calculated versus measured static capacity for two pile …

CALCULATED VERSUS MEASURED STATIC CAPACITY FOR TWO PILE

TYPES

_______________________________________

A Thesis

presented to

the Faculty of the Graduate School

at the University of Missouri – Columbia

_______________________________________________________

In Partial Fulfillment

of the Requirements for the Degree

Master of Science

_____________________________________________________

by

HUSEYIN AKKUS

Dr. John J. Bowders, P.E., - Thesis Supervisor

MAY 2018

The undersigned, appointed by the Associate Vice Chancellor of the Office of Research

and Graduate Studies, have examined the thesis entitled.

CALCULATED VERSUS MEASURED STATIC CAPACITY FOR TWO PILE

TYPES

Presented by Huseyin Akkus,

A candidate for the degree of Master of Science,

And hereby certify that in their opinion it is worthy of acceptance.

Professor John J. Bowders, P.E.

Department of Civil and Environmental Engineering

Associate Professor Brent Rosenblad, P.E.

Department of Civil and Environmental Engineering

Associate Professor Francisco Gomez

Department of Geological Sciences

DEDICATION

I would like to dedicate this thesis to my family who have always supported and

helped me during my whole life. I would like to present my many thanks to my father,

Ali AKKUS, my mother, Nazmiye AKKUS, and my sister, Seval AKKUS. I also would

like to express my extensive gratitude to my dear friends for all of their support and

help.

ii

ACKNOWLEDGEMENTS

I would like to express deep thanks to my advisors, Dr. John J. Bowders for his

guidance, patience, professional support, and advising at all times during my whole

study. I would also like to send many thanks my thesis committee members, Dr. Brent

Rosenblad and Dr. Francisco Gomez for their review, questions, comments and

valuable suggestions to develop this project.

Besides my advisor and my thesis committee members, I would like to thank

my classmate Paul Hilchen for sharing his CPT data and project site information. Many

thanks to Andrew Boeckmann for helping me with the results of field load tests and

providing marvelous field photographs.

I am very grateful for my colleagues and friends, Hashim G. Al-Sumaiday and

Benjamin H. Shetley They helped me so much during the revision of my thesis.

I am very grateful to the Turkish Ministry of Forest and Water Affairs - General

Directorate for Combatting Desertification and Erosion for providing financial support

and the opportunity to take advantage of education at the US.

iii

TABLE OF CONTENTS

DEDICATION ------------------------------------------------------------------------------------ i

ACKNOWLEDGEMENTS ------------------------------------------------------------------- ii

TABLE OF CONTENTS --------------------------------------------------------------------- iii

LIST OF FIGURES --------------------------------------------------------------------------- vi

LIST OF TABLES ----------------------------------------------------------------------------- xi

LIST OF ABBREVIATIONS --------------------------------------------------------------xiii

ABSTRACT -------------------------------------------------------------------------------------xv

CHAPTER 1 – INTRODUCTION ---------------------------------------------------------- 1

1.1 Background --------------------------------------------------------------------------- 1

1.2 Objective ------------------------------------------------------------------------------ 2

1.3 Scope of Work ------------------------------------------------------------------------ 2

1.4 Layout of Thesis ---------------------------------------------------------------------- 3

CHAPTER 2 – LITERATURE REVIEW ------------------------------------------------- 4

2.1 Introduction --------------------------------------------------------------------------- 4

2.2 Cone Penetration Test --------------------------------------------------------------- 7

2.2 Pile Capacity Prediction Methods Using Cone Penetration Test (CPT) ----- 9

2.2.1 Nottingham and Schmertmann -------------------------------------------------11

2.2.2 DeRuiter and Beringen (1979) -------------------------------------------------14

2.2.3 Tumay and Fakhroo (1981) -----------------------------------------------------15

2.2.4 Bustamante and Gianeselli (1982) – LCPC or French Method------------16

2.2.5 Eslami and Fellenius (1997) ----------------------------------------------------19

iv

2.3 Soil Type Based on CPT -----------------------------------------------------------21

2.4 Summary of Literature Review ---------------------------------------------------22

CHAPTER 3 – SITE DESCRIPTION ----------------------------------------------------24

3.1 Introduction --------------------------------------------------------------------------24

3.2 Project Overview and Location ---------------------------------------------------24

3.3 Site Geology -------------------------------------------------------------------------28

3.4 Sites Description --------------------------------------------------------------------29

3.5 Pile Length ---------------------------------------------------------------------------33

3.6 Available Information --------------------------------------------------------------38

3.7 Summary -----------------------------------------------------------------------------42

CHAPTER 4 – METHODOLOGY --------------------------------------------------------43

4.1 Introduction --------------------------------------------------------------------------43

4.2 Static Analysis of Ultimate Pile Capacity Based on CPT Results -----------43

4.2.1 Total Skin Resistance ------------------------------------------------------------44

4.2.2 Total Toe Resistance-------------------------------------------------------------45

4.2.3 Total Pile Capacity Using CPT Data ------------------------------------------45

4.3 Capacity of Piles from Static Load Tests ----------------------------------------47

4.4 Summary -----------------------------------------------------------------------------49

CHAPTER 5 – RESULTS AND DISCUSSION -----------------------------------------50

5.1 Introduction --------------------------------------------------------------------------50

5.2 Analysis of Calculated Pile Capacity---------------------------------------------50

v

5.3 Calculated versus Measured Pile Capacity --------------------------------------55

5.4 Discussion ----------------------------------------------------------------------------59

5.5 Summary -----------------------------------------------------------------------------64

CHAPTER 6 – CONCLUSIONS -----------------------------------------------------------65

6.1 Summary -----------------------------------------------------------------------------65

6.2 Conclusions --------------------------------------------------------------------------65

6.3 Recommendations -------------------------------------------------------------------66

LIST OF REFERENCES --------------------------------------------------------------------69

APPENDIX --------------------------------------------------------------------------------------72

Appendix – 1 Predicted Total Side Resistance, Total Toe Resistance and Ultimate

Capacity from CPT Prediction Methods --------------------------------------------------72

Appendix – 2 Existing Bridge Photographs, Taper Information and Cone

Penetration Test Soundings -----------------------------------------------------------------78

VITA ----------------------------------------------------------------------------------------------80

vi

LIST OF FIGURES

Figure Page

2.1 (a) Therminology for cone penetrometers (Robertson and Cabal, 2012) and (b)

ASTM D-5778 Cone penetration test procedure. .......................................................... 8

2.2 “from left: 2 cm2, 10 cm2, 15 cm2 and 40 cm2” CPT probes (Robertson and Cabal,

2012). ............................................................................................................................. 9

2.3 Schmertmann rules for the influence zone and cone tip resistance (qc) (Titi and

Murad, 1999)................................................................................................................ 11

2.4 Adjustment of the coefficient (C) to OCR (Fellenius, 2006)................................. 12

2.5 A dimensionless coefficient (Kf) for use in Eq. 2.3 when calculating the unit side

resistance in cohesive soils (Fellenius, 2006). ............................................................. 13

2.6 The average of cone tip resistance for the LCPC method (Bustamante and

Gianeselli, 1982). ......................................................................................................... 17

2.7 The Eslami-Fellenius profiling chart effective cone resistance (qE) versus sleeve

friction (fs) (Fellenius and Eslami, 2000). ................................................................... 20

2.8 Proposed soil behavior type classification chart based on normalized CPT

(Robertson 1989). ........................................................................................................ 21

2.9 Soil classification chart for standard electric friction cone (Robertson 1989). ...... 22

3.1 Location of pile load test projects. ......................................................................... 25

3.2 The site plan of replacement bridge Route WW (Structure No. A8472)............... 26

vii

3.3 The site plan of replacement bridge Route U (Structure No. A8414). .................. 27

3.4 The location of load test pile (LTP) for (a) 14-inch diameter CIP pile at site WW

and (b) 16-inch octagonal precast concrete pile at site U (Boeckmann et al., 2018). .. 31

3.5 The load test pile location with distance from CPT to load test pile at the Route WW

bridge plan. .................................................................................................................. 32

3.6 The load test pile location with distance from CPT to load test pile at the Route U

bridge plan. .................................................................................................................. 33

3.7 Exhumed 16-inch octagonal precast concrete piles at the bridge site U. ............... 35

3.8 Exhumed 14-inch diameter cast-in-place (CIP) piles at the bridge site WW. ....... 35

3.9 The location of CPT with soil profile and the location of load test pile to explain

vertical distance of soil types for 14-inch diameter CIP pile. ...................................... 37

3.10 The location of CPT with soil profile and the location of load test pile to explain

vertical distance of soil types for 16-inch octagonal precast concrete pile. ................. 38

4.1 Components of pile capacity (Qult). ....................................................................... 44

4.2 Load test results for existing piles Route WW and Route U bridge (Boeckmann,

2017). ........................................................................................................................... 48

4.3 The static load test for Route WW and Route U bridge (Boeckmann, 2017). ...... 49

5.1 Pile capacity versus depth calculated using the method of Nottingham and

Schmertmann for 14-inch CIP pile at the Route WW site the depth of pile tip at 50.9

feet and 16-inch precast concrete pile at the Route U site the depth of pile tip at 21.3

feet................................................................................................................................ 52

viii

5.2 Pile capacity versus depth calculated using the method of DeRuiter and Beringen

for 14-inch CIP pile at the Route WW site the depth of pile tip at 50.9 feet and 16-inch

precast concrete pile at the Route U site the depth of pile tip at 21.3 feet. .................. 53

5.3 Pile capacity versus depth calculated using the method of Tumay and Fakhroo for

14-inch CIP pile at the Route WW site the depth of pile tip at 50.9 feet and 16-inch


5.4 Pile capacity versus depth calculated using the method of Bustamante and

Gianeselli (LCPC) for 14-inch CIP pile at the Route WW site the depth of pile tip at

50.9 feet and 16-inch precast concrete pile at the Route U site the depth of pile tip at

21.3 feet........................................................................................................................ 54

5.5 Pile capacity versus depth calculated using the method of Eslami and Fellenius for

14-inch CIP pile at the Route WW site the depth of pile tip at 50.9 feet and 16-inch


5.6 Comparison of toe resistance (Rt) and side resistance (Rs) calculated using the CPT

methods for the 14-inch CIP at the Route WW site at the depth of pile tip at 50.9 feet.

...................................................................................................................................... 56

5.7 Comparison of toe resistance (Rt) and side resistance (Rs) calculated using the CPT

methods for the 16-inch precast concrete pile at the Route U site at the depth of pile tip

at 21.3 feet. ................................................................................................................... 57

5.8 Pile capacity predicted with CPT methods and pile load test result for the 14-inch

CIP pile at the Route WW site at the depth of pile tip at 50.9 feet. ............................. 57

ix

5.9 Pile capacity predicted with CPT methods and pile load test result for the16-inch

precast concrete pile at the Route WW site at the depth of pile tip at 21.3 feet. ......... 58

A1.1 The comparison of predicted total side resistance, total toe resistance and ultimate

capacity from Nottingham and Schmertmann prediction for 14-inch diameter CIP pile.

