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Geotechnical Engineering Journal of the SEAGS & AGSSEA Vol. 51 No. 2 June 2020 ISSN 0046-5828

Geotechnical Engineering Journal of the SEAGS & AGSSEA

Vol. 51 No. 2 June 2020

ISSN 0046-5828

Honouring Prof. Harry G Poulos Lead Guest Editor: Prof. John Carter

Liquefaction Induced Downdrag for the Juan Pablo II Bridge at the 2010

Maule Earthquake in Chile, after Fellenius et al., 2020. Some Factors that Influence the Prediction of the Behaviour of Piled Rafts

via Simplified (Numerical) Analyses, after Cunha et al., 2020.

Biodegradable Prefabricated Vertical Drains: from Laboratory to Field Studies, after Thanh Trung Nguyen et al., 2020.

P-Cone: A Novel Cone Penetration Test Device for Deep Foundation Design, after Hai and Anand, 2020.

Numerical and Simplified Methods for Soil-Pile Interaction Analysis, after Dezi et al., 2020.

Evaluation of Analytical and Numerical Techniques to Simulate Curtain Pile Walls in a Tropical Soil of the Federal District of Brazil, after Jacazz et

al., 2020.

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Pile-toeLoad-movementPivot Graph

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At TestRt = 380 kNδt = 15 mm

Rt = 750 kN

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Figure 6 Long-term distributions of load and resistance for a single pile

Journal of the Sponsored by

GEOTECHNICAL ENGINEERING

Note:

GOUW Tjie liong and Anthony GUNAWAN paper is on page 9 onward of this PDF.


Prof. Harry G. Poulos obtained a Civil Engineering degree from the

University of Sydney in 1961, and then went on to do a Ph.D. degree

in Soil Mechanics, graduating in 1965. He worked with the consulting

firm of McDonald Wagner and Priddle for a year before joining the

Department of Civil Engineering at Sydney University in 1965. He

was appointed a Professor in 1982, a position which he held until his

retirement in 2001. In 1989, he joined the consulting firm of Coffey

Partners International and is currently a Senior Principal with the

Coffey Group. He is also an Emeritus Professor at the University of

Sydney, and an Adjunct Professor at the Hong Kong University of

Science and Technology.

He has published books and technical papers on foundation

settlements, pile foundations, and offshore geotechnics. His main research interests continue to be in deep

foundations and their application to high-rise buildings, and to problems relating to ground movements near

foundations.

He has been involved in a large number of major projects in Australia and overseas including the Docklands

Project in Melbourne, the Crown tower development in Sydney, Egnatia Odos highway project in Greece,

high-rise foundation problems in Hong Kong, the Emirates twin Towers in Dubai, the Burj Khalifa tower

in Dubai, the Incheon 151 Tower in Korea, the Dubai Creek Tower in Dubai, the MahaNakon building in

Bangkok, and the Dubai tower in Doha, Qatar.

In 1993, he was made a Member of the Order of Australia for services to engineering. He was elected a

Fellow of the Australian Academy of Science in 1988, a Fellow of The Australian Academy of

Technological Sciences and Engineering in 1996, and an Honorary Fellow of the Institution of Engineers

Australia in 1999. In 2010, he was elected a Distinguished Member of the American Society of Civil

Engineers, the first Australian to receive this honour, and in 2014, he was elected as a Foreign Member of

the US National Academy of Engineering.

He has received a number of awards and prizes, including the Kevin Nash Gold Medal of the International

Society for Soil Mechanics and Geotechnical Engineering in 2005. He was the Rankine Lecturer in 1989

and the Terzaghi Lecturer in 2004, and was selected as the Australian Civil Engineer of the Year for 2003

by the Institution of Engineers Australia. In 2017, he received the ASCE Outstanding Projects And Leaders

(OPAL) award for design.

Prof. John Carter has more than 30 years’ experience in teaching,

research and consulting in civil, geotechnical and offshore engineering.

His research interests include analytical and numerical modeling, soil-

structure interaction, rock mechanics, the behaviour of cemented and

uncemented carbonate soils, soft soil engineering, tunnelling, and

offshore foundations. He has attracted more than $5 million in

competitive research funding and been associated with development

projects attracting additional grants of more than $4 million. He is the

author of several hundred refereed technical papers in geotechnical

engineering and engineering mechanics, covering a diverse range of

topics from theoretical mechanics to experimental applications. His

research output includes a significant body of work on the engineering

behaviour of seabed carbonate sediments.

Because of the expertise acquired during his research career in geotechnics, Prof. John Carter has been

called upon to consult widely to industry on a range of geotechnical projects, including soft clay foundations,

Honouring Prof. Harry G. Poulos

Lead Guest Editor: Emeritus

Professor John Carter


offshore foundations, retaining walls, and buried structures. He has also been retained as an expert

consultant on numerous offshore foundation problems for a number of major oil and gas companies,

including BHP, Esso, Woodside, Wapet, Bond Oil, Amoco, and Exxon. He is currently a consultant director

of Advanced Geomechanics, a geotechnical consultancy based in Perth, providing specialist advice to the

offshore industry on foundation problems and on-shore and offshore site investigations. He has also been

involved in the commercialization of research and the marketing of its outcomes, including his own

specialist geotechnical software.

