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PILE LOAD CAPACITY USING STATIC AND DYNAMIC LOAD TEST
By
ANUP KUMAR HALDER
A thesis submitted to the Department of Civil Engineering,
Bangladesh University of Engineering and Technology,
Dhaka, in partial fulfillment of the degree of
MASTER OF SCIENCE IN CIVIL ENGINEERING (Geotechnical)
BANGLADESH UNIVERSITY OF ENGINEERING AND TECHNOLOGY
APRIL, 2016
CADIDIDATE'S DECLARATION
It is hereby declared lpl this thesis or any part of it has not been sub,mitted elsewhere for
the award ofany degree or diploma.
(Anup Kumar Halder)
111
2 ,.nA*
es+r.
iv
ACKNOWLEDGEMENTS
The author is obliged to his supervisor Dr. Mehedi Ahmed Ansary, Professor,
Department of Civil Engineering, Bangladesh University of Engineering and Technology
(BUET), for his inspiration, encouragement, continuous guidance, important suggestions
throughout the various stages of this research. The author also expresses his profound
gratitude to Dr. Abdul Muqtadir, Professor and Head, Department of Civil Engineering,
BUET, Dhaka, for his valuable corrections and suggestions during writing of this thesis.
The author gratefully acknowledges the constructive criticisms and valuable suggestions
made by Dr. Abu Siddique, Professor, Department of Civil Engineering, BUET. Thanks
are due to Dr. Md. Abu Taiyab, Professor, Civil Engineering Department, DUET,
Gazipur for his review and comments.
Special thanks are also due to ‘Icon Engineers Services’ and ‘Prosoil’ for providing data
and technical assistance towards this thesis.
Last but not the least the author gratefully acknowledges the patience and encouragement
of his parents, spouse and daughter for supporting his endeavor of M. Sc. Engineering
study in BUET.
v
ABSTRACT
Piles are common for construction of deep foundation in Bangladesh. Confirming the pile
capacity is a job for a geotechnical engineer. From the soil investigation data, piles can be
designed but it need to be confirmed by static pile load test or dynamic pile load test. Generally,
static pile load test is used to estimate pile capacity whereas dynamic pile load test is a relatively
new method for the engineers of Bangladesh.
This study presents an evaluation of ultimate pile load capacity by static and dynamic load test
methods. To establish a comparison, a field experiment was conducted on two full scale driven
precast piles. Both piles were tested using dynamic and static load test. For dynamic load test pile
capacity was determined using CAPWAP (CAse Pile Wave Analysis Program). In case of static
load test pile capacity was calculated using Davission, Butler and Hoy, British standard and
BNBC (Bangladesh National Building Code) 1993 methods. The capacity of two test piles was
also calculated using soil investigation data applying BNBC-2015 (Draft version), AASHTO-
2002 method. For these two driven piles capacity calculations were also investigated following
driving equations. The relationship among capacity of static load test, dynamic load test,
predicted capacities (using BNBC-2015, BNBC SPT, AASHTO-2002, driving equations) were
compared and correlation values were obtained.
To generalize the study, ten cast-in-situ and fifteen precast test pile data were collected. In each
case, soil investigation report of the particular site, pile properties, CAPWAP capacity was
available for detailed study. From the collected data, it was found that predicted capacity of
precast driven piles using BNBC-2015 static bearing capacity has a very good co-relation with
CAPWAP capacity confirmed by dynamic load test. For BNBC-15 Static method, CAPWAP
capacity=1.10X BNBC 2015 Static capacity (r2=0.81).However, pile capacity calculated using
BNBC-2015 SPT method also showed good correlation compare with the CAPWAP capacity. In
this method CAPWAP capacity=1.06X BNBC 2015 SPT capacity (r2=0.77).
Similarly, cast-in-situ pile capacity matched fairly well with all the considered methods like:
BNBC-2015 static bearing capacity, BNBC-2015 SPT, AASHTO-2002 comparing with the
CAPWAP capacity. From this study three relations were established. They are CAPWAP
capacity=1.15X BNBC 2015 Static capacity (r2=0.81), CAPWAP capacity=1.04X BNBC 2015
SPT capacity (r2=0.89) and CAPWAP capacity=0.91X AASHTO-2002 capacity (r2=0.92).
Recommendation and conclusions were also made for piles of Bangladesh considering different
alternative methods.
vi
TABLE OF CONTENTS
Candidate's Declaration iii
Acknowledgements iv
Abstract v
Table of Contents vi
List of Tables ix
List of Figures x
Notations xii
CHAPTER 1: INTRODUCTION 1
1.1 General 1
1.2 Background of the Study 1
1.3 Objectives of the Study 2
1.4 Organization of the Thesis 3
CHAPTER 2: LITERATURE REVIEW 4
2.1 Introduction 4
2.2 Ultimate Pile Capacity 4
2.3 Driven Pile Capacity Using Static Formulae 5
2.3.1 Cohesive soil 5
2.3.2 Cohesion-less soil 6
2.4 Driven Pile Capacity Using SPT 7
2.4.1 Cohesive soil 7
2.4.2 Cohesion-less soil 8
2.5 Bored Pile Capacity Using Static Formulae 8
2.5.1 Cohesive soil 8
2.5.2 Cohesion-less soil 10
2.6 Bored Pile Capacity Using SPT Values 11
2.6.1 Cohesive soil 11
vii
2.6.2 Cohesion-less soil 11
2.7 Bored Pile Capacity Based on AASHTO 2002 12
2.8 Pile Capacity During Driving 15
2.8.1 Engineering News formula 15
2.8.2 Gates formula 16
2.8.3 Janbu formula 16
2.9 Pile Capacity by Static Load Test 17
2.9.1 Load test evaluation methods for axial compressive load 18
2.10 Dynamic Analysis by Wave Equation 20
2.10.1 The wave equation 20
2.10.2 Smith’s idealization 21
2.10.3 Pile modes-internal spring 23
2.10.4 Soil model external springs 23
2.10.5 Basic equation 25
2.10.6 Values of soil parameters 26
2.11 Dynamic Load Test 28
2.11.1 Test method 28
2.12 Methods Of Interpretation For Dynamic Load Test 29
2.12.1 CASE method 29
2.12.2 CAPWAP method 30
2.12.3 Summary 31
CHAPTER 3: INSTRUMENTATION AND TEST PROGRAM 32
3.1 General 32
3.2 Capacity Estimation 32
3.3 Pile Load Tests 36
3.4 Pile Driving and Driving Record 36
3.5 Dynamic Load Test Arrangement 37
3.6 Static Load Test Arrangement 40
viii
3.6.1 Loading sequnce 42
3.7 Data Collection 44
3.8 Summary 46
CHAPTER 4: RESULTS AND DISCUSSIONS 47
4.1 General 47
4.2 Pile Capacity of Precast Piles Using Driving Equations 47
4.3 Pile Capacity Using PDA Test Results 47
4.4 CAPWAP Analysis 50
4.5 Pile Capacity From Pile Load Tes 53
4.6 Pile Capacity Summary 55
4.7 Comparison with Collected Data for Cast-In-Situ Piles 57
4.8 Summary 59
CHAPTER 5: CONCLUSIONS 61
5.1 General 61
5.2 Concluding Remarks 61
5.3 Recommendations 62
References 63
APPENDIX A: PILE DRIVING RECORDS OF TP-1 AND TP-2 67
APPENDIX B: CAPACITY CALCULATION USING DRIVING EQUATIONS 72
APPENDIX C: CAPACITY CALCULATION OF PRECAST PILES 76
APPENDIX D: CAPACITY CALCULATION OF BORED PILES 107
ix
LIST OF TABLES
Table 2.1 Typical ϕs/ϕ and K/Ko values for the design of drilled Shaft 11
Table 2.2 Recommended values of α and fsi for estimation of drilled shaft side resistance in cohesive soil, after Reese and O’Neill (1988)
13
Table 2.3 Recommended values of unit end bearing for cohesion-less soil (Reese and O’Neill, 1988)
15
Table 2.4 Empirical values of Q,J and percent side adhesion 27
Table 2.5 Range of CASE damping values for different types of soil 30
Table 3.1 Load testing program for test piles 36
Table 3.2 Static load test program 40
Table 3.3 Typical loading sequence arrangement for pile load test 43
Table 3.4 Data summary for precast pile 45
Table 3.5 Data summary for cast-in-situ pile 46
Table 4.1 Beta value for pile integrity (Rausche and Goble, 1979) 48
Table 4.2 Capacity of piles using PDA 49
Table 4.3 Summary of dynamic test 52
Table 4.4 Test result summary 54
Table 4.5 Pile capacities from driving formulas 55
x
LIST OF FIGURES
Figure 2.1 Bearing capacity factor Nq for deep foundation (After Tomlinson, 1986)
7
Figure 2.2 Adhesion factor α for drilled shaft (after Kulhawy and Jackson, 1989)
9
Figure 2.3 Identification of Portions of drilled shafts neglected for estimation of drilled shaft side resistance in cohesive soil, after Reese and O’ neill (1988)
13
Figure 2.4 Smith’s spring model (Smith, 1960) 22
Figure 2.5 Load deformation relationships for internal springs 23
Figure 2.6 Load-deformation relationship of soil (after Lowery et al, 1969) 24
Figure 3.1 Flow diagram of the working process 33
Figure 3.2 Borehole log BH-1 34
Figure 3.3 Borehole log BH-2 35
Figure 3.4 Casting of pile at site for construction 36
Figure 3.5 Pile driving using drop hammer 37
Figure 3.6 Strain transducers and accelerometer bolted on the concrete piles 39
Figure 3.7 Pile driving analyser 39
Figure 3.8 Dynamic test arrangement for TP-1 40
Figure 3.9 Dynamic test arrangement for TP-2 40
Figure 3.10 Schematic diagram of typical arrangement of applying load in an axial compressive test
41
Figure 3.11 Schematic diagram of data collection for precast and cast in situ piles
44
Figure 4.1 Force and velocity record for TP-1 49
Figure 4.2 Force and velocity record for TP-2 50
Figure 4.3 CAPWAP Iteration force matched graph for TP-1 51
Figure 4.4 CAPWAP Iteration force matched graph for TP-2 51
Figure 4.5 Load settlement graph for Pile load test TP-1 52
xi
Figure 4.6 Load settlement graph for pile load test TP-1 53
Figure 4.7 Load settlement graph for pile load test TP-2 54
Figure 4.8 Correlation between CAPWAP and BNBC 2015 (static bearing) pile capacity for precast pile
56
Figure 4.9 Correlation between CAPWAP and BNBC 2015 (SPT) and pile capacity for precast pile
57
Figure 4.10 Correlation between CAPWAP and BNBC-2015 (static bearing) capacity
58
Figure 4.11 Correlation between CAPWAP capacity and BNBC-2015 SPT capacity for cast-in-situ pile
59
Figure 4.12 Correlation between CAPWAP and AASHTO-2002 pile capacity for cast-in-situ piles
59
xii
NOTATIONS
A = Cross sectional area of pile
A = End bearing area of pile
A = Skin friction area (perimeter area) of pile
B,D = Diameter or width of pile
D = Diameter of pile at base
D = Critical depth of soil layer
E = Modulus of elasticity of pile material
E = Modulus of elasticity of soil
FS = Factor of safety
H = Layer thickness
K = Coefficient of earth pressure
K = Coefficient of earth pressure at rest
L = Length of pile
N = Standard penetration test value (SPT)
N = Corrected SPT value for field procedures
N = Average SPT N value
(N ) = Corrected SPT value for overburden pressure (for sandy soil)
N , N , N = Bearing capacity factors
OCR = Over consolidation ratio
Q = Allowable load
Q = End bearing at the base or tip of the pile
Q = Load transferred to the soil at pile tip level
Q = Skin friction or shaft friction or side shear
Q = Ultimate bearing/load carrying capacity
W = Weight of the pile
c = Apparent cohesion of soil
c = Un-drained cohesion of soil
f = End bearing resistance on unit tip area of pile
f = Skin frictional resistance on unit surface area of pile
g = Gravitational acceleration
q = Unconfined compressive strength
xiii
s = Un-drained shear strength; same as c
z = Depth
∆z = Thickness of any (i ) layer
α = Adhesion factor
β = Friction factor due to overburden
γ, γ = Unit weight of the soil
γ = Unit weight of water
μ = Poisson’s ratio of soil
σ = Initial effective stress at mid-point of a soil layer
σ = Increase in effective stress at mid-point of a soil layer due to increase in stress
σ = Reference stress (100 kPa) for computation of pile settlement
σ = The total vertical stress
σ = Effective vertical stress
σ = Effective vertical stress; same as σ
ϕ = Apparent angle of internal fiction
ϕ = Effective/drained angle of internal fiction
1
CHAPTER 1
INTRODUCTION
1.1 General
Piles are conventionally the best possible solution in case of soft soil for transferring
structural load to the harder layers of soil strata. Generally, high safety factors are used
to get assurance in pile design as there are many uncertainties arise from concreting for
cast-in-situ piles and driving for precast piles. Pile load test shall be conducted to verify
design capacity and thus ensure economical design.
Generally, static pile load test provides best method for determining bearing capacity of
pile but it is time consuming and expensive. Under this condition dynamic load test can
be considered as an alternative of static load test. Since, the usage of static load test is
very common and dynamic test is newly adopted in our country, comparison between
the two tests is attempted in this project.
1.2 Background of the Study
Soft soil is very common in the southern part of Bangladesh which is not suitable for
construction of shallow foundation. Pile foundation provides the best possible solution
to transfer load to the deeper harder layers of soil. In Bangladesh, the traditional
practice is to construct cast in situ concrete piles. However, precast piles are also used
in large numbers because of their various advantages over cast in situ piles; like: high
quality of construction, idea of capacity during driving etc.
Estimating pile capacity accurately is a difficult job even for the experienced
geotechnical engineer. There are many conventional methods for calculating pile
capacity but selection of each requires knowledge of soil properties as well as the
limitation or applicability of any method in a regional boundary. Traditionally, pile
capacity can be evaluated by using bore log of subsoil investigation report (Bowles,
1997) later it need to be confirmed by static load test.
In the design process, ‘test piles’ need to be tested using static pile load test before
fixing the final length, capacity and cross section. It is a time consuming and expensive
test for a construction project which requires extensive supervision. Moreover, the test
has some problems like: transferring load to the pile due to frictional errors (Hoque et.
2
al, 1999). In addition, manual data collection system introduces human error
possibilities. In this circumstances, a suitable alternative to static load test or cross
checking options were necessary for foundation engineers.
Researchers in Bangladesh showed keen interest regarding pile related issues. Khan
(2002) has attempted to correlate ultimate pile capacity and settlement from static test
data of twenty one precast RCC piles and twenty five RCC cast in situ piles. Similarly,
Rahman (2008) verified axial load capacity of cast in situ piles with static load test in
stiff Dhaka clay. Prediction of load deformation behavior of axially loaded piles in sand
was also done by Morshed (1991). Rahman (2014) has studied performance of eight
methods based on cone penetration test (CPT) for predicting the ultimate load carrying
capacity of square precast RC concrete piles. Until now, no research work was done
considering application of dynamic load test in Bangladesh.
Pile dynamic analysis using wave equation requires very basic driving system, pile
parameters and few standard soil properties. It uses measurement of strain and
acceleration near the pile head when pile drives or restrikes with a pile driving hammer.
These dynamic measurements can be used to evaluate performance of pile driving
system, pile installation stress, pile integrity as well as static capacity. Test data can be
further evaluated using signal matching techniques to determine relative soil resistance
distribution and dynamic properties for use in wave equation analysis. A Pile Driving
Analyzer (PDA) receives data during driving or restrike of pile through two pair of
strain and acceleration transducers attached near the pile head. PDA instantly can
determine pile stress, integrity, approximate static pile capacity and energy
transmission to the pile. PDA data can be used for CAse Pile Wave Analysis Program
(CAPWAP) analysis to determine refine static capacity, soil resistance distribution, soil
quake and damping parameters for wave equation input (Rausche et al, 2000). Dynamic
analysis need to check with static load test method simultaneously to ensure
applicability. A firm relationship with static and dynamic load test method need to
establish before using dynamic load test in the context of our country which is truly
absent until now.
1.3 Objectives of the Study
The objectives of the study are as follows:
3
i. To determine the ultimate compressive pile load capacity of precast driven pile
using Pile Dynamic Analyzer (PDA).
ii. To determine the ultimate compressive pile load capacity of precast pile using
soil test data mainly, Standard Penetration Test (SPT) value and pile driving
records.
iii. To determine the ultimate compressive pile capacity using Static Pile load test.
iv. To compare the pile load capacity obtained from different methods.
1.4 Organization of the Thesis
The thesis is composed of five chapters. In Chapter One, background and objectives of
the research is described. Chapter two contains the literature review where methods for
calculating pile capacity using soil parameter are discussed. In this chapter pile load test
both static and dynamic method along with dynamic formulas, wave equation, dynamic
soil response, computational tools for wave equation, dynamic loading test etc. is also
described here.
Chapter three focus on the testing arrangement and program for data collections at site
and laboratory. Chapter four contains results and discussion of collected data. The final
Chapter contains conclusions and recommendations for further research.
4
CHAPTER 2
LITERATURE REVIEW
2.1 Introduction
There are numerous equations available for evaluating the pile capacity for engineering
professionals (Bowles, 1997). Based on soil classification, different equations have
been evolved to predict the ultimate capacity of pile. For precast pile, capacity
calculation is based on observing pile penetration per blow during driving. After the
pile is installed in the desired soil strata, capacity can be ascertain by applying pile load
test both static and dynamic. So, there is a scope to study pile capacity and compare or
correlate among the methods.
2.2 Ultimate Pile Capacity
The ultimate load capacity, Q , of a pile consists of two parts. One part is due to
friction called skin friction or shaft friction or side shear, Q and the other is due to end
bearing at the base or tip of the pile, Q The ultimate axial capacity (Q ) of piles shall
be determined in accordance with the following for compression loading.
Q = Q + Q − W (2.1)
Where, W is the weight of the pile. The skin friction, Q and end bearing Q can be
calculated as:
Q = A f (2.2)
Q = A f (2.3)
Where, A = skin friction area (perimeter area) of the pile = Perimeter × Length
f = skin frictional resistance on unit surface area of pile that depends on soil
properties and loading conditions (drained or un-drained)
A = end bearing area of the pile = Cross-sectional area of pile tip (bottom)
f = end bearing resistance on unit tip area of pile, that depends on soil
properties to a depth of 2B (B is the diameter for a circular pile section or
length of sides for a square pile section) from the pile tip and loading
conditions (drained or un- drained)
5
For a layered soil system containing n number of layers, end bearing resistance can be
calculated considering soil properties of the layer at which the pile rests, and the skin
friction resistance considers all the penetrating layers calculated as:
Q = ∑ ∆Z × (Perimeter) × (f ) (2.4)
Where, ∆Z represents the thickness of any i layer and (Perimeter) is the perimeter
of the pile in that layer. The manner in which skin friction is transferred to the adjacent
soil depends on the soil type.