...................................................................................................................................... 72

A1.2 Predicted total side resistance, total toe resistance and ultimate capacity from

DeRuiter and Beringen prediction for 14-inch diameter CIP pile. .............................. 73


Tumay and Fakhroo prediction for 14-inch diameter CIP pile. ................................... 73


Bustamante and Gianeselli - LCPC prediction for 14-inch diameter CIP pile. ........... 74


Eslami and Fellenius prediction for 14-inch diameter CIP pile. .................................. 74


Nottingham and Schmertmann prediction for 16-inch octagonal precast concrete pile.

...................................................................................................................................... 75


DeRuiter and Beringen prediction for 16-inch octagonal precast concrete pile. ......... 75


Tumay and Fakhroo prediction for 16-inch octagonal precast concrete pile. .............. 76

x


Bustamante and Gianeselli - LCPC prediction for 16-inch octagonal precast concrete

pile................................................................................................................................ 76


Eslami and Fellenius prediction for 16-inch octagonal precast concrete pile. ............ 77

A2.1 The cross-section of taper with plan drawing of 16-inch precast concrete pile for

bridge on Route U (Boeckmann et al., 2018). ............................................................. 78

A2.2 CPT parallel seismic test machine. ..................................................................... 78

A2.3 Existing 14-inch diameter cast-in-place (CIP) piles at the Route WW. ............. 79

A2.4 Existing 16-inch octagonal precast concrete piles at the Route U. ..................... 79

xi

LIST OF TABLES

Table Page

2.1 Comparison from literature that compare the CPT prediction methods with pile

types and soil conditions. ............................................................................................... 6

2.2 Method used to predict static capacity of piles with database details.................... 10

2.3 Correlation coefficients (CLCPC) of unit toe resistance in the LCPC Method

(Fellenius, 2006). ......................................................................................................... 18

2.4 A dimensionless coefficient (KLCPC) for different soil and pile types (Fellenius,

2006). ........................................................................................................................... 18

2.5 The value of shaft correlation coefficient (CS) (Eslami and Fellenius, 1997). ...... 20

3.1 The stratigraphy of sites from the general geology of the Mississippi Embayment

for Missouri (Cushing et al, 1964). .............................................................................. 28

3.2 Soil description depends on the borehole information of SPT and CPT for Route

WW. ............................................................................................................................. 30

3.3 Soil description depends on the borehole information of SPT and CPT for Route U.

...................................................................................................................................... 30

3.4 Distance from pile to sounding (Boeckmann et al., 2018). ................................... 31

3.5 Exhumed CIP pile length with pile tip depth at Route WW site and precast concrete

pile length with pile tip depth at Route U site (Boeckmann et al., 2018). LTP is the load

test pile. ........................................................................................................................ 34

xii

3.6 Soil Description with SPT and CPT data for the Site of Route WW (Fennessey,

2016). ........................................................................................................................... 40

3.7 Soil Description and CPT data for the Site of Route U (Hilchen, 2016). .............. 41

4.1 The equations for unit side (rs) and unit tip (rt) resistance based on CPT data. ..... 46

5.1 The results of predicted capacity with measured capacity and information on piles

and soils for the bridges on Route WW and Route U. ................................................. 59

5.2 Comparison between static load test results and the predictions of capacity for a 14-

inch diameter CIP at Route WW site at existing pile depth 50.9 feet. ........................ 60

5.3 Comparison between static load test results and the predictions of capacity for a 16-

inch octagonal precast concrete pile at Route U site existing pile depth 21.3 feet. ..... 61

5.4 Allowable design pile capacity according to described minimum factor of safety.

...................................................................................................................................... 62

5.5 Comparison from literature with the results of this thesis that compare the CPT

prediction methods with pile types and soil conditions. .............................................. 63

6.1 Summary of adjustment factors (coefficients) based on CPT with prediction

methods, pile types and soil condition. ........................................................................ 68

xiii

LIST OF ABBREVIATIONS

α Adhesion factor in the method of DeRuiter and Beringen

As Circumferential area of the pile at Depth z

At Toe area (normally, the cross-sectional area of the pile)

C Correlation coefficient in the method of Nottingham and Schmertmann

CLCPC Correlation coefficient in the method of LCPC

Cs Shaft correlation coefficient in the method of Eslami and Fellenius

Ct Toe correlation coefficient in the method of Eslami and Fellenius

D Pile diameter

e Base of natural logarithm = 2.718

F.S Factor of safety

fs Sleeve friction

Kf A coefficient in the method of Nottingham and Schmertmann

Kc A dimensionless coefficient; a function of the pile type and cone

resistance in the method of Nottingham and Schmertmann

KLCPC A dimensionless coefficient

LCPC Laboratoire central des ponts et chaussées

MoDOT The Missouri Department of Transportation

Nk A dimensionless coefficient, constant, Nk=20

N60 Blow counts

OCR Over consolidation ratio

xiv

Pa Atmosphere pressure

Qall Allowable design capacity

Qtm Measured total pile capacity

Qtp Predicted total pile capacity

Qult Ultimate axial pile capacity

qc Cone tip resistance

qca Average cone tip resistance in the influence zone

qcaa Average of the average cone tip resistance in the influence zone

qE Effective cone resistance

qEg Geometric average of the cone point resistance

qt Cone resistance corrected for pore water pressure on shoulder

Rs Total skin resistance

Rt Total toe resistance

rs Pile unit skin resistance (variable with CPT methods)

rt Pile unit toe resistance (variable with CPT methods)

u2 Pore water pressure from cone shoulder

Z Depth

xv

CALCULATED VERSUS MEASURED STATIC CAPACITY

FOR TWO PILE TYPES

Huseyin AKKUS

Dr. John J. Bowders, P.E., - Thesis Supervisor

ABSTRACT

The Missouri Department of Transportation decided to replace two bridges in

northeast New Madrid Country, Missouri. The bridges were in service for

approximately 50 years and both were founded on driven piles. The bridge on Route

WW (A-2141) was founded on driven steel shells which were then filled with concrete

(referred to as cast-in-place, CIP). The bridge on Route U (N-0771) was founded on

driven, precast concrete piles. The replacement bridges will be founded on new piles

thus presenting the opportunity to perform a load test on one of the 50-year old piles at

each site and further our knowledge of potential for re-use of existing foundations. A

cone penetration test (CPT) and a boring with standard penetration (SPT) were made at

each site. The objective of this thesis was to predict the axial static capacity of the load

test piles based on the CPT using various methods and compare the predicted with the

measured capacities.

The methods included: Nottingham and Schmertmann (1975) or Schmertmann

(1978), DeRuiter and Beringen (1979 – commonly called the European method),

Tumay and Fakhroo (1981), Bustamante and Gianeselli (1982 - commonly called the

LCPC or French method), and Eslami and Fellenius (1997) method. The soil

stratigraphy and CPT data were compiled for both sites. The subsurface profile at Route

WW consists of interbedded layers of sand, silt and clay with a thick layer of dense

xvi

sand (SPN-values of 30 to 60) beginning at about a depth of 55 feet on the west end of

the bridge and increases to over 70 feet on the east end below ground surface. The

subsurface profile at Route U consists of a surface layer of soft to stiff clay (about the

top 5 to 8 feet thick), underlain by sand with SPT N-values of about 30 at a depth of 25

feet below the ground surface. The groundwater table is near the surface at both sites.

The designed exhumed pile length is 50.9 feet for the Route WW site (14-inch

diameter CIP piles). The capacity measured during the load test was 124 tons while

the CPT predicted capacities ranged from 58 tons to 115 tons. The predicted capacities

ranged from 0.47 to 0.93 (conservative) times the measured capacity. The original

design capacity was 30 tons. It is customary to use a factor of safety (ultimate

capacity/design capacity) of two to three in design of deep foundations so the original

design has a factor of safety of about two to four.

The designed pile length is 21.3 feet for the Route U site (16-inch octagonal

precast concrete piles). The measured capacity was 134 tons while the predicted

capacities ranged from 90 tons to 140 tons. The predicted capacities ranged from 0.67

(conservative) to 1.05 (unconservative) times the measured capacity. The original

design capacity was 21 tons. The factor of safety for the original design is about six.

The analysis of the predicted versus measured capacities resulted in a range of

4 to 113 percent difference. The Eslami and Fellenius method performed best in

predicting the measured capacity of the piles for the CIP pile (Qtm/Qtp = 1.07). For the

precast concrete pile, the Nottingham and Schmertmann (Qtm/Qtp = 1.07), and Eslami

and Fellenius (Qtm/Qtp =0.96) methods estimated best in predicting the measured

capacity of piles.

1

CHAPTER 1 – INTRODUCTION

1.1 Background

A Missouri Department of Transportation (MDOT) project to investigate re-use

of existing foundations allowed an opportunity to compare calculated capacity to

measured capacity for two types of pile. The piles supported bridges in south east

Missouri and were approximately 50 years in service. Two piles were load tested and

CPT was performed in the area of the foundations.

Driven piles are used to provide performance and safety for construction.

Design of pile foundations is generally provided with the calculation of static pile

capacity in a probabilistic way and describes load transferred to the soil. The analysis

of load transfer is known as static pile capacity analysis or pile capacity analysis. The

main components of static capacity analysis are skin resistance and toe resistance,

which can be estimated from cone penetration tests (CPT) data.

The cone penetration test is a practical way to determine axial pile capacity.

There are two main approaches for implementation of CPT data to the design of driven

piles, indirect and direct methods (Fellenius, 2006). These methods determine driven

pile capacity and pile length. In this research, ultimate pile capacity is presented for a

14-inch diameter cast-in-place (CIP) pile - Route WW and a 16-inch octagonal precast

concrete pile - Route U with results from CPT, using the following methods:

Nottingham and Schmertmann (1975) or Schmertmann (1978), DeRuiter and Beringen

(1979 - commonly called the European method), Tumay and Fakhroo (1981),

2

Bustamante and Gianeselli (1982 - commonly called the LCPC or French method), and

Eslami and Fellenius (1997) method.

Bowders (2017) said that cast-in-place (CIP) typically means a hole is bored

into the ground and then concrete is placed in it to form the foundation. No

'driving/hammering' action is involved. However, at the WW site, steel shells were

'driven' into the ground and then were filled with concrete. These are considered to be

'driven' piles. On the other hand, precast concrete pile typically means is a prefabricated

and high-strength prestressed concrete column. Driving/hammering action is included.

The pile is also driven into the ground/soil with an impact pile driving hammer at the

U site.

1.2 Objective

The objective of this research is to compare calculated and measured static pile

capacity for two different pile types, a 14-inch diameter cast-in-place (CIP) and a 16-

inch octagonal precast concrete pile. Five pile capacity prediction methods were

utilized to calculate pile capacity. All methods have been applied to New Madrid soils

in Missouri.