Between 1997 and 2000 he was a director, representing the interests of the University of Sydney, of Benthic

GeoTech Pty Ltd, a $10 million joint venture company that conceived, designed, built and now operates

PROD, the Portable Remotely Operated Drill, which is used to penetrate the ocean floor, conduct in situ

tests and recover core samples. Prof. John Carter's experience with engineering projects has required him

to work in Australia, Britain, and the USA. He has authored more than 60 major consulting reports for a

range of clients, including mining companies, oil companies, other engineering consultancies, and lawyers.



EDITOR-IN-CHIEF

2020 - Present

Dr. Kuo Chieh Chao

Asian Institute of Technology

Thaliand

2010 - 2019

Dr. Teik Aun Ooi (Malaysia)

Prof. A.S. Balasubramaniam (Australia)

________________________________________

EDITORIAL ADVISERS

Prof. Za-Chieh Moh (Taiwan)

Dr. Teik Aun Ooi (Malaysia)

Prof. A.S. Balasubramaniam (Australia)

Dr. Edward W. Brand (U.K.)

Prof. Kwet Yew Yong (Singapore)

Prof. Harry G. Poulos (Australia)

Dr. Chin-Der Ou (Taiwan)

Dr. Suttisak Soralump (Thailand)

Dr. Wen Hui Ting (Malaysia)

Dr. John Chien-Chung Li (Taiwan)

Dr. Chung Tien Chin (Taiwan)

Prof. Pedro Seco E Pinto (Portugal)

Prof. Dennes T. Bergado (Philippines)

________________________________________

EDITORIAL PANEL

Prof. Paulus P. Rahardjo

Parahyangan Catholic University

Indonesia

Dr. Limin Zhang

Hong Kong University of

Science and Technology

Hong Kong

Dr. Erwin Oh

Griffith University

Australia

Dr. Dominic Ong

Griffith University

Australia

Dr. Apiniti Jotisankasa

Kasetsart University

Thailand

Dr. Jie-Ru Chen

National Chi Nan University

Taiwan

Dr. Phung Duc Long

Long GeoDesign

Vietnam

Dr. Darren Chian

National University of

Singapore

Singapore



Paper Contribution, Technical Notes, and Discussions

Geotechnical Engineering is the official journal of the Southeast Asian Geotechnical Society and the Association of

Geotechnical Societies in Southeast Asia. It is published four times a year in March, June, September, and December

and is free to members of the Society. Please visit our website at http://www.seags.ait.ac.th for the membership

information.

SEAGS & AGSSEA encourage the submission of scholarly and practice-oriented articles to its journal. The journal

is published quarterly. Both sponsors of the journal, the Southeast Asian Geotechnical Society and the Association

of Geotechnical Societies in Southeast Asia, promote the ideals and goals of the International Society for Soil

Mechanics and Geotechnical Engineering in fostering communications, developing insights and enabling the

advancement of the geotechnical engineering discipline. Thus, the publishing ethics followed is similar to other

leading geotechnical journals. The standard ethical behavior of the authors, the editor, and his editorial panel, the

reviewers, and the publishers is followed.

Before you submit an article, please review the guidelines stated herein for the manuscript preparation and submission

procedures. The paper template is available upon request.

Geotechnical Engineering Journal accepts submissions via electronic. The manuscript file (text, tables, and figures)

in both words and pdf format, together with the submission letter, should be submitted to the Secretariat and copied

to the Chief Editor of Geotechnical Engineering Journal. Email: [email protected].

The guidelines for authors are as follows:

1. The manuscript including abstract of not more than 150 words and references must be typed in Times New

Roman 9 on one side of A4 paper with a margin of 25 mm on each side. The abstract should be written

clearly stating the purpose, the scope of work, and procedure adopted together with the major findings

including a summary of the conclusions.

2. The paper title must not exceed 70 characters including spaces.

3. The maximum length of papers in the print format of the Journal is 12 two-column pages in single-spaced in

Times New Roman 9 including figures and tables. A Journal page contains approximately 1,040 words.

Authors can approximate manuscript length by counting the number of words on a typical manuscript page

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When reduced, the figure must be legible and its type size no smaller than 6 point font (after reduction).

4. Figures: Line art should be submitted in black ink or laser printed; halftones and color should be original

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6. All mathematics must be typewritten and special symbols identified. Letter symbols should be defined when

they first appear.

7. The paper must have an introduction and end with a set of conclusions.

8. Practical applications should be included, if appropriate.

9. If experimental data and/or relations fitted to measurements are presented, the uncertainty of the results must

be stated. The uncertainty must include both systematic (bias) errors and imprecisions.

10. Authors need not be Society members. Each author’s full name, Society membership grade (if applicable),

present title and affiliation, and complete mailing address must appear as a footnote at the bottom of the first

page of the paper.


11. Journal papers submitted are subject to peer review before acceptance for publication.

12. Each author must use SI (International System) units and units acceptable in SI. Other units may be given in

parentheses or in an appendix.

13. A maximum of five keywords should be given.

14. References

American Petroleum Institute (API) (1993). Recommended Practice for Planning, Designing, and

Constructing Fixed Offshore Platforms – Working Stress Design, API Recommended Practice 2AWSD

(RP 2A-WSD), 20th edition, 1993, p 191.

Earth, J.B., and Geo, W.P. (2011). “Asian Geotechnical amongst Authors of Conference Publications,”

Proceedings of Int. Conference on Asian Geotechnical, publisher, city, pp 133-137.

Finn WDL and Fujita N. (2002). “Piles in liquefiable soils: seismic analysis and design issues,” Soil

Dynamics and Earthquake Engineering, 22, Issues 9-12, pp 731-742.

