construction

industry. It uses hydraulic jacking system against a kentledge or against a beam

restraint by anchor piles. The load is measured by the reading of pressure gauge on

the hydraulic jack. At present the load is measured directly by a load cell interposed

between the pile head and jack or between the jack and platform to get an accurate

and reliable measurement. This test is also known as conventional test. It requires

proper setup, manpower, machinery and longer duration to maintain the load.

High strain dynamic test or dynamic pile testing is conducted using two to

four sets of sensors known as accelerometer and transducer attached to the pile. The

basis for this testing is wave mechanics. The test requires sensors, pile driving

analyzer and the pile driving system. On every impact of the driving system/ram, the

sensors capture the impact force and velocity. The captured signals of strain and

acceleration were conditioned and possessed by the pile driving analyzer to produce

plots of force and velocity versus time. The ability to accurately predict static

capacity for dynamic pile testing has resulted in many studies and has been the focus

3

of dynamic pile tests on many project sites. Standard practice requires performing

signal matching on the data to more accurately determine capacity from the dynamic

tests. CAPWAP (Case Pile Wave Analysis Program) analysis is the most used

program to evaluation capacity from high strain dynamic testing data. Previous

studies have demonstrated generally good correlation of CAPWAP signal matching

results on dynamically re-striked tests with that of static load tests.

Since, the usage of static load test and high strain dynamic test is rapid and

almost conducted in every site, comparisons between the two tests for bored pile is

attempted in this project paper.

1.2 Problem Statement

There are many studies conducted on the comparison between high strain

dynamic testing and CAPWAP analysis, and static load test in Malaysia, but most of

it was made for the displacement piles. I, in this project study however, will focus on

replacement piles (bored piles). Comparison is made between the static load test

results and the CAPWAP signal matching result on dynamic re-strike test.

Furthermore, an attempt is made to compare the results obtained from the maintain

load test and the high strain dynamic test and CAPWAP analysis.

4

1.3 Objectives

The objective of conducting this study is to compare the results obtained in

static load tests with that of high strain dynamic tests and CAPWAP analysis in

terms of:

1) The load transfer mechanism through pile;

2) The load and the corresponding settlement of the pile; and

3) The total bearing capacity of the pile.

1.4 Scope

In this project paper special attention is provided to the bored piles. The

bored piles are vertically tested with both static load test and high strain dynamic

test.

The data for this paper is obtained from real time projects conducted in

construction industry. In this case, the piles are fully instrumented for measurements

of stress and displacement. Static load test are conducted prior to the dynamic test.

The static load test is conducted using kentledge with load cell, whereas; the

dynamic test is conducted using a drop hammer.

The subject of this study is not the accuracy, but relative comparison between

static load test and high strain dynamic test to evaluate the capacity and load transfer

mechanisms within the piles.

CHAPTER 2

LITERATURE REVIEW

2.1 Bored Pile

A bored pile is a deep foundation that is constructed by placing fluid concrete

in a drilled hole. The bored piles are designed based on geotechnical engineering

properties of subsoil condition obtained from the soil investigation at proposed site

for foundation designs. In soil investigation work, in-situ test are conducted and

disturbed and undisturbed soil samples are collected for laboratory testing, and also

to determine ground water level at the site.

In a project site, piles are selected for a foundation based on loads to be

imposed, site subsurface materials, lateral capacity and also cost. In many projects,

bored pile has proven cost effective, especially in urban areas and large construction.

6

Bored piles have many advantages compared to the displacement pile. When

the piles are properly analyzed, designed and constructed, the advantages range from

reliability, economy and versatile.

Reliability in terms of shaft that can be located easily, soil/rock can be

inspected during construction and integrity can be assessed.

It is understood that bored piles have high resistance to lateral loads. Piles

driven into clay soils may produce ground heaving and cause driven piles to move

laterally. This does not occur in bored piles. Furthermore, the surface over which

the base of the bored pile is constructed can be visually inspected.

In terms of economy, a single bored pile can be used instead of a group of

piles and the pile cap. The construction of bored piles generally utilizes mobile

equipment, which under proper soil conditions, may prove to be more economical

than methods of constructing pile foundations.

Bored piles are also versatile. Depth and diameter of piles can are easily

varied. Constructing bored piles in deposits of dense sand and gravel is easier than

driving piles. Furthermore, the base of bored pile can be enlarged to provide greater

resistance to the uplifting load. Areas where driving piles can pose danger to the

adjacent structures due to vibration can be avoided by using bored pile.

7

2.1.1 Types of Bored Piles

Bored piles are classified according to the ways in which they are designed to

transfer the structural load to the substratum. The pile can be cased with pipe when

required. For such piles, the resistance to the applied load may develop from end

bearing and also from side friction at the shaft perimeter and soil interface.

A belled bored pile consists of a straight pile with a bell at the base, which

rests on good bearing soil. The bell can be constructed in the shape of a dome or it

can be angled. For the majority of bored piles, the entire load-carrying capacity is

assigned to the end bearing only. However, under certain circumstances, the end-

bearing capacity and the side friction are taken into account.

2.1.2 Construction Procedures

The most common construction procedure used involves drilling. There are

three major types of construction methods; the dry methods, the casing methods and

the wet methods.

2.1.2.1 Dry Method

This method is employed in soils and rocks that are above the water table as

shown in Figure 2.1. The soils are normally strong and not easily collapsible when

the hole is drilled to its full depth.

8

Dry hole – no water content

Figure 2.1 Bore hole created by dry method of construction

Construction in the dry method uses drilling tools to bore the hole. Spoilt of

the hole is dumped nearby or are exported to dumping yard. Concrete is then poured

into the hole and if there be any requirements for the reinforcement, then a rebar

cage is placed in the upper portion of the pile. Concreting is continued till the

required level. The process of the dry method is shown in Figure 2.2 shows.

2.1.2.2 Casing Method

The casing method is employed in soils and rocks, which are easily caving or

collapsible soils when the borehole is excavated as shown in Figure 2.3. The

9

construction method is almost the same as the dry method but requires an

introduction of slurry during drilling when collapsible soils are encountered.

Figure 2.2 Process of dry method

Casingintroduction into the hole

Figure 2.3 Bore Hole created by casing method

10

The drilling is continued past the collapsible soil layer into a more stable soil

layer. Casing is then introduced into the hole and the slurry is pumped out of the

hole. A smaller drill that passes through the casing is then used to drill further into

the soil. If there be any need for reinforcement, a rebar cage is introduced to the full

length of the pile.

Concreting work starts and the casing is retrieved from the hole gradually.

Concreting is completed when the concrete fill up to the required level. The Figure

2.4 shows the process of the wet method.

Figure 2.4 Process of casing method

11

2.1.2.3 Wet Method

This method is employed in a very soft soil condition as in the Figure 2.5.

This method is sometimes referred to as slurry displacement method. Slurry is used

to keep the borehole open during the entire depth of excavation.

Construction of a bored pile using this method starts with excavation by

drilling with the slurry in the hole. The entire depth is drilled with slurry. If needed,

reinforcement is introduced in the hole. Concreting starts by placing a tremie pipe to

the bottom of the borehole. As concreting progresses, the slurry is slowly displaced

to the ground surface where it is collected. Concreting completes when the finish

level is reached. Figure 2.6 shows the process of the wet method.

Introduction of Slurry into the hole

Figure 2.5 Bore hole created by wet method

12

Figure 2.6 Process of wet method

2.1.3 Techniques and Equipment

In a construction of a drilled shaft, more than one method can be employed in

accordance to the site requirement. No matter which method is employed, the boring

equipments are normally the same but require minimal adjustment for the required

work. Generally, the boring is carried out by mechanical auger, percussion/grab type

rig or continuous flight auger. The under reaming of the shaft if required is done by

using belly bucket.

13

2.1.3.1 Boring by Mechanical Auger

The large spiral auger or bucket auger rotary drilling machines are developed

for the installation of large diameter bored piles. These machines are capable of

drilling in wide range of soil and also weak rocks using different type of auger as in

the Figure 2.7. In cases where there is a potential cave in, a length of casing is

placed into the drilled hole by means of a crane or by the mast of the machine. The

casing would provide a seal against water entry. A smaller size drill plate is then

used inside the casing for the lower part of the hole.