1.3 Scope of Work

In this research, the scope of work involved the following:

1) Use five methods to calculate the static capacity of piles using cone penetration

test results.

2) Compare the calculated with measured the pile capacity.

3) Analyze the accuracy of each method.

3

1.4 Layout of Thesis

Chapter 2 is a literature review focused on the different methods used to

calculate pile axial load capacity using cone penetration test data. The site description

for the two pile load tests is presented in Chapter 3. The methods used to calculate pile

capacity are explained in Chapter 4. Chapter 5 contains the results and discussion.

Conclusions and recommendations are included in Chapter 6.

4

CHAPTER 2 – LITERATURE REVIEW

2.1 Introduction

This chapter evaluates the methods used for calculating static pile capacity

based on cone penetration test (CPT) data. The CPT is one of the most used in situ tests

to characterize geotechnical parameters. According to Robertson and Cabal (2012), the

purpose of the CPT is to provide soil profiling, material identification and evaluation

of geotechnical parameters and design. The procedure of the CPT is given by Robertson

and Cabal (2012) in the Guide to Cone Penetration Testing for Geotechnical

Engineering.

There are two main approaches, indirect CPT methods and direct CPT methods

(Eslami and Fellenius, 1995). In this chapter, direct CPT methods were evaluated, and

the evaluation of these methods depend on the measured sleeve friction (fs), cone tip

resistance (qc), and pore water pressure (u). According to Fellenius (2006), most of the

methods were improved to predict pile capacity after 1975. In this thesis the following

methods are presented for prediction of ultimate axial pile capacity using cone

penetration test data: Nottingham and Schmertmann (1975) or Schmertmann (1978),

DeRuiter and Beringen (1979), Tumay and Fakhroo (1981), Bustamante and Gianeselli

(1982), and Eslami and Fellenius (1997).

Previous, researchers studied CPT methods to predict pile capacity as shown in

Table 2.1. Alsamman and Long (1993) used three prediction methods for predicting

axial pile capacities using the CPT results and LCPC method provided the most reliable

prediction in clay. Titi and Murad (1999) presented an evaluation of the performance

5

of CPT methods to predict pile capacity for concrete prestressed piles driven into

Louisiana soils and the European method and LCPC method showed the best

performance. According to Reuter (2010), CPT based capacity methods provided very

good agreement of the results of static loading tests in Minnesota soils. Thus, the

success of CPT - predicted pile capacity is varied and Eslami and Fellenius, Togliani,

Takesue et al. provided very good agreement. Eslami et al. (2011) evaluated CPT based

pile capacity estimation methods using the pile records from Urmiyeh Lake Causeway

in Iran. They compared type of field tests results (static load and dynamic tests) and

predicted pile capacity using CPT data to design pile with the best CPT estimation

method, which is European method. Wang et al. (2015) estimated axial pile capacity

for different size precast prestressed concrete piles in southern Louisiana deposits.

European method and LCPC method showed close estimation with static load test

results. Hamman and Salam (2018) studied the behavior of bored piles to predict axial

pile capacity based on the CPT data in two soil layers, which were described with sand

overlaying compressible clay. They identified that Tumay and Fakhroo, LCPC and the

Canadian Code illustrate good performance to predict axial ultimate pile capacity.

6

Tab

le 2

.1 C

om

par

ison f

rom

lit

erat

ure

that

com

par

e th

e C

PT

pre

dic

tion m

ethods

wit

h p

ile

types

and s

oil

condit

ions.

7

2.2 Cone Penetration Test

The cone penetration test (CPT) is widely used, easliy repeatable, fast and

economical for in-situ site characterizetion. Accoding to Robertson and Cabal (2012),

the roles of the CPT are to idendify natural and sequence of the subsurface strata,

hydrologic regime, and physical and mechanical propeties of the underground strata.

For the clarification of soil parameters, cone tip resistance (qc), sleeve friction (fs), and

sometimes pore water pressure (u), are recorded during the cone penetration test as

shown in Figure 2.1 (a) and (b) (Robertson and Cabal, 2012). Figure 2.2 illustrates the

CPT probes, in which cone tip sizes range from 2 cm2 to 40 cm2.

Robertson and Cabal, 2012 explained that the cone penetration test (CPT)

measurements consists of two forces during the penetration. The cone tip resistance (qc)

was measured as the total force acting the cone (Qc) divided by cone projected area

(Ac). The sleeve friction (fs) was described with the ratio of between the total force

action on the friction sleeve (Fs) and the surface area of the friction sleeve (As). In the

Figure 2.1 (a), the pore pressure measurement is shown behind the cone in the u2 (pore

pressure measured at cone shoulder) location. In addition, the ratio of the sleeve friction

(fs) and cone tip resistance (qc) are represented as the friction ratio (Rf), which is a

parameter used to classify soil.

The CPT parameters has been used to estimate predicted axial static capacity of

driven piles using various methods. In these methods, the unit skin resistance (rs) is

usually computed from either cone tip resistance (qc) or sleeve friction (fs) while the

pile unit toe resistance (rt) is usually evaluated from cone tip resistance (qc) (Fellenius,

2018).

8

(a)

(b)

Figure 2.1 (a) Therminology for cone penetrometers (Robertson and Cabal, 2012) and

(b) ASTM D-5778 Cone penetration test procedure.

9

Figure 2.2 “from left: 2 cm2, 10 cm2, 15 cm2 and 40 cm2” CPT probes (Robertson and

Cabal, 2012).

2.2 Pile Capacity Prediction Methods Using Cone Penetration Test (CPT)

Pile capacity prediction methods were developed to find the best approach for

predicting axial pile capacity using CPT results. In this thesis, the prediction methods

are Nottingham and Schmertmann (1975) or Schmertmann (1978), DeRuiter and

Beringen or European (1979), Tumay and Fakhroo (1981), Bustamante and Gianeselli

or LCPC (1982), and Eslami and Fellenius (1997). Pile unit skin or side resistance (rs)

and pile unit toe or tip resistance (rt) are estimated from the CPT prediction methods.

The pile unit skin resistance (rs) is usually calculated using either the cone tip resistance

(qc) or the sleeve friction (fs) while the pile unit toe resistance (rt) is usually evaluated

using the cone tip resistance (qc). Table 2.2 shows the CPT prediction methods for

predicting the static capacity of piles with data base details and are further explained in

this chapter.

10

Tab

le 2

.2 M

ethod u

sed t

o p

redic

t st

atic

cap

acit

y o

f pil

es w

ith d

atab

ase

det

ails

.

11

2.2.1 Nottingham and Schmertmann

Nottingham (1975) and Schmertmann (1978) found different combinations of

their work on model and full-scale from CPT results to improve design equations. The

unit toe resistance (rt) was obtained as equal to the average of the cone resistance in

sand and clay. In addition, they described the average of the cone tip resistance (qca)

with minimum path values in an influence zone from a depth between 8D (D is pile

diameter) above and 0.7D to 4D below the pile toe as shown Figure 2.3.

Figure 2.3 Schmertmann rules for the influence zone and cone tip resistance (qc) (Titi

and Murad, 1999).

12

Unit toe resistance (rt) is found by:

rt = C × qca Eq. 2.1

where: rt = Pile unit toe resistance, an upper limit of 15 MPa is imposed

C = Correlation coefficient governed by the overconsolidation ratio (OCR) and

ranges from 0.5 through 1.0 (Figure 2.4) (Fellenius, 2006)

qca = The cone stress in the influence zone between 8b above and 4b below the

pile tip (Figure 2.3)

Figure 2.4 Adjustment of the coefficient (C) to OCR (Fellenius, 2006).

According to Schmertmann (1978), the estimation of the unit side resistance (rs)

is calculated from the sleeve friction (fs) in stiff cohesive soil. In addition, the unit skin

resistance may be determined for sand from the cone stress, qc, with Eq. 2.2. The unit

side resistance (rs):

13

In sand: rs = Kc x qc Eq. 2.2

In clay: rs = Kf x fs Eq. 2.3

where: rs = Pile unit skin resistance, an upper limit of 120 kPa is imposed

qc = Cone tip resistance

Kc = A dimensionless coefficient; a function of the pile type

for open toe, steel piles Kc = 0.8 % (0.008)

for closed-toe pipe piles Kc = 1.8 % (0.018)

for concrete piles Kc = 1.2 % (0.012)

Kf = A dimensionless coefficient (Figure 2.5)

fs = Sleeve friction

Figure 2.5 A dimensionless coefficient (Kf) for use in Eq. 2.3 when calculating the unit

side resistance in cohesive soils (Fellenius, 2006).

14

2.2.2 DeRuiter and Beringen (1979)

DeRuiter and Beringen (1979) studied soil near the North Sea using toe

resistance and shaft resistance to predict the ultimate pile capacity. Toe resistance was

defined using Nottingham (1975) and Schmertmann (1978) for sand (Eq. 2.4) and using

total stress analysis for clay (Eq. 2.5). The pile’s unit toe resistance (rt) is calculated as

follows:

In sand: rt = C × qca Eq. 2.4

In clay: rt = 5 x Su = 5 x qC

Nk Eq. 2.5






Nk = A dimensionless coefficient, usually, Nk=20 (Fellenius, 2006 and Mayne,

2007)

Su = Undrained shear strength

The pile’s skin resistance (rs) was described the smallest of sleeve friction (fs)

and qc/300 for sand (Eq. 2.6). rs is calculated as follows:

In sand: rs = fs and qc

300 Eq. 2.6

In clay: rs = α × Su = α ×qc

Nk Eq. 2.7

15

where: rs = Pile unit skin resistance, an upper limit of 120 kPa is imposed

fs = Sleeve friction – the unit skin resistance is the smallest of the sleeve friction

(Fellenius, 2006)

qc = Cone tip resistance,


Nk = A dimensionless coefficient, usually, Nk=20 (Fellenius, 2006 and Mayne,

2007)

α = Adhesion factor equal to 1.0 for normally consolidated clay and 0.5 for

overconsolidated clay (Fellenius, 2006)

2.2.3 Tumay and Fakhroo (1981)

Tumay and Fakhroo focused their pile capacity prediction method on

Louisiana’s clay soils (Fellenius, 2006). They evaluated the unit toe resistance (Eq. 2.8)

using the method of Nottingham (1975) and Schmertmann (1978).

Unit toe resistance (rt) is:

rt = C × qca Eq. 2.8






16

The pile’s skin resistance (rs):

rs = Kf × fs Eq. 2.9

where: rs = Pile unit skin resistance, kPa

Kf = A dimensionless coefficient

fs = Sleeve friction, kPa

Kf = 0.5 + 9.5e−90fs Eq. 2.10

where: fs = Sleeve friction, MPa

e = Base of natural logarithm = 2.718

2.2.4 Bustamante and Gianeselli (1982) – LCPC or French Method

This method is commonly called the LCPC (Laboratoire Central des Ponts et

Chaussées) or French method. Bustamante and Gianeselli (1982) focused on the

analysis of 197 full-scale static load tests for different type of soils: sand, clay, silt,

gravel, weathered chalk, weathered rock, peat and mud. In the LCPC method, the sleeve

friction (fs) was ignored and the unit toe resistance (rt) and the unit side resistance (rs)

were obtained from the cone tip resistance (Bustamante and Gianeselli, 1982).