2.3 Driven Pile Capacity using Static Formulae
2.3.1 Cohesive soil
The ultimate axial capacity of driven piles in cohesive soil may be calculated from
static formula, given by Equations 2.2, 2.3 and 2.4, using a total stress method for un-
drained loading conditions, or an effective stress method for drained loading
conditions. Appropriate values of adhesion factor (α) and coefficient of horizontal soil
stress (k ) for cohesive soils that are consistent with soil condition and pile installation
procedure may be used. The following α-method is used for calculating skin friction:
The α-method that is based on total stress analysis and is normally used to estimate the
short term load capacity of piles embedded in fine grained soils. In this method, a
coefficient α is used to relate the un-drained shear strength c or s to the adhesive
stress (f ) along the pile shaft. To calculate the skin friction of pile in cohesive soil,
Tomlinson (1971) proposed this method.
Q = αc A (2.5)
American Petroleum Institute (API, 1984) provides the following values to find the
skin friction in clay soils.
α = 1.0 for clays with c ≤ 25 kN/m2
α = 0.5 for clays with c ≥ 70 kN/m2
α = 1 − for clays with 25 kN/m2 < c < 70 kN/m2
The end bearing in such a case is found by analogy with shallow foundations and is
expressed by Mayerhof (1976) as:
Q = (c ) (N ) A (2.6)
6
N is a bearing capacity factor and for deep foundation the value is usually 9. c is the
undrained shear strength of soil at the base of the pile. The suffix b’s are indicatives of
base of pile. The general equation for N is, however, as follows (Skempton, 1951).
N = 6 1 + 0.2 ≤ 9 (2.7)
D represents the diameter of the pile at base and L is the total length of pile. The skin
friction value, f = (c ) (N ) should not exceed 4.0 Mpa (Engeling and Reese,
1974).
2.3.2 Cohesion-less soil
The 𝛽 -method is based on an effective stress analysis and is used to determine both the
short term and long term pile load capacities. Burland (1973) developed this method of
obtaining skin friction from effective stress on the shaft of pile. The friction along the
pile shaft is found using Coulomb’s friction law, where the friction stress is given
by f = μσ = σ tanϕ . The lateral effective stress, σ is proportional to vertical
effective stress, σ by a co-efficient, K. As such,
f = Kσ tanϕ = βσ (2.8)
Where,
β = Ktanϕ = K tanϕ = (1 − sinϕ′)√OCR (2.9)
ϕ is the effective angle of internal friction of soil and OCR is the over-consolidation
ratio. For normally consolidated clay, β varies from 0.25 to 0.29. The value of β
decreases for a very long pile, as such a correction factor is used (Kaniraj, 1988)
Correction factor for β = log ≥ 0.5 (2.10)
The end bearing capacity is calculated by analogy with the bearing capacity of shallow
footings and is determined from:
f = (σ ) N (2.11)
Where, N is a bearing capacity factor that depends on angle of internal friction ϕ of
the soil at the base of the pile, as presented in Figure 2.1. Subscript “b” designates the
parameters at the base soil.
7
Figure 2.1: Bearing capacity factor Nq for deep foundation (After Tomlinson, 1986)
2.4 Driven Pile Capacity Using SPT
2.4.1 Cohesive soil
Standard Penetration Test N-value is a measure of consistency of clay soil and
indirectly the measure of cohesion. The skin friction of pile can thus be estimated from
N-value. The following relation may be used for preliminary design of ultimate
capacity of concrete piles in clay soil. According to Mayerhof (1976)
For skin friction the relationship is as under.
f = 1.8N (in kPa) ≤ 70 kPa (2.12)
For end bearing, the relationship is as under.
f = 45N (in kPa) ≤ 4000 kPa (2.13)
Where, N is the average N-value over the pile shaft length and N is the N-value in
the vicinity of pile tip.
8
2.4.2 Cohesion-less soil
Standard Penetration Test N-value is a measure of relative density hence angles of
internal friction of cohesion less soil. The skin friction of pile can thus be estimated
from N-value. The following relation may be used for ultimate capacity of concrete
piles in cohesion less soil and non-plastic silt.
For skin friction the relationship is as under (Mayerhof, 1976)
For sand:
f = 2N (in kPa) ≤ 60 kPa (2.14)
For non-plastic silt:
f = 1.7N (in kPa) ≤ 60 kPa (2.15)
For end bearing, the relationship is as under (Mayerhof, 1976)
For sand:
f = 40N (in kPa) ≤ 400N and ≤ 11000 kPa (2.16)
For non-plastic silt:
f = 30N (in kPa) ≤ 300N and ≤ 11000 kPa (2.17)
Where, N is the average N-value over the pile shaft length and N is the N-value in
the vicinity of pile tip.
2.5 Bored Pile Capacity Using Static Formulae
2.5.1 Cohesive soil
Skin friction resistance in cohesive soil may be determined using either the α-method or
the β-method as described in the relevant section of driven piles. However, for clay
soil, α-method has wide been used by the engineers. This method gives:
f = αs (2.18)
Where,
f = Skin friction
s = undrained shear strength of soil along the shaft
9
α = adhesion factor =0.55 for undrained shear strength ≤ 190 kPa (4000 psf)
For higher values of s the value of α may be taken from Figure 2.2 as obtained from
test data of previous investigators.
Figure 2.2: Adhesion factor α for drilled shaft (after Kulhawy and Jackson, 1989)
The skin friction resistance should be ignored in the upper 1.5 m of the shaft and along
the bottom one diameter of straight shafts because of interaction with the end bearing.
If end bearing is ignored for some reasons, the skin friction along the bottom one
diameter may be considered. For belled shaft, skin friction along the surface of the bell
and along the shaft for a distance of one shaft diameter above the top of bell should be
ignored. For end bearing of cohesive soil, the following relations given by Equations
2.19 and 2.20 are recommended.
f = N S ≤ 4000 kPa (2.19)
Where, N = 6 1 + 0.2 ≤ 9 (2.20)
10
Where,
f = End bearing stress
S = undrained shear strength of soil along the shaft
N = Bearing capacity factor
L = Length of the pile (Depth to the bottom of the shaft)
D = Diameter of the shaft base
2.5.2 Cohesion less soil
Skin friction resistance in cohesion less soil is usually determined using the β-method.
The relevant equation is reproduced again:
f = βσ (2.21)
β = Ktanϕ (2.22)
Where,
f = Skin friction
σ = Effective vertical stress at mid-point of soil layer
K = Coefficient of lateral earth pressure
ϕ = Soil shaft interface friction angle
The values of K and ϕ can be obtained from the chart of Tables 2.1, from the soil
friction angle, ϕ and preconstruction coefficient of lateral earth pressure K . However,
K is very difficult to determine. An alternative is to compute β directly using the
following empirical relation.
β = 1.5 − 0.135 (2.23)
Where,
Br = Reference width=1 ft = 0.3 m = 12 inch = 300 mm
z = Depth from the ground surface to the mid-point of the strata
11
Table 2.1: Typical 𝛟𝐬/𝛟 and 𝐊/𝐊𝐨 values for the design of drilled shaft
Construction method
𝛟𝐬 /𝛟
Construction method
𝐊/𝐊𝐨
Open hole or temporary casing
1.0 Dry construction with minimal side wall disturbance and prompt concreting
1
Slurry method – minimal slurry cake
1.0 Slurry construction – good workmanship
1
Slurry method – heavy slurry cake
0.8 Slurry construction – poor workmanship
2/3
Permanent casing 0.7 Casing under water 5/6
2.6 Bored Pile Capacity Using SPT Values
2.6.1 Cohesive soil
The following relations may be used for preliminary design of ultimate capacity of
concrete bored piles in clay soils. According to Mayerhof (1976)
For skin friction the relationship is as under.
f = 1.2N (in kPa) ≤ 70 kPa (2.24)
For end bearing, the relationship is as under.
f = 25N (in kPa) ≤ 4000 kPa (2.25)
Where, N is the average N-value over the pile shaft length and N is the N-value in
the vicinity of pile tip.
2.6.2 Cohesionless soil
Standard Penetration Test N-value is a measure of relative density hence angle of
internal friction of cohesion less soil. The skin friction of pile can thus be estimated
from N-value. The following relation may be used for ultimate capacity of concrete
piles in cohesion less soil and non-plastic silt.
For skin friction the relationship is as under (Mayerhof, 1976).
For sand:
f = 1.0 N (in kPa) ≤ 60 kPa (2.26)
12
For non-plastic silt:
f = 0.9N (in kPa) ≤ 60 kPa (2.27)
For end bearing, the relationship is as under (Mayerhof, 1976).
For sand:
f = 15N (in kPa) ≤ 150N and ≤ 4000 kPa (2.28)
For non-plastic silt:
f = 10N (in kPa) ≤ 100N and ≤ 4000 kPa (2.29)
Where, N is the average N-value over the pile shaft length and N is the N-value in
the vicinity of pile tip.
2.7 Bored Pile Capacity Based on AASHTO 2002
The ultimate axial capacity (Qult) of drilled shafts shall be determined in accordance
with the following for compression:
Qult=Qs+QT -W (2.30)
Shaft in cohesive soils may be designed by total and effective stress methods of
analysis, for un-drained and drained loading conditions, respectively. Shafts in
cohesion-less soil shall be designed by effective stress methods of analysis for drained
loading conditions.
Side resistance in cohesive soil
For shafts in cohesive soil located under un-drained loading conditions, the ultimate
side resistance may be estimated using the following equation:
Qs=πB ∑ αi Sui Δzi (2.31)
The ultimate unit load transfer in side resistance at any depth fsi is equal to the product
of αi and Sui. Refer to Table 2.2 for guidance regarding selection of αi and limiting
values of fsi for excavated dry in open or cased holes in cohesive soil after Reese and
O’neill (1988). Environmental long term loading or construction factor may dictate that
a depth greater than five feet should be ignored in estimating QS. Refer to Figure 2.3 for
identification of portions of drilled shaft not considered in contributing to the complete
13
value of QS. For shaft in cohesive soil under drained loading conditions may be
determined using the procedure in the next article.
Where time dependent changes in soil shear strength may occur (e.g., swelling of
expansive clay or down drag from a consolidating clay), effective stress method should
be used to compute QS in the zone where such changes may occur.
Table 2.2: Recommended values of α and fsi for estimation of drilled shaft side
resistance in cohesive soil, after Reese and O’Neill (1988)
Location of drilled shaft Value of α
Limiting value of load transfer, fsi
(ksf)
From ground surface to depth along drilled shaft of 5ft*
0 -
Bottom 1 diameter of the drilled shaft or 1 stem diameter above the top of the bell (if skin friction is being used)
0 -
All other points along the sides of the drilled shaft 0.55 5.5
*The depth of 5 ft may need adjustment if the drilled shaft is installed in expansive clay or if there is substantial ground line deflection from lateral loading
Figure 2.3: Identification of Portions of drilled shafts neglected for estimation of drilled shaft side resistance in cohesive soil, after Reese and O’ neill (1988)
14
Side resistance in cohesion-less soil
For shafts in cohesion-less soil or for effective stress analysis of shafts in cohesive soils
under drained loading conditions, the ultimate side resistance of axially loaded drilled
shafts may be estimated using the following equation:
QS=πB∑ γi'ziβiΔzi (2.32)
The βi may be determined using the following:
βi=1.5-0.135√zi ; 1.2> βi>0.25 (2.33)
The value of γi' should be determined from measurements from undisturbed sample
along the length of the shaft or from empirical correlations with SPT or other in-situ
test methods. The ultimate unit load transfer in side resistance at any depth, fsi, is equal
to the product of βi and σvi. The limiting value of fsi for shafts in cohesion-less soil is 4
ksf.
Tip resistance in cohesive soil
For axially loaded shafts in cohesive soil subjected to un-drained loading conditions,
the ultimate tip resistance of drilled shafts may be estimated using the following:
QT=qTAT=Nc Sut AT (2.34)
qT=Unit end bearing
AT=Cross section area of pile
Sut=Un-drained shear strength
Values of bearing capacity factor Nc may be determined using the following:
Nc=6.0[1+0.2(D/Bi)];Nc≤9 (2.35)
The limiting value of unit end bearing (qT=NcSut) is 80ksf.
The value of Sult should be determined from the results of in-situ and or laboratory
testing of un-drained samples obtained within a depth of 2B below the tip of the shaft.
If soil within 2B of the tip is of soft consistency the value of Nc should be reduced by
one-third.
Tip resistance in cohesion-less soil
15
There is a tendency for the sand to loosen slightly at the bottom of excavation due to
relief of stress. Some densification of sand occurs below the base of a drilled shaft as
settlement occurs. The load-settlement curve that have been obtained by experiment for
the base of drilled shafts are consistent with the above concepts. The load continued to
increase for some of the tests to a settlement of more than 15 percent of the diameter of
the base. Such a large amount of settlement could not be tolerated for most structures;
therefore, it was decided to limit the values of end bearing for drilled shafts in granular
soil to that which could occur at a downward movement of the base of 5 percent of the
diameter of the base.
Table 2.3: Recommended values of unit end bearing for cohesion-less soil (Reese
and O’Neill, 1988)
Range of value of NSPT (Uncorrected) Values of qb (Tsf)
0 to 75 0.60 N
Above 75 45
2.8 Pile Capacity during Driving
It has been observed that a pile exerting greater resistance against driving can sustain
greater load. A number of formulae have been evolved to determine the load carrying
capacity based on the principle that the energy supplied to the pile is utilized in useful
work done in driving the pile and in other loses. These formulae are known as
‘Dynamic formulae’.
The Engineering News formula is generally recognized to be one of the most popular
dynamic formula (Agerschou, 1962). Chellis (1961) list more than 30 different
formulae in his text book. Despite of their obvious deficiencies and unreliability the
pile formulae enjoy a great popularity among practicing engineers because of the use of
these formulae reduces the design of pile foundations to a very simple procedure.
2.8.1 Engineering News formula
This formula was published by Wellington in Engineering News in 1888 and it was
called Engineering News Record Formula (ENR). This is expressed as follows,
Pu= (2.36)
16
Pu =Ultimate capacity of pile
e =Hammer efficiency
W =Weight of ram
h=height of all of ram
s=amount of point penetration per blow
2.8.2 Gates formula
This method was the results of a research performed by Gates (1957). The basic
assumption is that the resistance is directly proportional to the squared root of the net
hammer energy. The relationship is presented by
P =a e E (b − log ) (2.37)
P = Ultimate pile capacity (kN)
Hammer efficiency, e =0.75 for drop hammer
Manufactures hammer energy rating E =kN.m
s= Point penetration per blow-set
a=104.5
b=2.4
A suggested safety factor to be used is 3.
In this formula, the following assumptions were made:
a) Hammer and pile may be treated as impinging particles
b) Hammer gives up its entire energy on impact.
c) On impact the resistance increases in an elastic manner as the pile is displaced,
remains constant for further displacement and then falls to zero in an elastic manner as
the pile rebounds.
2.8.3 Janbu formula
The Janbu formula as mentioned by Olson et al (1967). Pile resistance as measured
during driving using this method shall be taken as
17
P =
(2.38)
Wr =Weight of ram
Wp =Weight of pile
s=Pile set
E=Modulus of elasticity
e =Hammer efficiency
Eh=Manufactures hammer energy rating
L=Pile length
Cd=0.75+0.15 (2.39)
ku=Cd 1 + 1 + (2.40)
λ=
It also based on some assumptions such as:
a) There is frictional or other loss in the hammer system so that energy actually applied
at impact is less than energy delivered.
b) There is loss due to elastic compression of the pile.
c) There is loss due to impact.
Recommended factor of safety is 3 to 6.
2.9 Pile Capacity by Static Load Test
Static load tests relied upon an accurate measure of a pile’s ultimate resistance.
Ultimate resistance is the maximum resistance mobilized by the positive shaft
resistance and toe bearing in the soil. Static load testing involves loading the pile
statically by placing increments of load and recording settlements as the load is applied
following ASTM D1143. As the pile resistance may set up (resistance increased with
time) or relax (resistance decrease with time), static load tests are often performed after
some wait period so that equilibrium conditions are re-established .Two principal types
18
of test may be used for compression loading on piles - the constant rate of penetration
(CRP) test and the maintained load (ML) test.
Maintained load (ML) test will be used in this study. In the ML test the load is
increased in stages to 1.5 times or twice the working load with time settlement curve
recorded at each stage of loading and unloading. The general procedure is to apply
static loads in increments of 25% of the anticipated design load. The ML test may also
be taken to failure by progressively increasing the load in stages. In the ML test, the
load test arrangements as specified in ASTM D1143 shall be followed. According to
ASTM D1143 each load increment is maintained until the rate of settlement is not
greater than 0.25 mm/hr or 2 hours is elapsed, whichever occurs first. After that the
next load increment is applied. This procedure is followed for all increments of load.
After the completion of loading if the test pile has not failed the total test load is
removed any time after twelve hours if the butt settlement over one hour period is not
greater than 0.25 mm otherwise the total test load is kept on the pile for 24 hours. After
the required holding time, the test load is removed in decrement of 25% of the total test
load with 1 hour between decrement. If failure occurs, jacking the pile is continued
until the settlement equals 15% of the pile diameter or diagonal dimension.
2.9.1 Load test evaluation methods for axial compressive load
A number of arbitrary or empirical methods are used to serve as criteria for determining
the allowable and ultimate load carrying capacity from pile load test. Some are based
on maximum permissible gross or net settlement as measured at the pile but while the
others are based on the performance of the pile during the progress of testing Chellis
(1961); Whitaker (1976); Poulos and Davis (1980); Fuller (1983). It is recommended to
evaluate the load carrying capacity of piles and drilled shaft using any of the following
methods along with the arbitrary methods:
(a) Davission Offset Limit
(b) British Standard Institution Criterion
(c) Indian Standard Criteria
(d) Butler-Hoy Criterion
(e) Brinch-Hansen 90% Criterion
19
The recommended criteria to be used for evaluating the ultimate and allowable load
carrying capacity of piles and drilled shaft are summarized below.
(a) A very useful method of computing the ultimate failure load has been reported by
Davisson (1972). This method is based on offset method that defines the failure
load. The elastic shortening of the pile, considered as point bearing, free standing
column, is computed and plotted on the load-settlement curve, with the elastic
shortening line passing through the origin. The slope of the elastic shortening line
is 20o. An offset line is drawn parallel to the elastic line. The offset is usually 0.15
inch plus a quake factor, which is a function of pile tip diameter. For normal size
piles, this factor is usually taken as 0.1D inch, where D is the diameter of pile in
foot. The intersection of offset line with gross load-settlement curve determines the
arbitrary ultimate failure load. Davisson method is too restrictive for drilled piles,
unless the resistance is primarily friction. This method is recommended for driven
precast piles.
(b) Terzaghi (1942) reported that the ultimate load capacity of a pile may be considered
as that load which causes a settlement equal to 10% of the pile diameter. However,
this criterion is limited to a case where no definite failure point or trend is indicated
by the load-settlement curves. This criterion has been incorporated in BS 8004
“Code of Practice for Foundations” which recommends that the ultimate load
capacity of pile should be that which causes the pile to settle a depth of 10% of pile
width or diameter.
(c) The allowable load capacity of pile should be 50% of the final load, which causes
the pile to settle a depth of 10% of pile width or diameter BS 8004.