15. Discussions on a published paper shall be made in the same format and submitted within six months of its

appearance and closing discussion will be published within twelve months.

For additional information, please write to:

Dr. Kuo Chieh Chao

Hon. Secretary-General

Southeast Asian Geotechnical Society

Email: [email protected]

Website: http://www.seags.ait.ac.th

Ir. Peng Tean SIN

Hon. Secretary-General

Association of Geotechnical Societies in Southeast Asia

Email: [email protected]

Website: http://www.agssea.org



TABLE OF CONTENTS List of Papers Page

1. Liquefaction Induced Downdrag for the Juan Pablo II Bridge at the 2010 Maule Earthquake in Chile 1 - 8

By Bengt H. Fellenius, Babak Abbasi, and Balasingam Muhunthan

2. Deep Compaction of Sand Causing Horizontal Stress Change 9 - 21

By K. R. Massarsch and B. H. Fellenius

3. Some Factors that Influence the Prediction of the Behaviour of Piled Rafts via Simplified 22 - 29

(Numerical) Analyses

By Renato P. Cunha, Harry G. Poulos, and John C. Small

4. Evaluation of Analytical and Numerical Techniques to Simulate Curtain Pile Walls in a Tropical 30 - 38

Soil of the Federal District of Brazil

By S. Jacazz, Y. M. P. de Matos, F. F. Monteiro, R. P. Cunha, J. C. Ruge, and G. Gassler

5. Biodegradable Prefabricated Vertical Drains: from Laboratory to Field Studies 39 - 46

By Thanh Trung Nguyen, Buddhima Indraratna, and Pankaj Baral

6. P-Cone: A Novel Cone Penetration Test Device for Deep Foundation Design 47 - 53

By Hai M. N. and Anand J. P.

7. Analysis of Stiffened Granular Piled Raft 54 - 64

By Madhav Madhira, Jitendra Kumar Sharma, and Raksha Rani Sanadhya

8. Can a Pile Load Tested to ‘Failure’ be used as a Working Pile? 65 - 72

By T. L. Gouw and A.Gunawan

9. Displacement of Piles from Pressuremeter Test Results - A Summary of French Research 73 - 82

and Practice

By R. Frank

10. Effect of Seismic Action on Settlement and Load Sharing of Piled Rafts Based on Field Monitoring 83 - 94

By K. Yamashita, J. Hamada and T. Tanikawa

11. Model Vibration Tests on Piled Raft and Pile Group Foundations in Dry Sand 95 - 102

By Anh-Tuan Vu, Tatsunori Matsumoto, and Kohei Kenda

12. BEM and FEM Approaches to the Analysis of Negative Skin Friction on Piles 103 - 110

By Gianpiero Russo

13. Effective Stress Friction Angle of Normally Consolidated and Overconsolidated Intact Clays from 111 - 116

Piezocone tests

By Zhongkun Ouyang and Paul W. Mayne

14. Numerical and Simplified Methods for Soil-pile Interaction Analysis 117 - 129

By Dezi F., Carbonari S., Morici M., and Leoni G.

15. The Behaviour of Pile Group and Combined Piled-Raft Foundation in Liquefiable Soil under 130 - 138

Seismic Conditions

By Aniruddha Bhaduri, Vansittee Dilli Rao, and Deepankar Choudhury

16. Foundation Investigation and Analysis for Tall Tower Developments 139 - 149

By C. M. Haberfield, J.E. Finlayson, and A. L .E. Lochaden


17. Effects of Cyclic Behaviour during Pile Penetration on Pile Performance in Model Load Tests 150 - 158

By S. Moriyasu, T. Matsumoto, M. Aizawa, S. Kobayashi, and S. Shimono

18. FD Analysis on Piled Raft Foundation Settlements under Vertical Loads 159 - 165

By D. W. Chang, H. W. Lien, and M. H. Hung

19. Analysis for Laterally Loaded Offshore Piles in Marine Clay 166 - 171

By S. Jeong, and Y. Kim

20. Pile Design in Seismic Areas: Small or Large Diameter? 172 - 178

By R. Di Laora

Cover Photograph

1. Liquefaction Induced Downdrag for the Juan Pablo II Bridge at the 2010 Maule Earthquake in Chile

By Bengt H. Fellenius, Babak Abbasi, and Balasingam Muhunthan

2. Some Factors that Influence the Prediction of the Behaviour of Piled Rafts via Simplified (Numerical) Analyses

By Renato P. Cunha, Harry G. Poulos, and John C. Small

3. Biodegradable Prefabricated Vertical Drains: from Laboratory to Field Studies

By Thanh Trung Nguyen, Buddhima Indraratna, and Pankaj Bara

4. P-Cone: A Novel Cone Penetration Test Device for Deep Foundation Design

By Hai M.N. and Anand J. P.

5. Numerical and Simplified Methods for Soil-pile Interaction Analysis

By Dezi F., Carbonari S., Morici M., and Leoni G.

6. Evaluation of Analytical and Numerical Techniques to Simulate Curtain Pile Walls in a Tropical Soil

of the Federal District of Brazil

By S. Jacazz, Y. M. P. de Matos, F. F. Monteiro, R. P. Cunha, J. C. Ruge, and G. Gassler


65

Can a Pile Load Tested to ‘Failure’ be Used as a Working Pile?

