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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
precast concrete pile at the Route U site the depth of pile tip at 21.3 feet. .................. 53
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
precast concrete pile at the Route U site the depth of pile tip at 21.3 feet. .................. 54
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
A1.3 Predicted total side resistance, total toe resistance and ultimate capacity from
Tumay and Fakhroo prediction for 14-inch diameter CIP pile. ................................... 73
A1.4 Predicted total side resistance, total toe resistance and ultimate capacity from
Bustamante and Gianeselli - LCPC prediction for 14-inch diameter CIP pile. ........... 74
A1.5 Predicted total side resistance, total toe resistance and ultimate capacity from
Eslami and Fellenius prediction for 14-inch diameter CIP pile. .................................. 74
A1.6 Predicted total side resistance, total toe resistance and ultimate capacity from
Nottingham and Schmertmann prediction for 16-inch octagonal precast concrete pile.
...................................................................................................................................... 75
A1.7 Predicted total side resistance, total toe resistance and ultimate capacity from
DeRuiter and Beringen prediction for 16-inch octagonal precast concrete pile. ......... 75
A1.8 Predicted total side resistance, total toe resistance and ultimate capacity from
Tumay and Fakhroo prediction for 16-inch octagonal precast concrete pile. .............. 76
x
A1.9 Predicted total side resistance, total toe resistance and ultimate capacity from
Bustamante and Gianeselli - LCPC prediction for 16-inch octagonal precast concrete
pile................................................................................................................................ 76
A1.10 Predicted total side resistance, total toe resistance and ultimate capacity from
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
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)
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,
Su = Undrained shear strength
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
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)
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.
The pile’s skin resistance (rs):
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
The pile’s skin resistance (rs):
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
Layer Range Depth (feet) Description
1 0 - 48.2 Soft Clay
2 48.2 - 53.7 Soft Clay with free water
3 53.7 - 71.9 Sand
4 71.9 Bottom of Borehole
Table 3.3 Soil description depends on the borehole information of SPT and CPT for
Route U.
SPT Boring, A-16-03
Layer Range Depth (feet) Description
1 0 – 5.9 Fat Clay
2 5.9 – 66.5 Sand
3 66.5 Bottom of Borehole
CPT Boring, H-16-12
Layer Range Depth (feet) Description
1 0 - 8 Soft Clay
2 8 - 49.1 Sand
3 49.1 Bottom of Borehole
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
qca = The cone stress in the influence zone between 8b above and 4b below the
pile tip (Figure 2.3)
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
Su = Undrained shear strength
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
Environmental Engineering.
Bowders, J. J., (2017) Personal Communication William A. Davidson Professor, P.E.
Department of Civil Engineering, University of Missouri, Columbia.
Cushing, E. M., Boswell, E. H. and Hosman, R. L. (1964) “General Geology of the
Mississippi Embayment.” U.S. Geological Survey Professional Paper 448-B, the
Superintendent of Documents, U.S. Government Printing Office Washington,
D.C. 20402. http://pubs.er.usgs.gov/publication/pp448B.
Bustamante, M., and Gianeselli, L. (1982) “Pile bearing capacity predictions by means
of static penetrometer CPT.” Proc., 2nd European Symp. on Penetration Testing,
ESOPT-II, Amsterdam, The Netherlands, Vol. 2, 493–500.
DeRuiter, J., and Beringen, F. L. (1979) “Pile foundations for large North Sea
structures.” Mar. Geotech., 3(3), 267–314.
70
Eslami, A., and Fellenius, B. H. (1997) “Pile capacity by direct CPT and CPTU methods
applied to 102 case histories.” Can. Geotech. J., 34, 886–904.
Eslami, A., and Fellenius, B. H. (1995) “Toe Bearing Capacity of Piles from Cone
Penetration Test (CPT) Data” Proceedings of the International Symposium on
Cone Penetration Testing, CPT’95, no. 1979 (1995): vol. 2, pp. 453–60.
Eslami, A., Aflaki, E. and Hosseini, B. (2011) “Evaluating CPT and CPTu Based Pile
Bearing Capacity Estimation Methods Using Urmiyeh Lake Causeway Piling
Records.” Scientia Iranica 18, no. 5 (2011): 1009–19.
https://doi.org/10.1016/j.scient.2011.09.003.
Fellenius, B. H. and Eslami A. (2000) “Soil Profile Interpreted from CPTu Data.” “Year
2000 Geotechnics” Geotechnical Engineering Conference, Asian Institute of
Technology, Bangkok, Thailand, November 27 - 30, 2000, 18 p.
Fellenius, B. H. (2006). “Basics of Foundation Design” Electronic Edition, 1905
Alexander Street SE Calgary, Alberta, Canada, T2G 4J3, January 2006, 285 pp.