The toe resistance is described with the cone tip resistance in an influence zone

of 1.5D (D is pile diameter) above the pile toe depth and 1.5D below the pile toe depth

(Figure 2.6). Also, average of the average cone tip resistance (qcaa) is obtained from

cone tip resistance (qc) within a range of 0.7qca through 1.3qca (qca is the first average

of cone tip resistance between 1.5D below and 1.5D above the pile tip) in Figure 2.6.

17

Figure 2.6 The average of cone tip resistance for the LCPC method (Bustamante and

Gianeselli, 1982).

The pile’s toe resistance (rt):

rt = CLCPC × qcaa Eq. 2.11

where: rt = Pile unit toe resistance

qcaa = Average of the average cone tip resistance in the influence zone (Figure

2.6)

CLCPC = Correlation coefficient (Table 2.3)

18

Table 2.3 Correlation coefficients (CLCPC) of unit toe resistance in the LCPC Method

(Fellenius, 2006).

Soil

Type

Cone Stress

(MPa)

Bored Piles Driven Piles

CLCPC CLCPC

Clay

qc < 1 0.04 0.5

1 < qc < 5 0.35 0.45

5 < qc 0.45 0.55

Sand qc < 12 0.4 0.5

12 < qc 0.3 0.4

The unit skin resistance depends on the type of soil, pile type and pile

installation method. Bustamante and Gianeselli (1982) identified a dimensionless

coefficient (Kc), based on cone tip resistance and pile types.


rs= KLCPC × qc Eq. 2.12

where: rs = Pile unit skin resistance

qc = Cone tip resistance (note, uncorrected for pore pressure)

KLCPC = A dimensionless coefficient based on the nature at the soil and the pile

installation method (Tables 2.4)

Table 2.4 A dimensionless coefficient (KLCPC) for different soil and pile types

(Fellenius, 2006).

Soil

Type

Cone

Stress

(MPa)

Concrete Piles

& Bored Piles Steel Piles Maximum rs

KLCPC KLCPC J (kPa)

CLAY

qc < 1 0.011 0.033 15

1 < qc < 5 0.025 0.011 35

5 < qc 0.017 0.008 35

(for qc > 5, the unit shaft resistance, rs, is always larger than 35 kPa)

SAND

qc < 5 0.017 0.008 35

5 < qc <

12 0.010 0.005 80

12 < qc 0.007 0.005 120

19

2.2.5 Eslami and Fellenius (1997)

Eslami and Fellenius (1997) evaluated 102 cases around the world to predict

ultimate pile capacity. In their method, the effective cone resistance (qE) was obtained

from measured total cone tip resistance by subtracting measured pore water pressure

(Eslami and Fellenius, 1997).

The pile’s toe resistance (rt):

rt= Ct × qEg Eq. 2.13

where: rt = Pile unit toe resistance

D = Pile diameter

qEg = Geometric average of the effective cone point resistance over and

influence zone extending from 4D below the pile toe through a height of 8D

(2D for a dense soil into a weak soil) above the pile toe when a pile is installed

through a weak soil in to a dense soil

Ct = Toe correlation coefficient and can be taken as equal to unity in most cases.

For pile diameters larger than about 0.4 meter, the adjustment factor should be

determined by the relation given in Eq. 2.14 (Eslami and Fellenius, 2018)

Ct =1

3D, D in meter Ct =

12

D, D in inch Eq. 2.14


rs = Cs × qE Eq. 2.15

where: rs = Pile unit skin resistance

Cs = Shaft correlation coefficient (Table 2.5)

20

qE = Effective cone resistance (Figure 2.7) after correction for pore pressure

on the cone shoulder and adjustment to apparent “effective” stress; qE = qt – u2

(Fellenius, 2006)

qt = Total cone resistance (Fellenius and Eslami, 2000)

u2= Pore pressure measured at cone shoulder (corrected for pore pressure

acting against the shoulder - Fellenius and Eslami, 2000)

Figure 2.7 The Eslami-Fellenius profiling chart effective cone resistance (qE) versus

sleeve friction (fs) (Fellenius and Eslami, 2000).

Table 2.5 The value of shaft correlation coefficient (CS) (Eslami and Fellenius, 1997).

Soil type Shaft Correlation Coefficient

CS % (Decimal)

Soft sensitive soils 8 (0.08)

Clay 5 (0.05)

Silty clay, stiff clay and silt 2.5 (0.025)

Sandy silt and silt 1.5 (0.015)

Fine sand or silty sand 1 (0.01)

Sand to sandy gravel 0.4 (0.004)

21

2.3 Soil Type Based on CPT

Simplified soil classification using CPT results by Robertson et al. (1986) is

shown in Figures 2.8 and 2.9. Clayey soils usually demonstrate high sleeve friction and

low cone tip resistance, thus clayey soils show a high friction ratio. On the other hand,

sandy soils show low sleeve friction and high cone tip resistance, therefore sandy soils

show a low friction ratio.

Figure 2.8 Proposed soil behavior type classification chart based on normalized CPT

(Robertson 1989).

22

Figure 2.9 Soil classification chart for standard electric friction cone (Robertson 1989).

2.4 Summary of Literature Review

The cone penetration test (CPT) is an in-situ method to obtain data for the

characterization of soil. The soil parameters, cone tip resistance (qc), sleeve friction (fs),

and sometimes pore water pressure (u), are obtained and recorded during the cone

penetration test. Furthermore, the parameters of sleeve friction (fs) and cone tip

resistance (qc) are key factors used to predict pile capacity. These five methods were

23

described to calculate the ultimate static axial capacity of piles using CPT data. All of

the methods include some empirical factors. Each method was developed using

different data bases of load tests on piles.

24

CHAPTER 3 – SITE DESCRIPTION

3.1 Introduction

The objective of this thesis is to compare predicted pile capacity with static load

test results. Site characterization is necessary to compute predicted pile capacity. Piles

were tested at two bridge project sites (Route WW and Route U) in New Madrid, MO

for the Missouri Department of Transportation (MoDOT). The location of the projects

and site characterizations are presented in this chapter.

3.2 Project Overview and Location

This research has two project sites. One is Route WW Bridge (Structure No.

A8472) and the second is Route U Bridge (Structure No. A8414). The project on Route

WW (Figure 3.1) is located in New Madrid County where Route WW crosses over

Wilson Bayou about 6.5 miles northeast of New Madrid, MO (Fennessey, 2016). The

other project on Route U (Figure 3.1) crosses Dry Run Ditch about 2.9 miles northeast

of New Madrid, MO (Hilchen, 2016). The site plan for both bridges is shown in Figures

3.2 and 3.3. The project on Route WW includes an existing 102-foot long bridge while

the project on Route U includes an existing 65-foot long bridge. The two existing

bridges are supported on pile foundations including 14-inch diameter cast-in-place

(CIP) and 16-inch octagonal precast concrete piles.

25

Fig

ure

3.1

Loca

tion o

f p

ile

load

tes

t pro

ject

s.

26

Fig

ure

3.2

The

site

pla

n o

f re

pla

cem

ent

bri

dge

Ro

ute

WW

(S

truct

ure

No.

A8472).

27

Fig

ure

3.3

The

site

pla

n o

f re

pla

cem

ent

bri

dge

Ro

ute

U (

Str

uct

ure

No.

A84

14

).

28

3.3 Site Geology

The areas of both bridge are located in northeast New Madrid County, Missouri.

The general geology of the New Madrid County constitutes from the sediments of

Mississippi Embayment, which is ranging in age from Cretaceous to Quaternary

(Cushing, E. M., Boswell, E. H. and Hosman, R. L., 1964). From the Cretaceous to the

Quaternary, the geologic characteristic of the Mississippi Embayment includes deposits

of gravel, sand silt, clay lignite, marl, chalk, and limestone.

The stratigraphic characteristics of the Mississippi Embayment are highly

complex. According to Cushing, E. M., Boswell, E. H. and Hosman, R. L. (1964), the

part of the stratigraphic characteristics of northern Mississippi Embayment for Missouri

was described with Eocene series (Wilcox Formation), Paleocene Series (Midway

Group – Porters Creek Clay and Clayton Formation), and Upper Cretaceous Series

(Owl Creek Formation, McNairy Sand). The soil characteristics are shown with the

stratigraphic characteristics in the Table 3.1. In addition, Arsdale and TenBrink (2000)

defined late Cretaceous and Cenozoic of the New Madrid seismic zone and the

summary of northern Mississippi Embayment lithology was explained sands, silts and

clays.

Table 3.1 The stratigraphy of sites from the general geology of the Mississippi

Embayment for Missouri (Cushing et al, 1964).

Series Formation Soil Characteristics

Eocene Wilcox Formation Lower predominantly sand and

upper predominantly shale or clay

Paleocene

Porters Creek Clay Very dark or black blocky clay

Clayton Formation Mostly of limestone, calcareous

sand, and sandstone

Upper

Cretaceous

Owl Creek Formation Clay

McNairy Sand Fine Sand

29

3.4 Sites Description

All historical records of the Route WW site (Fennessey, 2016) show that a total

of two borings (one SPT and one CPT) were drilled in the beginning of 2016. The CPT-

H-16-22 which is near the load test pile, is near the west end of the existing structure

while the SPT (Boring A-16-14) was performed near the east end of the existing

structure. As shown Table 3.2, a sand layer exists at a depth of 54 feet at the west end

of existing bridge (site WW) based on the CPT data while the depth to sand is almost

76 feet at the east end of the existing bridge based on the SPT data. Moreover, the clay

layer contains seams of sands. The Route U site (Hilchen, 2016) has one SPT and one

CPT test performed in 2016. The CPT-H-16-12, which is near the load test pile, was

near the east end of the existing bridge while the SPT (A-16-03) was performed at the

west end of the structure. Based on Table 3.3, site U has sand beginning at about 8 feet

below the surface and extending to a depth of 66 feet.

In general, both sites include layers of soft or stiff clays overlying layers of

poorly-graded or well-graded sand and silty sand. Sites consist of interbedded layers of

clay, silt and sand. In addition, four CPT parallel seismic tests (SCPT) were performed

in late 2016 and one load test was performed on site at the Route WW and Route U

bridge sites (Boeckmann et al., 2018). The location of the load test pile for both sites is

shown in Figure 3.4. The distance between the CPT and the load test pile is shown for

both sites in the Table 3.4. The load test was made at the west end of existing bridge on

Route WW (pile number 2) while the load test was performed at the east end of existing

bridge on Route U as shown Figure 3.4.

30

Table 3.2 Soil description depends on the borehole information of SPT and CPT for

Route WW.