(d) Ultimate load capacity of pile is smaller of the following two IS: 2911 Part-4:
(i) Load corresponding to a settlement equal to 10% of the pile diameter in the case
of normal uniform diameter pile or 7.5% of base diameter in case of under-
reamed or large diameter cast in-situ pile.
(ii) Load corresponding to a settlement of 12 mm.
(e) Allowable load capacity of pile is smaller of the following IS: 2911 Part-4:
(i) Two thirds of the final load at which the total settlement attains a value of 12
mm.
20
(ii) Half of the final load at which total settlement equal to 10% of the pile diameter
in the case of normal uniform diameter pile or 7.5% of base diameter in case of
under-reamed pile.
(f) Butler and Hoy (1977) states that the intersection of tangent at initial straight
portion of the load-settlement curve and the tangent at a slope point of 1.27 mm/ton
determines the arbitrary ultimate failure load.
(g) The Brinch Hansen (1963) proposed a definition for ultimate load capacity as that
load for which the settlement is twice the settlement under 90 percent of the full test
load.
(h) Where failure occurs, the ultimate load may be taken to calculate the allowable load
using a factor of safety of 2.0 to 2.5.
2.10 Dynamic Analysis by Wave Equation
Pile driving could not accurately be analyzed by rigid-body mechanics led to the
development of an analysis that utilizes wave theory. The wave equation analysis of
pile driving has eliminated many shortcomings related with dynamic formulae by
accurately simulating the hammer impacts and pile penetration process. The use of
wave equation was considered by Isaacs (1931) and Glanville et al (1938); but not until
the works of Smith (1960), that the methodology was fully developed.
2.10.1 The wave equation
The wave equation may be derived from consideration of the internal forces and motion
produced on a segment of a freely-suspended prismatic bar subject to and impact at one
end. The resulting equation is
= (2.41)
Where D=longitudinal displacement of a point of the bar from its original position
E=modulus of elasticity of bar
ρ=density of bar material
t=time
x=direction of longitudinal axis
21
For a pile, the resistance of the surrounding soil must also be considered and the
equation becomes
= (±)R (2.42)
Where R= soil-resistance term
This equation may be solved for the appropriate initial and boundary conditions, to
determine the relationship among displacement, time and position in the pile. From
which the stress variation in the pile may be determined.
2.10.2 Smith’s idealization
Pile driving analyses are generally accomplished by modeling 1-D wave propagation in
an elastic rod (pile). The methods routinely used are based on a lumped mass
discretization of the pile with simplified rheological models of pile-soil interaction
following the framework first proposed by Smith (1960). The Smith model simulates 1-
D wave propagation in the pile idealized as in Figure 2.4 and consists of-
1. A ram, to which an initial velocity is imparted by the pile driver.
2. A cap-block
3. A pile cap.
4. A cushion block (cushioning material).
5. The pile.
6. The supporting soil.
22
Figure 2.4: Smith’s spring model (Smith, 1960)
The ram, cap block, pile cap, cushion block, and pile are represented by appropriate
discrete weights and springs. The frictional resistance on the side of the pile is
represented by a system of springs and dashpots (Figure 2.4), while the point resistance
is represented by a single spring and dashpot. The characteristics of the components are
considered subsequently. If the actual situation differs from that shown in Figure 2.4
that is, if the cushion block is not used or if an anvil is placed between ram and cap
block – the idealization of the system can of course be modified.
23
2.10.3 Pile modes-internal spring
The ram, cap block, pile cap, and cushion block may be considered to consist of
internal springs, although the ram and pile cap can often be treated as rigid bodies. The
load, deformation behavior of these elements is most simply taken to be linear (Figure
2.5a) although the internal damping may also be consider (e.g., as shown in Figure
2.5b), for components such as the cap block and the cushion block.
a) No internal Damping pile elements b) Internal damping cap block and cushion block
Figure 2.5: Load deformation relationships for internal springs.
2.10.4 Soil model external springs
Smith’s model of the load-deformation characteristics of the soil, represented as
external springs, subjected to static loading, is shown in Figure 2.6.The path
OABCDEFG represents loading and unloading in side friction. For the point, only
compressive loading is considered and the loading and unloading path is OABCF. The
quantities defining this static behavior are Q and Ru where
Q = “quake”, the maximum soil deformation that may occur elastically
Ru= ultimate soil resistance
A load deformation diagram such as Figure 2.6 may be established separately for each
spring, so that
K (m)=( )
( ) (2.43)
24
Where K (m) is the spring constant during elastic deformation for external spring m.
(c) Equivalent rheological model of soil
Figure 2.6: Load-deformation relationship of soil (after Lowery et al, 1969)
To allow for the effects of dynamic loading during driving in increasing the
instantaneous resistance of the soil, the dynamic load-settlement behavior of the soil is
taken to be that shown in Figure 2.6b, which is pointed out by Lowery et al (1969),
corresponds to a Kelvin rheological model (Figure 2.6c). This dynamic behavior is
characterized by a further parameter J, the damping constant. The dashpot in the model
produces an additional resisting force proportional to the velocity of loading (V).
25
2.10.5 Basic equation
In solving the wave equation numerically, Equation 2.44 could be expressed in finite-
differential form for each element, and then the resulting equations, incorporating the
appropriate boundary conditions, could be solved simultaneously for each time-interval
considered. This method is the conventional method for solving such equations and has
been suggested by Soderberg (1962); it may also be applied to periodic dynamic
loading of the pile. However, it has been shown by Smith (1960) that the finite-
difference form of the wave equations and this form of expression of the wave equation
has been adopted for pile-driving analysis. The basic equations are as follows:
D(m,t)=D(m,t-1)+Δt V(m,t-1)………………………............................ ....(2.44)
C(m,t)=D(m,t)-D(m+1,t) …….………………………………… …… …(2.45)
F(m,t)=C(m,t)K(m)………………………………………… ……….… ..(2.46)
R(m,t)=[D(m,t)-D (m,t)][K (m)[1+J(m)V(m,t- 1)]……………………… ..(2.47)
V(m,t)=V(m,t-1)+[F(m-1,t)+W(m)-R(m,t)]( )
…………… …… .…. .(2.48)
Where,
m=element number
t= time
Δt = time interval
C(m,t)= compression of internal spring m at time t
D(m,t)= displacement of external spring m at time t
Dˊ(m,t)=plastic displacement of external spring m at time t
F(m,t)= force in internal spring m at time t
g= acceleration caused by gravity
J(m)= soil damping constant at element m
K(m)= spring constant for internal spring m
26
K (m)= spring constant for external spring m
R(m,t)= force exerted by external spring m on element m at time t
V(m,t)= velocity of element m at time t
W(m)= weight of element m
Equation 2.48 applies for elastic pile elements for which internal damping is ignored.
For elements such as the cap block and the cushion block, in which internal damping
should be considered, the following equation should be used instead of equation 2.48.
F(m,t)=( )
[ ( )]. C(m, t) −
[ ( )]− 1 . K(m). C(m, t)max………………..... (2.49)
Where e(m)=coefficient of restitution of internal spring m
C(m,t)max= temporary maximum value of C(m,t)
The above equation characterizes the path OABCDEO shown in the Figure 2.6b .For a
pile cap or cushion block, no tensile forces can exist and hence only this part of the
diagram applies. Intermittent unloading-loading is typified by path ABC, established by
control of C(m,t) max in equation: 2.46. The slope of the of lines AB, BC and DE
depends on the value of e(m).
Smith (1960) notes that Equation 2.47 produces no damping when D(m,t)-D (m,t)
becomes zero, and suggests anal ternate equation to be used after D(m,t) first becomes
equal to Q(m), where Q(m) is the “quake” for element m.
R(m,t)=[D(m,t)-D (m,t)].K (m)+J(m).Ru(m).V(m,t- 1)………… ………… ....(2.50)
Where Ru(m) is the ultimate static soil-resistance of element m.
Equation 2.44 to 2.48 are solved for each of the pile elements involved, m=1 to m=p
(point), for a succession of time intervals starting when the hammer [W(1)] travelling
with known velocity touches the first spring. The solution of these equations continues
until the permanent set or plastic displacement of the soil at the point D (p,t) is a
maximum.
2.10.6 Values of soil parameters
The soil parameters required for the wave-equation analysis are the ultimate soil
resistance, Ru; quake Q; and damping factor, J.
27
Ultimate soil resistance, Ru
Various values of Ru are input into the computer program and the corresponding
permanent set determine the relative proportions of shaft and base resistance. A
reasonable estimate of these proportions may be made by made by estimating the static
shaft and base resistance from the known or assumed soil properties. A somewhat
higher ultimate resistance for a given driving resistance is obtained if some shaft
resistance is considered, rather than only end-bearing. As rough guide where other
information is not available, value of the percentage of shaft resistance suggested by
Forhan and Reese (1964) are shown in Table 2.4.
Table 2.4: Empirical values of Q, J and percent side adhesion
Soil Q(in) J(p) (sec/ft) Side Adhesion
(% of Ru)
Coarse sand 0.10 0.15 35
Sand and gravel mixed 0.10 0.15 75-100
Fine sand 0.15 0.15 100
Sand and clay or loam, at least 50% of pile in sand
0.20 0.20 25
Silt and fine sand underlain by hard strata 0.20 0.20 40
Sand and gravel underlain by had strata 0.15 0.15 25
Quake
Values of Q have obtained empirically to date, and the single empirical values of Q for
all elements of the pile suggested by Forhand and Reese (1964) are shown in Table
2.4.It is however possible to derive values of Q theoretically from pile settlement
theory if the “elastic” soil parameters are known. On the basis of this theory, the value
of Q varies along the pile, with the value at the pile tip being greater than the values
along the shaft. Alternatively, Q could also be estimated from the soil-resistance curve
employed by Seed and Reese (1957) and Coyle and Reese(1966).
Damping factor, J
Empirical correlations between J and soil type obtained by Forehand and Reese (1964)
are shown in Table 2.4.The values in the Table are for the pile point [i.e., J (p)]. The
average value for the sides of the pile J(m) have been found to be less than J(p), and for
practical purposes, it has been suggested that
28
J(m)= J(p)………………………………… ………………………………… (2.51)
Where J(m)= Soil damping constant for sides of pile
J(p)= Soil damping constant for pile point
2.11 Dynamic Load Test
Various techniques for dynamic loading tests are now available. These tests are
relatively cheap and quick to carry out compared with static loading tests. Information
that can be obtained from a dynamic loading test includes:
(a) Static load capacity of the pile,
(b) Energy delivered by the pile driving hammer to the pile,
(c) Maximum driving compressive stresses (tensile stress should be omitted), and
(d) Location and extent of structural damage.
2.11.1 Test method
The dynamic loading test is generally carried out by driving a prefabricated pile or by
applying impact loading on a cast-in-place pile by a drop hammer. A standard
procedure for carrying out a dynamic loading test is given in ASTM 4945-00.The
equipment required for carrying out a dynamic pile loading test includes a driving
hammer, strain transducers and accelerometers, together with appropriate data
recording, processing and measuring equipment. The hammer should have a capacity
large enough to cause sufficient pile movement such that the resistance of the pile can
be fully mobilized. A guide tube assembly to ensure that the force is applied axially on
the pile should be used. The strain transducers contain resistance foil gauges in a full
bridge arrangement. The accelerometers consist of a quartz crystal which produces a
voltage linearly proportional to the acceleration. A pair of strain transducers and
accelerometers are fixed to opposite sides of the pile, either by drilling and bolting
directly to the pile or by welding mounting blocks, and positioned at least two
diameters or twice the length of the longest side of the pile section below the pile head
to ensure a reasonably uniform stress field at the measuring elevation. It should be
noted that change of cross-section of the pile due to connection may affect the
proportionality of the signals and hence the quality of the data. An electronic theodolite
29
may also be used to record the displacements of the pile head during driving (ASTM
D4945-00) .In the test, the strain and acceleration measured at the pile head for each
blow are recorded. The signals from the instruments are transmitted to a data recording,
filtering and displaying device to determine the variation of force and velocity with
time.
2.12 Methods of Interpretation for Dynamic Load Test
Two general types of analysis based on wave propagation theory, namely direct and
indirect methods are available. Direct methods of analysis apply to measurements
obtained directly from a (single) blow, whilst indirect methods of analysis are based on
signal matching carried out on results obtained from one or several blows. Examples of
direct methods of analysis include CASE, IMPEDANCE and TNO method, and
indirect methods include CAPWAP, TNOWAVE and SIMBAT. CASE and CAPWAP
analyses are used mainly for displacement piles, although in principle they can also be
applied to cast-in-place piles. SIMBAT has been developed primarily for cast-in place
piles, but it is equally applicable to displacement piles. In a typical analysis of dynamic
loading test, the penetration resistance is assumed to be comprised of two parts, namely
a static component, Rs, and a dynamic component, Rd.
Two methods of analysis are described below.
2.12.1 CASE method
This method assumes that the resistance of the soil is concentrated at the pile toe. In the
analysis, the dynamic component is given by:
Rd = jc Z vb ……………………………………………………………..(2.52)
Here jc = the CASE damping coefficient
Z = impedance =Ep Ap/cw
Ap = cross sectional area of the pile
Ep = Young's modulus of the pile
cw = wave speed through the pile
vb = velocity of pile tip
The appropriate jc is dependent on the type of soil at the pile toe and the actual pile
dimensions. A range of jc values appropriate to different soil types was proposed by
Rausche et al (1985) and has been further refined by Pile Dynamics Inc. (PDI, 1996).
30
Typical ranges of jc are given in Table 2.5 These represent the damping factors at pile
toe and are correlated with dynamic and static loading tests. In practice, jc values can
vary significantly, particularly in layered and complex ground conditions, causing
potential errors in pile capacity prediction. For large piling projects where CASE
method is to be used to ascertain the load-carrying capacity of piles, site-specific tests
can be conducted to determine the appropriate damping factors by correlating the
CASE results with static loading tests or results of CAPWAP analysis.
Table 2.5: Range of CASE damping values for different types of soil
Soil type at pile toe CASE damping
(Rausche et al, 1985)
Updated CASE damping
(PDI, 1996)
Clean sand 0.05 – 0.20 0.10 – 0.15
Silty sand, sand silt 0.15 – 0.30 0.15 – 0.25
Silt 0.20 – 0.45 0.25 – 0.40
Silty clay, clayey silt 0.40 – 0.70 0.40 – 0.70
Clay 0.60 – 1.10 0.70 or higher
2.12.2 CAPWAP method
In a CAPWAP (CAse Pile Wave Analysis Program) analysis, the soil is represented by
a series of elasto-plastic springs in parallel with a linear dashpot similar to that used in
the wave equation analysis proposed by Smith (1960). The soil can also be modeled as
a continuum when the pile is relatively short. CAPWAP measures the acceleration-time
data as the input boundary condition. The program computes a force versus time curve
which is compared with the recorded data. If there is a mismatch, the soil model is
adjusted. This iterative procedure is repeated until a satisfactory match is achieved
between the computed and measured force-time diagrams. The dynamic component of
penetration resistance is given by
Rd = js vp Rs …………………………………………………….... ........ (2.53)
Where js = Smith damping coefficient
vp = velocity of pile at each segment
Rs = static component of penetration resistance
Input parameters for the analysis include pile dimensions and properties, soil model
parameters including the static pile capacity, Smith damping coefficient, js and soil
quake (i.e. the amount of elastic deformation before yielding starts), and the signals
31
measured in the field. The output will be in the form of distribution of static unit shaft
resistance against depth and base response, together with the static load-settlement
relationship up to about 1.5times the working load. It should be noted that the analysis
does not model the onset of pile failure correctly and care should be exercised when
predicting deflections at loads close to the ultimate pile capacity.
Results of CAPWAP analysis also provide a check of the CASE method assumptions
since the ultimate load calculated from the CAPWAP analysis can be used to calculate
the CASE damping coefficient. Sound engineering judgment is required in determining
whether a satisfactory match has been achieved and whether the corresponding
combination of variables is realistic.
2.12.3 Summary
This chapter describes the methods to calculate the pile capacity. Two types of pile was
discussed both precast and cast-in-situ type. Later each pile type was discussed based
on the soil classification. In addition to that, pile capacity using driving formula was
mentioned. To ascertain the predicted pile capacity load test was discussed. Based on
the aforementioned literature the capacity of pile will be determined in this study.
32
CHAPTER 3
INSTRUMENTATION AND TEST PROGRAM
3.1 General
The study location is at a construction site in Tangail. First, a detailed subsoil
investigation was done, with the help of two bore holes namely BH-1 and BH-2 which
was approximately 5m apart. Based on subsoil investigation precast rectangular piles
were selected. In this site detailed study of two precast piles was carried out. In the
preliminary design phase pile section 12˝X12˝ (300X300 mm2) and length 45ˊ-0˝
(13.71m) was fixed. Next these piles were cast at site and cured for twenty eight days.
Mature piles were driven in two locations namely TP-1 (Test pile) and TP-2 (Test pile).
Drop hammer of 3.5 Ton was used and maximum height of fall was 5'-0''. During
driving the driving records were collected for calculating the pile capacity which was
also attached at Appendix B. After 14 days of interval these piles were tested using Pile
Dynamic Analyzer (PDA) Test. At the last two feet (from top) of each pile, transducers
and strain gages were attached with the pile for estimating dynamic capacity by PDA.
Later CAPWAP analysis was carried out using the signal matching techniques for
evaluating refine capacity of piles. Later these piles were tested by static load test
method as well.
3.2 Capacity Estimation
The pile capacity will be calculated by using sub soil investigation report. Methods that
are considered for this study are based on the draft versions of Bangladesh National
Building Code (BNBC-2015), where pile capacity estimation technique is described
both for driven and cast-in-situ piles. It has presented two methods: one is Static
bearing capacity (Alpha-Beta method) and the other is SPT method. Generally,
professional geotechnical expert uses American Association of State Highway and
Transportation Officials guidelines (AASHTO, 2002), which is widely used in
Bangladesh. For this study AASHTO-2002 method is also applied and results are
compared with the BNBC-2015.
During driving the precast piles, there is an option for using the driving equations. This
has also been used for pile capacity estimation. Figure 3.1 summaries the working
process of the study.
33
Figure 3.1: Flow diagram of the working process
From the soil test report it was found that the soil is uniform in horizontal and vertical
direction. Mainly soil type was non-cohesive (Silt followed by Sand) up to the depth of
investigation. Considering the imposed building loading deep foundation was
considered. Figure 3.2 and 3.3 shows the two test borehole logs. The test pile driving
records are attached at Appendix A.