T. L. Gouw1 and A. Gunawan2

1Universitas Katolik Parahyangan, Bandung, Indonesia 2Bina Nusantara University, Jakarta, Indonesia

1E-mail: [email protected] 2E-mail: [email protected]

ABSTRACT: There are a few available loading test methods to obtain a load-settlement curve of a pile. Likewise, there are many definitions

to determine the ‘ultimate’ pile capacity from a load-settlement curve. Although pile load tests have been widely used over the past decades,

there are still many questions regarding its practice and interpretation. Frequently asked questions include: when does a pile test considered to

have failed? From an economic point of view, a failure in pile loading test can cost quite a lot of money. To what load can the pile be loaded

till it is considered to have failed? Can a pile loaded to failure still be used as a working pile? What is a bidirectional pile load test (BD-test)?

When should a BD-test be used? Can a pile tested with a BD be used as a working pile? What are the differences between kentledge or reaction

piles static loading test with the bidirectional test? Do the different pile tests produce the same results? This paper aims to shed light on these

questions, one case history where the pile tested to ‘failure’ and later used as working piles is presented.

KEYWORDS: Pile static load test, Bidirectional test, Ultimate pile capacity, Fail Pile

1. INTRODUCTION

Foundation piles have been used for over one hundred years. There

are many methods to construct the piles. Likewise, there are also

many methods to test the pile capacity. In Indonesia, foundation piles

are very common, and engineers in Indonesia are willing to adopt

state-of-the-art testing methods. From the common kentledge loading

test, static load test with reaction piles, dynamic loading test (also

known as PDA - pile driving analyzer), to the more recent one,

bidirectional test (BD-test). Although these testing methods have

been widely adopted in Indonesia, there are still questions regarding

these testing methods. Often, engineers have different perspective on

the practice of these testing methods. This paper aims to shed light to

the following frequently asked questions:

• A pile load test should not be determined as failure as the project

owner has spent thousands or tens of thousands of US dollars for

it. So, in what scenario does a pile load test considered to have

failed?

• Can a pile tested to “failure” still be used as a working pile?

• What is a bidirectional load test or O’ Cell? When is it necessary

to apply this test method?

• Can a pile tested by bidirectional load test still be used as a

working pile?

• Will a pile tested by kentledge load test, static load test by

reaction pile, and bidirectional test give the same results?

The paper first discusses what “ultimate” pile capacity is, the

principles of each pile tests, followed by answers to the above

questions.

2. ULTIMATE PILE CAPACITY

Eurocode 7 (BS EN 1997-1, 2004) defines ultimate pile capacity, also

known as ultimate limit states, as compressive or tensile resistance

failure of a single or piles system. However, according to Fellenius

(2017), “Ultimate pile capacity” is a very imprecise concept in most

soil conditions. This can be seen from a typical load-settlement curve

shown in Figure 1. As shown in Figure 1, pile “capacity” continues

to increase the further it is loaded. So, when does a pile fail? Figure 2

shows the 3 types of load-settlement curves that can be obtained in

the field. The first type is a general failure, which as stated previously,

the pile capacity continues to increase with pile settlement. The

second type is punching failure with a relatively constant capacity, in

which pile continues to move under constant load. The third type is

punching failure with a reduction in capacity. Geotechnical pile

failure only occurs when type 2 or type 3 occurs. For types 2 and 3, a

true “ultimate” capacity can be defined. It is important to differentiate

the peak and ultimate capacity for type 3. These three types of curves

obtained can be explained with ultimate shaft resistance and toe

resistance.

Figure 1 Typical load-settlement curve from a pile-load test in

medium dense sand (Zhang and Tang, 2001)

Figure 2 Three types of load settlement curve: 1 – general failure, 2

– punching failure with constant capacity, 3 – punching failure with

reduction in the pile capacity

mailto:[email protected]


66

2.1 Ultimate Shaft Resistance

Development of shaft resistance is the consequence of relative

movement between the pile and soil. If the pile settles more than the

soil, a positive shaft resistance is generated. Whereas, when the soil

settles more than the soil, a negative shaft resistance is generated. To

fully mobilize shaft resistance, very small relative movement is

required, often only a few millimeters (Fellenius, 2017). The relative

movement required is independent of pile size but depends on soil

type and roughness of the pile.

Shaft resistance is a function of the magnitude of relative

movement and soil type as observed from direct shear test results

shown in Figure 3. At first, the shear stress vs. movement increases

more or less linearly, then, for loose sand or normally consolidated

clay, after some magnitude of movement has been reached, the slope

gets flatter and, finally, the shaft resistance becomes approximately

constant. For dense sand or overconsolidated clay, the shaft resistance

usually reaches a peak value, thereafter it decreases with movement

to a residual strength. Some will define the ultimate shaft resistance

as the peak value, others prefer to define it as the residual strength.

Figure 3 Shear stress versus shear displacement on dense and loose

sand (Modified after Das, 2014)

2.2 Toe Resistance

Unlike shaft resistance, toe resistance does not have an ultimate value.

The load-movement of pile-toe is a function of the stiffness and

effective stress of the soil. Figure 4 shows an example of load versus

pile toe movement measured in a 1.5 m and 1.8 m diameter piles.

Even after a large movement of 150 mm, which is nearly 10% the pile

diameter, the load-movement curve does not indicate reaching

“failure”.