Boring by mechanical auger under water or bentonite slurry can cause some

loosening of the soil at pile base level. If a higher base resistance is required, then

the soil needs to be compacted by injection pressure.

A flat circular steel plate is suspended from the bottom of the reinforcing

cage, and a thin flexible steel sheet is attached to the bottom of the plate. After

concreting the pile, grout is injected around the bottom few meters of the shaft to

lock the shaft to the surrounding soil. After a hardening period grout is then injected

at high pressure to fill the space between the steel plate and the steel sheet. This

forces the sheet down and compresses the underlying soil. Resistance to uplift of the

pile at this stage is provided by grout injections around the pile shaft.

14

(c)

(b)(a)

(d)

Figure 2.7 Auger a) Spiral auger b) bucket auger c) rock auger d) earth auger

15

2.1.3.2 Boring by Percussion or Grab-type Rig

In ground where mechanical auger drilling is impossible (in water-bearing

sands or gravels, stony or boulder clays, or very soft clays and silts), a conventional

cable percussion boring rigs are used as shown in Figure 2.8.

Figure 2.8 Percussion drilling equipment

In these type of boring, the casing is given a continuous semi-rotary motion

to keep it sinking as the borehole is advanced. The casing may be with welded joints

and left in position, or with bolted joints and withdrawn while the shaft is concreted.

A problem in drilling of bored piles in granular soils, either by cable

percussion rigs in the case of small diameter piles, or grabbing rigs for the larger

diameters, is the risk of excessive removal of soil during drilling. This is expected to

16

happen when drilling by cable percussion methods since the soil is drawn up into the

‘shell’ or baler by a sucking action.

Water is required to induce the flow of soil into the drilling tool and if natural

ground water is not present it must be poured into the pile borehole. Violent raising

and lowering of the ‘shell’ can cause flow of soil from the surrounding ground with

the risk of settlement of any adjacent structures. It is possible to minimize the risk of

loss of ground by driving the casing ahead of the boring, but this can make it

impossible to withdraw the casing after concreting the pile shaft since driving the

casing cause the soil to tighten around it.

If there are services or buildings around the piling area than it is best to use

rotary-auger drilling method under bentonite slurry or a continuous flight auger.

2.1.3.3 Boring by Continuous Flight Auger Drilling

Continuous Flight Auger drilling machine is made of spiral auger throughout

the stem as in Figure 2.9. The auger can be withdrawn after drilling to the required

depth in a stable ground and the pile is concreted by feeding a flexible pressure hose

to the bottom of the unlined hole and withdrawing it as sand-cement mortar is

pumped down.

In cases of unstable ground, the flight auger is provided with a hollow central

stem closed by a plug at the bottom. During drilling, the walls of the borehole are

supported at all times by the soil rising within the flights. When the required depth

is reached, concrete is injected down the hollow stem, which pushes out the bottom

plug and the pile is concreted by raising the auger with or without rotation.

17

Figure 2.9 Continuous flight auger machineries

During concreting, the auger is rotated for a number of revolutions before

raising it to ensure that the concrete has completely filled the bottom of the hole.

After removing the auger, reinforcing cage is pushed down the shaft, while the

concrete in the shaft is still in the form of fluid.

The use of continuous flight auger rig avoids many of the problems of drilling

and concreting piles experienced when using conventional power augers. However,

continuous flight auger piles operation must be monitored closely during

construction.

2.1.3.4 Under-reammed Bored Piles

An under-reammed pile (also known as a belled shaft) is one with an

enlarged base. The under-reams are made with special equipments and techniques.

The equipment used showed in the Figure 2.10 below. The larger the base of under-

reammed pile, the higher their end bearing capacity.

18

Figure 2.10 Belling Tool

However, the displacement required to mobilize the full end bearing is

typically on the order of 10% of the base diameter, which may be more than the

structure can tolerate. Under-reammed piles also have greater uplift capacities due

to bearing between the ceiling of the under-ream and the soil above as is in Figure

2.11.

The construction of under-reammed pile can be hazardous to the workmen.

The bottom of the under ream must be cleaned of loose soil before placing concrete.

This task is typically done by hand. Thus, under-reammed shafts are not as common

as they once were.

19

Figure 2.11 Under reamed bored pile

2.2 Load Test

Pile load test are executed in two alternative ways based on site investigation,

laboratory soil testing and desk study:

1) Test pile – piles are tested to failure. This test is done during the

preliminary design stage. Load test is then carried out to refine and

finalize the design of the pile foundation.

2) Test on working pile – piles are tested to two times the design load

(working load). This test is done in areas where previous experience

20

is available. Pile load test are then carried out on randomly selected

actual piles to check the pile design capacities.

The equipment and the procedures for these two alternatives are essentially

similar. Generally there are two types of testing performed in most part of the

world: the static load test and the high strain dynamic test.

2.2.1 Static Load Test (Maintained Load Test)

The most accurate way to determine the load capacity is to install a full-size

prototype pile at the site of the proposed production piles and load it to failure.

However, load tests also are much more expensive, and thus must be used more

judiciously.

Varieties of equipment and procedures have been used to conduct load tests.

The differences in the equipment and procedures can influence the results and

become the point of debate among engineers. Therefore, there is no single correct

capacity for most piles. Nevertheless, engineers judge the accuracy of all other

methods by comparing them to full-scale load tests.

2.2.1.1 Test Equipment and Instruments

Test equipments and instruments consist of load application arrangements

and the instruments to measure the resulting movements or deformations. Stacking

21

large weight on top of the pile as imposed load, posed danger because it is difficult

to place large weights without creating excessive eccentricities that can cause them

to collapse. As an alternative, a hydraulic jack is used to provide the test load. This

system is more stable and less prone to collapse.

Figure 2.12 shows the actual setup of static load test using hydraulic jack

performed on a bored pile.

Figure 2.12 Static load test in progress

Traditionally, engineers have measured the applied load by calibrating the

hydraulic jack and monitoring the pressure of the hydraulic fluid during the test.

However, even when done carefully, this method is subject to errors. Therefore,

load cells (an instrument that measures force) are developed. The load cell is placed

between the jack and the pile and is used to measure the applied load.

Displacement is another measurement that is very important in conducting

load test besides the capacity. The displacement is measured by utilizing dial gauges

mounted on the reference beams. Surveyor’s level can also be used as a cross

reference to the measured records of displacement.

22

Another measurement employed in load test is the incremental strain

measurement along the pile length to determine the distribution of load transfer from

pile to the soil. These provide information on pile tip movements or deflections

along the pile. In order to obtain this measurement, a pile needs to be instrumented

prior to installation. Instruments that can be used are the strain rods (or telltales) and

the electric strain gauges (or vibrating wire strain gauges).

Telltales or strain rods (vibrating wire extensometer) normally consist of

polyvinyl chloride (PVC) tubing extended to steel end plates embedded inside a

concrete pile or welded on the steel pile or housed in sonic logging pipe at various

locations along the pile length. Inside the sonic logging pipe tubing, a stainless

steel/graphite/fiberglass rod is installed extending from the end plate to the top of the

pile.

Both the tubing and the steel rod extend to the top of pile. The steel rod must

be allowed to move freely in the tube. The movement of the top of the telltale or

strain rod relative to the top of the test pile is measured with a dial gauge or the

measurement of the vibrating wire extensometer is logged using a data logger.

Normally, telltale readings are referenced to the top of the pile. By noting

the location of the specific telltale rod anchor plate and by measuring the relative

movement of the individual rod, elastic shortening of pile at that location can be

obtained.

At present, data recoded by the data logger can give the elastic shortening of

the pile without having to measure the top measurements. With this information, the

load in the pile at the midpoint between two telltale anchor plates separated by a

distance L can be obtained by the following relationship:

23

raA LEQ =

L

where

Qra = load in the pile midway between two anchor plates

A = cross section area of the pile

L = difference in movement between two telltale rods

E = modulus of elasticity of the pile material

L = distance along the pile between the two telltale anchor plates

Electric strain gauges or vibrating wire strain gauge can be mounted along

the pile length at various locations before the pile is installed. In bored piles, these

gauges can be tied up with the reinforcing bars and wires can be brought up through

a casing just like the vibrating wire extensometer. Since these gauges are

temperature sensitive, additional temperature-compensating gauges should be used

for each strain gauge. The strain can be determined directly by noting the changes

in the strain gauge reading from the unstrained to any desired load. At present the

measurements are data logged using a data logger. The load at the point will then be

calculated by the following relationship:

raQ =AE

where

Qra = load in the pile at the location of the strain gauge

A = cross section area of the pile

E = modulus of elasticity of the pile material

= strain gauge reading

24

2.2.1.2 Test Procedures

There are two categories of load tests: controlled stress tests and controlled

strain tests. The former uses predetermined loads (the independent variable) and

measured movements (the dependent variable), while the latter uses movement as

independent variable and load as dependent variable.