PILE CAPACITY
BASED ON SOIL
TEST REPORT
DRIVING EQUATION
DYNAMIC LOAD TEST (PDA)
STATIC LOAD TEST
1. BNBC-2015
2. AASHTO-2002
1. ENGINEERS NEWS
2. GATES FORMULA
3. JANBU FORMULA
1. DAVISSION METHOD
2. BNBC-93 GUIDELINE
3. BS 8004 (BRITISH STANDARD)
4. IS: 2911 (INDIAN STANDARD)
5. BUTLER & HOY
6. BRINCH HANSEN
CAPWAP ANALYSIS
34
Borehole No-1
Method of boring-Percussion Method Boring dia (mm)-100
Soil Classification- ASTM D-2487 & D-2488
Dep
th b
elow
EG
L(m
)
Thi
ckne
ss (
m)
D
escr
ipti
on o
f
soil
stra
ta
SPT
N-
Val
ue
(Raw
fie
ld d
ata)
Graphical representation of
SPT N-value
1.5
3.0
4.5
6.0
7.5
9.0
10.5
12
13.5
15
16.5
18
19.5
21
22.5
3.75
Brown, non-
plastic, SILT, ML,
trace mica
2
5
9
10
16
20
22
22
24
27
28
35
38
42
42
20.25
Gray, loose to
medium dense,
Silty SAND, SM,
trace mica
Figure 3.2: Borehole log BH-1
35
Borehole No-2
Method of boring-Percussion Method Boring dia (mm)-100
Soil Classification- ASTM D-2487 & D-2488 D
epth
bel
ow
EG
L(m
)
Thi
ckne
ss (
m)
Des
crip
tion
of
soil
stra
ta
SPT
N-
Val
ue
(Raw
fie
ld d
ata)
Graphical representation of
SPT N-value
1.5
3.0
4.5
6.0
7.5
9.0
10.5
12
13.5
15
16.5
18
19.5
21
22.5
2.25
21.7
5
Brown, non-
plastic, SILT, ML,
trace mica
4
7
11
11
12
13
16
10
17
26
26
29
31
35
39
Gray, loose to
medium dense,
Silty SAND, SM,
trace mica
Figure 3.3: Borehole log BH-2
36
3.3 Pile Load Tests
Based on the sub soil investigation, pile length was selected as 45ft with a section of
12''X12'' (300mmX300mm). Initial estimated capacity was 40 Ton following equation
of Schmertmann (1970). Table 3.1 shows the static and dynamic load testing program.
Table 3.1: Load testing program for test piles
Sl. No. Purpose of test Name of the test Number of tests
1. Dynamic Pile Capacity
PDA followed by CAPWAP analysis
2
2. Static Pile Capacity Static Load Test 2
Figure 3.4: Casting of pile at site for construction
3.4 Pile Driving and Keeping Driving Record
Piles are generally marked every one feet of interval and which is visible from the data
observer during record keeping. In a proper formatted data sheet pile penetration and
37
hammer blow need to be recorded for per feet of penetration of pile. Data sheet
provides necessary information like: pile section, length, casting date, pile
identification mark, capacity of pile, hammer weight, drop height of hammer, blows
required for a fixed penetration depth, refusal etc. From the driving of the two piles
initial capacity can be calculated using available driving formulas like Engineering
News, Gate etc. Figure 3.5 shows the driving of pile using a drop hammer.
Figure 3.5: Pile driving using drop hammer
3.5 Dynamic Load Test Arrangement
A typical dynamic testing system consists of a minimum of two strain transducers and
two accelerometers bolted to diametrically two opposite sides of the pile to monitor
strain and acceleration and account for non-uniform impacts and bending. The use of
38
two diametrically opposite mounted strain transducers is essential for a valid test.
Generally, strain transducers and accelerometers are attached two to three diameters
below the pile head.
Figure 3.6 to Figure 3.9 illustrate the typical pile preparation procedures required for
dynamic testing. In Figure 3.6 a concrete pile is being prepared for gage attachment by
drilling. Pile preparation and gage attachment typically requires 10 to 20 minutes per
pile. After the gages are attached, the driving process continues following usual
procedures. The individual cables from each gage are combined into single main cable
which in turn relays the signals from each hammer blow to the data acquisition system
on the ground. The data acquisition system, such as the Pile Driving Analyzer shown in
the Figure 3.7 receives and converts the strain and acceleration signals to force and
velocity records versus time. The force is computed from the measured strain times the
product of the pile elastic modulus, and cross sectional area. The velocity is obtained by
integrating the measured acceleration record. During driving, the Pile Driving Analyzer
performs integrations and all other required computations to analyze the dynamic
records for transferred energy, driving stress, structural integrity, and pile capacity.
Numerical results for dynamic quantities are electronically stored in a file which can be
later used to produce graphical and numeric summary outputs. In this system, force and
velocity records are also viewed on a graphic LCD computer screen during pile driving
to evaluate data quality, soil resistance distribution, and pile integrity. Complete force
and velocity versus time records from each gage are also digitally stored for later
reprocessing and analysis by CAPWAP.
During pile driving in the field, the Pile Driving Analyzer uses the Case Method
capacity equations for estimating the ultimate static pile capacity. Case Method
capacity results are calculated in real time from the measured force and velocity records
obtained for each hammer blow. Correlating Case Method capacity results with pile
penetration resistance information is another means of establishing the driving criteria.
The CAPWAP analysis method is a more rigorous numerical analysis procedure that
uses the measured force and velocity records (PDA data) from one hammer blow. The
CAPWAP program uses the dynamic measurement data along with wave equation and
soil modelling to calculate the ultimate static pile capacity, the relative soil resistance
distribution, the dynamic soil properties of quake and damping, and the driving stresses
39
throughout the pile. CAPWAP capacity results are considered a more accurate
assessment of the ultimate static pile capacity (Likins et al, 1996).
Figure 3.6: Strain transducers and accelerometer bolted on the concrete piles
Figure 3.7: Pile driving analyser
40
Figure 3.8: Dynamic test arrangement for TP-1
Figure 3.9: Dynamic test arrangement for TP-2
3.6 Static Load Test Arrangement
Maintain load (ML) method with standard loading procedure has been followed under
complying ASTM D1143 and load applied by hydraulic ram against Kent ledge. ASTM
D1143 recommends several alternative systems for applying compressive load to the
pile, and measuring movements. Table 3.2 presents load testing details.
Table 3.2: Static load test program
Criteria Attributes
Design Load 40 Ton
Target test load 2.5 X Design load=100 Ton
Type of pile Reinforced concrete pre-cast pile
Dimension 300mmX300mm (12”X12”)
Method of installation Impact hammering
41
Criteria Attributes
Driving equipment Skid mounted pile driver
Hammer detail Drop hammer
Hammer weight=3.5 Ton
Drop height=5 Ft (max)
Compressive loads are applied by hydraulic jacking against a weighted platform. The
primary means of measuring the load applied to the pile should be with a calibrated
load cell. The jack load should also be recorded from a calibrated pressure gauge. Axial
pile movements are usually measured by dial gages that measure the movement
between the pile head and an independently supported reference beam.
Figure 3.10: Schematic diagram of typical arrangement of applying load in an axial compressive test
42
The steps are to be followed is given below:
Arrangement of instrument and calibration.
Preparation of mass of heavy material, termed “Kentledge” is placed on
platform.
Installation of reference beam
Finish pile top for seating hydraulic jack, installation of pile collar, placement
of jack, dial gauges and strain gauges and reading.
Taking safety measures.
3.6.1 Loading sequence
Detailed loading procedure is presented in ASTM D1143 for Maintained load (ML)
test. The general procedure is to apply static loads in increments of 25% of the
anticipated design load (BNBC-2015). According to ASTM D1143 each load
increment is maintained until the rate of settlement is not greater than 0.25mm/hr or 2hr
is elapsed, whichever occurs first. This procedure is applied for all increment of load.
After completion of loading if the test pile has not failed the total test load is removed
any time after twelve hours if the butt settlement over one hour period is not greater
than 0.25mm otherwise the total test load is kept on the pile for 24 hours. After the
required holding time, the test load is removed in decrement of 25% of the total test
load with 1 hour between decrement. If failure occurs, jacking the pile is continued
until the settlement equals 15% of the pile diameter or diagonal dimension.
43
Table 3.3: Typical loading sequence arrangement for pile load test.
Design Load (kip)=80 Design Load (kg)=40,000 Test Load(kg)=100,000 Diameter of ram (cm)=24.13 Area of ram (cm2)=457.30 Regression equation: Y actual(kg/ cm2)=1.019X(kg/ cm2)-5.561
Loading steps
Theoretical As planned
% of Design Load
Load (kg)
Required Pressure (kg/ cm2)
Required Corrected Pressure (kg/ cm2)
Observed
Pressure (kg/ cm2)
Load (kg)
% of Design Load
Holding Time
Reading Intervals
1st increment 25 10,000 21.87 26.92 25 9,107 22.77 A/B 10 min
2nd increment 50 20,000 43.73 48.38 50 20,757 51.89 A/B 10 min
3rd increment 75 30,000 65.60 69.84 70 30,076 75.19 A/B 10 min
4th increment 100 40,000 87.47 91.30 90 39,396 98.49 A/B 10 min
5th increment 125 50,000 109.34 112.76 115 51,046 127.62 A/B 10 min
6th increment 150 60,000 131.20 134.21 135 60,366 150.91 A/B 10 min
7th increment 175 70,000 153.07 155.67 155 69,698 174.21 A/B 10 min
8th increment 200 80,000 174.94 177.13 180 81,336 203.34 A/B 10 min
9th increment 225 90,000 196.81 198.59 200 90,655 226.64 A/B 10 min
10th increment 250 100,000 218.67 220.05 220 99,975 249.94 C D
1st decrement 187.5 75,000 164.00 166.40 165 74,346 185.86 20 min 10 min
2nd decrement 125 50,000 109.34 112.76 115 51,046 127.62 20 min 10 min
3rd decrement 62.5 25,000 54.67 59.11 60 25,416 63.54 20 min 10 min
4th decrement 0 0 0.00 0.00 0 0 0.00 1 hr 10 min Notes: Holding time: A= Any time, if the rate of settlement is less than 0.25 mm/hr B= Max 2 hr if the rate of settlement is greater than 0.25 mm/hr C= Any time after 12 hr if the butt settlement is not greater than 0.25mm in 1 hr but otherwise 24 hr Reading time: D= At interval 10 min for 1st 1 hr for next 10 hr, 2hr for next 12 hr When pile fails: If the pile fails at any load the pile will be jacked up to 15% of pile diagonal/diameter of settlement.
44
3.7 Data Collection
Data was collected for both precast and cast-in-situ piles were done following the flow diagram.
Figure 3.11: Schematic diagram of data collection for precast and cast in situ piles.
Precast pile
Two piles were tested for both dynamic and static load test at Tangail site. All the soil
investigation report, static load test, dynamic load test data were collected for these two
piles. Total fifteen precast pile data (pile length and cross section), soil investigation
report, dynamic load test data were collected from Public Works Department (PWD).
The Table 3.4 shows the collected data and predicted pile capacity based on different
method.
DATA COLLECTION
SOIL
TEST REPORT
PILE DETAILS DYNAMIC LOAD TEST (PDA)
1. BNBC-2015 (SPT)
2. BNBC-2015 (STATIC BEARING)
3. AASHTO-2002
CAPWAP ANALYSIS
COMPARE & CORELATE
CAPACITY CALCULATION
45
Table 3.4: Data summary for precast pile
SL No
Project name
Pile data Pile capacity
calculated (kN) Collected
capacity CAPWAP
(kN)
Length
(m)
Section
(m x m)
Pile ID BNBC-2015
Static Beari
ng SPT
1 Nursing College, Pabna
21.34 0.3 X 0.3 P-26
(H-07) 793 857 991
2 Nursing College, Pabna
21.34 0.3 X 0.3 P-04 (G-07) 1770 1386 1756
3 Sadar Hospital, Manikganj
13.72 0.3 X 0.3 PC-4 P-4 645 777 822
4 Sadar Hospital, Manikganj
13.72 0.3 X 0.3 PC-8B P-134 624 803 788
5 Sadar Hospital, Manikganj
13.72 0.3 X 0.3 PC-5 P-67 710 840 1158
6 Sadar Hospital, Manikganj
13.72 0.3 X 0.3 PC-4 P-218 603 812 654
7 Teachers Training College, Shariatpur
16.16 0.35 X 0.35
TP-02 834 937 846
8 Teachers Training College, Shariatpur
16.16 0.35 X 0.35
TP-04 867 907 879
9 Bangabandhu Textile Institute, Tangail
13.72 0.3 X 0.3 P-24 1083 1224 1214
10 Bangabandhu Textile Institute, Tangail
13.72 0.3 X 0.3 P-141 649 774 500
11 Keraniganj Sub Jail 12 0.3 X 0.3 TP-2 659 1034 905
12 Cox’s bazar Medical College
12 0.3 X 0.3 TP-2 1282 1310 1402
13 Cox’s bazar 12 0.3 X 0.3 TP-3 1065 1036 1192
14 Medical College 12 0.3 X 0.3 TP-5 1475 1464 1644
15 Teachers Training College, Barguna
16.7 0.35 X 0.35
P-106 1141 1091 1128
Source: Icon Engineering services
Cast-in situ pile
Recently, Padma multipurpose bridge project service area-2, Mogbazar flyover project
and few other projects used dynamic load test. For cast-in situ piles total ten dynamic
load test, soil investigation report and pile data (pile length and cross section) were
46
collected for capacity calculation. Table 3.5 presents the collected data and capacity
calculation based on different method.
Table 3.5: Data summary for cast-in-situ pile
SL No
Project Name
Pile Data Pile capacity calculated
(kN) Collected Capacity
CAPWAP (kN)
Diameter (m)
Length (m)
BNBC-2015 SPT
BNBC-2015 Static bearin
g AASHTO-2002
1 Walton Office, Basundhara, Dhaka *
0.5 28.5 1503 1435 2130 2118
2 Titas Railway Bridge, Akhaura *
1.2 30.8 5036 6016 4984 5000
3 Padma Bridge, Naodoba, Zazira, Shariatpur *
1.2 29.5 3141 4291 4924 3520
4 Mogbazar Fly over, Dhaka*
1.2 29.5 4911 4204 6328 5043
5 Mogbazar Fly over, Dhaka*
1.5 44.4 9185 7907 10936 10374
6 Mogbazar Fly over, Dhaka*
1.2 44 6516 6611 8009 7221
7 Dhaka Road research Lab( P1) #
1 22.5 2280 2753 3406 2196
8 Dhaka Road research Lab(P2) #
1 28 3987 3221 3630 4589
9 Zinzira-Nawabganj Bridge (LRP,P3) #
1 23.7 4005 3339 3784 3635
10 Zinzira-Nawabganj Bridge (LRP,P4) #
1.2 24 5239 2760 3854 3408
Source: * Icon Engineering services, # Prosoil
3.8 Summary
The test program focuses on two test pile which will provide adequate information
regarding pile capacity. After load test confirmation both static and dynamic will allow
the opportunity to compare with the predicted capacity by different methods in detail.
Later data collection of soil test report, pile details and CAPWAP capacity will be done
for both precast and cast in situ piles. Pile capacity prediction by different method will
be done using the collected data which will be compared with CAPWAP capacity.
47
CHAPTER 4
RESULTS AND DISCUSSIONS
4.1 General
In this study, the main focus is to determine compressive load capacity of piles using
different existing methods of pile capacity estimation and compare with dynamic and
static load test. In this chapter pile capacity calculation was done based on BNBC-
2015(Static bearing capacity and SPT methods) and AASHTO-2002. For selected two
precast test pile capacity was predicted and later compared with CAPWAP and static
load test. Later part of the study uses collected data for capacity prediction and
correlate with CAPWAP capacity for precast and cast in situ piles.
4.2 Pile Capacity of Precast Piles Using Driving Equations
Using pile driving record the capacity was calculated for two testing piles. In this test
drop hammer weight was 3.5 ton. Piles were marked per 0.3m (1'-0'') interval and lifted
by one point lifting at 4.5m from the top. After fixing the pile with the tripod stand the
hammer dropped from height varying from 0.6m (2'-0'') to max 1.52m (5'-0''). From the
driving chart it was evident that the pile section penetrated up to 4.57m (15'-0'') by self-
weight. Next each penetration of 0.3m (1'-0'') required 12 to 37 numbers of blows.
Engineers News Formula, Janbu and Gates formula was used for capacity calculation.
In the Engineering News formula efficiency of drop hammer value 0.75 was considered
according to Bowles (1997). Resistance under working load was calculated using
equation 2.36. In this formula only weight of ram, point penetration per blow, height of
ram need to be considered. Engineering News and Janbu equations are based on
impulse momentum principles with various assumptions. The calculations of pile
capacity based on the driving formulas are attached in the Appendix-C.
4.3 Pile Capacity Using PDA Test Results
Dynamic testing on the piles was conducted by striking the piles by several blows.
During testing of pile, complete dynamic measurements were obtained for each
hammer blow delivered to the pile. The input of a weave equation analysis consists of
information about the soil, pile, hammer, cushions, and any other devices which
participates in the transfer of energy from hammer to soil.
48
In this test re-strike method was applied on driven pile. Before testing the upper portion
of pile 150mm to 225mm (6'' to 9'') was recast and a smooth top was prepared for
maintain level for hammer impact over pile top properly. Weight of the hammer was
1600kg. The sensor both strains gages and accelerometers were placed 0.6m (2'-0'')
below the pile top. Height of fall was 1m. For analysis pile segment was divided into
six segments. Ply wood was used as cushion material in two layers each was 16mm
thick. Elastic modulus of pile material was considered 23500 MPa. Wave speed and
specific weight of concrete was 3500 m/s and 24.5 kN/m3 consecutively. Soil
parameters like quake skin, quake toe, damping skin, damping toe was used as the
default values provided by PDA.
In Figure 4.1 hammer blows were given to TP-1 and all the records were measured.
Capacity found at the field PDA is represented by Rsu=1346 kN and Rmx=1408kN.
The degree of convergence between the force and velocity records is expressed by the
BTA (Beta value) integrity value as a percentage of the approximate reduce cross
sectional area. Pile integrity, BTA, value reading 100% indicate no damage was
present.
Table 4.1: Beta value for pile integrity (Rausche and Goble, 1979).
Beta value Pile condition
100% OK
60% -80% Slightly damage
≤60% Damage
49
Figure: 4.1: Force and velocity record for TP-1.
For TP-2 hammer blows were given and data was collected. Pile integrity BTA is 73%
which indicate pile defect i.e. reduction of cross section area. Capacity found at the
field PDA is represented by Rsu=1317 kN and Rmx=569kN. The data record of force
and velocity presented in the Figure 4.2. The PDA measures the total (static and
dynamic) resistance acting on the pile. Table 4.2 shows the pile capacity using PDA.
Table 4.2: Capacity of piles using PDA.
Capacity (kN) TP-1(P-24) TP-2(P-141)
Rsu 1396 1317
Rmx 1408 569
50
Figure 4.2: Force and velocity record for TP-2
4.4 CAPWAP Analysis
CAPWAP (CAse Pile Wave Analysis Program) is a signal matching procedure based
on pile top force and velocity measurements during hammer impact, extracts static and
dynamic soil resistance parameters for pile shaft and toe. It refines the raw data of PDA
by signal matching procedure through iteration. In Figure 4.3 and 4.4 shows CAPWAP
force wave matching was done for TP-1 and TP-2. A reasonable matching was done in
shaft, toe resistance, total resistance and soil unloading behaviour starting from zone 1
to 4. A large separation between force and velocity record in Figure 4.5 suggests a large
shaft resistance on the pile. From the analysis the shaft resistance was found 1213.6 kN
and toe resistance 297.9 kN which support the point.