Figure 4 Unit toe resistance measured on a 1.5 and 1.8 m diameter

bored pile constructed in silty sandy clay and clayey sand

(Fellenius, 2017)

2.3 Failure in Pile

The three types of failure shown in Figure 2 can be explained from

the ultimate shaft and toe resistance. For general failure, although

ultimate shaft resistance has been mobilized, the toe resistance can

continue to develop resistance as load is added. A Type 3 punching

failure can occur, when the shaft resistance reduces more than the

increase of toe resistance. Punching or plunging failure with relatively

constant capacity or with reduced resistance is rather rare. For general

failure, there is no obvious pile capacity. If a capacity value is

necessary, a specific definition must be used and agreed on by the

parties involved in the evaluation of the static loading test.

2.4 Failure Criterion

For pile which experience general failure, specific criterion to derive

pile capacity is needed. In the early days (1960s-1970s), pile capacity

is defined by identifying the initial relatively gentle part of the curve

and the latter steeper part of the curve. Examples include Hansen 80%

and 90% criteria (1963), Chin-Kondner extrapolation (Chin, 1971;

Kondner 1963), DeBeer intersection load (1968), and many others.

A straighter forward method to define a pile capacity is by taking

the pile load under certain displacement, usually based on the pile

diameter. Eurocode 7 defines pile capacity as the load that resulted in

a movement equal to 10% of the pile-toe diameter (BS EN 1997-1,

2004). Indonesian standard applies similar criterion, in which pile

capacity is taken as the load that produced 25 mm movement in a pile

with a diameter smaller than 800 mm, and a movement equal to 4%

pile diameter for piles with a diameter larger than 800 mm (SNI

8640:2017).

There is also pile capacity derivation which includes elastic

shortening of pile from the axial load. This method is adopted by

Davisson (1973), AS2159 (2009), Ng et al. (2001), etc.

From the numerous different approaches available, many

different pile capacities can be derived. As shown in Figure 1, the

difference can be more than 150%! Naturally different approach also

has their own respective accepted factor of safety. Engineers should

abide by their respective local standards, unless for special reasons

stricter settlement is required.

Before understanding the different types of pile load tests, an

engineer needs to understand the basis of determining pile capacity.

In essence, the capacity does not exist until it is defined. With this

appreciation, one can have a clearer picture of the advantages and

disadvantages of each testing methods, as well as their

appropriateness in different situations.

3. THE STATIC LOADING TEST

A static loading test is a test whereby tested pile is loaded axially,

either using dead-weights (kentledge) or reaction piles/frames. The

choice of pile tested is usually based on the pile installed in the most

adverse soil conditions. This is to ensure that the obtained results are

most conservative and that there is no overestimation of pile capacity

in other areas.

The main purpose of the static loading test is to obtain load versus

movement relationship of the test pile. The pile capacity can be

derived from the results based on the specific criterion. Some also

assess a creep response of movement versus time under constant load.

Another useful information that can be obtained through a static load

test is the rebound behavior, when the pile tested is unloaded (BS EN

1997-1, 2004). More useful information can be obtained by using

instrumented piles, e.g. separating shaft and toe resistance (Fellenius,

2017). In the next sections, the procedure of static loading test by

kentledge and reaction piles are discussed.

3.1 Kentledge System

Figure 5 and 6 shows a schematic diagram and photograph of static

load test with kentledge system, respectively. A pile capacity can

range from a hundred of kN to thousands of kN. To load a pile to that

level, a sufficient reaction force is required. One method to provide


67

the reaction force is by kentledge, where blocks of concrete are placed

on a platform to act as a reaction to loading of the pile. ASTM D1143

states that the total weights should at least be 10% larger than the

maximum load that is going to be applied. The center of the cross

beams needs to be in the center of the pile to prevent eccentric

loading. Only 1% eccentric loading and an eccentric distance of 25

mm is allowed. To stabilize the cross beams, temporary support of the

platform, such as timber or concrete cribs, need to be built. Care must

be taken in determining the clear distance between the pile to the

cribs. The distance is important because the kentledge load is

transferred to the soil underneath the cribs adding stress to the ground

and the supports must be placed far enough to not let the change of

vertical stress affect the shaft resistance of tested pile. As a general

guideline, ASTM D1143 states that the clear distance should not be

less than 1.5 m.

Figure 5 Schematic diagram of static load test with kentledge

system (ASTM D 1143, 2007)

Figure 6 Photograph of static load test with kentledge system

(Courtesy of Khmer D&C Technical Consultant, 2018)

3.2 Reaction Piles or Anchors

Alternative to kentledge, reaction piles or anchors can be used to

provide the reaction force for pile loading. Figure 7 and 8 shows a

schematic diagram and photograph of reaction pile system. Care must

be taken to ensure sufficient resistance from anchors or reaction piles.

Movement of anchors or reaction piles also must be measured to

calculate the net movement of the tested pile. Another thing to note is

the different requirements in clear distance between the tested pile

and its anchors or reaction piles. ASTM D1143 states that the required

clear distance is 5 times the largest pile/anchor diameter (can be the

test pile or reaction pile) or 2.5 m, whichever is larger. The required

clear distance is larger than the kentledge system, because for the

kentledge system, the larger the load applied on the test pile, the lower

the load on the cribs. However, when reaction piles or anchors are

used, the larger the load applied on the test pile, the larger the opposite

load acts on the reaction piles or anchors.

Figure 7 Schematic diagram of a static load test with anchored

reaction frame (ASTM D 1143, 2007)

Figure 8 Photograph of static load test with reaction piles

(Courtesy of Structville, 2018)

3.3 Loading Procedure

Ideally, the load applied should reach a “failure” that reflects the axial

static compressive capacity of the pile. Care must be taken that the

load applied does not exceed the axial structural strength of the pile.