Controlled stress tests are the slow maintained load test and quick maintained

load test. In slow maintained load test, the pile is loaded in eight equal increments

(i.e. 25%, 50%, 75%, 100%, 125%, 150% 175% and 200%) to two times of the

design load. The load is maintained under each increment until the rate of settlement

is acceptably small. At two times the design load, the load is maintained for 24

hours. After the required holding time, the loading is removed in decrement of 25%

with 1 hour between decrements.

After one cycle of the load, the pile is reloaded to test load in increments of

50% of the design load, allowing 20 minutes between load increments. Then the

load is increased in increments of 10% of design load until failure, allowing 20

minutes between load increments. This method is commonly considered as the

ASTM Standard test method and is generally used for site investigation prior to

installing contract piles and writing specifications. The disadvantage of this test is

that it is time consuming.

In quick maintained test the procedure is almost the same as slow maintained

test except that each load increment is held for a predetermined time interval

regardless of the rate of pile movement at the end of that interval. Pile is loaded in

20 increments to three times of the design load (i.e. each increment is 15% of the

25

design load). Each load increment is maintained for 5 minutes with readings taken

every 2.5 minutes until the test load has been reached.

After 5 minutes interval, the full load is removed in four equal decrements

with 5 minutes between decrements. The advantage of this test is that it is fast and

economical. The method represents a more nearly undrained condition. This

method cannot be used for settlement estimation because it is a quick method.

Controlled strain test is the constant rate of penetration test, which presses the

pile into the ground at a constant rate. As the test progresses, the load and

settlements are measured to develop a load-settlement curve. In this test, the pile

head is forced to settle at typically 0.01 to 0.05 in/min (0.25 to 1.25 mm/min) for

clays and 0.03 to 0.10 in/min (0.75 to 2.5 mm/min) for sands. The force required to

achieve the penetration rate is recorded. The test is carried out to a total penetration

of 2 to 3 in. (50 to 75 mm).

The advantage of this test method is that the test is very fast and economical.

This method can be employed for friction piles but less practical for the end bearing

piles because of high force requirements to cause penetration through hard bearing

stratum.

2.2.2 High Strain Dynamic Test

High strain dynamic test is a powerful tool to access pile driving, which may

supplement or replace static testing. This test is conducted in a fraction of time

26

unlike the static load test. This test is based on the dynamic method of analysis.

Actual field test is performed on pile by measuring strain and acceleration records

under impact of a falling mass.

Wave equation analysis program (WEAP) is utilized to design the weight,

drop height and cushion of the hammer apparatus to assure a successful test. The

pile driving analyzer and the CAPWAP methods are used for data acquisition and

analysis. Testing results yield information regarding pile static bearing capacity,

structural integrity, and pile-soil load transfer and pile load-movement relationship.

High strain dynamic test is conducted using; a pair of strain transducers

mounted near the top of the pile, a pair of accelerometers mounted also near the top

of the pile and the a pile driving analyzer also known as PDA (pile driving analyzer)

as shown in Figure 2.13. The pile driving analyzer monitors the output from the

strain transducers and accelerometers as the pile is being driven, and evaluates the

data as follows:

1) The strain data combined with the modulus of elasticity and cross section area

of the pile, gives the axial force in the pile;

2) The acceleration data integrated with time produces the particle velocity of the

waves traveling through the pile;

3) The acceleration data, double integrated with time produces the pile set per

blow.

27

(a) (b)

(c) (d)

Figure 2.13 Test Equipments a) 30 tonne steel ram with hydraulic release

b) Pile Driving Analyser c) accelerometer d) transducer

Using the above data, the PDA computes the Case method capacity and

displays the results immediately. Case method analysis is an analytical technique for

determining the static pile capacity from wave trace data. The Case method

computations include an empirical correlation factor, jc that can be determined from

an on-site pile load test.

It is also possible to use the Case method without an on-site pile load test by

using jc values from other similar soils. This approach is less accurate, but still very

28

valuable. The PDA can also store the field data on a floppy disk to provide input for

a CAPWAP analysis.

The Case method, while useful, is a simplification of the true dynamics of

pile driving. The empirically obtained damping factor, jc calibrates the analysis, so

the final results are no better than the engineer’s ability to select the proper value. In

contrast, a wave equation analysis utilizes a much more precise numerical model, but

suffers from weak estimates of the actual energy delivered by the hammer.

Fortunately, the strengths and the weaknesses of these two methods are

complimentary, so we can combine them to form an improved analysis called

CAPWAP (Case Pile Wave Analysis Program). It is a rigorous numerical method

for a comprehensive analysis of pile and soil behavior under hammer impacts and

also under static loading conditions. The analysis is done in an iterative environment

using measured force and acceleration in a wave equation type analysis employing

signal matching technique that produces values of Ru (the ultimate resistance in the

soil ‘springs’), q (the quake), and jc (the Case method damping factor). CAPWAP

analyses are not a substitute for pile load tests. However, they may reduce the

required number of tests.

2.2.3 Correlation Studies

During the past decade, high-strain dynamic testing of bored piles has

enjoyed widespread acceptance around the world. Discuss here are some of the case

histories of dynamic and static test results.

29

Case 1: Jianren and Shihong (1992). A study was conducted on drilled piles

for a 257m high tower span crossing the Yangtze River in Tai Sheng Quan Nanking,

China where test shaft consisted of two each 800 and 1500mm diameter with

corresponding lengths of 30 and 60m. Subsurface conditions at the site consisted of

clay, sand and gravel layers over highly weathered sandstone. Project specifications

required that comparisons between dynamic and static load test results be made in a

Class A prediction manner. The hammer used for the dynamic testing had a weight

of 12 tons with drop heights up to 1 and 2.5m for the 800 and 1500mm diameter

shafts respectively. Comparison of dynamic and static was performed within the

same time frame indicated that the two methods produced capacity values that were

within 2.6% relative to each other.

Case 2: Seidel and Rausche (1984). A static and dynamic test program was

initiated on drilled shafts for the West Gate Freeway in Melbourne, Australia after

questions were raised regarding the shafts bearing capacity and serviceability.

Twelve shafts ranging in size between 1100 and 1500mm diameter and 35 to 64m in

lengths were dynamically tested. Nine shafts were socketed into mudstone and the

remaining three into basalt. Six of the shafts socketed into the mudstone were also

statically tested. A hammer with a weight of 20 tons and drop heights between 1.6

and 2.5m was used for the dynamic tests. Dynamic and static tests were done totally

independently and results were compared in a Class A prediction fashion. Dynamic

activation of static pile resistance forces exceeded 3000 tons for some 1500mm

diameter shafts. Direct correlation of ultimate pile capacities was not possible since

maximum values were not usually reached during the static tests. Skin friction

predictions from dynamic tests and values obtained from instrumented shafts under

static tests were remarkably similar. Pile head load-movement relationships

obtained from both testing methods was comparable.

Case 3: Chambers and Morgano (2004). A 457 mm diameter auger-cast pile

was drilled to a depth of 19.8 m on a site in Owensboro, Kentucky. The pile was

tested dynamically to evaluate the static load capacity with further analysis by signal

matching software, CAPWAP. The test was carried out using a 3 tons ram. Four

30

days later, the pile was tested statically using four reaction piles. The test results

from the static load test compares well with the computed static load deflection

determined from CAPWAP analysis.

Based on Case 1 and 2, a reduction on time and cost was anticipated in the

project with the use of high strain dynamic testing as a complimentary to the existing

static load test.

Likins and Rausche (1980) concluded that statistical evaluation of previous

studies and the current compilation of results showed the CAPWAP analysis of

dynamic pile testing data for re-strikes to be very reliable in determination of

ultimate capacity of both driven piles and cast-in-situ piles (e.g. drilled shafts and

auger-cast-CFA piles). Accuracy is slightly better for driven piles than for cast-in-

situ piles. Comparison of CAPWAP results with static load tests on the same piles

shows excellent agreement.