SPT Boring, A-16-14

Layer Range Depth (feet) Description

1 0 - 14 Stiff Clay

2 14 - 24 Silt

3 24 - 34 Sand

4 34 - 76.2 Soft Clay

5 76.2 - 106.5 Sand

6 106.5 Bottom of Borehole

CPT Boring, H-16-22


1 0 - 48.2 Soft Clay

2 48.2 - 53.7 Soft Clay with free water

3 53.7 - 71.9 Sand


Table 3.3 Soil description depends on the borehole information of SPT and CPT for

Route U.

SPT Boring, A-16-03


1 0 – 5.9 Fat Clay

2 5.9 – 66.5 Sand


CPT Boring, H-16-12


1 0 - 8 Soft Clay

2 8 - 49.1 Sand


31

Table 3.4 Distance from pile to sounding (Boeckmann et al., 2018).

Distance (feet) from Pile to Sounding for

14-inch Diameter Cast-In-Place Piles at

Site WW

Distance (feet) from Pile to

Sounding for 16-inch Octagonal

Precast Concrete Piles at Site U

Pile

Number CPT H-16-22

SCPT

H-16-76

Pile

Number CPT H-16-12

2 (LTP) 15 (near the west end of existing structure)

17.5 LTP 20 (near the east end of the existing structure)

LTP: Load test pile.

Figure 3.4 The location of load test pile (LTP) for (a) 14-inch diameter CIP pile at site

WW and (b) 16-inch octagonal precast concrete pile at site U (Boeckmann et al., 2018).

As shown Figures 3.5 and 3.6, five cone penetration tests were performed at

each bridge site. The distance from the CPT to the load test piles are shown in Figures

32

3.5 and 3.6. All distance values were estimated from the report of Foundation Reuse:

Length, Condition, and Capacity of Existing Driven Piles (Boeckmann et al., 2018).

The distance from the CPT to the load test pile ranges from 3.4 feet to 60 feet for the

bridge on Route WW while it ranges from 3 feet to 68 feet for the bridge on Route U.

The CPTs closest to each pile load test was used to predict the pile capacity. CPT H-

16-22 is closest to the load test pile for Route WW bridge site while CPT H-16-12 is

closest the load test pile for Route U bridge site (Figures 3.5 and 3.6).

Figure 3.5 The load test pile location with distance from CPT to load test pile at the

Route WW bridge plan.

33

Figure 3.6 The load test pile location with distance from CPT to load test pile at the

Route U bridge plan.

3.5 Pile Length

The length and width of piles are a significant to predict ultimate axial static

capacity. The CIP pile at Route WW are 14-inch diameter close-end pie pile with the

wall thickness of 0.25-inch while the precast concrete pile at Route U are 16-inch wide

octagonal. Moreover, the precast concrete pile includes taper (Appendix), which has

10-inch width (inside width is 8-inch) and over the 5 feet length of the pile (Boeckmann

et al., 2018).

After field tests, six piles were exhumed to describe the length of existing piles

for both structures. (Boeckmann et al., 2018). The exhumed 14-inch diameter cast-in-

place piles were piles 1, 2 (LTP), 3, 4, 5 and 8 Route WW site (Figure 3.4 (a)) while

the exhumed 16-inch octagonal precast concrete piles were piles 1, 2, 4, 5, 6 and load

test piles from Route U site (Figure 3.4 (b)). The exhumed load test pile length with

34

pile location and elevation of pile tip were shown in the Table 3.5 for CIP piles and for

precast concrete piles. The exhumed length of the load test pile is 50.9 feet for bridge

on Route WW and 21.33 feet for bridge on Route U. In addition, embedded load test

pile length (minus 1 feet or 2 feet from exhumed pile length) was described the

elevation of pile tip, the elevation of exhumed pile and the length of exhumed pile to

estimate predicted ultimate axial capacity in this thesis.

Table 3.5 Exhumed CIP pile length with pile tip depth at Route WW site and precast

concrete pile length with pile tip depth at Route U site (Boeckmann et al., 2018). LTP

is the load test pile.

The Pile Information of Cast-In-Place Pile at Route WW

Pile

Number

Pile top

Elevation

(feet)

Exhumed

Pile Top

Cutoff

Elevation

(feet)

Exhumed

Pile

Length

(feet)

Pile

Location

from

Structure

Elevation

of CPT

H-16-22

(feet)

Elevation

of Pile

Tip (feet)

2 (LTP) 294.83 290.07 50.9 West End 288.9 239.17

The Pile Information of Precast Concrete Pile at Route U

Pile

Number

Pile top

Elevation

(feet)

Exhumed

Pile Top

Cutoff

Elevation

(feet)

Exhumed

Pile

Length

(feet)

Pile

Location

from

Structure

Elevation

of CPT

H-16-12

(feet)

Elevation

of Pile

Tip (feet)

LTP 295.44 290.22 21.33 East End 297 268.89

35

Figure 3.7 Exhumed 16-inch octagonal precast concrete piles at the bridge site U.

Figure 3.8 Exhumed 14-inch diameter cast-in-place (CIP) piles at the bridge site WW.

For 14-inch diameter CIP pile, the location of CPT with soil profile is seen to

explain the vertical distance of sand to silty sand and clay to silty clay in the Figure 3.9.

According to Boeckmann et al. (2018), the soil consists of the clay to silty clay between

36

surface and almost 55 feet depth (almost the elevation of 235 feet) at the west end of

the existing bridge on Route WW. The dense sand layer depth is increasing from 55

feet on the west end to over 70 feet on the east end of the existing bridge on Route WW

(Figure 3.9). The depth of pile tip did not reach dense poorly graded sand in the west

end of the existing bridge on Route WW according to CPT records (Figure 3.9).

For 16-inch octagonal precast concrete pile, the location of CPT with soil profile

is seen to explain the vertical distance of dense poorly graded sand and soft or stiff clay

in the Figure 3.10. The top of the soil layer 5 feet – 8 feet consists of the soft or stiff

clay to silty clay (Boeckmann et al., 2018). This clay layer is underlying dense poorly

graded sand to a depth of 66 feet in the Figure 3.10. The depth of pile tip reached dense

poorly graded sand (almost 20 feet the length of embedded pile) in the east end of the

existing bridge on Route U according to CPT records (Figure 3.10).

37

Figure 3.9 The location of CPT with soil profile and the location of load test pile to

explain vertical distance of soil types for 14-inch diameter CIP pile.

38

Figure 3.10 The location of CPT with soil profile and the location of load test pile to

explain vertical distance of soil types for 16-inch octagonal precast concrete pile.

3.6 Available Information

A standard penetration test (SPT) and a cone penetration test (CPT) were

available for both bridge sites. The standard penetration test value of N60 ranges from

1 to 99. This value depends on the characterization of soil and the depth of tests (Tables

3.6 and 3.7). In addition, the value of the internal friction angle is shown between 160

and 430 and the total unit weight (range from 75 to 150 pcf) and the effective unit weight

39

(range from 13 to 121 pcf) change based on the type of soils and water level for both

sites in Tables 3.6 and 3.7.

According to Fennessey (2016), the CPT sounding for Route WW contains 53.7

feet of soft clay to silty clay having cone tip resistance (qc) of roughly 4 to 150 ksf. The

observation of sleeve friction (fs) ranges from 0.5 ksf to 1.8 ksf for the clay layer. After

53.7 feet, the sand layer is observed until the depth of 71.9 feet in the CPT sounding.

The values of qc appear on the order of 150 to 800 ksf, while the reading of the fs ranges

from 1.8 ksf to 6 ksf. Measured friction ratio (Rf) values ranges from 2 to 6% for the

clay layer, while the maximum value of Rf is approximately 1% for the sand layer

(Fennessey, 2016).

According to Hilchen (2016), the CPT sounding for Route U contains 8 ft of

soft clay to silty clay having cone tip resistance (qc) of approximately 0.1 to 30 ksf. The

observation of sleeve friction (fs) ranges from 0.2 ksf to 1 ksf for clay layer. Below 8

feet, the sand layer is observed until the depth of 49.1 feet in the CPT sounding. The

values of qc are on the order of 30 to 375 ksf, while the reading of the fs ranges from 1

ksf to 2.8 ksf. Measured friction ratio (Rf) shows a maximum 10% and a minimum 2%

for the clay layer, while the maximum value of Rf ranges from 1 to 2% for the sand

layer (Hilchen, 2016).

40

Table 3.6 Soil Description with SPT and CPT data for the Site of Route WW

(Fennessey, 2016).

SPT Boring, A-16-14

Layer Depth

(feet) Description

Total Unit

Weight

(pcf)

Effective

Unit Weight

(pcf)

Internal

Friction

Angle (Φ)

Blow

Counts

(N60)

1 0 - 14 Stiff Clay 120(1) 120(1) - 8

2 14 - 24 Silt 95(1) 33(1) 29(1) 4

3 24 - 30 Sand 105(1) 43(1) 30(1) 7

4 30 - 34 Sand 75(1) 13(1) 26(1) 1

5 34 - 38 Soft Clay 115(1) 53(1) - 4

6 38 - 44 Soft Clay 110(1) 48(1) - 3

7 44 - 50 Soft Clay 120(1) 58(1) - 9

8 50 - 55 Soft Clay 115(1) 53(1) - 5

9 55 - 65 Soft Clay 120(1) 58(1) - 8

10 65 - 76.2 Soft Clay 120(1) 58(1) - 12

11 76.2 - 82 Sand 122(1) 60(1) 36(1) 32

12 82 - 95 Sand 130(1) 68(1) 38(1) 43

13 95 - 100 Sand 150(1) 88(1) 38(1) 30

14 100 - 106.5 Sand 142(1) 80(1) 43(1) 80

CPT Boring, H-16-22

Layer Depth

(feet) Description

Total Unit

Weight

(pcf)

Effective

Unit Weight

(pcf)

Internal

Friction

Angle (Φ)

Blow

Counts

(N60)

1 0 - 9 Soft Clay 111(1) 111(1) - 5(1)

2 15-Sep Soft Clay 111(1) 111(1) - 2(1)

3 15 - 28 Soft Clay 111(1) 49(1) - 3(1)

4 28 - 40 Soft Clay 114(1) 52(1) - 4(1)

5 40 - 46 Soft Clay 111(1) 49(1) - 5(1)

6 46 - 50 Soft Clay 114(1) 52(1) - 7(1)

7 50 - 53.7 Soft Clay 114(1) 52(1) - 10(1)

8 53.7 - 60 Sand 127(1) 65(1) 44(1) 63(1)

9 60 - 64 Sand 124(1) 62(1) 41(1) 42(1)

10 64 - 70 Sand 124(1) 62(1) 40(1) 43(1)

11 70 - 71.9 Sand 124(1) 62(1) 40(1) 42(1)

(1) = Assumed, water level = 14 feet

41

Table 3.7 Soil Description and CPT data for the Site of Route U (Hilchen, 2016).