As pile capacity changes with time (setup effect, when strength is

gained; relaxation, when strength decreases) a qualified engineer

should specify the waiting period before testing. Moreover, for a cast-

in-place pile or a bored pile, sufficient time should be given for the

concrete to gain adequate strength.

ASTM D1143 lists 7 loading procedures that can be adopted for

static loading tests. In Indonesia, the most commonly used loading

procedure is the maintained test (ASTM D1143, 2007). The test pile

is loaded to a minimum of 200% design load in 25% increments, the

pile is then unloaded in four or five equal decrements. When higher

capacity is anticipated, the pile can be reloaded to a higher load level.

Figure 9 shows an example of a test pile loaded to 100%, 200% then

300% design load performed by the authors.

Figure 9 Static loading test result


68

3.4 Results, Failures in Execution of Static Load Test

Results from a non-instrumented pile static loading test comes in the

form of load-settlement curve (an example is shown in Figure 1 and

9). From the load-settlement curve, the pile capacity can be

determined using a definition based on local national standards.

However, without any geotechnical instrumentation, it is not possible

to separate the shaft or toe resistance. The importance of

instrumentation is discussed in the next section.

Failures in the execution of static loading tests cost a lot of time

and money. Causes of failures include bearing capacity failure of the

concrete block supports/cribs, e.g. in Figure 10; instrumentation

errors; insufficient reaction force; support platform located too close

to the pile. These failures can be prevented and should not be allowed

to occur.

Figure 10 Failure of kentledge system before loading

(Courtesy of Profound BV, 2017)

3.5 Importance of Instrumentation

The most common instrumentation installed in a pile are strain gages.

Strain gages provide the load distribution along the pile shaft, e.g. in

Figure 11. From the axial load distribution, it is possible to derive the

shaft resistance by differentiating the curve. It is also possible to

estimate the toe resistance from the bottom-most strain gage. From

the results, design can be verified, and optimization can be carried

out.

Figure 11 Development of axial load distribution with load steps

4. BIDIRECTIONAL TEST

The bidirectional test (BD-test) was first used in the 1980s in Brazil

and the USA (Fellenius, 2017), and widely accepted internationally

from 1990 onward (Osterberg, 1998). Because of Dr. Jorj Osterberg’s

pioneering work, the bidirectional cell (BD-cell) is also known as the

Osterberg Cell test, or O-cell test. Figure 12 shows a schematic

diagram of a bidirectional test. The BD-cell is in principle a hydraulic

jack placed at some depth within the pile shaft. The cells are

sacrificial, as they cannot be retrieved after the test completion. When

pressure is applied to the O-cell, the cell expands, pushing the upper

part of the test pile upward, and the lower part downward. The BD

test can be used for both cast-in-place and precast piles.

Figure 12 Schematic diagram of a bidirectional test (ASTM, 2018)

4.1 O-cell Test Apparatus, Instrumentation and Installation

Currently, there is no guideline available for bidirectional tests in the

Indonesian Standard. For guideline, one can refer to ASTM D8169

(2018). For an O-cell test, the only apparatus required are the O-cell

itself and hydraulic pump. Required instruments are pile head

measuring device, e.g. digital survey, or reference beam with dial

gauges, the BD-cell top, and bottom plate movement measuring

device which are in the form of either electronic displacement

indicators or telltales. Optional instrumentation are strain gauges

along the pile shaft.

For cast-in-place pile, the reinforcement cage is separated into 2

sections. The first section is welded onto the top bearing plate of BD-

cell, while the second section is welded onto the bottom bearing plate

(see Figure 13). The bearing plate needs to have sufficient spacing to

allow grouting to flow through.

For precast pile, the BD-cell can be prefabricated with the pile.

Alternatively, the precast pile can be separated into two segments,

that are spliced in the field with the segments attached to one of the

BD-cell’s bearing plates (Figure 14). The installation of precast pile

with BD-cell attached is the same as normal precast piles.

4.2 Loading, Measurement of O-cell and Results

The BD test is carried out by applying hydraulic pressure using a

hydraulic pump at the ground surface (refer to Figure 12). The applied

pressure expands the BD-Cell, pushing the upper shaft upward, and

the lower downward.

Figure 15 shows the typical results from a BD test. During the

initial loading phase, the BD-cell shows zero movement as it has to

overcome the buoyant weight of the upper length of the pile, as well

as any residual load. As the BD-cell is further loaded, the shaft and

toe resistance start to get mobilized until either the shaft or toe

ultimate resistance is reached. The difference between the pile head

movement and the top bearing plate movement is the shortening of

the upper length of the pile. From the measurements, one can obtain


69

a load-movement curve for both the pile shaft and pile toe. Therefore,

the shaft and toe resistance can be evaluated separately.

Figure 13 Reinforcement cage welded onto bearing plates of BD-

cell (Courtesy of Foundation Alliance, 2018)

Figure 14 Installation of BD-cell in precast pile

(Courtesy of YJack, 2018)

Figure 15 Typical result of a BD-cell test (Fellenius, 2017)

4.3 Failures in Execution of BD-cell test

Ideally, the BD-cell should be placed at a level that allows full

mobilization of the upper length of the pile, and as much toe

resistance as possible. Therefore, in most cases, the BD-cell is placed

either at the pile toe, or very close to the pile toe. However, in cases

where the pile sits on very soft soil, and depends mostly on the shaft

resistance, it may be necessary to place the BD-cell higher up the pile.