51
Figure 4.3: CAPWAP Iteration force matched graph for TP-1
A rigorous CAPWAP analysis of the data acquired from the PDA, confirmed that the
pile had achieved an activated CAPWAP capacity of 1213.6 KN.
In Figure 4.5 showed a reasonable match of force wave. Though both zone 2 and zone
3 disagrees slightly regarding matching. The resulting model will fairly estimate static
pile capacity, soil resistance distribution, soil quake and damping characteristics.
Figure 4.4: CAPWAP Iteration force matched graph for TP-2
From the Figure 4.5 it was found that a minimum separation occurred between the
force and velocity records between time O, or the time of impact and time 2L/c. Hence
this record indicated a minimum shaft and tow resistance on the pile. A rigorous
52
CAPWAP analysis of the data acquired from the PDA, confirmed that the pile had
achieved an activated CAPWAP capacity of 499.9 kN. There is a 45.11% reduction of
pile impedance at around 4.0m below the sensors which indicates a major defect.
Figure 4.5: Investigation of pile damage and beta factor
Table 4.3: Summary of dynamic test
Test pile ID TP-1 TP-2
Type of Testing Restrike
Blow Number 5 4
Pile Length (m) 13.719 13.719
Le (m) 13.10 13.10
Lp (m) 13.70 13.70
Max Comp. stress (MPa) 20.40 12.20
Set (DFN) (mm) 3.00 3.00
CAPWAP Capacity
Shaft (kN) 915.7 369.4
Toe (kN) 297.9 130.5
Total (kN) 1213.6 499.9
53
4.5 Pile Capacity from Pile Load Test
Static pile capacity was determined in the TP-1 and TP-2 piles. Design load was 40 ton
and the target load was 2.5 times the design load i.e. 100 ton. Using the test settlement
under working load, adequacy of bearing capacity will be ensured. Maintained load test
were performed to accomplish the above objectives.
In case of TP-1 loading was done in ten consecutive steps which produce settlement 8.9
mm at a final loading of 99,975 kg for 12 hour. The unloading causes a 3.57 mm
permanent settlement. One cycle of loading and unloading was done for the load test.
During the test the settlement was within the capacity of the pile which suggests the
pile capacity is more than the design load arrangement. After the test the Davission
offset method applied which shows no point of failure. Other methods were applied for
calculating the pile capacity.
Figure 4.6: Load settlement graph for pile load test TP-1
In case of TP-2 one cycle of loading was done up to design load and unload was done.
Later pile load was increased up to the test load previously set. At load 90,318 kg load
settlement was 37.96mm. After the unloading it experience 30.03 mm permanent set.
0
2
4
6
8
10
12
14
16
18
200 15 30 45 60 75 90 105 120
Pile
set
tlem
ent (
mm
)
Load (MT)
Davission offset line, out of range
54
Figure 4.7: Load settlement graph for pile load test TP-2
For TP-1 ultimate capacity pile is more than 1000 kN and for TP-2 capacity was
derived using different methods. The capacity trend of static load test is similar to the
CAPWAP analysis. The pile load test summary is given below for the two piles in
Table 4.4.
Table 4.4: Test result summary
Pile ID
Capacity Ton (kN)
Davission Offset
BS 8004 IS: 2911 Butler and Hoy
Brinch Hansen
TP-1 Out of range Out of range
Out of range Out of range Out of range
TP-2 81 Ton
(807 kN)
88.5 Ton
(881 kN)
78 Ton
(777 kN)
79 Ton
(787 kN)
+90 Ton
(896 kN)
Table 4.5 presents the pile capacity for two piles in different methods. From the Table
4.4 shows that pile capacity using Janbu formula provides higher capacity for both
piles.
0
5
10
15
20
25
30
35
400 15 30 45 60 75 90 105 120
Pile
set
tlem
ent (
mm
)
Load (MT)
Davission offset line
55
Table 4.5: Pile capacities from driving formulas
Formulas used Total resistance
TP-1(kN)
Total resistance
TP-2(kN)
Engineering News 804 792
Janbu 1790 1733 Gates 1049 1026 CAPWAP(Dynamic) 1213 500 Static (Average) 1000 830
However, Engineers News formula provides the least capacity value. Gates formula
provides closer values comparing with the CAPWAP dynamic analysis. However,
driving formulas fail to provide information of pile condition during driving. Static pile
load test resembles with the CAPWAP capacity for the two piles though the capacity
differs maximum 40%.
4.6 Pile Capacity Summary
Fifteen dynamic test data of precast pile were collected. In the data predicted pile
capacity, CAPWAP analysis was available. By observing the collected data the
following comments were made.
1. There is good co-relation exist with the BNBC-15 methods with the CAPWAP
capacity, which is shown in Figure 4.8 and 4.9. For BNBC-15 Static method an
equation was developed as CAPWAP capacity =1.10X BNBC 2015 Static capacity and
r2=0.81.
For the case of BNBC SPT the equation was developed as CAPWAP capacity=1.06X
BNBC 2015 SPT capacity and r2=0.77.
2. Generally, BNBC-2015 Static capacity method under predict precast pile capacities
most of the times (87%) comparing with the CAPWAP capacity.
3. CAPWAP analysis suggests that due to layer change in same vicinity pile capacity
can be different. That is also reflected in the calculation of BNBC-2015 static bearing
method.
56
4. CAPWAP analysis shows exact precast piles capacity considering the integrity of
pile, as well as soil damping, driving and other relevant issues. If during driving the
pile is injured it shows the integrity by beta value. Predicted pile capacity can very
considering these variable which is beyond the scope of traditional equations based on
soil parameter.
Figure 4.8: Correlation between CAPWAP and BNBC 2015 (static bearing) pile
capacity for precast pile
CAPWAP capacity= 1.10xBNBC2015 Static Capacityr² = 0.81
0
250
500
750
1000
1250
1500
0 250 500 750 1000 1250 1500
CA
PW
AP
cap
acit
y (k
N)
BNBC-2015 Static bearing capacity(kN)
57
Figure 4.9: Correlation between CAPWAP and BNBC 2015 (SPT) and pile capacity for precast pile
4.7 Comparison with Collected Data for Cast-In-Situ Piles
Data of ten cast-in-situ piles were collected. In the data predicted pile capacity,
CAPWAP analysis was also available. Following observations were found
1. In case of cast-in-situ piles the predicted capacity generally agrees with the
CAPWAP capacity.
2. There is very good co-relation exist between BNBC-2015 static bearing capacity of
pile with the CAPWAP capacity for these cast-in-situ piles. The equation was
developed as CAPWAP capacity=1.15X BNBC 20215 static capacity and r2=0.81
which is shown in Figure 4.10.
CAPWAP capacity = 1.06x BNBC 2015 SPT capacityr² = 0.77
0
250
500
750
1000
1250
1500
1750
2000
0 250 500 750 1000 1250 1500 1750 2000
CA
PW
AP
cap
acit
y (k
N)
BNBC-2015 SPT capacity(kN)
58
Figure 4.10: Correlation between CAPWAP and BNBC-2015 (static bearing) capacity.
3. The co-relation between BNBC-2015 SPT cast-in-situ pile and CAPWAP is
developed as CAPWAP capacity=1.04X BNBC SPT capacity and r2=0.89 which is
shown by Figure 4.11.
4. The co-relation between AASHTO-2002 cast-in-situ pile and CAPWAP is developed
as CAPWAP capacity=0.91X AASHTO 2002 capacity and r2=0.92 which is presented
by Figure 4.12.
CAPWAP capacity = 1.15x BNBC 2015 Static bearing capacity r² = 0.81
0
2000
4000
6000
8000
10000
0 2000 4000 6000 8000 10000
CA
PW
AP
cap
acit
y (k
N)
BNBC-2015 Static bearing capacity(kN)
59
Figure 4.11: Correlation between CAPWAP capacity and BNBC-2015 SPT capacity for cast-in-situ pile
Figure 4.12: Correlation between CAPWAP and AASHTO-2002 pile capacity for cast-in-situ piles.
4.8 Summary
There is a very good co-relationship exist with static pile load test and dynamic load
test which is evident in this case. In a mega project where pile number is huge it is very
CAPWAP capacity = 1.04x BNBC 2015 SPTcapacityr² = 0.89
0
2000
4000
6000
8000
10000
0 2000 4000 6000 8000 10000
CA
PW
AP
cap
acit
y (k
N)
BNBC-2015 SPT capacity(kN)
CAPWAP capacity = 0.91x AASHTO 2002 capacity r² = 0.92
0
2000
4000
6000
8000
10000
0 2000 4000 6000 8000 10000
CA
PW
AP
cap
acit
y (k
N)
AASHTO capacity(kN)
60
difficult to carry out the static load test frequently due to shortage of money or time.
Application of dynamic test may be appropriate in those conditions.
In the upcoming BNBC-2015 the static bearing capacity method and SPT methods are
presented as a guideline for calculating both precast and cast-in-situ piles. Geotechnical
experts over the years are familiar with the AASHTO-2002 method for practicing real
life work. Considering both soil test report and CAPWAP analysis co-relationships
were established for precast and cast-in-situ piles. Further study is necessary in this
regard to validate proposed equations of BNBC-2015.
During the study it was found that beta value is a very good indicator for pile integrity.
In case of cast-in-situ piles it shows the casting quality and in case of precast pile it
suggests the pile condition after driving. This is an excellent tool need to be utilized
properly by our professionals.
61
CHAPTER 5
CONCLUSIONS
5.1 General
The aim of the study was to determine the ultimate pile load capacity using Pile
Dynamic Analyzer (PDA) along with static load test which is very common in our
country. For the two test pile (precast) this was done together with the driving
equations, BNBC-2015 guideline and AASHTO-2002. Later for fifteen precast pile and
ten cast-in-situ pile CAPWAP analysis, BNBC-2015 capacity, AASHTO-2002 capacity
was also used to summarized and establish co-relations.
5.2 Concluding Remarks
Pile capacity was calculated for two test piles (TP-1 and TP-2) of this study using
driving record. In each method the capacity of two piles are close. It suggests that soil
variation in those two piles were not considered in driving equations. Each driving
equation shows same pair of pile capacity values derived from Engineer’s News, Janbu
and Gates formula. However, inconsistency of capacity was observed. Results suggest
that these methods should not be applied due to large inconsistency in capacity
prediction.
Capacity from static pile load test and dynamic load test for the two piles are close. In
case of capacity obtained from BNBC-2015 guidelines and AASHTO-2002 fails to
match with TP-2 but aggress well with TP-1. From dynamic load test it was found that
beta factor for TP-1 was 100% and beta factor for TP-2 was 73%. This suggests TP-2
has major defects. It can be concluded that predicted pile capacity can vary widely if
piles were not properly casted (in case of cast-in-situ pile) or driven (in case of precast
pile) maintaining quality.
In case of collected sample data analysis of soil test report, Dynamic Load Test,
BNBC-2015 and AASHTO-2002 very useful co-relationships has been established. It
can be improved by further study.
62
5.3 Recommendations
From the lessons of the present study, the recommendations for future study may be
summarized as follows:
In this study, only the capacity of piles was estimated and compared but the
effect of soil ‘set-up’ (change of soil strength and adhesion) was not considered. Thus
considering the effect of soil set-up modified pile capacity can be studied. This can be
done by assessing a pile capacity after a time interval using dynamic load test.
In our country selection of pile hammer depends on the availability of hammer.
Proper selection of hammer or study is necessary for driving a pile without damaging it.
This can be ensured by using PDA data of energy transfer ratio, pile stress and other
indicator for optimize the appropriate diesel hammer. Application of drop hammer
should be restricted for important projects.
Attention should be given to beta values from the PDA during driving and take
note any possible damage on the driving record. That will reduce the chance of
overdriving of piles.
There is no study for selection of damping factor and quake value for
Bangladesh for CAPWAP analysis. Only prescribed guideline is used for signal
matching. There is a scope to develop site specific factors for Bangladesh.
Though dynamic analysis is already use in our country there is no guideline in
BNBC-2015. There should be a guideline along with standard to use it efficiently.
63
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67
APPENDIX A
PILE DRIVING RECORDS OF TP-1 AND TP-2
68
PILE DRIVING RECORD OF TP-1
Name of the project: Bangabondhu Textile Engineering College Tangail, (Boys hostel) Location of the project: Kalihati Tangail Pile length: 45ft (13.71m) Pile section: 12”X12”(300 mm X300mm) Weight of hammer: 3.5 Ton Hammer Type: Drop hammer
Table B1: Pile driving data of TP-1
Pile id no Depth driven (ft) Height of fall (ft) Number of blows Remarks
TP-1 1 - -
Pile
penetrated
due to self-
weight only.
2 - - 3 - - 4 - - 5 - - 6 - - 7 - - 8 - -
9 - - 10 - - 11 2 1 12 2 1 13 2 1 14 4 2 15 4 2 16 4 2 17 4 2 18 4 3 19 4 3 20 4 3 21 4 3 22 4 4 23 4 4 24 4 4 25 4 5 26 4 5 27 4 6 28 4 7 29 4 8 30 4 9 31 4 10 32 4 14 33 4 15 34 4 17
69
Pile id no Depth driven (ft) Height of fall (ft) Number of blows Remarks
35 4 24 36 4 26 37 4 24 38 4 22 39 4 24 40 5 26 41 5 32 42 5 33 43 5 35 44 5 36 45 5 40
70
PILE DRIVING RECORD OF TP-2
Name of the project: Bangabondhu Textile Engineering College Tangail , (Boys hostel) Location of the project: Kalihati Tangail Pile length: 45ft (13.71m) Pile section: 12”X12” (300 mm X300mm) Weight of hammer: 3.5 Ton Hammer Type: Drop hammer
Table B2: Pile driving data of TP-2
Pile id no Depth driven (ft) Height of fall (ft) Number of blows Remarks
TP-2 1 - -
Pile
penetrated
due to self-
weight only.