CHAPTER 3

METHODOLOGY

3.1 Introduction

The study was conducted on five data from 3 sites. The data was grouped in

high strain dynamic testing and CAPWAP analysis, and static results. All the data

was analyzed separately.

High strain dynamic test and CAPWAP analysis results from the each of the

data were reviewed in terms of shaft distribution and pile load-settlement. Similarly

the same procedures were employed to instrumented static load test results. The

output of the high strain dynamic test and CAPWAP analysis, and the static load test

analysis was compared to obtain a relationship. The results were compared based on

the pile load – settlement, shaft friction and load bearing capacity. A conclusion is

made for the results obtained. Suggestion and improvement is outlined based on the

comparison as in Figure 3.1.

32

Data of High Strain Dynamic Test & CAPWAP analysis

Data of Static Load Test

Bored Piles

Pile Load - Settlement Pile Load - Settlement

Shaft Distribution Shaft Distribution

Load Bearing Capacity

Relationship

Conclusion & Suggestion

Stage 1 – Data Collection

Stage 2 – Data Analysis & Results

Stage 3 - Summary

Figure 3.1 Flow Chart of the Study

3.2 Data Collection

The first stage of this study included identification of sites that used bored

pile as foundation for the structure. The data required was from instrumented bored

piles that were statically and dynamically load tested. The results were made sure to

be complete for comparison purpose.

33

There were many data obtained but data that contains the static load test

results alone is rejected during this stage of study. In the same manner, data that

contains only the high strain dynamic load test results were rejected.

3.3 Data Analysis and Results

The second stage of this study was to analysis the data that was obtained from

the three sites. Based on the data, a plot on pile load – settlement was tabulated and

plotted. The pile load – settlement was for both the data obtained from the static load

test and the high strain dynamic load test. The results obtained were compared

between each other.

The data were also analyzed based on shaft distribution. The shaft

distribution was obtained from the readings of the strain gauges at different levels for

the static test, whereas for the high strain dynamic load test, results from CAPWAP

were tabulated. The percentage of shaft distribution through the length of the pile in

regards to the total capacity obtained was compared between each other.

In static load test, we obtained a certain capacity. We also obtained certain

capacity from the high strain dynamic load test. Both the capacities were compared

using various methods available and plotted to get a comparison for all the five data

that’s available.

34

3.4 Summary

The third and final stage of the study was to draw a conclusion based on the

results of the analysis. It is understood that from previous study there has been good

correlation between high strain dynamic test and static load test. It was verified in

this stage for the piles in Malaysia.

The result that was derived from the analysis was carefully studied based on

the objectives. The closeness and the deviation between the results obtained were

checked.

If there seem to be deviation between the results, then the causes were

identified. Suggestions were included to improve the quality of the tests and to

refine the tests for better comparison in the future.

CHAPTER 4

DATA ANALYSIS AND DISCUSSION

This chapter presents the data analysis on five instrumented bored piles. The

descriptions of the piles are outlined in following section. All these piles were

founded in two types of formation. Each formation has its own characteristic and

influence on the pile and corresponding results. In Section 4.3, the static test data is

analyzed using various methods available and a brief detail on the employment of the

methods. CAPWAP (Case Pile Wave Analysis Program) is also discussed to analyze

the dynamic test data in Section 4.4. Finally the results are compared between static

load test and dynamic load test.

4.1 Data Description

In a routine static load test, the measurements of load and settlement are

taken at the pile head only. It is impossible to obtain the shaft friction values in

different soil/rock layers. It is also difficult to estimate the contribution of shaft

friction and end bearing accurately. Therefore, piles are instrumented with strain

gauges and extensometer at appropriate depths along the pile. Figure 4.1 shows an

example of the instrumented bore pile in a schematic diagram.

36

Figure 4.1 Instrumented Bore Pile Schematic Diagram

Instrumentation is generally carried out on trial piles where the piles are

loaded three times its estimated working load or preferably to failure to obtain

maximum information. An instrumented pile will enables the evaluation of shaft

resistance, end bearing resistance and the development of these resistances during

static load test. The development of shaft and end bearing resistances represent the

load transfer behavior of the pile system. The cost may be marginal to install

37

additional instruments to a normal static load, but the information obtained is

beneficial for design verifications and optimization of pile lengths for a project of a

big scale.

In a pile dynamic (PDA) test, the pile force and velocity measurements are

obtained by a set of strain gauges and accelerometers attached to the pile head. For

the evaluation of the static pile capacity, relative soil distribution, and soil quake and

damping characteristic, a more rigorous evaluation using the signal matching

technique is utilized with computer software, e.g. Case Pile Wave Analysis Program

(CAPWAP).

4.2 Analysis of field data

The data used for this study are collected from five numbers of instrumented

bored piles. Three of these piles were constructed using dry method of construction

and the other two using wet method of construction. Each pile was statically and

dynamically tested. Typically, the static load test was conducted prior to the PDA

test on each pile.

The data was obtained from construction site at three different sites. Based

on the Geological Map of Selangor (Scale 1:63,360) and the borehole logs, the Site 1

is located in Kenny Hill Formation. A relationship is tabulated in Table 4.1 between

the SPT (Standard Penetration Test), N value obtained from bore hole and the

weathering grade of the rocks. Site 2 and Site 3 are located in Old Alluvium based on

the Geological Map of Johor Bahru (Scale 1:63,360).

38

Kenny Hill Formation consists of monotonous sequence of interbedded

clastic sedimentary rocks such as sandstones, siltstones, shale/mudstone. Frequently

this formation is also referred to as meta-sedimentary with interbedded meta-arenite

and meta-argillite, taking into account that the sedimentary rocks have been partly

metamorphosed into quartzite and phyllite.

Old Alluvium is consider to be of the pliestocene age that comprises of

continental deposits of consolidated sand, clay and boulder beds of fluviate and

shallow-marine origin. Holocene marine clays are nearly absent. Studies of these

types of sediments, mainly from exposures were done by Kumar (1972) in Johor and

Tai (1972) in Singapore. Their measurements of paleo-current directions show a

south to eastward trending sediment transport. From this it was concluded that

Straits of Johor did not exist at the time of deposition of the Older Alluvium (Bosch,

1988). In the drill holes data of the Public Works Department of Singapore, the base

of the formation was found between 100m and 145m below sea-level, while the

highest deposits were found at 45m above sea level.

Table 4.1: Relationship between SPT, N Value and Weathering Grade

Weathering Grade Ting (1979) – SPT Komoo (1986) - SPT

VI 0-20

V

<50

20-50

IV >50 50-200

III *CRR<70%

*CRR-Core Recovery Rate

Table 4.2 shows the subsoil classification based on the weathering grade.

Based on the geological condition, Kenny Hill formation at Site 1 predominantly

Grade IV material with SPT – N value greater than 50. The subsoil exists at shallow

depth, thus the pile length ranges from 7m to 12m. These piles can be categorized as

short piles.

39

Old Alluvium formation at Site 2 and Site 3 are generally overlain by

comparatively weak alluvium called young alluvium to depths of between 10 to 30m.

The SPT, N values are generally less than 15. The old alluvium underlies the young

alluvium extends to depths beyond the toe of all piles. The SPT, N values in this

type of formation are generally varies between 20 and 100. All the pile length in this

formation ranges between 40m to 50m. These piles can be categorized as long piles.

The location of the site and the reference number; date of casting as well as

the length and diameter of the piles are tabulated in Table 4.3. The piles from Site 1

are cylindrical with diameter of 750mm. The length of the piles ranges between 7m

to 12m. All these piles were cast in July of 2003. The pile from Site 2 pile is

1000mm in diameter and was cast on the end of 2002. The length of the pile is about

48m. The pile from Site 3 is also cylindrical with diameter 1200mm and length of

42m. The pile was cast at the end of September 2004.

Static load test was conducted on the piles at some time after the installation.

The PDA test was carried out after a certain interval of time. The date of testing and

the interval durations for the static and PDA tests are tabulated in Table 4.4.

The waiting period would allow for the curing of concrete and set-up of the

soil. The time interval between the tests will govern the capacity of the piles because

it related to the development of shaft friction along the pile. The longer the time

interval, it is expected that the shaft contribution would be larger towards the

capacity.