5. CASE HISTORY

The case history is based on the authors’ work at a project in the

central business district area of Jakarta, the capital city of Indonesia.

Two bored piles of 1.0 m diameter and embedded to 52.5m depth

below ground were tested up to 300% of its design load. The design

load is 6400 kN. The subsoil condition is as shown in Table 1 below.

Table 1 Subsoil Layers and Their Properties

Both piles were instrumented with vibrating wire strain gauges

(VWSG). Eight layers of VWSG were installed, i.e. at 0.7, 8.0, 15.3,

23.1, 30.0, 37.2, 44.8 and 52.0 m depths; with 3 numbers of VWSG

at each layer. The static loading tests were carried out following

ASTM 1143.

With a safety factor of around 2.5, a preliminary estimate gave an

allowable axial pile capacity of 6400 kN. To optimize the design, it

was decided to carry out preliminary load tests on two piles placed at

a presumably weaker area as revealed by the boreholes. The two piles

were tested to 300% of their design load.

Before the loading test is carried out the integrity of the piles were

tested by sonic logging. Figure 16 shows the test pile no. 1 has good

integrity. Test pile no. 2 also has good integrity.

Figures 17 and 18 show the load distribution along the pile shaft.

The graphs show that with 300% design load, i.e. up to 19,200 kN,

the shaft resistance more or less already fully mobilized, except the

segment below 45m depth where the shaft resistance and the end

bearing has been not fully mobilized. Figure 19 shows the pile

settlement curve along with the ‘ultimate’ capacity derived by various

methods. The load settlement curves show type 1 behavior as defined

in Figure 2, which means the pile bearing capacity increases with its

settlement.


70

Figure 16 Sonic logging test result show good pile integrity

Figure 17 Load distribution curve of test pile no. 1

Figure 18 Load distribution curve of test pile no. 2

Figure 19 Load settlement curve of TP-01 and TP-02

19,200

14,672

11,227

5,341

4,812

4,253

3,505

372

-55

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

0 1,0

00

2,0

00

3,0

00

4,0

00

5,0

00

6,0

00

7,0

00

8,0

00

9,0

00

10,0

00

11,0

00

12,0

00

13,0

00

14,0

00

15,0

00

16,0

00

17,0

00

18,0

00

19,0

00

20,0

00

Dep

th (

m)

Load (kN)Load Distribution - TP 2 - Last Test Cycle


71

The ultimate capacity derived by using various definitions is

tabulated in Table 2. The average ‘ultimate’ capacity of the two test

piles is around 18,000 kN. Taking the minimum safety factor of 2.5

as defined by the Indonesian National Standard (SNI 8640:2017), the

allowable capacity of the pile is 7200 kN. At the 7200 kN allowable

load, the settlement of the test piles are still less than 6 mm, which is

also one of the criteria set in the Indonesian standard where at design

load under non-seismic condition, i.e. the pile head settlement should

be less than 6 mm. With these results, the initial design load of 6400

kN was increased to 7200 kN, and these two test piles were also used

as working piles without any problem to the building constructed.

Table 2 Pile ‘Ultimate’ Capacity

6. DISCUSSION

The pile geotechnical ‘failure’, capacity, or ultimate resistance is

basically a definition determined in the design stage, specifically by

its magnitude of settlement (movement) at a certain load.

6.1 Using Pile Loaded to Failure as Working Pile

As discussed in section 2, in most cases, piles will not reach

‘geotechnical’ failure during pile load tests. In most soils, a pile’s toe

resistance continues to increase the further a pile is loaded. What is

meant by pile loaded to ‘failure’ is when the tested pile is loaded

beyond a certain failure criterion, e.g. pile head settle more than 4%

pile diameter or other definition.

Therefore, as long as the tested pile is not structurally damage, a

pile loaded to ‘failure’ does not mean it become unusable. In other

words, a pile loaded to reach a failure criterion can still be used as a

working pile as long as there is no structural damage. Furthermore,

when a pile experience unloading, the next time it is loaded, it will

show a stiffer response, until the previous maximum load is exceeded

(see Figure 20). This behavior is very much like loading an

overconsolidated soil.

However, one must pay attention when punching failure with a

reduction of pile capacity occurs (type 3 failure in Figure 2). When

reusing such a pile, the ultimate pile capacity has to be used instead

of peak pile capacity. However, for other piles which weren’t loaded,

the peak pile capacity can be used as long as sufficient factor of safety

is given to ensure that the pile will not be loaded beyond its peak

capacity during its design life.

Figure 20 Load-settlement curve in cyclic pile load test

(Trishna, 2018)

6.2 Using Pile Tested by Bidirectional Test as Working Pile

Similar to that discussed in Section 6.1, a pile tested by a bidirectional

test can be reused as a working pile. Although there is a fracture zone

in the pile, the upper and lower reinforcement cages are connected by

the BD-cell’s bearing plates. Besides, the fracture zone is always

grouted, making the pile acts as one body.

It is also very costly to not use a pile tested by a bidirectional test.

Bidirectional tests are common for large piles and offshore piles. This

is because building a kentledge system or reaction piles would be

time-consuming and costly. Therefore, due to economical reason,

most piles tested by bidirectional tests are reused as working piles. Of

course, this is also because conducting a bidirectional test does not

significantly diminish the tested pile performance.