2 - - 3 - - 4 - - 5 - - 6 - - 7 - - 8 - - 9 - - 10 - - 11 2 1 12 2 1 13 2 1 14 4 2 15 4 2 16 4 2 17 4 2 18 4 3 19 4 3 20 4 3 21 4 3 22 4 4 23 4 4 24 4 4 25 4 5 26 4 5 27 4 6
28 4 8 29 4 9 30 4 9 31 4 11 32 4 13 33 4 15 34 4 19
35 4 21
71
Pile id no Depth driven (ft) Height of fall (ft) Number of blows Remarks
36 4 22 37 4 24 38 4 26
TP-2 39 4 27 40 5 25 41 5 30 42 5 32 43 5 35 44 5 35 45 5 37
72
APPENDIX B
CAPACITY CALCULATION OF TWO TEST PILES USING DRIVING EQUATIONS
73
1.A) ENGINEERING NEWS FORMULA (TP-1)
Weight of ram, Wh = 3.5 Ton
Number of blows for last one feet of penetration = 40 Nos
Penetration of pile under last blow of hammer, s = 0.30 in
Height of fall of ram, H = 5 ft
Resistance under working load, R = Wh.H/(s+1)
= 13.46 Ton
= 134 kN FS=6
Ultimate capacity = 804 kN
1.B) ENGINEERING NEWS FORMULA (TP-2)
Weight of ram, Wh = 3.5 Ton
Number of blows for last one feet of penetration = 37 Nos
Penetration of pile under last blow of hammer, s = 0.32 in
Height of fall of ram, H = 5 ft
Resistance under working load, R = Wh.H/(s+1)
= 13.21 Ton
= 132 kN FS=6
Ultimate capacity = 792 kN
2.A) JANBU FORMULA (TP-1)
Pile area, A = 144 sqin
Length of pile, L = 45 ft
Weight of pile, Wp = 6.75 kip
Compressive strength of concrete, f'c = 3500 psi
Modulus of elasticity of concrete, Ec = 57500√3500
= 3401746 psi
= 3402 Ksi
AE = 489851 Kip
cd = 0.75+0.15(Wp/Wr)
= 0.75
74
For drop hammer, eh = 0.75
Weight of hammer = 7.00 kip
Height of fall = 5.00 ft
Eh = 35.00 ft-lb
s = 0.30
λ = ehEhL/AEs2
= 3.86
ku = Cd(1+√(1+(λ/Cd))
= 2.61
Pu = ehEh/kus
= 402.44 Kip
= 1790.12 kN
Fs = 4.5
2.B) JANBU FORMULA (TP-2)
Pile area, A = 144 sqin
Length of pile, L = 45 ft
Weight of pile, Wp = 6.75 kip
Compressive strength of concrete, f'c = 3500 psi
Modulus of elasticity of concrete,Ec = 57500√3500
= 3401746 psi
= 3402 Ksi
AE = 489851 Kip
cd = 0.75+0.15(Wp/Wr)
= 0.75
For drop hammer, eh = 0.75
Weight of hammer = 7.00 kip
Height of fall = 5.00 ft
Eh = 35.00 ft-lb
s = 0.32
λ = ehEhL/AEs2
= 3.30
ku = Cd(1+√(1+(λ/Cd))
75
= 2.49
Pu = ehEh/kus
= 389.57 Kip
= 1732.89 kN
Fs = 4.5
3.A) GATES FORMULA (TP-1)
Pu = a√(ehEh(b-logs)
s a b
FPS in 27 1
Hammer wt = 7 kip
Drop of hammer = 5 ft
Eh = 35 kip-ft
eh = 0.75
s = 0.30 in/blow
SF = 3
Pu = 210.67 Kip
= 1049.55 kN
3.B) GATES FORMULA (TP-2)
Pu = a√(ehEh(b-logs)
s a b
FPS in 27 1
Hammer wt = 7 kip
Drop of hammer = 5 ft
Eh = 35 kip-ft
eh = 0.75
s = 0.32 in/blow
SF = 3
Pu = 205.98 Kip
= 1026.21 kN
76
APPENDIX C
CAPACITY CALCULATION OF PRECAST PILES
(BNBC 2015 STATIC FORMULA AND SPT METHOD)
77
SL No : 1 (Precast pile) Method
: BNBC-2015 Static formula (α and β method)
Site
: Pabna Pile ID : P-26(H -07) Pile sec : 0.3mX0.3m Length : 21.34m
Soil Profile and properties Bore Hole Data of BH-5
Soil Depth
(m) SPT ϕ °
sil 1.5 4 24
3 3 23
Clay 4.5 2
silt 6 2 21
7.5 4 24
Clay 9 5
10.5 11 30
12 17 33
13.5 21 35
silt 15 18 34
16.5 16 33
18 11 30
Clay 19.5 13
silt 21 13 31
Avg Angle of internal friction ϕ = 29
Friction factor β= 0.10 Confirm from chart
Unit wt of soil γ= 17.29 kN/m3
Unit skin friction f = 17.45 kPa (Equation 2.8)
Skin friction Q = 400 kN (Equation 2.2)
Bearing capacity factor N = 28 (L/d=71)
Effective vertical stress σ = 174.49≤240 kPa=174.49 kPa
Unit end bearing f = 4886 kN/m2 (Equation 2.11)
End bearing Q = 468 kN (Equation 2.3)
Weight of pile W= 46 kN
Total ultimate capacity 𝐐𝐮𝐥𝐭= 857 kN (Equation 2.1)
78
SL No : 2 (Precast pile) Method
: BNBC-2015 Static formula (α and β method)
Site
: Pabna Pile ID : P-04(G -07) Pile sec : 0.3mX0.3m Length : 22.5m
Soil Profile and properties Bore Hole Data of BH-6
Soil Depth
(m) SPT φ°
Cu (kPa)
α
1.5 3 23
ML 3 4 24
4.5 2 21
6 4 24
7.5 5 25
CL 9 3 23 72.78 0.50
10.5 12 30
12 14 32
ML 13.5 18 34
15 19 34
16.5 12 30
CL 18 14 32 134.06 0.5
19.5 16 33
SM 21 19 34
22.5 25 37
Angle of friction ϕ = 29 (Avg)
Friction factor β= 0.11 Confirm from chart
Unit wt of soil γ= 17.29 kN/m3
Unit skin friction f = 17.45kPa(1-4.5m), 36.39kPa(6-
2m),3.71kPa(12-5m),67.03kPa(16.5-19.5m)
(Equation 2.8)
and fs=α cu
Skin friction Q = 833 kN (Equation 2.2)
Bearing capacity N = 65 (L/d=75)
Effective stress σ = 168≤240 kPa=168 kPa
Unit end bearing f = 10951 kN/m2 (Equation 2.11)
End bearing Q = 986 kN (Equation 2.3)
Weight of pile W= 49 kN
Total ultimate capacity 𝐐𝐮𝐥𝐭= 1770 kN (Equation 2.1)
79
SL No : 3 (Precast pile) Method
: BNBC-2015 Static formula (α and β method)
Site
: Manikgonj Pile ID : PC-4 P-4 Pile sec : 0.3mX0.3m Length : 13.72m
Soil Profile and properties Bore Hole Data of BH-1
Soil Depth
(m) SPT ϕ°
1.5 2 21
Silt 3 1 19
4.5 1 19
6 2 21
7.5 4 24
9 12 30
10.5 14 32
SM 12 16 33
13.5 18 34
Avg Angle of internal friction ϕ = 26
Friction factor β= 0.11 Confirm from chart
Unit wt of soil γ= 17.29 kN/m3
Unit skin friction f = 12.92 kPa (Equation 2.8)
Skin friction Q = 178 kN (Equation 2.2)
Bearing capacity factor N = 47 (L/d=46)
Effective vertical stress σ = 117≤240 kPa=117 kPa
Unit end bearing f = 5519 kN/m2 (Equation 2.11)
End bearing Q = 497 kN (Equation 2.3)
Weight of pile W= 30 kN
Total ultimate capacity 𝐐𝐮𝐥𝐭= 645 kN (Equation 2.1)
80
SL No : 4 (Precast pile) Method
: BNBC-2015 Static formula (α and β method)
Site
: Manikgonj Pile ID : PC-8B P-134 Pile sec : 0.3mX0.3m Length : 13.72m
Soil Profile and properties Bore Hole Data of BH-2
Soil Depth
(m) SPT ϕ°
1.5 1 19
Silt 3 1 19
4.5 2 21
6 2 21
7.5 6 26
9 8 28
10.5 11 30
Sand 12 15 32
13.5 17 33
Avg Angle of internal friction ϕ = 26
Friction factor β= 0.11 Confirm from chart
Unit wt of soil γ= 17.29 kN/m3
Unit skin friction f = 12.92 kPa (Equation 2.8)
Skin friction Q = 178 kN (Equation 2.2)
Bearing capacity factor N = 45 (L/d=46)
Effective vertical stress σ = 117≤240 kPa=117 kPa
Unit end bearing f = 5285 kN/m2 (Equation 2.11)
End bearing Q = 497 kN (Equation 2.3)
Weight of pile W= 30 kN
Total ultimate capacity 𝐐𝐮𝐥𝐭= 624 kN (Equation 2.1)
81
SL No : 5 (Precast pile) Method
: BNBC-2015 Static formula (α and β method)
Site
: Manikgonj Pile ID : PC-5 P-67 Pile sec : 0.3mX0.3m Length : 13.72m
Soil Profile and properties Bore Hole Data of BH-2
Soil Depth
(m) SPT 𝛟 °
1.5 1 19
ML 3 2 21
4.5 2 21
6 2 21
7.5 4 24
9 7 27
10.5 8 28
SM 12 17 33
13.5 18 34
Avg Angle of internal friction ϕ = 25
Friction factor β= 0.11 Confirm from chart
Unit wt of soil γ= 17.29 kN/m3
Unit skin friction f = 11.74 kPa (1-6m),11.74 Kpa (Equation 2.8)
Skin friction Q = 233 kN (Equation 2.2)
Bearing capacity factor N = 48 (L/d=46)
Effective vertical stress σ = 117≤240 kPa=117 kPa
Unit end bearing f = 5637 kN/m2 (Equation 2.11)
End bearing Q = 507 kN (Equation 2.3)
Weight of pile W= 30 kN
Total ultimate capacity 𝐐𝐮𝐥𝐭= 710 kN (Equation 2.1)
82
SL No : 6 (Precast pile) Method
: BNBC-2015 Static formula (α and β method)
Site
: Manikgonj Pile ID : PC-4 P-218 Pile sec : 0.3mX0.3m Length : 13.72m
Soil Profile and properties Bore Hole Data of BH-4
Soil Depth
(m) SPT
𝛟 °
1.5 4 24
Silt 3 4 24 (MH)
4.5 1 19
6 2 21
7.5 4 24
9 8 28
10.5 12 30
Sand 12 14 32 (SM)
13.5 17 33
Avg Angle of internal friction ϕ = 26
Friction factor β= 0.11 Confirm from chart
Unit wt of soil γ= 17.29 kN/m3
Unit skin friction f = 12.92 Kpa (Equation 2.8)
Skin friction Q = 178 kN (Equation 2.2)
Bearing capacity factor N = 43 (L/d=46)
Effective vertical stress σ = 117≤240 kPa=117 kPa
Unit end bearing f = 5050 kN/m2 (Equation 2.11)
End bearing Q = 454 kN (Equation 2.3)
Weight of pile W= 30 kN
Total ultimate capacity 𝐐𝐮𝐥𝐭= 603 kN (Equation 2.1)
83
SL No : 7 (Precast pile) Method
: BNBC-2015 Static formula (α and β method)
Site
: Shariat Pile ID : TP -02 Pile sec : 0.35mX0.35m Length : 16.16m
Soil Profile and properties Bore Hole Data of BH-1
Soil Depth
(m) SPT 𝛟 °
1.5 3 23
ML 3 3 23
4.5 10 29
6 7 27
7.5 8 28
9 20 35
10.5 8 28
SM 12 14 32
13.5 15 32
15 18 34
16.5 14 32
Avg Angle of internal friction ϕ = 29
Friction factor β= 0.11 Confirm from chart
Unit wt of soil γ= 17.29 kN/m3
Unit skin friction f = 14.93 Kpa (Equation 2.8)
Skin friction Q = 283 kN (Equation 2.2)
Bearing capacity factor N = 36 (L/d=46)
Effective vertical stress σ = 136≤240 kPa=136 kPa
Unit end bearing f = 4885 kN/m2 (Equation 2.11)
End bearing Q = 598 kN (Equation 2.3)
Weight of pile W= 48 kN
Total ultimate capacity 𝐐𝐮𝐥𝐭= 834 kN (Equation 2.1)
84
SL No : 8 (Precast pile) Method
: BNBC-2015 Static formula (α and β method)
Site
: Shariat Pile ID : TP -4 Pile sec : 0.35mX0.35m Length : 16.16m
Soil Profile and properties Bore Hole Data of BH-2
Soil Depth
(m) SPT 𝛟 °
1.5 4 24
ML 3 2 21
4.5 8 28
6 4 24
7.5 8 28
9 17 33
10.5 14 32
SM 12 18 34
13.5 16 33
15 20 35
16.5 15 32
Avg Angle of internal friction ϕ = 29
Friction factor β= 0.11 Confirm from chart
Unit wt of soil γ= 17.29 kN/m3
Unit skin friction f = 14.93 Kpa (Equation 2.8)
Skin friction Q = 283 kN (Equation 2.2)
Bearing capacity factor N = 38 (L/d=46)
Effective vertical stress σ = 136≤240 kPa=136 kPa
Unit end bearing f = 5157 kN/m2 (Equation 2.11)
End bearing Q = 632 kN (Equation 2.3)
Weight of pile W= 48 kN
Total ultimate capacity 𝐐𝐮𝐥𝐭= 867 kN (Equation 2.1)
85
SL No : 9 (Precast pile) Method
: BNBC-2015 Static formula (α and β method)
Site
: Tangail Pile ID : P -24 Pile sec : 0.35mX0.35m Length : 16.16m
Soil Profile and properties Bore Hole Data of BH-1
Soil Depth
(m) SPT
𝛟 °
1.5 2 21
Silt 3 5 25 (ML)
4.5 9 28
6 10 29
7.5 16 33
9 18 34
10.5 19 34
Sand 12 18 34 (SM)
13.5 19 34
Avg Angle of internal friction ϕ = 30
Friction factor β= 0.11 Confirm from chart
Unit wt of soil γ= 17.29 kN/m3
Unit skin friction f = 12.92 Kpa (Equation 2.8)
Skin friction Q = 161 kN (Equation 2.2)
Bearing capacity factor N = 90
Effective vertical stress σ = 117≤240 kPa=117 kPa
Unit end bearing f = 10569 kN/m2 (Equation 2.11)
End bearing Q = 951 kN (Equation 2.3)
Weight of pile W= 30 kN
Total ultimate capacity Q = 1083 kN (Equation 2.1)
86
SL No : 10 (Precast pile) Method
: BNBC-2015 Static formula (α and β method)
Site
: Tangail Pile ID : P -141 Pile sec : 0.3mX0.3m Length : 13.7m
Soil Profile and properties Bore Hole Data of BH-6
Soil Depth
(m) SPT 𝛟 °
Silt 1.5 5 25 (MH)
3 7 27
4.5 9 28
6 10 29
7.5 11 30
9 16 33
10.5 14 32
Sand 12 10 29 (SM)
13.5 13 31
Avg Angle of internal friction ϕ = 29
Friction factor β= 0.1 Confirm from chart
Unit wt of soil γ= 17.29 kN/m3
Unit skin friction f = 11.73 Kpa (Equation 2.8)
Skin friction Q = 161 kN (Equation 2.2)
Bearing capacity factor N = 49 L/d=46
Effective vertical stress σ = 117≤240 kPa=117 kPa
Unit end bearing f = 5747 kN/m2 (Equation 2.11)
End bearing Q = 517 kN (Equation 2.3)
Weight of pile W= 30 kN
Total ultimate capacity 𝐐𝐮𝐥𝐭= 649 kN (Equation 2.1)
87
SL No : 11 (Precast pile) Method
: BNBC-2015 Static formula (α and β method)
Site
: Keranigonj Pile ID : TP -2 Pile sec : 0.3mX0.3m Length : 12m
Soil Profile and properties Bore Hole Data of BH-2
Soil Depth
(m) SPT 𝛟 °
1.5 6 26
3 6 26
Silt 4.5 5 25
6 7 27
7.5 8 28
9 16 33
10.5 17 33
Sand 12 17 33
13.5 19 34
15 20 35
Avg Angle of internal friction ϕ = 30
Friction factor β= 0.1 Confirm from chart
Unit wt of soil γ= 17.29 kN/m3
Unit skin friction f = 11.73 Kpa (Equation 2.8)
Skin friction Q = 161 kN (Equation 2.2)
Bearing capacity factor N = 50 L/d=46
Effective vertical stress σ = 117≤240 kPa=117 kPa
Unit end bearing f = 5864 kN/m2 (Equation 2.11)
End bearing Q = 528 kN (Equation 2.3)
Weight of pile W= 30 kN
Total ultimate capacity 𝐐𝐮𝐥𝐭= 659 kN (Equation 2.1)
88
SL No : 12 (Precast pile) Method
: BNBC-2015 Static formula (α and β method)
Site
: Coxs Bazar Pile ID : TP -02 Pile sec : 0.3mX0.3m Length : 12m
Soil Profile and properties Bore Hole Data of BH-2
Soil Depth
(m) SPT 𝛟 °
1.5 4 24
3 2 21
4.5 5 25
Sand 6 10 29
7.5 25 37
9 19 34
10.5 20 35
12 26 38
Avg Angle of internal friction ϕ = 31
Friction factor β= 0.1 Confirm from chart
Unit wt of soil γ= 17.29 kN/m3
Unit skin friction f = 10.46 Kpa (Equation 2.8)
Skin friction Q = 122 kN (Equation 2.2)
Bearing capacity factor N = 126 L/d=40
Effective vertical stress σ = 104≤240 kPa=104 kPa
Unit end bearing f = 13174 kN/m2 (Equation 2.11)
End bearing Q = 1186 kN (Equation 2.3)
Weight of pile W= 26 kN
Total ultimate capacity 𝐐𝐮𝐥𝐭= 1282 kN (Equation 2.1)
89
SL No : 13 (Precast pile) Method
: BNBC-2015 Static formula (α and β method)
Site
: Coxs Bazar Pile ID : TP -03 Pile sec : 0.3mX0.3m Length : 12m
Soil Profile and properties Bore Hole Data of BH-34
Soil Depth
(m) SPT 𝛟 °
1.5 1 19
3 3 23
silt 4.5 3 23
6 5 25
7.5 5 25
9 6 26
10.5 16 33
Sand 12 5 25
13.5 24 37
Avg Angle of internal friction ϕ = 26
Friction factor β= 0.1 Confirm from chart
Unit wt of soil γ= 17.29 kN/m3
Unit skin friction f = 11.58 Kpa (Equation 2.8)
Skin friction Q = 156 kN (Equation 2.2)
Bearing capacity factor N = 90 L/d=45
Effective vertical stress σ = 116≤240 kPa=116 kPa
Unit end bearing f = 10421 kN/m2 (Equation 2.11)
End bearing Q = 938 kN (Equation 2.3)
Weight of pile W= 29 kN
Total ultimate capacity Q = 1065 kN (Equation 2.1)
90
SL No : 14 (Precast pile) Method
: BNBC-2015 Static formula (α and β method)
Site
: Coxs Bazar Pile ID : TP -05 Pile sec : 0.3mX0.3m Length : 12m
Soil Profile and properties Bore Hole Data of BH-1
Soil Depth
(m) SPT
φ°
silt 1.5 4 24
3 2 21
4.5 5 25
6 10 29
7.5 25 37
9 19 34
10.5 20 35
Sand 12 26 38
13.5 32 40
Avg Angle of internal friction ϕ = 32
Friction factor β= 0.1 Confirm from chart
Unit wt of soil γ= 17.29 kN/m3
Unit skin friction f = 3.37 Kpa (Equation 2.8)
Skin friction Q = 45 kN (Equation 2.2)
Bearing capacity factor N = 140 L/d=45
Effective vertical stress σ = 116≤240 kPa=116 kPa
Unit end bearing f = 16210 kN/m2 (Equation 2.11)
End bearing Q = 1459 kN (Equation 2.3)
Weight of pile W= 29 kN
Total ultimate capacity 𝐐𝐮𝐥𝐭= 1475 kN (Equation 2.1)