40

Table 4.2: Subsoil Classification (Komoo and Morgana, 1988)

Weathering Classification Grade Description

Residual Soils VI All rock material is converted to soil.

The mass structures and material

fabric are destroyed. The material has

not been significantly transported.

Completely Weathered V All rock material is decomposed

and/or disintegrated to soil. The

original mass structure is still largely

intact.

Highly Weathered IV More than 50% of the rock material is

decomposed and/or disintegrated to

soil. Fresh or discolored rock is

present either as a discontinuous

framework or corestones.

Moderately Weathered III Less than 50% of the rock material is

decomposed and/or disintegrated to

soil. Fresh or discolored rock is

present either as a discontinuous

framework or corestones.

Slightly Weathered II Discoloration indicates weathering of

rock material and discontinuity

surfaces. All the material may be

discolored by weathered and maybe

somewhat weaker than in its fresh

condition.

Fresh Rock I No visible sign of rock material

weathering, some discoloration on

major discontinuity surfaces.

41

Table 4.3: Pile Details

Location Pile ReferencePile Diameter

(mm)

Pile Length

(m)

Date of

Casting

Pile 1 750 7 04/07/2003

Pile 2 750 9 11/07/2003Site 1

Pile 3 750 12 17/07/2003

Site 2 Pile 4 1000 48.2 28/12/2002

Site 3 Pile 5 1200 41.5 24/09/2004

Static load test was conducted on piles at Site 1 within one month of casting.

The piles at Site 1 are consists of short piles, therefore there is no need for long wait

period to allow for soil-setup since large contribution is expected from the base of

the piles. Pile 4 and Pile 5 was tested three weeks to two months from the casting

date.

PDA tests were conducted on the piles that were earlier tested statically.

Piles at Site 1 and Site 3 were tested after about seven to eleven weeks after casting

the piles. Pile 4 at Site 2 was tested about 9 months after conducting static load test.

A large shaft friction is expected for Pile 4 from the PDA test results due to the wait

period.

The piles at Site 1 were tested 3.3 times the working load or to failure and

piles at Site 2 and Site 3 were tested 2.5 of working load or to failure. Table 4.5

show the maximum load applied to the pile during static load test.

42

Table 4.4: Date and time interval between tests

Pile

ReferenceS.L.T. Date

Time Between

Casting and

S.L.T.

(days)

PDA Test

Date

Time Between

S.L.T. and

PDA Test

(days)

Pile 1 18/07/2003 14 11/09/2003 55

Pile 2 30/07/2003 19 03/09/2003 35

Pile 3 12/08/2003 26 03/09/2003 22

Pile 4 18/01/2003 21 07/10/2003 262

Pile 5 13/11/2004 50 08/12/2004 25

Note: S.L.T. = Static Load Test

The working load and test load and the pile settlements for the given

working load and test load from both static load and pile driving analyzer are

tabulated in Table 4.6. All the tested piles have achieved the required test load of

two times the working load. It can be seen from Table 4.6 that the short piles exhibit

small settlements for both static and dynamic test. Large settlements were noted for

the long piles founded in old alluvium soil. Overview of the settlement results shows

that the settlements predicted from the PDA tests is lower compared to that of static

load test. The settlement at working load for PDA tests is observed to be plus or

minus 2mm of that obtained from static load tests.

Table 4.5: Maximum Load Implied During Static Load Test

Pile Reference Maximum Load – Static Load Test (kN)

Pile 1 10,064 (3.3xWL)

Pile 2 10,000 (Failure)

Pile 3 10,027 (3.3xWL)

Pile 4 14,974 (2.5xWL)

Pile 5 16,573 (2.0xWL)

Note: WL = working load

43

Table 4.6: Pile Settlement

Settlement (mm)

Static Load Test PDA TestPile

Reference

Working

Load,WL

(kN)

Test

Load,TL

(2xWL)

(kN)

WL TL WL TL

Pile 1 3,000 6,000 2.3 4.5 2.3 4.8

Pile 2 2,250 4,500 2 4.9 2.3 6.3

Pile 3 3,000 6,000 3.5 9.8 2.4 5.1

Pile 4 5,800 11,600 6.5 15 5.3 10.7

Pile 5 8,400 16,800 7 52 5.3 12

4.3 Analysis of Static Load Test Data

There are various methods of interpretation proposed by various authors to

obtain the pile failure load capacity from load-deformation curve obtained in a static

load test (Fellenius , 1980). The following methods are used for obtaining the pile

capacities:

1) Davisson’s method,

2) Fuller and Hoy method,

3) Butler and Hoy method,

4) Brinch Hanson’s 90% criteria method,

5) De Beers method,

6) Mazurkie method, and

7) Chin’s method.

The following paragraphs are discussed briefly the interpretation of the results of

static load test as outlined by Fellenius (1980).

44

Davisson’s method is proposed by Davisson (1972) to obtain the load

corresponding to the movement which exceeds the elastic compression of the pile by

a value of 4mm plus a factor equal to the diameter of the pile divided by 120. This

method was developed in conjunction with the wave equation analysis.

Fuller and Hoy (1970), proposed a simple definition that the failure load is

equal to the test load for where the load movement curve is sloping 0.14mm/kN.

This method penalizes the long pile because the larger elastic movements occurring

for a long pile, as opposed to the short pile, causes the slope 0.14mm/kN to occur

sooner.

Butler and Hoy (1977), developed the above definition defining the failure

load as the load at the intersection of the tangent sloping 0.14mm/kN and the tangent

to the inertial straight portion of the curve, or to a line that is parallel to the rebound

portion of the curve. Butler and Hoy took into account the elastic deformation,

substantially offsetting the length effect.

Brinch Hansen (1963) defines failure as the load that gives twice the

movement of the pile head as obtained for 90% of the load. It is also known as

Brinch Hansen’s 90% criterion.

De Beer (1967) and De Beer & Wallays (1972) proposed a method, where the

load movement values are plotted in double logarithmic diagram. When, the value

fall on two approximately straight lines, the intersection of these defines the failure

value.

Mazurkiewicz (1972) illustrates a method where a series of equal pile head

movement lines are arbitrarily chosen and the corresponding load lines are

constructed from the intersection of the movement lines with the load movement

45

curve. From the intersection of each load line with the load axis, a 45º line is drawn

to intersect with the next load line. These intersections fall approximately on a

straight line the intersection of which with the load axis defines the failure load. This

method considers an assumption that the load movement curve is approximately

parabolic.

Chin (1970 and 1971) proposed a method that assumes that the load

movement curve is of hyperbolic shape when the load approaches the failure load. In

this method, each load value is divided with its corresponding movement value and

the resulting value is plotted against the movement. After some variation, the plotted

values will fall on a straight line. The inverse slope of this line is the failure load.

All the above methods will provide different ultimate capacity for the same

pile load deformation data. The pile capacity obtain for the piles are tabulated in

Table 4.7. A typical graph consists all the failure loads obtained on from all the

methods is as in Figure 4.2.

Table 4.7: Pile capacity for static load test using various methods

MethodsPile 1

(kN)

Pile 2

(kN)

Pile 3

(kN)

Pile 4

(kN)

Pile 5

(kN)

1 8000 7150 7650 17500 14750

2 10600 10250 10100 21000 16833

3 10100 9300 9800 20000 16417

4 9630 9315 9180 19530 15300

5 8167 7950 8000 21333 16364

6 11929 12250 10929 21250 18400

7 11600 11467 11882 22167 19380

46

COMPARISON OF FAILURE CRITERIA

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

11000

12000

13000

14000

15000

0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300

Pile Top Settlement (mm)

Pil

e T

op L

oad

(kN

)

1. Davisson’s Method – 7,650kN

2. Fuller & Hoy’s Method – 10,100kN

3. Butler & Hoy’s Method – 9,800kN

4. Brinch Hansen’s 90% Criterion – 9,180kN

5. De Beer’s Method – 8,000kN

6. Mazurkiewicz’s Method – 10,929kN

7. Chin’s Method – 11,882kN

1

2

3

4

5

6

7

Figure 4.2 Typical Comparisons of Methods for Pile 3

As presented in Table 4.3, Davisson’s method gives the lowest value

compared to all the other methods for all the piles. The highest capacity values for

the piles were obtained from Chin’s method. The values obtained from Chin’s

method are 20% to 40% higher than Davisson’s method. The ultimate capacity

obtained from De Beer’s method for the piles are higher by 5% to 20% of the

capacity obtained from Davisson’s method. Therefore, the capacity from the

Davisson’s method is used because it is more conservative, allows more static tests

to reach “failure” rather than other methods (Likins et.al, 1996).