6.3 Similarity of Results from Static Load Test and BD-Test

The main objective of conducting pile load tests, regardless of the

methods is to obtain the ‘ultimate’ capacity of the tested pile. Despite

the difference in the measurement system, provided the same

definition is used to determine the ‘ultimate’ capacity, theoretically,

the static loading test and BD-test should produce more or less the

same ultimate pile bearing capacity. This is because the bidirectional

test is essentially a static load test as well. Bidirectional tests can

provide information on both the shaft and toe resistance, while

conventional static load test can only produce the total pile capacity.

Fellenius (2017) considers the bidirectional tests to be superior as

compared to conventional static load tests.

7. CONCLUSION

The ‘ultimate’ or ‘failure’ capacity is a definition which has to be

defined and agreed upon in its design stage. A pile tested to its

‘ultimate’ or ‘failure’ load, either by a kentledge static loading test or

by a bidirectional test, can still be used as working piles as long as the

tested pile is not structurally damaged. Geotechnically speaking there

is no difference between static loading test and bidirectional loading

test.

8. REFERENCES

Allnamics (2018). Pile Driving Analyzer (PDA).

http://allnamics.eu/products-2/allnamics-pda-pile-driving-

analyser/ [Accessed 3 June 2018]

AS 2159-2009 (2009). Piling – Design and Installation.


72

ASTM D 1143/D 1143M – 07 (2007). Standard Test Methods for

Deep Foundation Under Static Axial Tensile Load. DOI:

10.1520/D1143

ASTM D 4945 – 17 (2017). Standard Test Method for High-Strain

Dynamic Testing of Deep Foundations.

ASTM D 8169/D 8169M – 18 (2018). Standard Test Methods for

Deep Foundations Under Bi-Directional Static Axial

Compressive Load.

Axelsson, G. (2000). Long-Term Set-Up of Piles in Sand. PhD thesis,

Department of Civil and Environmental Engineering, Royal

Institute of Technology, Stockholm.

Banerjee, P. K. and Butterfield, R. (1991). Advanced Geotechnical

Analyses: Development in Soil Mechanics and Foundation

Engineering. CRC Press.

BS EN 1997-1. (2004). Geotechnical design Part 1: General rules.

Eurocode 7.

Chin, F. K. (1971). Discussion on pile test. Arkansas River Project.

Journal for Soil Mechanics and Foundation Engineering, 97,

930-932.

Das, B. M. (2014). Principles of Geotechnical Engineering (8th

Edition). Cengage Learning, Stamford, United States of

America.

Davisson, M. T. (1973). High capacity piles. in Innovations in

Foundation Construction. Proceedings of a lecture series,

Illinois Section ASCE, Chicago.

DeBeer, E. E. (1968). Proefondervindelijke bijdrage tot de studie van

het grensdraag vermogen van zand onder funderingen op staal.

Tijdshift der Openbar Verken van Belgie. (in Dutch)

Decourt, L. (2008). Loading tests: interpretation and prediction of

their results. Geo Institute Geo Congress, ASCE, New Orleans.

Fellenius, B. H. (2017). Basics of foundation design. Electronic

Edition. www.Fellenius.net [Accessed 31 May 2017]

Foundation Alliance (2018). Pile Tests – Osterberg Cell.

https://www.foundation-

alliance.com/gal_details.php?title=pile-

tests&stitle=compression-load-test&id=75 [Accessed 5 June

2018]

Hansen, J. B. (1963). Discussion on hyperbolic stress-strain response.

Cohesive soils. Journal for Soil Mechanics and Foundation

Engineering, ASCE, 89, 241-242

Kondner, R. L. (1963). Hyperbolic stress-strain response. Cohesive

soils. Journal for Soil Mechanics and Foundation Engineering,

ASCE, 89, 115-143.

Khmer D&C Technical Consultant (2018). Static Load Test.

www.khmerdandc.com/products/141380-static-load-test

[Accessed 31 May 2018]

Ng, C.W.W., Yau, T.L., Li, J.H., and Tang, W.H. (2001). New failure

load criterion for large diameter bored piles in weathered

geomaterials. Journal of Geotechnical and Geoenvironmental

Engineering, 127(6): 488–498.

Ng, K W., Rolling, M., and AbdelSalam, S. S. (2013). Pile Setup in

Cohesive Soil. I: Experimental Investigation. Journal of

Geotechnical and Geoenvironmental Engineering, ASCE.

DOI: 10.1061/(ASCE)GT.1943-5606.0000751

Osterberg, J. O. (1998). The Osterberg load test method for drilled

shaft and driven piles. The first ten years. Deep Foundation

Institute, Seventh International Conference and Exhibition on

Piling and Deep Foundations, Vienna, Austria.

Profound B.V. (2017). Personal discussion on pile testing.

Samson, C. H. (1987). Pile Driving Analysis – Historical Review,

Course on Pile Driving Analysis and Shaft Integrity Testing.

Texas A & M University, Texas.

SNI 8460:2017 (2017). Standar Nasional Indonesia - Persyaratan

perancangan geoteknik. Badan Standardisasi Nasional.

Structville (2018). Design of Pile Foundation Using Pile Load Test

(Eurocode 7). https://www.structville.com/2018/01/design-of-

pile-foundation-using-pile.html [Accessed 31 May 2018]

Trishna, B. (2018). Estimating the Load Capacity of Pile.

http://www.soilmanagementindia.com/pile-foundations/load-

capacity-of-piles/estimating-the-load-capacity-of-pile-

foundation-soil-engineering/14285 [Accessed 3 June 2018]

YJack (2018). YJack pile test – Home Page.

http://www.yjackpiletest.com/ [Accessed 3 June 2018]

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