SPT Boring, A-16-03

Layer Depth

(feet) Description

Total Unit

Weight

(pcf)

Effective

Unit Weight

(pcf)

Internal

Friction

Angle (Φ)

Blow

Counts

(N60)

1 0 - 5.9 Fat Clay 120(1) 120(1) - 4

2 5.9 - 10 Sand 99(1) 99(1) 29(1) 9

3 10 - 19 Sand 112(1) 112(1) 33(1) 22

4 19 - 25 Sand 129(1) 67(1) 34(1) 26

5 25 - 30 Sand 137(1) 75(1) 37(1) 37

6 30 - 35 Sand 128(1) 66(1) 33(1) 22

7 35 - 40 Sand 127(1) 65(1) 33(1) 18

8 40 - 45 Sand 132(1) 70(1) 36(1) 33

9 45 - 50 Sand 133(1) 71(1) 37(1) 37

10 50 - 55 Sand 135(1) 73(1) 40(1) 53

11 55 - 60 Sand 138(1) 76(1) 45(1) 99

12 60 - 65 Sand 135(1) 73(1) 39(1) 50

13 65 - 66.5 Sand 136(1) 74(1) 39(1) 61

CPT Boring, H-16-12

Layer Depth

(feet) Description

Total Unit

Weight

(pcf)

Effective

Unit Weight

(pcf)

Internal

Friction

Angle (Φ)

Blow

Counts

(N60)

1 0 - 8 Soft Clay 111(1) 111(1) 16(1) 5(1)

2 8 - 12 Sand 121(1) 121(1) 38(1) 11(1)

3 12 - 20 Sand 121(1) 121(1) 38(1) 16(1)

4 20 - 21 Sand 121(1) 59(1) 38(1) 16(1)

5 21 - 26 Sand 124(1) 62(1) 42(1) 36(1)

6 26 - 32 Sand 121(1) 59(1) 34(1) 11(1)

7 32 - 37 Sand 124(1) 62(1) 43(1) 54(1)

8 37 - 43 Sand 127(1) 65(1) 43(1) 52(1)

9 43 - 49.1 Sand 124(1) 62(1) 42(1) 41(1)

(1) = Assumed, water level = 19 feet

42

3.7 Summary

The main purpose of this research is to compare predicted axial static pile

capacity to measured static pile capacity for piles at bridges on Route WW (Structure

No. A2141) and Route U (Structure No. N-0771) near New Madrid, MO. Therefore,

CPT soundings, standard penetration testing and static load test were performed at each

project site. According to CPT and SPT soundings, both sites include layers of soft or

stiff clays interbedded with layers of poorly-graded or well-graded sand with silty sand.

The value of N60 ranges from 1 to 99, the internal friction angle ranges between 160 and

430 and the total unit weight ranges from 75 to 150 pcf. The load test was made at the

west end of existing bridge on Route WW and at the east end of existing bridge on

Route U. The exhumed pile lengths were measured to determine actual pile tip depths

or embedded load test pile lengths, which is 50.9 feet for the bridge on Route WW and

21.3 feet for the bridge on Route U. In addition, the CPT data profiles for both sites

give information about cone tip resistance (qc), sleeve friction (fs), pore pressure (u),

friction ratio (Rf) and equivalent N60 (blow counts) as show in Figures 3.11 and 3.12.

43

CHAPTER 4 – METHODOLOGY

4.1 Introduction

The main objective of this thesis is to compare predicted pile capacity with

measured pile capacity for two piles in New Madrid soils in Missouri. Five prediction

methods using CPT data to predict capacity of driven piles have been studied. The pile

capacity prediction methods include: Nottingham (1975) and Schmertmann (1978),

DeRuiter and Beringen (1979), Tumay and Fakhroo (1981), Bustamante and Gianeselli

(1982), and Eslami and Fellenius (1997). In this chapter, the general procedures are

described to predict capacity of the driven piles.

4.2 Static Analysis of Ultimate Pile Capacity Based on CPT Results

The five CPT methods were used to estimate predicted pile capacity and the

methods were described in Chapter 2. Moreover, Fellenius (2006) proposed the use of

two equations with variable depth to predict skin resistance (Rs) and toe resistance (Rt)

(Figure 4.1). The two components are determined from the soil properties and effective

overburden stress (Equations 4.1 and 4.2).

44

Figure 4.1 Components of pile capacity (Qult).

4.2.1 Total Skin Resistance

Typically, total skin resistance (Rs) is calculated the using relationship pile unit

skin resistance (rs) and circumferential area (As) from the surface through depth Z in

Equation 4.1. The pile unit skin resistance (rs) can be calculated from the effective cone

tip resistance (qc) and cone sleeve friction (fs) as defined in the Chapter 2 (Equations

2.2, 2.3, 2.6, 2.7, 2.9, 2.12, and 2.15). As shown in Equation 4.1, the total skin resistance

(Rs) increases based on increasing depth and designated circumferential pile area at

depth Z.

Rs = ∫As rs dz Eq. 4.1

where: Rs = Total skin resistance

rs = Pile unit skin resistance (variable with different CPT methods)

As = Circumferential area of the pile at Depth z

45

4.2.2 Total Toe Resistance

As shown in Equation 4.2, total toe resistance (Rt) can be estimated with the

pile unit toe resistance (rt) and toe area (At). The unit toe resistance (rt) was identified

in the Chapter 2 (Equations 2.1, 2.4, 2.5, 2.8, 2.11, and 2.13). The total toe resistance

(Rt) increases as the unit toe resistance (rt) increases.

Rt = At rt Eq. 4.2

where: Rt = Total toe resistance

At = Toe area (normally, the cross-sectional area of the pile)

rt = Pile unit toe resistance (variable with different CPT methods)

4.2.3 Total Pile Capacity Using CPT Data

According to Fellenius (2006), the total pile capacity using CPT data consists

of end-bearing capacity of total skin resistance (Rs) and the total toe resistance (Rt). The

total pile capacity is calculated as follows:

Qult = Rs + Rt Eq. 4.3

where: Qult = Ultimate resistance or the capacity of the pile

Rs = Total skin resistance

Rt = Total toe resistance

Determining the unit skin resistance (rs) and the unit toe resistance (rt) are the

two main components in estimating pile capacity. A summary of the two components

is presented alongside the five CPT methods in Table 4.1.

46

Table 4.1 The equations for unit side (rs) and unit tip (rt) resistance based on CPT data.

Method

Equations

Pile unit skin or side

resistance

Pile unit toe or tip

resistance

Nottingham and

Schmertmann

(1975;1978)

rs = Kc x qc for sand rt = C × qca

rs = Kf x fs for clay

DeRuiter and

Beringen (1979)

rs = fs and qc

300 for sand rt = C × qca for sand

rs = α × Su = α ×qc

Nk for clay rt = 5 x Su, Su =

qc

Nk for clay

Tumay and

Fakhroo (1981) rs = Kf × fs, Kf = 0.5 + 9.5e−90fs rt = C × qca

Bustamante and

Gianeselli (1982) rs= KC × qc rt = CLCPC × qcaa

Eslami and

Fellenius (1997) rs = Cs × qE rt= Ct × qEq

where: rt = Pile unit toe or tip resistance

rs = Pile unit skin or side resistance

qc = Cone tip resistance



qcaa = Average of the average cone tip resistance in the influence zone (Figure

2.6)

qE = Effective cone resistance (Figure 2.7)

qEg = Geometric average of the cone point resistance

fs = Sleeve friction


47

Nk = A dimensionless coefficient, usually, Nk=20, (Fellenius, 2006 and Mayne,

2007)

α = Adhesion factor equal to 1.0 for normally consolidated clay and 0.5 for

overconsolidated clay (Fellenius, 2006)

e = Base of natural logarithm = 2.718

Kc = A dimensionless coefficient (Chapter 2 - Nottingham and Schmertmann

method)

Kf = A dimensionless coefficient in Figure 2.5 (Chapter 2 - Nottingham and

Schmertmann method)

KLCPC = A dimensionless coefficient based on the nature at the soil and the pile

installation method (Chapter 2 - Bustamante and Gianeselli method Tables 2.4)

Ct = Toe correlation coefficient (Chapter 2 - Eslami and Fellenius method, page

19)

Cs = Shaft correlation coefficient (Chapter 2 - Eslami and Fellenius method,

Table 2.5)

CLCPC = Correlation coefficient (Chapter 2 - Bustamante and Gianeselli method,

Table 2.3)

C = Correlation coefficient governed by the overconsolidation ratio and ranges

from 0.5 through 1.0 (Chapter 2 - Nottingham and Schmertmann method, Figure

2.4)

4.3 Capacity of Piles from Static Load Tests

Static load tests were performed on one pile at each bridge site. For both bridges,

the same reaction beam was designed to measure load capacity (Boeckmann, 2018).

The observed load-displacement curves and foundation data are presented in Figure

4.2. Photographs of the load test setups are shown in Figure 4.3. The maximum

48

measured capacity of the CIP pile (Route WW) was about 247 kips (123.5 tons) at 0.14

inches vertical displacement at the pile head. As shown Figure 4.2, the CIP pile did not

reach ultimate capacity because a visible crack appeared in the reaction beam and

loading was stopped. The precast concrete pile (Route U) showed an ultimate capacity

of about 268 kips (134 tons) at 0.32 inches vertical displacement.

Figure 4.2 Load test results for existing piles Route WW and Route U bridge

(Boeckmann, 2017).

49

Figure 4.3 The static load test for Route WW and Route U bridge (Boeckmann, 2017).

4.4 Summary

The work in this thesis depends on cone penetration test results and uses static

analysis to predict pile capacity. Total skin resistance (Rs) and total toe resistance (Rt)

were defined in the calculated pile capacity analyses. The estimated pile capacities and

comparison to the results of the field load tests are presented in the following chapter.

50

CHAPTER 5 – RESULTS AND DISCUSSION

5.1 Introduction

The objective of this thesis is the comparison of pile capacity based on the CPT

methods to measured pile capacity for cast-in-place and precast concrete pile in New

Madrid Missouri. Five CPT methods were used to predict the pile capacity. The

predicted pile capacities were compared with the measured pile capacities for each CPT

method. In this chapter, the results of measured versus predicted pile capacity are

compared.

5.2 Analysis of Calculated Pile Capacity

The results of the CPT test closest to each load test pile was were used to predict

the capacity of the piles. Five methods using CPT results were used to predict the

capacity of the piles. The methods include Nottingham and Schmertmann, DeRuiter

and Beringen, Tumay and Fakhroo, Bustamante and Gianeselli (LCPC), and Eslami

and Fellenius.

The soil profile consists of soft or stiff clays with interbedded layers of poorly-

graded or well-graded sand with silty sand for both bridge sites. The embedded length

of each load test pile was determined using the exhumed length of the piles and the

cutoff elevation. The load test was performed at the exhumed pile top cut off elevation,

which is 290.07 feet for 14-inch diameter CIP pile and 290.22 for the 16-inch octagonal

precast concrete pile (Boeckmann et al., 2018). The exhumed pile lengths (Chapter 3 –

Table 3.5) are 50.9 and 21.3 feet for a 14-inch diameter cast-in-place (CIP) and a 16-

inch octagonal precast concrete pile, respectively. The elevation of the CPT (CPT H-

51

16-22 the for cast-in-place pile and CPT H-16-12 for the precast concrete pile) was

considered in the pile capacity predictions to ensure the correct soil parameters at the

pile tip elevation.