91
SL No : 15 (Precast pile) Method
: BNBC-2015 Static formula (α and β method)
Site
: Borguna Pile ID : P-106 Pile sec : 0.35mX0.35m Length : 16.7 : 16.7m
Soil Profile and properties Bore Hole Data of BH-1
Soil Depth
(m) SPT 𝛟 °
1.5 1 19
3 1 19
4.5 2 21
6 2 21
7.5 4 24
9 8 28
10.5 11 30
Sand 12 11 30
13.5 14 32
15 14 32
16.5 17 33
Avg Angle of internal friction ϕ = 26
Friction factor β= 0.1 Confirm from chart
Unit wt of soil γ= 17.29 kN/m3
Unit skin friction f = 3.93 Kpa (Equation 2.8)
Skin friction Q = 77 kN (Equation 2.2)
Bearing capacity factor N = 65 L/d=45
Effective vertical stress σ = 140≤240 kPa=140 kPa
Unit end bearing f = 9084 kN/m2 (Equation 2.11)
End bearing Q = 1113 kN (Equation 2.3)
Weight of pile W= 49 kN
Total ultimate capacity 𝐐𝐮𝐥𝐭= 1141 kN (Equation 2.1)
92
SL No : 1 (Precast pile) Method
: BNBC-2015 SPT Based
Site
: Pabna Pile ID : P-26(H -07) Pile sec : 0.3mX0.3m Length : 21.34m
Soil Profile and properties Bore Hole Data of BH-5
Soil Depth
(m) SPT
silt 1.5 4
3 3
Clay 4.5 2
silt 6 2
7.5 4
Clay 9 5
10.5 11
12 17
13.5 21
silt 15 18
16.5 16
18 11
Clay 19.5 13
silt 21 13
Average N-value N = 10
N-value at pile tip N = 13
Unit skin friction f = 17 kPa≤60 kPa (Equation 2.15)
Unit end bearing f =
=
27742 kPa ≤5200 kPa ≤11000 kPa
5200 kPa
(Equation 2.17)
Skin friction Q = 435 kN (Equation 2.2)
End bearing Q = 468 kN (Equation 2.3)
Weight of pile W= 46 kN
Total ultimate capacity 𝐐𝐮𝐥𝐭= 857 kN (Equation 2.1)
93
SL No : 2 (Precast pile) Method
: BNBC-2015 SPT Based
Site
: Pabna Pile ID : P-04(G -07) Pile sec : 0.3mX0.3m Length : 22.5m
Soil Profile and properties Bore Hole Data of BH-6
Soil Depth
(m) SPT
𝐍𝟔𝟎
1.5 3 3 silt 3 4
4.5 2
6 4
8 7.5 5
Clay 9 3
10.5 12
12 14
silt 13.5 18 19
15 19
16.5 12 14 Clay 18 14
19.5 16
21 19
Sand 22.5 25 22
Average N-value N = As per table
N-value at pile tip N = 25
Unit skin friction f = 5. kPa (0-4.5m);13.68 kPa (4.5m-12m),31.45
kPa (13.5-15m),25.2 kPa (16.5-19.5m),37.40
kPa (21m-End)
(Equation
2.15&2.12)
Unit end bearing f =
=
75000 kPa ≤10000 kPa ≤11000 kPa
10000 kPa
(Equation
2.17)
Skin friction Q = 535kN (Equation 2.2)
End bearing Q = 900 kN (Equation 2.3)
Weight of pile W= 49 kN
Total capacity 𝐐𝐮𝐥𝐭= 1386 kN (Equation 2.1)
94
SL No : 3 (Precast pile) Method
: BNBC-2015 SPT Based
Site
: Manikgonj Pile ID : PC-4 P-4 Pile sec : 0.3mX0.3m Length : 13.72m
Soil Profile and properties Bore Hole Data of BH-1
Soil Depth
(m) SPT 𝐍𝟔𝟎
1.5 2
Silt 3 1
4.5 1
6 2
2
7.5 4
9 12
10.5 14
Sand 12 16 15
13.5 18
Average N-value N = As per table
N-value at pile tip N = 17
Unit skin friction f = 3.6 kPa (1-7.5m);30 kPa (9m-
13.5m)
(Equation 2.12 &
2.14)
Unit end bearing f =
=
34986 kPa ≤6800 kPa ≤11000 kPa
6800 kPa
(Equation 2.17)
Skin friction Q = 194 kN (Equation 2.2)
End bearing Q = 612 kN (Equation 2.3)
Weight of pile W= 30 kN
Total ultimate capacity 𝐐𝐮𝐥𝐭= 777 kN (Equation 2.1)
95
SL No : 4 (Precast pile) Method
: BNBC-2015 SPT Based
Site
: Manikgonj Pile ID : PC-8B P-134 Pile sec : 0.3mX0.3m Length : 13.72m
Soil Profile and properties Bore Hole Data of BH-2
Soil Depth
(m) SPT 𝐍𝟔𝟎
1.5 1
Silt 3 1
4.5 2
6 2 2
7.5 6
9 8
10.5 11
Sand 12 15 13
13.5 17
Average N-value N = As per table
N-value at pile tip N = 17
Unit skin friction f = 4.08 kPa (silt);25.50 kPa (sand) (Equation 2.15 &
2.14)
Unit end bearing f =
=
31098 kPa ≤6800 kPa ≤11000 kPa
6800 kPa
(Equation 2.16)
Skin friction Q = 220 kN (Equation 2.2)
End bearing Q = 612 kN (Equation 2.3)
Weight of pile W= 30 kN
Total ultimate capacity 𝐐𝐮𝐥𝐭= 803 kN (Equation 2.1)
96
SL No : 5 (Precast pile) Method
: BNBC-2015 SPT Based
Site
: Manikgonj Pile ID : PC-5 P-67 Pile sec : 0.3mX0.3m Length : 13.72m
Soil Profile and properties Bore Hole Data of BH-2
Soil Depth
(m) SPT 𝐍𝟔𝟎
1.5 1
Silt 3 1
4.5 2
6 2 2
7.5 6
9 8
10.5 11
Sand 12 15 13
13.5 17
Average N-value N = As per table
N-value at pile tip N = 18
Unit skin friction f = 2.98 kPa (silt);21.60 kPa (sand) (Equation 2.15 &
2.14)
Unit end bearing f =
=
32928 kPa ≤7200 kPa ≤11000 kPa
7200 kPa
(Equation 2.16)
Skin friction Q = 222 kN (Equation 2.2)
End bearing Q = 648 kN (Equation 2.3)
Weight of pile W= 30 kN
Total ultimate capacity 𝐐𝐮𝐥𝐭= 840 kN (Equation 2.1)
97
SL No : 6 (Precast pile) Method
: BNBC-2015 SPT Based
Site
: Manikgonj Pile ID : PC-4 P-218 Pile sec : 0.3mX0.3m Length : 13.72m
Soil Profile and properties Bore Hole Data of BH-4
Soil Depth
(m) SPT 𝐍𝟔𝟎
1.5 4
Silt 3 4
4.5 1
6 2 3
7.5 4
9 8
10.5 12
Sand 12 14 13
13.5 17
Average N-value N = As per table
N-value at pile tip N = 17
Unit skin friction f = 5.10 kPa (silt);25.50 kPa (sand) (Equation 2.15 &
2.14)
Unit end bearing f =
=
31098 kPa ≤6800 kPa ≤11000 kPa
6800 kPa
(Equation 2.16)
Skin friction Q = 229 kN (Equation 2.2)
End bearing Q = 612 kN (Equation 2.3)
Weight of pile W= 30 kN
Total ultimate capacity 𝐐𝐮𝐥𝐭= 812 kN (Equation 2.1)
98
SL No : 7 (Precast pile) Method
: BNBC-2015 SPT Based
Site
: Shariat Pile ID : TP -02 Pile sec : 0.35mX0.35m Length : 16.16m
Soil Profile and properties Bore Hole Data of BH-1
Soil Depth
(m) SPT 𝐍𝟔𝟎
1.5 3
Silt 3 3
4.5 10
6 7 6
7.5 8
9 20
Silty 10.5 8
Sand 12 14 15
13.5 15
15 18
16.5 14
Average N-value N = As per table
N-value at pile tip N = 14
Unit skin friction f = 10.54 kPa (silt);29.67 kPa (sand) (Equation 2.15 &
2.14)
Unit end bearing f =
=
19392 kPa ≤4200 kPa ≤11000 kPa
4200 kPa
(Equation 2.16)
Skin friction Q = 470 kN (Equation 2.2)
End bearing Q = 515 kN (Equation 2.3)
Weight of pile W= 48 kN
Total ultimate capacity 𝐐𝐮𝐥𝐭= 937 kN (Equation 2.1)
99
SL No : 8 (Precast pile) Method
: BNBC-2015 SPT Based
Site
: Shariat Pile ID : TP -4 Pile sec : 0.35mX0.35m Length : 16.16m
Soil Profile and properties Bore Hole Data of BH-2
Soil Depth
(m) SPT 𝐍𝟔𝟎
1.5 4
ML 3 2
4.5 8
6 4 5
7.5 8
9 17
10.5 14
SM 12 18 17
13.5 16
15 20
16.5 15
Average N-value N = As per table
N-value at pile tip N = 15
Unit skin friction f = 8.84 kPa (silt);33.33 kPa (sand) (Equation 2.15 &
2.14)
Unit end bearing f =
=
20777 kPa ≤4500 kPa ≤11000 kPa
4500 kPa
(Equation 2.16)
Skin friction Q = 404 kN (Equation 2.2)
End bearing Q = 551 kN (Equation 2.3)
Weight of pile W= 48 kN
Total ultimate capacity 𝐐𝐮𝐥𝐭= 907 kN (Equation 2.1)
100
SL No : 9 (Precast pile) Method
: BNBC-2015 SPT Based
Site
: Tangail Pile ID : P -24 Pile sec : 0.35mX0.35m Length : 16.16m
Soil Profile and properties Bore Hole Data of BH-1
Soil Depth
(m) SPT 𝐍𝟔𝟎
1.5 2
Silt 3 5
4.5 9
6 10 15
7.5 16
9 20
10.5 22
Sand 12 22
13.5 25
Average N-value N = As per table
N-value at pile tip N = 25
Unit skin friction f = 24.74 kPa (Equation 2.15)
Unit end bearing f =
=
45667 kPa ≤10000 kPa ≤11000 kPa
10000 kPa
(Equation 2.16)
Skin friction Q = 353 kN (Equation 2.2)
End bearing Q = 900 kN (Equation 2.3)
Weight of pile W= 30 kN
Total ultimate capacity 𝐐𝐮𝐥𝐭= 1224 kN (Equation 2.1)
101
SL No : 10 (Precast pile) Method
: BNBC-2015 SPT Based
Site
: Tangail Pile ID : P -141 Pile sec : 0.3mX0.3m Length : 13.7m
Soil Profile and properties Bore Hole Data of BH-6
Soil Depth
(m) SPT 𝐍𝟔𝟎
1.5 5
Silt 3 7 6
4.5 9
6 10 12
7.5 11
9 16
10.5 14
Sand 12 10
13.5 13
Average N-value N = As per table
N-value at pile tip N = 13
Unit skin friction f = 10.20 kPa (silt), 23.71 kPa(sand) (Equation 2.15 &
2.14)
Unit end bearing f =
=
23747 kPa ≤5200 kPa ≤11000 kPa
5200 kPa
(Equation 2.16)
Skin friction Q = 336 kN (Equation 2.2)
End bearing Q = 468 kN (Equation 2.3)
Weight of pile W= 30 kN
Total ultimate capacity 𝐐𝐮𝐥𝐭= 774 kN (Equation 2.1)
102
SL No : 11 (Precast pile) Method
: BNBC-2015 SPT Based
Site
: Keranigonj Pile ID : TP -2 Pile sec : 0.3mX0.3m Length : 12m
Soil Profile and properties Bore Hole Data of BH-2
Soil Depth
(m) SPT 𝐍𝟔𝟎
1.5 6
3 6
4.5 5
Silt 6 7 8
7.5 8
9 16
10.5 17
Sand 12 17
13.5 19 18
15 20
Average N-value N = As per table
N-value at pile tip N = 20
Unit skin friction f = 13.60 kPa (silt), 36.50 kPa(sand) (Equation 2.15 &
2.14)
Unit end bearing f =
=
36533 kPa ≤8000 kPa ≤11000 kPa
8000 kPa
(Equation 2.16)
Skin friction Q = 344 kN (Equation 2.2)
End bearing Q = 720 kN (Equation 2.3)
Weight of pile W= 30 kN
Total ultimate capacity 𝐐𝐮𝐥𝐭= 1034 kN (Equation 2.1)
103
SL No : 12 (Precast pile) Method
: BNBC-2015 SPT Based
Site
: Coxs Bazar Pile ID : TP -02 Pile sec : 0.3mX0.3m Length : 12m
Soil Profile and properties Bore Hole Data of BH-2
Soil Depth
(m) SPT 𝐍𝟔𝟎
1.5 4
3 2
4.5 5
Sand 6 10 14
7.5 25
9 19
10.5 20
12 26
Average N-value N = As per table
N-value at pile tip N = 26
Unit skin friction f = 27.75 kPa(sand) (Equation 2.14)
Unit end bearing f =
=
41600 kPa ≤10400 kPa ≤11000 kPa
10400 kPa
(Equation 2.16)
Skin friction Q = 400 kN (Equation 2.2)
End bearing Q = 936 kN (Equation 2.3)
Weight of pile W= 26 kN
Total ultimate capacity 𝐐𝐮𝐥𝐭= 1310 kN (Equation 2.1)
104
SL No : 13 (Precast pile) Method
: BNBC-2015 SPT Based
Site
: Coxs Bazar Pile ID : TP -03 Pile sec : 0.3mX0.3m Length : 12m
Soil Profile and properties Bore Hole Data of BH-34
Soil Depth
(m) SPT 𝐍𝟔𝟎
1.5 1
3 3
Silt 4.5 3
6 5 3
7.5 5
9 6
10.5 16
Sand 12 5 11
13.5 24
Average N-value N = As per table
N-value at pile tip N = 24
Unit skin friction f = 5.10kPa (silt),22.40 kPa(sand) (Equation 2.14 &
2.15)
Unit end bearing f =
=
38400 kPa ≤9600 kPa ≤11000 kPa
9600 kPa
(Equation 2.16)
Skin friction Q = 198 kN (Equation 2.2)
End bearing Q = 864 kN (Equation 2.3)
Weight of pile W= 26 kN
Total ultimate capacity 𝐐𝐮𝐥𝐭= 1036 kN (Equation 2.1)
105
SL No : 14 (Precast pile) Method
: BNBC-2015 SPT Based
Site
: Coxs Bazar Pile ID : TP -05 Pile sec : 0.3mX0.3m Length : 12m
Soil Profile and properties Bore Hole Data of BH-1
Soil Depth
(m) SPT 𝐍𝟔𝟎
1.5 4
silt 3 2
4.5 5
6 10 5
7.5 25
9 19
10.5 20 24
Sand 12 26
13.5 32
Average N-value N = As per table
N-value at pile tip N = 32
Unit skin friction f = 8.93kPa (silt),48.40 kPa(sand) (Equation 2.14 &
2.15)
Unit end bearing f =
=
57600 kPa ≤12800 kPa ≤11000 kPa
11000 kPa
(Equation 2.16)
Skin friction Q = 503 kN (Equation 2.2)
End bearing Q = 990 kN (Equation 2.3)
Weight of pile W= 29 kN
Total ultimate capacity 𝐐𝐮𝐥𝐭= 1464 kN (Equation 2.1)
106
SL No : 15 (Precast pile) Method
: BNBC-2015 SPT Based
Site
: Borguna Pile ID : P-106 Pile sec : 0.35mX0.35m Length : 16.7m
Soil Profile and properties Bore Hole Data of BH-1
Soil Depth
(m) SPT 𝐍𝟔𝟎
1.5 1
3 1
4.5 2
6 2 8
7.5 4
9 8
10.5 11
Silty 12 11
Sand 13.5 14
15 14
16.5 17
Average N-value N = As per table
N-value at pile tip N = 17
Unit skin friction f = 13.14 kPa(sand) (Equation 2.15)
Unit end bearing f =
=
24334 kPa ≤6800 kPa ≤11000 kPa
6800 kPa
(Equation 2.16)
Skin friction Q = 307 kN (Equation 2.2)
End bearing Q = 833 kN (Equation 2.3)
Weight of pile W= 49 kN
Total ultimate capacity 𝐐𝐮𝐥𝐭= 1091 kN (Equation 2.1)
107
APPENDIX D
CAPACITY CALCULATION OF BORED PILES
(BNBC 2015 AND AASHTO 2002 METHOD)
108
SL No : 1 (Bored pile) Method
: BNBC-2015 SPT Based
Site
: Walton Office, Basundhara, Dhaka Pile ID : TP-01 Pile diameter : 0.5m Length : 28.5m
Soil Profile and properties Bore Hole Data of BH-2
Soil Depth
(m) SPT 𝐍𝟔𝟎
1.5 6 3 4 4.5 8
Clay 6 7 7.5 2 9.1 9 12 10.5 7 12 21 13.5 15 15 19
Sand 16.5 20 23 18 24 19.5 24 21 26 22.5 26 24 25 25.5 25 27 24 28.5 24
Unit skin friction f = 10.93 kPa(Clay), 22.75 kPa (Sand) (Equation 2.24 & 2.26)
Skin friction Q = 767 kN (Equation 2.2)
Unit end bearing f =
=
21375 kPa ≤ 3750 kPa ≤4000 kPa
3750 kPa
(Equation 2.28)
End bearing Q = 736 kN (Equation 2.3)
Weight of pile W= 134 kN
Total capacity 𝐐𝐮𝐥𝐭= 1503 kN (Equation 2.1)
109
SL No : 2 (Bored pile) Method
: BNBC-2015 SPT Based
Site
: Titas Railway Bridge, Akhaura Pile ID : Pile No-19 Pile diameter : 1.2 m Length : 30.8m
Soil Profile and properties Bore Hole Data of BH-2
Soil Depth
(m) SPT 𝐍𝟔𝟎
1.5 1 Silt 3 1 1
4.5 1 Clay 6 1 2
7.5 4 9 4 10.5 17 12 10 13.5 17 15 22
Silt 16.5 6 18 6 19.5 19 18 21 15 22.5 28 24 19 25.5 27 27 26 28.5 26 30 26
Unit skin friction f = 0.9 kPa(Sand), 2.40 kPa (Clay),16.08 kPa
(Silt)
(Equation
2.26,2.24 & 2.27)
Skin friction Q = 1463 kN (Equation 2.2)
Unit end bearing f =
=
6673 kPa ≤ 3900 kPa ≤4000 kPa
3900 kPa
(Equation 2.27)
End bearing Q = 4409 kN (Equation 2.3)
Weight of pile W= 836 kN
Total capacity 𝐐𝐮𝐥𝐭= 5036 kN (Equation 2.1)
110
SL No : 3 (Bored pile) Method
: BNBC-2015 SPT Based
Site
: Padma Bridge, Naodoba, Zazira Pile ID : Bridge 01 Abutment 02 Pile diameter : 1.2 m Length : 29.5m
Soil Profile and properties Bore Hole Data of BH-8
Soil Depth
(m) SPT 𝐍𝟔𝟎
1.5 2 3 7 4.5 6 6 12 7.5 10 9 8 10.5 8
Silty 12 9 12 Sand 13.5 18
15 7 16.5 11 18 15 19.5 18 21 10 22.5 16 24 16 25.5 24 27 24
Unit skin friction f = 11.05 kPa (Equation 2.27)
Skin friction Q = 1228 kN (Equation 2.2)
Unit end bearing f =
=
5900 kPa ≤ 2400 kPa ≤4000 kPa
2400 kPa
(Equation 2.29)
End bearing Q = 2713 kN (Equation 2.3)
Weight of pile W= 800 kN
Total capacity 𝐐𝐮𝐥𝐭= 3141 kN (Equation 2.1)
111
SL No : 4 (Bored pile) Method
: BNBC-2015 SPT Based
Site
: Mogbazar Fly over, Dhaka Pile ID : TP-2 Pile diameter : 1.2 m Length : 29.5m
Soil Profile and properties Bore Hole Data of BH-43
Soil Depth
(m) SPT 𝐍𝟔𝟎
2 15
Clay 6 12 13
8 11
10 12
12 19
14 20
16 23
18 20 22.4
Sand 20 22
22 27
24 30
27 29
30 22
Unit skin friction f = 15.20 kPa (Clay), 20.16 kPa(Silt) (Equation 2.24&
2.27)
Skin friction Q = 3730 kN (Equation 2.2)
Unit end bearing f =
=
8112 kPa ≤ 3300 kPa ≤4000 kPa
3300 kPa
(Equation 2.28)
End bearing Q = 3730 kN (Equation 2.3)
Weight of pile W= 800 kN
Total capacity 𝐐𝐮𝐥𝐭= 4911 kN (Equation 2.1)
112
SL No
:
5 (Bored pile)
Method
: BNBC-2015 SPT Based
Site
: Mogbazar Fly over, Dhaka Pile ID : P-114 Pile diameter : 1.5 m Length : 44m
Soil Profile and properties Bore Hole Data of BH-43
Soil Depth
(m) SPT 𝐍𝟔𝟎
2 15
Clay 6 12 13
8 11
10 12
12 19
14 20
16 23
18 20 24