Fellenius, B. H. (2018). “Basics of Foundation Design” Electronic Edition, 2375
Rothesay Avenue Sidney, British Columbia Canada, V8L 2B9, 466 pp.
Fennessey T. W. (2016) MoDOT Missouri Department of Transportation Construction
– Materials Central Laboratory, Memorandum from T. W. Fennessey “Materials
Geotechnical Section Foundation Investigation for Structure No. A8472 Job No.
J9S3146 Route WW, New Madrid, MO,” March 21, 2016, 39 pp.
Hammam, A. H. and Salam, A.E. A. (2018) “Behavior of Bored Piles in Two Soil
Layers, Sand Overlaying Compressible Clay (Case Study)” Springer International
Publishing AG 2018, Housing and Building National Research Center, Cairo,
Egypt. https://doi.org/10.1007/978-3-319-61642-1.
Hilchen P. (2016) MoDOT Missouri Department of Transportation Construction –
Materials Central Laboratory, Memorandum from P. Hilchen “Materials
Geotechnical Section Foundation Investigation for Structure No. A8414 Job No.
J9S330 Route U, New Madrid, MO,” March 7, 2016, 12 pp.
71
Mayne, P. W. (2007) “Cone Penetration Testing a Synthesis of Highway Practice.”
National Cooperative Highway Research Program Synthesis 368, Georgia
Institute of Technology Atlanta, Georgia, 126 pp.
Nottingham, L. and Schmertmann, J. (1975) “An investigation of pile capacity design
procedures,” Final Report D629 to Florida Department of Transportation from
Department of Civil Engineering, University of Florida: 159 pp.
Reuter, G. R. (2010) “Pile Capacity Prediction in Minnesota Soils Using Direct CPT
and CPTu Methods.” 2nd International Symposium on Cone Penetration Testing
3, American Consulting Services, Ins., St. Paul, Minnesota, USA.
Robertson, P. K. (1989) “Soil Classification by the Cone Penetration Test.” Canadian
Geotechnical Journal, October 13, 1989.
Robertson, P. K., Cabal K.L. (2012) “Guide to Cone Penetration Testing for
Geotechnical Engineering”, Gregg Drilling & Testing, Inc., 5th Edition, November
2012, 134 pp.
Salgado R. and Lee J. (1999) “Pile Design Based on Cone Penetration Test Results.”
Report No FHWA/IN/JTRP-99/8. Joint Transportation Research Program Purdue
University., no. October (1999): 267 p.
Schmertmann, J. H. (1978a) “Guidelines for cone penetration test, performance and
design.” Rep. No. FHWA-TS-78-209, U.S. Department of Transportation,
Washington, D.C., 145 pp.
Titi and Murad (1999) “Evaluation of Bearing Capacity of Piles from Cone Penetration
Test Data” LTRC Project No. 98-3Gt, State Project No. 736-99-0533, Louisiana
Transportation Research Center 4101 Gourrier Avenue Baton Rouge, LA 70808,
115 pp.
Wang, J. X. et al. (2015) “Estimating Pile Set-up Using 24-H Restrike Resistance and
Computed Static Capacity for PPC Piles Driven in Soft Louisiana Coastal
Deposits.” Geotechnical and Geological Engineering 34, no. 1 (2016): 267–83.
https://doi.org/10.1007/s10706-015-9943-z.
72
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.
73
Figure A1.2 Predicted total side resistance, total toe resistance and ultimate capacity
from DeRuiter and Beringen prediction for 14-inch diameter CIP pile.
Figure A1.3 Predicted total side resistance, total toe resistance and ultimate capacity
from Tumay and Fakhroo prediction for 14-inch diameter CIP pile.
74
Figure A1.4 Predicted total side resistance, total toe resistance and ultimate capacity
from Bustamante and Gianeselli - LCPC prediction for 14-inch diameter CIP pile.
Figure A1.5 Predicted total side resistance, total toe resistance and ultimate capacity
from Eslami and Fellenius prediction for 14-inch diameter CIP pile.
75
Figure A1.6 Predicted total side resistance, total toe resistance and ultimate capacity
from Nottingham and Schmertmann prediction for 16-inch octagonal precast concrete
pile.
Figure A1.7 Predicted total side resistance, total toe resistance and ultimate capacity
from DeRuiter and Beringen prediction for 16-inch octagonal precast concrete pile.
76
Figure A1.8 Predicted total side resistance, total toe resistance and ultimate capacity
from Tumay and Fakhroo prediction for 16-inch octagonal precast concrete pile.
Figure A1.9 Predicted total side resistance, total toe resistance and ultimate capacity
from Bustamante and Gianeselli - LCPC prediction for 16-inch octagonal precast
concrete pile.
77
Figure A1.10 Predicted total side resistance, total toe resistance and ultimate capacity
from Eslami and Fellenius prediction for 16-inch octagonal precast concrete pile.
78
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.
79
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.
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