The soil description for the bridge on Route WW is sandy soils between depths

of 53.7 feet and 71.9 feet. Clayey soils, including seams of silt, cover the sandy soils

until the surface (CPT H-16-12). The site description for the bridge on Route U

indicates that the depth of between 8 feet and 49 feet is comprised of sandy soils. Seams

of silty and clayey soils overly the sand. In Figures 5.1 through 5.5 plots of predicted

pile capacity versus depth are presented for the 14-inch diameter cast-in-place (CIP)

and the 16-inch octagonal precast concrete pile, respectively.

For the 14-inch diameter CIP pile, the pile capacity shows a large increase

between depth of 54 and 60 feet. The reason is that the soil is changing from clay with

seams of silt to sand at between 54 and 60 feet. Sandy soils usually show higher cone

tip resistance (qc). The higher cone tip resistance (qc) has significant influence on pile

capacity and thus the reason for the large increase in capacity between 50 and 60 feet.

The measured capacity of the precast concrete pile was about 123.5 tons while the

original design pile capacity was about 30 tons (Boeckmann, 2017). The five CPT

predictions range from 58 tons to 115 tons (Figures 5.1, through 5.5). The predicted

pile capacities ranged from 0.47 to 0.94 (conservative) times the measured pile

capacity. The Eslami and Fellenius prediction is the closest with the measured capacity

(~115 tons vs 123 tons in the Figure 5.5).

For the 16-inch octagonal precast concrete pile, the calculated pile capacities

versus depth are presented with the measured capacity and design capacity for the

precast concrete pile in Figures 5.1 through 5.5. The measured capacity of the precast

52

concrete pile was about 134 tons while the original design pile capacity was about 21

tons (Boeckmann, 2017). The pile capacity predicted using the CPT results ranged from

0.67 (conservative) to 1.05 (unconservative) times the measured pile capacity. The

Nottingham and Schmertmann and Eslami and Fellenius predictions are the closest with

the measured capacity (126 tons and 140 tons vs 134 tons) (Figures 5.1 and 5.5). The

DeRuiter and Beringen (European), Tumay and Fakhroo, and Bustamante and

Gianeselli (LCPC) methods underestimate the measured capacity (Figures 5.2, 5.3 and

5.4).

Figure 5.1 Pile capacity versus depth calculated using the method of Nottingham and

Schmertmann for 14-inch CIP pile at the Route WW site the depth of pile tip at 50.9

feet and 16-inch precast concrete pile at the Route U site the depth of pile tip at 21.3

feet.

53

Figure 5.2 Pile capacity versus depth calculated using the method of DeRuiter and

Beringen for 14-inch CIP pile at the Route WW site the depth of pile tip at 50.9 feet

and 16-inch precast concrete pile at the Route U site the depth of pile tip at 21.3 feet.

Figure 5.3 Pile capacity versus depth calculated using the method of Tumay and

Fakhroo for 14-inch CIP pile at the Route WW site the depth of pile tip at 50.9 feet and

16-inch precast concrete pile at the Route U site the depth of pile tip at 21.3 feet.

54

Figure 5.4 Pile capacity versus depth calculated using the method of Bustamante and

Gianeselli (LCPC) for 14-inch CIP pile at the Route WW site the depth of pile tip at

50.9 feet and 16-inch precast concrete pile at the Route U site the depth of pile tip at

21.3 feet.

Figure 5.5 Pile capacity versus depth calculated using the method of Eslami and

Fellenius for 14-inch CIP pile at the Route WW site the depth of pile tip at 50.9 feet

and 16-inch precast concrete pile at the Route U site the depth of pile tip at 21.3 feet.

55

5.3 Calculated versus Measured Pile Capacity

A static load test was performed and the load at failure with pile head

displacement was recorded at each bridge site. The load test information was presented

in Chapter 4. The measured pile capacity is 123.5 tons for the 14-inch diameter cast-in-

place pile at the Route WW site and 134 tons for the 16-inch octagonal precast concrete

pile at the Route U site. The ultimate loads predicted using the five CPT methods were

compared to ultimate loads interpreted from the load tests. The prediction methods are

the Nottingham and Schmertmann (1975) or Schmertmann (1978), DeRuiter and

Beringen (1979), Tumay and Fakhroo (1981), Bustamante and Gianeselli (1982), and

Eslami and Fellenius (1997).

The predicted pile capacity should always be considered together with the toe

resistance (Rt) and side resistance (Rs). The toe resistance (Rt) and side resistance (Rs)

calculated using CPT methods for the 14-inch diameter cast-in-place pile and the 16-

inch octagonal precast concrete pile are shown in Figures 5.6 and 5.7. The toe resistance

shows the same value for Nottingham and Schmertmann, and Tumay and Fakhroo

prediction methods because these two prediction methods used the same concept (the

concept of Nottingham and Schmertmann) to calculate toe resistance (Chapter 2). The

DeRuiter and Beringen (European) and Tumay and Fakhroo predictions show close

agreement about the components of pile capacity (Rt and Rs) for the 16-inch octagonal

precast concrete pile at Route U site (Figure 5.7). The pile capacity (Qt) by the CPT

methods and the measured capacities from the load tests are compared for both pile

types in Figures 5.8 and 5.9. The Eslami and Fellenius prediction is in close agreement

with the pile load test result for the 14-inch diameter CIP pile at site WW while the

Nottingham and Schmertmann and Eslami and Fellenius prediction methods are in

56

close agreement with measured pile capacity for the 16-inch octagonal precast concrete

pile at site U.

As shown Figures 5.6 and 5.7, the toe and side resistances were compared for

both pile types. For the CIP pile at site WW, most of the predicted capacity was from

side resistance (Figure 5.6). The reason is that the tip of the CIP pile (load test pile) did

not reach the sandy soil. The capacity is dominated by the clay soil (above the sandy

soil). Clay usually shows lower cone tip resistance (qc) which results in low toe

resistance. Therefore, the pile toe resistances are small for the CIP piles at site WW

(Figure 5.6). The side resistance and toe resistance vary based on prediction method for

the precast concrete pile at site U (Figure 5.7). A summary of predicted capacity based

on CPT methods and measured capacity based on load tests are shown Table 5.1 with

pile and soil identification for both pile types.

Figure 5.6 Comparison of toe resistance (Rt) and side resistance (Rs) calculated using

the CPT methods for the 14-inch CIP at the Route WW site at the depth of pile tip at

50.9 feet.

0

20

40

60

80

100

120

Nottingham

and

Schmertmann

DeRuiter and

Beringen

(European)

Tumay and

Fakhroo

Bustamante

and Gianeselli

(LCPC)

Eslami and

Fellenius

Cap

aci

ty (

Ton

s)

Total Toe Resistance

Total Side Resistance

57

Figure 5.7 Comparison of toe resistance (Rt) and side resistance (Rs) calculated using

the CPT methods for the 16-inch precast concrete pile at the Route U site at the depth

of pile tip at 21.3 feet.

Figure 5.8 Pile capacity predicted with CPT methods and pile load test result for the

14-inch CIP pile at the Route WW site at the depth of pile tip at 50.9 feet.

0

10

20

30

40

50

60

70

80

90

100

Nottingham

and

Schmertmann

DeRuiter and

Beringen

(European)

Tumay and

Fakhroo

Bustamante

and Gianeselli

(LCPC)

Eslami and

Fellenius

Ca

pa

city

(T

on

s)

Total Toe Resistance

Total Side Resistance

0

20

40

60

80

100

120

140

Nottingham

and

Schmertmann

DeRuiter and

Beringen

(European)

Tumay and

Fakhroo

Bustamante

and Gianeselli

(LCPC)

Eslami and

Fellenius

Load Test

Ca

pa

city

(T

on

s)

Measured Pile Capacity (Qtm) = 123.5 Tons

58

Figure 5.9 Pile capacity predicted with CPT methods and pile load test result for the16-

inch precast concrete pile at the Route WW site at the depth of pile tip at 21.3 feet.

0

20

40

60

80

100

120

140

160

Nottingham

and

Schmertmann

DeRuiter and

Beringen

(European)

Tumay and

Fakhroo

Bustamante

and Gianeselli

(LCPC)

Eslami and

Fellenius

Load Test

Ca

pa

city

(T

on

s)

Measured Pile Capacity (Qtm) = 134 Tons

59

Table 5.1 The results of predicted capacity with measured capacity and information on

piles and soils for the bridges on Route WW and Route U.

Bridge Site Route WW Route U

Piles and

Soils

Identification

Pile ID 14-inch Diameter

Cast-In-Place

16-inch Octagonal

Precast Concrete

CPT CPT H-16-22 CPT H-16-12

Exhumed Pile

Length (feet) 50.9 21.3

Soil Behavior Cohesive Cohesionless

Capacity (Tons) Qs Qt Qult Qs Qt Qult

Methods of

Predicting

Pile Capacity

using CPT

Nottingham &

Schmertmann 46.2 17 63.2 67.8 57 125.6

DeRuiter &

Beringen

(European)

98.5 11.4 110 34.9 57 91.8

Tumay &

Fakhroo 73.2 17 90.2 32.6 57 90.4

Bustamante and

Gianeselli

(LCPC)

48.3 9.6 58 57.3 42 99.3

Eslami &

Fellenius 79.7 35.2 115 91.5 48.7 140.2

Static Load

Test

Measured

Capacity ** ** 123.5 ** ** 134

5.4 Discussion

The approach by Reuter (2010) was used to compare the pile capacity (Qt)

obtained from the load tests to the prediction using the CPT methods. Analyses included

the ratio of measured pile capacity (Qtm) to predicted pile capacity (Qtp).

Ratios of the measured to predicted capacities for each bridge site are shown in

Tables 5.2 and 5.3. The ratio of Qtm/Qtp ranges from 1.07 to 2.13 for the cast-in-place

pile at the Route WW site and ranges from 0.96 to 1.48 for the precast concrete pile at

60

the Route U site. The meaning of Qtm/Qtp > 1.0 is that the predicted pile capacity is less

than the measured pile capacity, i.e., predicted capacity is conservative. The meaning

of Qtm/Qtp < 1.0 is that the predicted pile capacity is greater than the measured pile

capacity, i.e., predicted capacity is unconservative.

Table 5.2 Comparison between static load test results and the predictions of capacity

for a 14-inch diameter CIP at Route WW site at existing pile depth 50.9 feet.