47

4.4 Analysis of PDA test Data

Pile capacity obtained from the CAPWAP analysis on the PDA test results is

considered to be fully mobilized if the net set of 3 mm at the time of testing (PDA

Manual, 1997). In a PDA test, the capacity is obtained from CAPWAP analysis for a

selected blow.

In the CAPWAP method, the pile is modeled by a series of continuous pile

segments and the soil resistance is modeled by elasto-plastic springs (static

resistance) and dashpots (dynamic resistance) as in Figure 4.3. The force and

acceleration data from the PDA are used to quantify pile force and pile motion,

which are two of the three unknowns. The remaining unknown is the boundary

conditions, which are defined by the soil model. First reasonable estimates of the

soil resistance distribution and quake and damping parameters are made. Then the

measured acceleration is used to set the pile model in motion. The program then

computes the equilibrium pile head force, which can be compared to the PDA

determined force. Initially, the computed and measured pile head forces will not

agree with each other. Adjustments are made to the soil model assumptions and the

calculation process repeated.

48

SSooiill sseeggmmeennttlleennggtthh

MMaassss ddeennssiittyy,,MMoodduulluuss,, EE

SSpprriinngg ((ssttaattiicc rreessiissttaannccee))DDaasshhppoott ((ddyynnaammiicc rreessiisstt))

WWaavveessppeeeedd,, cc == ((EE// ))

TTrraavveell ttiimmee,, tt == LL//cc

t

t

t

t

t

t

t

XX--sseeccnn aarreeaa,, AA

PPiillee IImmppeeddaannccee,,ZZ == EEAA//cc

PPiillee sseeggmmeennttlleennggtthh

Model

Figure 4.3 Pile – Soil Model Used in the CAPWAP Analysis

With each analysis, the program evaluates the match quality by summing the

absolute values of the relative differences between the measured and computed

waves. The program computes a match quality number for each analysis. Through

trial and error iteration adjustment process to the soil model, the soil model is refined

until no further agreement can be obtained between measured and computed pile

forces. Figure 4.4 presents the iteration program used in CAPWAP analysis. The

resulting model is then considered the best estimate of the static pile capacity, the

49

soil resistance distribution and the soil quake and damping characteristic. The

CAPWAP provides an automated analysis for wave matching primarily which need

subsequent adjustments to the parameters to refine the match quality (smaller match

quality number).

3333 CCoommppaarree FFcc wwiitthh mmeeaassuurreedd FFmm

vvvvmvvmvvvvvvmmvvvv FFmm FFcc

11 SSeett uupp ppiillee mmooddeell aanndd aassssuummeeRRsshhaafftt aanndd RRttooee

2222 AAppppllyy oonnee mmeeaassuurreedd ccuurrvvee ((vvmm));;CCaallccuullaattee ccoommpplleemmeennttaarryy FFcc

5555 GGoo ttoo sstteepp22

4444 AAddjjuusstt RRsshhaafftt aanndd RRRttRRttooooeeee

RRsshhaafftt

RRRRttttoottooeeee

RReeppeeaatt uunnttiill mmaattcchhiiss ssaattiissffaaccttoorryy

Figure 4.4 CAPWAP Method – Iteration Program

4.5 Comparison between Static Load Test and Pile Driving Analyser

Table 4.8 summarizes the comparison between the Davisson’s method for the

static capacity and the capacity obtained from CAPWAP analysis. The static load

test results are apparently lower than the results obtained from PDA test. Pile 4 was

tested after a very long duration therefore the capacity of that pile is 30% higher than

50

the capacity obtained from static load tests. All the other piles except for Pile 2

exhibit 20% higher capacity relative to static load test. Pile 2 was tested to 10,000kN

and the displacement was large. After a wait period the pile was tested dynamically

but, the results shows that there has been no appreciable gain in soil setup. Refer to

Table 4.2 for time between static load test and PDA test.

The overall results indicate that the gain in capacity is not appreciable in the

weathered Kenny Hill Formation – Site 1. However at Site 2 and Site 3, the capacity

appreciation reached 30%, indicating capacity gain with time for the young alluvium

underlain with old alluvium. It is not clear if the gain in the capacity was actually

due to soil setup or due to the difference in testing method.

Table 4.8: Pile Capacity

Pile Capacity (kN) Location

Pile

Reference Static Load Test PDA Test

Pile 1 8,000 9,429

Pile 2 7,150 5,750Site 1

Pile 3 7,650 9,550

Site 2 Pile 4 17,500 22,861

Site 3 Pile 5 14,750 17,504

It should be noted that the load considered in this comparison was based on

estimation made based on the ultimate capacity of a pile obtained from Davisson’s

method. This ultimate capacity is contributed by the shaft and end bearing.

However, it is not possible to subtract the contribution of shaft friction or end bearing

from the total capacity obtained. Therefore, comparing the shaft resistance based on

the Davisson’s failure load is not possible.

51

It is also noted that during static load test the piles were tested to 3.3 times the

working load or to failure at Site 1, 2.5 times the working load at Site 2, and 2.0

times the working load at Site 3. The instruments installed in the pile at different

level will provide the load transfer at that location, thus enable the determination of

shaft friction for the pile.

CAPWAP analysis using wave matching technique is used for derivation of

shaft friction distribution for the dynamic load test. Table 4.9 summarizes the

percentage of load distribution toward the distribution of the shaft and end bearing

based on the available information from CAPWAP analysis.

Table 4.9: Shaft and End Bearing contributions

Percentage (%)

Static Load Test PDA TestPile

ReferenceShaft End Bearing Shaft End Bearing

Pile 1 65 35 36 64

Pile 2 64 36 45 55

Pile 3 92 8 53 47

Pile 4 99 1 89 11

Pile 5 88 12 70 30

In static load test, for the piles at Site 1, the contribution of shaft friction was

noted to be higher as compared to end bearing. This scenario occurred even though

the piles are short due to large movement at the base of the pile. The pile load was

fully mobilized causing the toe to displace. Since the base of the pile started to be

displaced, the corresponding load would be taken by the shaft.

On the other hand, the PDA test were conducted based on the force induced

from the ram was able to mobilize the shaft resistance and a major contribution of the

52

resistance was transferred to the base. This load is lower compared to when it was

statically loaded. Therefore, the load was not sufficient to mobilize the pile base.

Hence, the contribution from the base is larger than the shaft.

The scenario is different for Site 2 and Site 3 as the piles are long. The load

applied is taken by the shaft and only part of it had been transferred to the base. This

is mainly because of the soil-setup or normally called as re-moulded strength of the

alluvium soil. Site 2 and Site 3 results for PDA agrees well with that of static load

test, where the major contributions are from the shaft of the piles.

CHAPTER 5

CONCLUSION AND RECOMMENDATION FOR FUTURE STUDY

5.1 Conclusion

The results obtained from the analysis enables a platform for comparison

between static load test results and that of dynamic test results. Based on the output,

the following conclusions can be derived:

1) The distribution of load along the pile shaft dependant on the time interval

and the effect of soil setup. The longer the time interval for the pile that been

analyzed, the shaft distribution apparently contributed substantially towards

the capacity;

2) The settlements of the piles are plus minus 2mm between static load test and

dynamic load test at working load. At test load, dynamic load test predicted

settlement is smaller compared to that of static load settlement measured;

3) The load bearing capacity of the piles are dependant on the method used to

estimate the ultimate capacity. Based on the results, the Davisson’s method

is comparable to that of CAPWAP analysis for both static and dynamic test.

54

5.2 Recommendations for Future Study

This study focuses on the comparison of the result of Maintained Load Test

and PDA. In future, studies can be conducted in the following grey areas:

1) Comparison between Static Load Test and Statnamic Test;

2) Comparison between High Strain Dynamic Test and Statnamic Test;

3) Incoporating the impedance of the piles precisely in Instrumented

Static Load Test;

4) Evaluation of High Strain Dynamic Test on Displacement Piles and

Replacement Piles;

5) Effects of Time in different soil to determine the setup factors with

the use of Dynamic Pile Test;

6) GRLWEAP and its effectiveness in predictions of pile drivability.