Method

Total Pile

Capacity -

Qt (Tons)

Qtm/Qtp Basis

Load Test 123.5 1.00 Measured

Nottingham and

Schmertmann (1975, 1978) 63.2 1.95

Predicted

DeRuiter and Beringen

(1979) 110 1.12

Tumay and Fakhroo (1981) 90.3 1.37

Bustamante and Gianeselli

or LCPC (1982) 58.0 2.13

Eslami and Fellenius (1997) 115.0 1.07

61

Table 5.3 Comparison between static load test results and the predictions of capacity

for a 16-inch octagonal precast concrete pile at Route U site existing pile depth 21.3

feet.

Method

Total Pile

Capacity -

Qt (Tons)

Qtm/Qtp Basis

Load Test 134.0 1.00 Measured

Nottingham and

Schmertmann (1975, 1978) 125.7 1.07

Predicted

DeRuiter and Beringen

(1979) 91.8 1.46

Tumay and Fakhroo (1981) 90.4 1.48

Bustamante and Gianeselli

or LCPC (1982) 99.3 1.35

Eslami and Fellenius (1997) 140.2 0.96

According to Fellenius (2006), the minimum, or usual, factor of safety applied

is three (3) based on geotechnical engineering analysis to calculate allowable pile

capacity from predicted capacity. A factor of safety of two (2) is applied to measured

ultimate capacity to determine allowable pile capacity (Eq. 5.1).

Factor of Safety (F. S) =Qult, Ultimate Capacity

Qall, Allowable Capacity Eq. 5.1

For site WW, the original design capacity was 30 tons, therefore the original design has

a factor of safety (F.S) of about four. At site U, the original design capacity was 21

tons and the factor of safety for the original design is about six. The allowable pile

capacity (Qall) as calculated using Eq. 5.1 and based on the minimum required factor of

safety (F.S) for pile load test data or CPT data are shown in Table 5.4. The allowable

design pile capacity (Qall) ranges from 19 tons to 62 tons for site WW while it ranges

from 30 tons to 67 tons for site U.

62

The results of this thesis are compared with past research in Table 5.5. In this

thesis, Eslami and Fellenius (Qtm/Qtp = 1.07) provided a good agreement with the

measured capacity for the CIP pile. Both Eslami and Fellenius (Qtm/Qtp = 0.96) and

Nottingham and Schmertmann (Qtm/Qtp = 1.07) methods showed good agreement with

the load test result for the precast concrete pile (Table 5.5). There is no clear correlation

between the best prediction methods as found in this thesis with the pile type or soil

types identified in the other studies.

Table 5.4 Allowable design pile capacity according to described minimum factor of

safety.

Method

Minimum

Factor of

Safety (F.S)

Site WW Site U

Total Pile

Capacity

- Qt

(Tons)

Allowable

Design

Capacity -

Qall (Tons)

Total Pile

Capacity-

Qt (Tons)

Allowable

Design

Capacity -

Qall (Tons)

Load Test 2 124 62 134 67

Original

Design

Capacity

** ** 30 ** 21

Nottingham

and

Schmertmann

3 63 21 126 42

DeRuiter and

Beringen 3 110 37 92 31

Tumay and

Fakhroo 3 90 30 90 30

Bustamante

and Gianeselli

or LCPC

3 58 19 99 33

Eslami and

Fellenius 3 115 38 140 47

63

Tab

le 5

.5 C

om

par

ison f

rom

lit

erat

ure

wit

h t

he

resu

lts

of

this

thes

is t

hat

com

par

e th

e C

PT

pre

dic

tio

n m

ethods

wit

h p

ile

types

and s

oil

condit

ions.

64

5.5 Summary

The predicted pile capacities were obtained using CPT data for a 14-inch

diameter cast-in-place pile with an embedment length of 50.9 feet and a 16-inch

octagonal precast concrete pile with an embedment length of 21.3 feet. Predicted total

pile capacity is defined using five CPT methods with the soil profiles identified using

CPT data consisting of clayey soils and sandy soils at both project sites. The predicted

and measured pile capacity is compared. The ratio of Qtm/Qtp in the range of 0.9 ≤

Qtm/Qtp ≤ 1.1 was considered to be an acceptable accuracy (Bowders, 2017). Finally,

Eslami and Fellenius methods shows closer prediction with measured capacity for the

CIP pile while Eslami and Fellenius and Nottingham and Schmertmann prediction

methods are close agreement with the load test result for the precast concrete pile.

65

CHAPTER 6 – CONCLUSIONS

6.1 Summary

In this research, the axial pile capacity predicted based on CPT data and the

measured capacity from load tests for two driven piles were compared. Five CPT

methods were used to predict the capacity of driven piles: Nottingham and

Schmertmann (1975) or Schmertmann (1978), DeRuiter and Beringen (1979), Tumay

and Fakhroo (1981), Bustamante and Gianeselli (1982), and Eslami and Fellenius

(1997) methods.

A static pile load test was performed on one pile at each bridge site. The results

of the load test and the five predicted capacities were compared for a cast-in-place pile

at the Route WW site and a precast pile at the Route U site. The ratio of measured pile

capacity to predicted pile capacity (Qtm/Qtp) was calculated to evaluate overestimation

and underestimation of the pile capacity. The tip resistance and side resistance were

predicted; however, the load tests were not instrumented to determine either.

6.2 Conclusions

A procedure for each bridge site was established to utilize the CPT methods to

predict the capacity of the driven piles. The ratio of measured pile capacity to predicted

pile capacity (Qtm/Qtp) was used to quantify the differences between measured and

calculated pile capacity. The ratio of Qtm/Qtp ranges from 1.07 to 2.13 for the cast-in-

place pile at the Route WW site and ranges from 0.96 to 1.48 for the precast concrete

pile at the Route U site. Based on the results of the five CPT methods, the method of

Eslami and Fellenius (Qtm/Qtp = 1.07) was the best for the CIP pile in clayey soils. The

66

methods of Eslami and Fellenius (Qtm/Qtp =0.96) and Nottingham and Schmertmann

(Qtm/Qtp = 1.07) were best for precast concrete pile in sand.

6.3 Recommendations

The results of this thesis show the potential of CPT methods in predicting the

measured capacity of cast-in-place and precast piles driven into New Madrid soils in

Missouri. The predicted pile capacities were calculated using CPT data for driven piles.

Based on the results of the analyses, the Eslami and Fellenius, and Nottingham

and Schmertmann methods are recommended for predicting the pile capacity for driven

piles using CPT data. Additional, recommendations are as follows:

1. The Eslami and Fellenius, and Nottingham and Schmertmann methods gave the

most accurate predictions of the measured pile capacities. The predicted

capacity consists side resistance and toe resistance for the all methods. At the

WW site, the tip of the pile was founded in soft clay (SPT N-values of 1 to 12).

At the U site, the tip was founded on relatively dense sand (SPT N-values of 9

to 99). Given soft clay at site WW and the dense sand at site U at the pile tips,

one would expect a low tip capacity (clay) and a high tip capacity (sand) as a

contribution to the total capacity of the pile. A closer inspection of the

variability of the underlying sand or clay interface elevations can help make the

predicted capacities more accurate.

2. Provided the SPT-Nvalue data can be located for the two sites, it might be

insightful to use several Nvalue methods to estimate the capacity of the piles.

Granted, Nvalue methods may be the least reliable method of predicting pile

capacity, it would be interesting to look at the trends of capacity versus depth

between the CPT and SPT methods.

67

3. There are numerous ‘adjustment factors’ used throughout the various CPT

methods for estimating axial capacity of piles (Table 6.1). Factors such as Kc,

Kf, C, NK, Cs and CLCPC are empirically derived. It is entirely possible that the

factors are not appropriate for the New Madrid soil deposits. A careful

examination of the origin of each factor and evaluation of its appropriateness

for the New Madrid sites is warranted for the three methods that best predicted

the pile capacities (Table 6.1).

68

Tab

le 6

.1 S

um

mar

y o

f ad

just

men

t fa

ctors

(co

effi

cien

ts)

bas

ed o

n C

PT

wit

h p

redic

tion m

ethods,

pil

e ty

pes

and s

oil

condit

ion.

69

LIST OF REFERENCES

Alsamman, O. M. and Long, J. H. (1993) “Prediction of Drilled Shafts Axial Capacities

Using CPT Results.” International Conference on Case Histories in Geotechnical

Engineering, 1993, 113–17.

ASTM, (2007) “Standard Test Method for Electronic Friction Cone and Piezocone

Penetration Testing of Soils.” ASTM Standard Test Method D5778-7, no. January

(2007): 1–19. https://doi.org/10.1520/D5778-07.N.

Arsdale, R. B. V. and TenBrink R. K. (2000) “Late Cretaceous and Cenozoic Geology

of the New Madrid Seismic Zone.” Bulletin of the Seismological Society of

America 90, no. 2 (2000): 345–56. https://doi.org/10.1785/0119990088.

Boeckmann, A. (2017) Personal Communication Research Engineer Department of Civil

Engineering, University of Missouri, Columbia.

Boeckmann, A. et al. (2018) “Foundation Reuse: Length, Condition, and Capacity of

Existing Driven Piles” University of Missouri Department of Civil and

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APPENDIX

Appendix – 1 Predicted Total Side Resistance, Total Toe Resistance and

Ultimate Capacity from CPT Prediction Methods

Figure A1.1 The comparison of predicted total side resistance, total toe resistance and

ultimate capacity from Nottingham and Schmertmann prediction for 14-inch diameter

CIP pile.

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Figure A1.2 Predicted total side resistance, total toe resistance and ultimate capacity

from DeRuiter and Beringen prediction for 14-inch diameter CIP pile.


from Tumay and Fakhroo prediction for 14-inch diameter CIP pile.

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from Bustamante and Gianeselli - LCPC prediction for 14-inch diameter CIP pile.


from Eslami and Fellenius prediction for 14-inch diameter CIP pile.

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from Nottingham and Schmertmann prediction for 16-inch octagonal precast concrete

pile.


from DeRuiter and Beringen prediction for 16-inch octagonal precast concrete pile.

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from Tumay and Fakhroo prediction for 16-inch octagonal precast concrete pile.


from Bustamante and Gianeselli - LCPC prediction for 16-inch octagonal precast

concrete pile.

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from Eslami and Fellenius prediction for 16-inch octagonal precast concrete pile.

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Appendix – 2 Existing Bridge Photographs, Taper Information and Cone

Penetration Test Soundings

Figure A2.1 The cross-section of taper with plan drawing of 16-inch precast concrete

pile for bridge on Route U (Boeckmann et al., 2018).

Figure A2.2 CPT parallel seismic test machine.

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Figure A2.3 Existing 14-inch diameter cast-in-place (CIP) piles at the Route WW.

Figure A2.4 Existing 16-inch octagonal precast concrete piles at the Route U.

80

VITA

Huseyin AKKUS was born in Ankara, Turkey on April 8, 1988. He received his

bachelor’s degree in Geological Engineering from Ankara University, Ankara, Turkey

in 2012. He was accepted for his master’s degree in Civil & Environmental Engineering

at the University of Missouri-Columbia in 2016 and received master’s degree in Civil

and Environmental Engineering (Geotechnical specially) in 2018 under the supervision

of Dr. John J. Bowders, P.E.