55

REFERENCES

Barends, Frans B. J., (1992). Application of Stress Wave Theory to Piles. A. A.

Balkema, Netherlands.

Bengt. H. Fellenius (1980). The Analysis of Results from Routine Pile Load Test.

Ground Engineering, Geotechnical News Magazine, September 1980.

Bengt. H. Fellenius (1990). Static or Dynamic Test – Which To Trust?

Geotechnical News Magazines, December 1990, Vol. 8, No.4.

Bengt. H. Fellenius (2001). From Strain Measurements to Load in an

Instrumented Pile. Geotechnical News Magazine, Vol. 19, No. 1.

Canadian Foundation Engineering Manual, (1993). Third edition Canadian

Geotechnical Society, Technical Committee on Foundations, Canada.

Chin Y.K., Tan S.L. and Tan S.B. (1985). Ultimate Load Tests on Instrumented

Bored Piles in Singapore Old Alluvium. Eight Southeast Asian Geotechnical

Conference, Kuala Lumpur.

Coduto, Donald P., (1994). Foundation Design: Principles and Practices.

Prentice Hall, United States of America.

56

Das, Braja M. (2004). Principles of Foundation Engineering. Fifth edition

Brooks/Cole, United States of America.

Frank Rausche, Fred Moses, George G. Goblen (1972). Soil Resistance

Predictions from Pile Dynamics. Journal of the Soil Mechanics and

Foundation Division ASCE, September 1972.

Garland Likins, Frank Rausche (2004). Correlation of CAPWAP with Static Load

Test. Proceedings of The Seventh International Conference on the

Application of Stresswave Theory to Piles 2004, The Institute of Engineers

Malaysia.

Goble Rausche Likins and Associates (1996). CAPWAP Introduction to Dynamic

Pile Testing Methods. Pile Dynamic Inc.

Institute of Engineers Malaysia, (2004). The Seventh International Conference on

the Application of Stresswave Theory to Piles. Geotechnical Engineering

Technical Division, Malaysia.

Jean Authier, Bengt. H. Fellenius (1981). Pile Integrity, Soil Setup and

Relaxation. Second Seminar on the Dynamics of Pile Driving. Pile Research

Laboratory, Department of Civil Engineering, University of Colorado,

Boulder.

Jorge William Beim, Reynaldo Luiz De Rosa (2004). Comparison of Static and

Dynamic Load Tests Results. Proceedings of The Seventh International

Conference on the Application of Stresswave Theory to Piles, The Institute of

Engineers Malaysia.

Paul Hewitt, Dr. Wong K.Y. and Gue S.S. (1995). Properties of Kenny Hill

Formation for Piled Raft Foundation Design, Kuala Lumpur. Forum on Soil

and Rock Properties, Geotechnical Society of Malaysia.

57

Pile Driving Analyser (1995). PAK User Manual. Pile Dynamic Inc.

Sharma, Hari D. and Prakash, Shamsher, (1990). Pile Foundation in Engineering

Practice. Wiley-Interscience Publication, New York.

Tomlinson, M. J., (2001). Foundation Design and Construction. Seventh edition

Pearson Education, England.

58

Appendix A

Site 1/Pile 1

DAVISSON'S METHOD

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

5500

6000

6500

7000

7500

8000

8500

9000

9500

10000

10500

11000

0 5 10 15 20 25 30 35 40 45 50 55 60

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

8000 kN

E = 28.44 kN/mm2

A = 441 786 mm2

L = 7 000 mm

P = (AE )/L

P = 1795

x = 4 + (750/120)

x = 10.25

P = 8 000 kN

59

FULLER AND HOY'S METHOD

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

5500

6000

6500

7000

7500

8000

8500

9000

9500

10000

10500

11000

0 5 10 15 20 25 30 35 40 45 50 55 60

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

10600 kN

Slope

1 kN

0.14 mm

P = 10 600 kN

60

BUTLER AND HOY'S METHOD

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

5500

6000

6500

7000

7500

8000

8500

9000

9500

10000

10500

11000

0 5 10 15 20 25 30 35 40 45 50 55 60

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

10 100 kN

Slope

1 kN

0.14 mm

P = 10 100 kN

61

BRINCH-HANSEN'S 90% METHOD

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

5500

6000

6500

7000

7500

8000

8500

9000

9500

10000

10500

11000

0 5 10 15 20 25 30 35 40 45 50 55 60

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

90% x 10 700 = 9 630 kN

10 700 kN

P’= 10 700 kN @ set = 50 mm

90% of P @ 50% of set

90% x 10700 = 9630 kN @ 50% x 50 = 25 mm

P = 9 630 kN

62

DEBEER'S METHOD

100

1000

10000

100000

0 1 10 100

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

8 167 kN

P = 8 167 kN

63

MAZURKIEWICZ'S METHOD

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

11000

12000

13000

14000

15000

-20 -15 -10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

11 929 kN

P = 11 929 kN

64

CHIN-KONDNER'S METHOD

0.0000

0.0010

0.0020

0.0030

0.0040

0.0050

0.0060

0 5 10 15 20 25 30 35 40 45 50 55 60

Pile Top Settlement (mm)

Pile

Top

Set

tlem

ent/

Pile

Top

Loa

d (

mm

/kN

)

(20.3, 0.0023)

c = 0.00055

y = mx + c

c = 0.00055

m = (0.0023 – 0.00055)/20.3

m = 8.62 x 10-5

P = 1/(8.62 x 10-5)

P = 11 600 kN

65

COMPARISON OF FAILURE CRITERIA

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

5500

60006500

7000

7500

8000

8500

9000

9500

10000

10500

11000

11500

12000

0 5 10 15 20 25 30 35 40 45 50 55 60

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

672

34

5

1

Note:

1. Davisson’s method

2. Fuller and Hoy method

3. Butler and Hoy method

4. Brinch Hanson’s 90% criterion method

5. De Beers method

6. Mazurkie method

7. Chin’s method

66

Appendix B

Site 1/Pile 2

DAVISSON'S METHOD

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

5500

6000

6500

7000

7500

8000

8500

9000

9500

10000

10500

11000

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

) 7 160 kN

E = 24.60 kN/mm2

A = 441 786 mm2

L = 9 000 mm

P = (AE )/L

P = 1208

x = 4 + (750/120)

x = 10.25

P = 7 150 kN

67

FULLER AND HOY'S METHOD

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

5500

6000

6500

7000

7500

8000

8500

9000

9500

10000

10500

11000

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

10 250 kN

Slope

1 kN

0.14 mm

P = 10 250 kN

68

BUTLER AND HOY'S METHOD

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

5500

60006500

7000

7500

8000

8500

9000

9500

10000

10500

11000

11500

12000

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

9 300 kN

Slope

1 kN

0.14 mm

P = 9 300 kN

69

BRINCH-HANSEN'S 90% METHOD

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

5500

6000

6500

7000

7500

8000

8500

9000

9500

10000

10500

11000

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

90% x 10 350 = 9 315 kN

10 350 kN

P’= 10 350 kN @ set = 110 mm

90% of P @ 50% of set

90% x 10350 = 9315 kN @ 50% x 110 = 55 mm

P = 9 315 kN

70

DEBEER'S METHOD

100

1000

10000

100000

0 1 10 100 1000

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

7 950 kN

P = 7 950 kN

71

MAZURKIEWICZ'S METHOD

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

11000

12000

13000

-20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

12 250 kN

P = 12 250 kN

72

CHIN-KONDNER'S METHOD

0.0000

0.0010

0.0020

0.0030

0.0040

0.0050

0.0060

0.0070

0.0080

0.0090

0.0100

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100

Pile Top Settlement (mm)

Pile

Top

Set

tlem

ent/

Pile

Top

Loa

d (

mm

/kN

)

(48.16, 0.0053)

c = 0.0011

y = mx + c

c = 0.0011

m = (0.0053 – 0.0011)/48.16

m = 8.72 x 10-5

P = 1/(8.72 x 10-5)

P = 11 467 kN

73

COMPARISON OF FAILURE CRITERIA

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

11000

12000

13000

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

76

2

34

1

5

Note:

1. Davisson’s method

2. Fuller and Hoy method

3. Butler and Hoy method

4. Brinch Hanson’s 90% criterion method

5. De Beers method

6. Mazurkie method

7. Chin’s method

74

Appendix C

Site 1/Pile 3

DAVISSON'S METHOD

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

5500

6000

6500

7000

7500

8000

8500

9000

9500

10000

10500

11000

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

7 650 kN

E = 28.98 kN/mm2

A = 441 786 mm2

L = 12 000 mm

P = (AE )/L

P = 1067

x = 4 + (750/120)

x = 10.25

P = 7 650 kN

75

FULLER AND HOY'S METHOD

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

5500

6000

6500

7000

7500

8000

8500

9000

9500

10000

10500

11000

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

10 100 kN

Slope

1 kN

0.14 mm

P = 10 100 kN

76

BUTLER AND HOY'S METHOD

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

5500

6000

6500

7000

7500

8000

8500

9000

9500

10000

10500

11000

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

9 800 kN

Slope

1 kN

0.14 mm

P = 9 800 kN

77

BRINCH-HANSEN'S 90% METHOD

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

5500

6000

6500

7000

7500

8000

8500

9000

9500

10000

10500

11000

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

90% x 10 200 = 9 180 kN

10 200 kN

P’= 10 200 kN @ set = 60 mm

90% of P @ 50% of set

90% x 10200 = 9180 kN @ 50% x 60 = 30 mm

P = 9 180 kN

78

DEBEER'S METHOD

100

1000

10000

100000

0 1 10 100

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

8 000 kN

P = 8 000 kN

79

MAZURKIEWICZ'S METHOD

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

11000

12000

-20 -15 -10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

10 929 kN

P = 10 929 kN

80

CHIN-KONDNER'S METHOD

0.0000

0.0010

0.0020

0.0030

0.0040

0.0050

0.0060

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80

Pile Top Settlement (mm)

Pile

Top

Set

tlem

ent/

Pile

Top

Loa

d (

mm

/kN

)

(34.46, 0.0037)

c = 0.008

y = mx + c

c = 0.008

m = (0.0037 – 0.008)/34.46

m = 8.4 x 10-5

P = 1/(8.4 x 10-5)

P = 11 882 kN

81

COMPARISON OF FAILURE CRITERIA

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

11000

12000

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

76

32

4

1

5

Note:

1. Davisson’s method

2. Fuller and Hoy method

3. Butler and Hoy method

4. Brinch Hanson’s 90% criterion method

5. De Beers method

6. Mazurkie method

7. Chin’s method

82

Appendix D

Site 2/Pile 4

DAVISSON'S METHOD

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

11000

12000

13000

14000

15000

16000

17000

18000

19000

20000

21000

22000

0 10 20 30 40 50 60 70 80 90 100 110 120

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

17 500 kN

E = 35.07 kN/mm2

A = 785 398 mm2

L = 48 200 mm

P = (AE )/L

P = 571

x = 4 + (1000/120)

x = 12.3

P = 17 500 kN

83

FULLER AND HOY'S METHOD

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

11000

12000

13000

14000

15000

16000

17000

18000

19000

20000

21000

22000

0 10 20 30 40 50 60 70 80 90 100 110 120

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

21 000 kN

Slope

1 kN

0.14 mm

P = 21 000 kN

84

BUTLER AND HOY'S METHOD

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

11000

12000

13000

14000

15000

16000

17000

18000

19000

20000

21000

22000

0 10 20 30 40 50 60 70 80 90 100 110 120

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

20 000 kN

Slope

1 kN

0.14 mm

P = 20 000 kN

85

BRINCH-HANSEN'S 90% METHOD

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

11000

12000

13000

14000

15000

16000

17000

18000

19000

20000

21000

22000

0 10 20 30 40 50 60 70 80 90 100 110 120

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

21 700 kN

90% x 21 700 = 19 530 kN

P’= 21 700 kN @ set = 110 mm

90% of P @ 50% of set

90% x 21700 = 19530 kN @ 50% x 110 = 55 mm

P = 19 530 kN

86

DEBEER'S METHOD

100

1000

10000

100000

0 1 10 100 1000

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

) 21 333 kN

P = 21 333 kN

87

MAZURKIEWICZ'S METHOD

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

11000

1200013000

14000

15000

16000

17000

18000

19000

20000

21000

22000

23000

24000

-30 -20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

21 250 kN

P = 21 250 kN

88

CHIN-KONDNER'S METHOD

0.0000

0.0010

0.0020

0.0030

0.0040

0.0050

0.0060

0.0070

0.0080

0.0090

0.0100

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140

Pile Top Settlement (mm)

Pile

Top

Set

tlem

ent/

Pile

Top

Loa

d (

mm

/kN

)

(26.6, 0.0018)

c = 0.0006

y = mx + c

c = 0.0006

m = (0.0018 – 0.0006)/26.6

m = 4.5 x 10-5

P = 1/(4.5 x 10-5)

P = 22 167 kN

89

COMPARISON OF FAILURE CRITERIA

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

11000

12000

13000

14000

15000

16000

17000

18000

19000

20000

21000

22000

23000

0 10 20 30 40 50 60 70 80 90 100 110 120 130

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

6 5 72

43

1

Note:

1. Davisson’s method

2. Fuller and Hoy method

3. Butler and Hoy method

4. Brinch Hanson’s 90% criterion method

5. De Beers method

6. Mazurkie method

7. Chin’s method

90

Appendix E

Site 3/Pile 5

DAVISSON'S METHOD

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

11000

12000

13000

14000

15000

16000

17000

18000

19000

20000

0 10 20 30 40 50 60 70 80 90 10

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

0

14 750 kN

E = 27.07 kN/mm2

A = 1 130 973 mm2

L = 41 500 mm

P = (AE )/L

P = 738

x = 4 + (1200/120)

x = 14

P = 14 750 kN

91

FULLER AND HOY'S METHOD

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

11000

12000

13000

14000

15000

16000

17000

18000

19000

20000

0 10 20 30 40 50 60 70 80 90 10

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

0

16 833 kN

Slope

1 kN

0.14 mm

P = 16 833 kN

92

BUTLER AND HOY'S METHOD

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

11000

12000

13000

14000

15000

16000

17000

18000

19000

20000

0 10 20 30 40 50 60 70 80 90 10

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

0

16 417 kN

Slope

1 kN

0.14 mm

P = 16 417 kN

93

BRINCH-HANSEN'S 90% METHOD

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

11000

12000

13000

14000

15000

16000

17000

18000

19000

20000

0 10 20 30 40 50 60 70 80 90 10

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

0

17 200 kN

90% x 17 200 = 15 300 kN

P’= 17 200 kN @ set = 80 mm

90% of P @ 50% of set

90% x 17200 = 15300 kN @ 50% x 80 = 40 mm

P = 15 300 kN

94

DEBEER'S METHOD

100

1000

10000

100000

0 1 10 100 1000

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

) 16 364 kN

P = 16 364 kN

95

MAZURKIEWICZ'S METHOD

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

11000

12000

13000

14000

15000

16000

17000

18000

19000

20000

21000

-30 -20 -10 0 10 20 30 40 50 60 70 80 90 100

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

18 400 kN

P = 18 400 kN

96

CHIN-KONDNER'S METHOD

0.0000

0.0010

0.0020

0.0030

0.0040

0.0050

0.0060

0.0070

0.0080

0.0090

0.0100

0 10 20 30 40 50 60 70 80 90 10

Pile Top Settlement (mm)

Pile

Top

Set

tlem

ent/

Pile

Top

Loa

d (

mm

/kN

)

0

(54, 0.0033)

c = 0.0005

y = mx + c

c = 0.0005

m = (0.0033 – 0.0005)/54

m = 5.16 x 10-5

P = 1/(5.16 x 10-5)

P = 19 380 kN

97

COMPARISON OF FAILURE CRITERIA

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

11000

12000

13000

14000

15000

16000

17000

18000

19000

20000

0 10 20 30 40 50 60 70 80 90 10

Pile Top Settlement (mm)

Pile

Top

Loa

d (

kN

)

0

76

54

32

1

Note:

1. Davisson’s method

2. Fuller and Hoy method

3. Butler and Hoy method

4. Brinch Hanson’s 90% criterion method

5. De Beers method

6. Mazurkie method

7. Chin’s method