Sand 20 22
22 27
24 30
27 29
30 22
33 28
37 28
40 27
44 27
Unit skin friction f = 15.20 kPa (Clay), 21.47 kPa(Silt) (Equation 2.24& 2.27)
Skin friction Q = 3985 kN (Equation 2.2)
Unit end bearing f =
=
11880 kPa ≤ 4050 kPa ≤4000 kPa
4000 kPa
(Equation 2.28)
End bearing Q = 7065 kN (Equation 2.3)
Weight of pile W= 1865 kN
Total capacity 𝐐𝐮𝐥𝐭= 9185 kN (Equation 2.1)
113
SL No
:
6 (Bored pile)
Method
: BNBC-2015 SPT Based
Site
: Mogbazar Fly over, Dhaka Pile ID : P-180 Pile diameter : 1.2 m Length : 44m
Soil Profile and properties Bore Hole Data of BH-43
Soil Depth
(m) SPT 𝐍𝟔𝟎
2 15
Clay 6 12 13
8 11
10 12
12 19
14 20
16 23
18 20 24
Sand 20 22
22 27
24 30
27 29
30 22
33 28
37 28
40 27
44 27
Unit skin friction f = 15.20 kPa (Clay), 21.47 kPa(Silt) (Equation 2.24& 2.27)
Skin friction Q = 3188 kN (Equation 2.2)
Unit end bearing f =
=
14850 kPa ≤ 4050 kPa ≤4000 kPa
4000 kPa
(Equation 2.28)
End bearing Q = 4522 kN (Equation 2.3)
Weight of pile W= 1194 kN
Total capacity 𝐐𝐮𝐥𝐭= 6516 kN (Equation 2.1)
114
SL No
:
7 (Bored pile)
Method
: BNBC-2015 SPT Based
Site
: Dhaka Road Research Lab Pile ID : P1 Pile diameter : 1.2 m Length : 44m
Soil Profile and properties Bore Hole Data of BH-1
Soil Depth
(m) SPT 𝐍𝟔𝟎
1.5 7
3 12 11
Clay 4.5 7
6 13
7.5 16
9 27
10.5 26
12 19 21
Sand 13.5 23
15 22
16.5 22
18 23
19.5 21
21 12
22.5 14
Unit skin friction f = 13.20 kPa (Clay), 18.81 kPa(Silt) (Equation 2.24& 2.27)
Skin friction Q = 3188 kN (Equation 2.2)
Unit end bearing f =
=
4725 kPa ≤ 2100 kPa ≤4000 kPa
2100 kPa
(Equation 2.28)
End bearing Q = 1648 kN (Equation 2.3)
Weight of pile W= 424 kN
Total capacity 𝐐𝐮𝐥𝐭= 2280 kN (Equation 2.1)
115
SL No
:
8 (Bored pile)
Method
: BNBC-2015 SPT Based
Site
: Dhaka Road Research Lab Pile ID : P2 Pile diameter : 1.2 m Length
: 44m Soil Profile and properties Bore Hole Data of BH-1
Soil Depth
(m) SPT 𝐍𝟔𝟎
1.5 7 3 12 11
Clay 4.5 7 6 13 7.5 16 9 27 10.5 26 12 19 22
Sand 13.5 23 15 22 16.5 22 18 23 19.5 21 21 12 22.5 14 24 24 25.5 27 27 26 28.5 26
Unit skin friction f = 13.20 kPa (Clay), 20.06 kPa(Silt) (Equation 2.24& 2.27)
Skin friction Q = 1453 kN (Equation 2.2)
Unit end bearing f =
=
10920 kPa ≤ 3900 kPa ≤4000 kPa
3900 kPa
(Equation 2.28)
End bearing Q = 3062 kN (Equation 2.3)
Weight of pile W= 528 kN
Total capacity 𝐐𝐮𝐥𝐭= 3987 kN (Equation 2.1)
116
SL No
:
9 (Bored pile)
Method
: BNBC-2015 SPT Based
Site
: Zinzira-Nawabganj (Bridge LRP) Pile ID : P3 Pile diameter : 1 m Length : 23.7m
Soil Profile and properties Bore Hole Data of BH-1
Soil Depth
(m) SPT
𝐍𝟔𝟎
1.5 5 Clay 3 11 6
4.5 3 6 5 7.5 7 9 6 10.5 23
12 25 26.8
Sand 13.5 24 15 31 16.5 24 18 29 19.5 29 21 28 22.5 28 24 27 25.5 27
Unit skin friction f = 7.40 kPa (Clay), 24.14 kPa(Silt) (Equation 2.24& 2.27)
Skin friction Q = 1311 kN (Equation 2.2)
Unit end bearing f =
=
9599 kPa ≤ 4050 kPa ≤4000 kPa
4000 kPa
(Equation 2.28)
End bearing Q = 3140 kN (Equation 2.3)
Weight of pile W= 446 kN
Total capacity 𝐐𝐮𝐥𝐭= 4005 kN (Equation 2.1)
117
SL No
:
10 (Bored pile)
Method
: BNBC-2015 SPT Based
Site
: Zinzira-Nawabganj (Bridge LRP) Pile ID : P4 Pile diameter : 1 m Length : 23.7m
Soil Profile and properties Bore Hole Data of BH-43
Soil Depth
(m) SPT 𝐍𝟔𝟎
1.5 3 Clay 3 2 6
4.5 4 6 4 7.5 8 9 15 10.5 20
12 21 22
Sand 13.5 24 15 22 16.5 23 18 17 19.5 24 21 22 22.5 20 24 27 25.5 27
Unit skin friction f = 7.20 kPa (Clay), 20.21 kPa(Silt) (Equation 2.24& 2.27)
Skin friction Q = 1369 kN (Equation 2.2)
Unit end bearing f =
=
8100 kPa ≤ 4050 kPa ≤4000 kPa
4000 kPa
(Equation 2.28)
End bearing Q = 4522 kN (Equation 2.3)
Weight of pile W= 651 kN
Total capacity 𝐐𝐮𝐥𝐭= 5239 kN (Equation 2.1)
118
SL No : 1 (Bored pile) Method
: α and β method (BNBC-2015)
Site
: Walton Office, Basundhara, Dhaka Pile ID : TP-01 Pile diameter : 0.5m Length : 28.5m
Soil Profile and properties
Bore Hole Data of BH-2
Adhesion factor α= 0.55 (Table 2.2)
Effective vertical stress σ = 162.86 kpa ( mid soil layer)
Friction factor for overburden β = 0.35 (Equation 2.23)
Skin friction f = 1.00 kpa (Clay), 55.12 kpa (Sand-1), 57.09 (Sand-2)
Total skin friction Q = 1275 kN (Equation 2.2)
Unit end bearing f = 27.30 kpa (Table 2.3)
Tip resistance Q = 294 kN [Q = qb
X Area of pile]
Weight of pile W= 134 kN
Total capacity Q = 1435 kN (Equation 2.1)
SoilDepth
(m)SPT γ Su(kpa)
z (m)
1.5 63 4
4.5 8Clay 6 7 17.3 1.8 6
7.5 29 12
10.5 712 21
13.5 1515 19
Sand 16.5 2018 24 17.3 22
19.5 2421 26
22.5 2624 25
25.5 2527 24
28.5 24
119
SL No
:
2 (Bored pile)
Method
: α and β method (BNBC-2015)
Site
: Titas Railway Bridge, Akhaura Pile ID : Pile No-19 Pile diameter : 1.2 m Length : 30.8m
Soil Profile and properties Bore Hole Data of BH-2
Adhesion factor α= 0.55 (Table 2.2)
Effective vertical stress σ = 134.78 kpa ( mid soil layer)
Friction factor for overburden β= 1.20 (1-3m),0.41 (9-30.8m) (Equation 2.23)
Skin friction f = 13.46 kpa (1-3m), 19.15 kpa(3-7.5m),55.48 kpa (7.5
-30.8m)
Total skin friction Q = 5020 kN (Equation 2.2)
Unit end bearing f = 1620 kpa (Table 2.3)
Tip resistance Q = 1831 kN [Q = qb
X Area of pile]
Weight of pile W= 835 kN
Total capacity Q = 6016 kN (Equation 2.1)
SoilDepth
(m)SPT γ
Su kpa
z (m)
1.5 1Silt 3 1 17 1.5
4.5 1Clay 6 1 17 19.2
7.5 49 4
10.5 1712 10
13.5 1715 22
Silt 16.5 618 6
19.5 19 17 19.521 15
22.5 2824 19
25.5 2727 26
28.5 2630 26
120
SL No
:
3 (Bored pile)
Method
: α and β method (BNBC-2015)
Site
: Padma Bridge, Naodoba, Zazira Pile ID : Bridge 01 Abutment 02 Pile diameter : 1.2 m Length : 29.5m
Soil Profile and properties
Bore Hole Data of BH-8
Adhesion factor α= 0.55 (Table 2.2)
Effective vertical stress σ = 101.09 kpa ( mid soil layer)
Friction factor for overburden β= 0.59 (Equation 2.23)
Skin friction f = 60.09 kpa
Total skin friction Q = 3464 kN (Equation 2.2)
Unit end bearing f = 1440 kpa (Table 2.3)
Tip resistance Q = 1628 kN [Q = qb X Area of pile]
Weight of pile W= 800 kN
Total capacity 𝐐𝐮𝐥𝐭= 4291 kN (Equation 2.1)
Soil Depth (m) SPT γ z (m)
1.5 23 7
4.5 66 12
7.5 109 8
10.5 8Silty 12 9Sand 13.5 18 17.29 13.5
15 716.5 1118 15
19.5 1821 10
22.5 1624 16
25.5 2427 24
121
SL No : 4 (Bored pile) Method
: α and β method (BNBC-2015)
Site
: Mogbazar Fly over, Dhaka Pile ID : TP-2 Pile diameter : 1.2 m Length : 29.5m
Soil Profile and properties
Bore Hole Data of BH-43
Adhesion factor α= 0.38 (Table 2.2)
Effective vertical
stress
σ = 149.76 kpa ( mid soil layer)
Friction factor for
overburden
β= 0.40 (Equation 2.23)
Skin friction f = 46.09 kpa (Clay), 53.61 (Sand)
Total skin friction Q = 3512 kN (Equation 2.2)
Unit end bearing f = 1320 kpa (Table 2.3)
Tip resistance Q = 1492 kN [Q = qb X Area of pile]
Weight of pile W= 800 kN
Total capacity 𝐐𝐮𝐥𝐭= 4204 kN (Equation 2.1)
SoilDepth
(m)SPT γ
Su kpa
z (m)
2 15
Clay 6 12 17.3 121 4
8 11
10 12
12 19
14 20
16 23
18 20
Sand 20 22 17.3 20
22 27
24 30
27 29
30 22
122
SL No : 5 (Bored pile) Method
: α and β method (BNBC-2015)
Site
: Mogbazar Fly over, Dhaka Pile ID : P-114 Pile diameter : 1.5 m Length : 44m
Soil Profile and properties Bore Hole Data of BH-43
Adhesion factor α= 0.5 (Table 2.2)
Effective vertical stress σ = 187.20 kpa ( mid soil layer)
Friction factor for
overburden
β= 0.30 (Equation 2.23)
Skin friction f = 60.65 kpa (Clay), 45.09 (Sand)
Total skin friction Q = 6911 kN (Equation 2.2)
Unit end bearing f = 1620 kpa (Table 2.3)
Tip resistance Q = 2861 kN [Q = qb X Area of pile]
Weight of pile W= 1865 kN
Total capacity 𝐐𝐮𝐥𝐭= 7907 kN (Equation 2.1)
SoilDepth
(m)SPT γ
Su (kpa)
z (m)
2 15
Clay 6 12 17.3 121.3 4
8 11
10 12
12 19
14 20
16 23
18 20
Sand 20 22
22 27
24 30 17.3 25
27 29
30 22
33 28
37 28
40 27
44 27
123
SL No : 6 (Bored pile) Method
: α and β method (BNBC-2015) : Site
: Mogbazar Fly over, Dhaka Pile ID : P-180 Pile diameter : 1.2 m Length : 44m
Soil Profile and properties
Bore Hole Data of BH-43
Adhesion factor α= 0.52 (Table 2.2)
Effective vertical
stress
σ = 187.20 kpa ( mid soil layer)
Friction factor for
overburden
β= 0.27 (Equation 2.23)
Skin friction f = 63.07 kpa (Clay), 36.07 (Sand)
Total skin friction Q = 4780 kN (Equation 2.2)
Unit end bearing f = 1620 kpa (Table 2.3)
Tip resistance Q = 1831 kN [Q = qb X Area of pile]
Weight of pile W= 1194 kN
Total capacity 𝐐𝐮𝐥𝐭= 5416 kN (Equation 2.1)
SoilDepth
(m)SPT γ
Su kpa
z (m)
2 15Clay 6 12 17.3 121 4
8 1110 1212 1914 2016 2318 20
Sand 20 2222 2724 30 17.3 2527 2930 2233 2837 2840 2744 27
124
SL No : 7 (Bored pile) Method
: α and β method (BNBC-2015)
Site
: Dhaka Road Research Lab Pile ID : P1 Pile diameter : 1.2 m Length : 44m
Soil Profile and properties Bore Hole Data of BH-1
Adhesion factor α= 0.52 (Table 2.2)
Effective vertical stress σ = 108.58 kpa ( mid soil layer)
Friction factor for overburden β= 0.56 (Equation 2.23)
Skin friction f = 54.77 kpa (Clay), 63.06 (Sand)
Total skin friction Q = 2517 kN (Equation 2.2)
Unit end bearing f = 840 kpa (Table 2.3)
Tip resistance Q = 659 kN [Q = qb X Area of pile]
Weight of pile W= 424 kN
Total capacity 𝐐𝐮𝐥𝐭= 2752 kN (Equation 2.1)
SoilDepth
(m)SPT γ
Su kpa
z (m)
1.5 73 12 17 105 4.5
Clay 4.5 76 13
7.5 169 27
10.5 2612 19
Sand 13.5 23 17 1515 22
16.5 2218 23
19.5 2121 12
22.5 14
125
SL No
:
8 (Bored pile)
Method
: α and β method (BNBC-2015)
Site
: Dhaka Road Research Lab Pile ID : P2 Pile diameter : 1.2 m Length : 44m
Soil Profile and properties Bore Hole Data of BH-1
Adhesion factor α= 0.55 (Table 2.2)
Effective vertical stress σ = 112.32 kpa ( mid soil layer)
Friction factor for overburden β= 0.45 (Equation 2.23)
Skin friction f = 57.93 kpa (Clay), 51.03 (Sand)
Total skin friction Q = 2533 kN (Equation 2.2)
Unit end bearing f = 1560 kpa (Table 2.3)
Tip resistance Q = 1225 kN [Q = qb X Area of pile]
Weight of pile W= 537 kN
Total capacity 𝐐𝐮𝐥𝐭= 3221 kN (Equation 2.1)
SoilDepth
(m)SPT γ
Su kpa
z (m)
1.5 73 12 17.3 105 4.5
Clay 4.5 76 13
7.5 169 27
10.5 2612 19
Sand 13.5 23 17.3 1815 22
16.5 2218 23
19.5 2121 12
22.5 1424 24
25.5 2727 26
28.5 26
126
SL No : 9 (Bored pile) Method
: α and β method (BNBC-2015)
Site
: Zinzira-Nawabganj (Bridge LRP) Pile ID : P3 Pile diameter : 1 m Length m
: 23.7m
Soil Profile and properties Bore Hole Data of BH-1
Adhesion factor α= 0.7 (Table 2.2)
Effective vertical stress σ = 112.32 kpa ( mid soil layer)
Friction factor for overburden β= 0.30 (Equation 2.23)
Skin friction f = 41.34 kpa (Clay), 56.03 (Sand)
Total skin friction Q = 2557 kN (Equation 2.2)
Unit end bearing f = 1680 kpa (Table 2.3)
Tip resistance Q = 1319 kN [Q = qb
X Area of pile]
Weight of pile W= 537 kN
Total capacity 𝐐𝐮𝐥𝐭= 3339 kN (Equation 2.1)
SoilDepth
(m) SPT γSu kpa
z (m)
1.5 53 11 17 59.1 4.5
Clay 4.5 36 5
7.5 79 6
10.5 2312 25
Sand 13.5 24 17 1715 31
16.5 2418 29
19.5 2921 28
22.5 2824 27
25.5 27
127
SL No
:
10 (Bored pile)
Method
: α and β method (BNBC-2015)
Site
: Zinzira-Nawabganj (Bridge LRP) Pile ID : P4 Pile diameter : 1 m Length : 23.7m
Soil Profile and properties Bore Hole Data of BH-1
Adhesion factor α= 0.7 (Table 2.2)
Effective vertical stress σ = 112.32 kpa ( mid soil layer)
Friction factor for overburden β= 0.50 (Equation 2.23)
Skin friction f = 40.22 kpa (Clay), 56.03 (Sand)
Total skin friction Q = 2354 kN (Equation 2.2)
Unit end bearing f = 1200 kpa (Table 2.3)
Tip resistance Q = 942 kN [Q = qb
X Area of pile]
Weight of pile W= 537 kN
Total capacity 𝐐𝐮𝐥𝐭= 2760 kN (Equation 2.1)
SoilDepth
(m) SPT γSu
kpaz
(m)1.5 33 2 17 57.5 4.5
Clay 4.5 46 4
7.5 89 15
10.5 2012 21
Sand 13.5 24 17 1715 22
16.5 2318 17
19.5 2421 22
22.5 2024 27
25.5 27
128
SL No : 1 (Bored pile) Method
: AASHTO(2002)
Site
: Walton Office, Basundhara, Dhaka Pile ID : TP-01 Pile diameter : 0.5m Length : 28.5m
Soil Profile and properties Bore Hole Data of BH-2
Adhesion factor α= 0.55 (Table 2.2)
Un-drained shear
strength
s = 1.31 ksf [N(avg)/5]
Skin friction Q =
=
93.06 kip(Clay)+ 356.53 kip (Sand)
449.59 kip
(Equation 2.31 &
2.32)
Unit end bearing q = 27.30 ksf (Table 2.3)
Tip resistance Q = 59.53 kip Q = q X Area of pile
Weight of pile W= 30.18 kip
Total capacity Q = 478.94 kip (Equation 2.30)
2130 kN
Soil SPT Zi (ft)γ'
lb/cftγ'Zi (ksf)
βi
6 4.924 9.84 47.608 14.76
Clay 7 19.682 24.6
12 29.527 34.44
21 39.36 47.60 1.87 0.6515 44.28 2.11 0.6019 49.2 2.34 0.55
Sand 20 54.12 2.58 0.5124 59.04 2.81 0.4624 63.96 3.04 0.4226 68.88 3.28 0.3826 73.8 3.51 0.3425 78.72 3.75 0.3025 83.64 3.98 0.2724 88.56 4.22 0.2324 93.48 4.45 0.19
129
SL No : 2 (Bored pile) Method
: AASHTO(2002)
Site
: Titas Railway Bridge, Akhaura
Pile ID : Pile No-19 Pile diameter : 1.2 m Length : 30.8m
Soil Profile and properties Bore Hole Data of BH-2
Adhesion factor α= 0.55 (Table 2.2)
Un-drained shear
strength
s = 0.4 ksf [N(avg)/5]
Skin friction Q =
=
27.17 kip(Clay)+ 1011.77 kip (Sand)
1038.96 kip
(Equation 2.31 &
2.32)
Unit end bearing q = 76.75 ksf (Table 2.3)
Tip resistance Q = 269.29 kip Q = q X Area of pile
Weight of pile W= 187.86 kip
Total capacity Q = 1120.39 kip (Equation 2.30)
4983 kN
Soil SPT Zi (ft)γ'
lb/cftγ'Zi (ksf)
βi
1 4.92Silt 1 9.84 47.60
1 14.76 0.70 0.981Clay 1 19.68 0.94 0.90
4 24.6 1.17 0.834 29.52 1.41 0.7717 34.44 1.64 0.7110 39.36 47.60 1.87 0.6517 44.28 2.11 0.6022 49.2 2.34 0.55
Silt 6 54.12 2.58 0.516 59.04 2.81 0.4619 63.96 3.04 0.4215 68.88 3.28 0.3828 73.8 3.51 0.3419 78.72 3.75 0.3027 83.64 3.98 0.2726 88.56 4.22 0.2326 93.48 4.45 0.1926 98.4 4.68 0.16
130
SL No : 3 (Bored pile) Method
: AASHTO(2002)
Site
: Padma Bridge, Naodoba, Zazira Pile ID : Bridge 01 Abutment 02 Pile diameter : 1.2 m Length : 29.5m
Soil Profile and properties Bore Hole Data of BH-8
Adhesion factor α = 0.55 (Table 2.2)
Un-drained shear
strength
s = 0.4 ksf [N(avg)/5]
Skin friction Q = 1101.81 kip (Equation 2.32)
Unit end bearing q = 14.73 ksf (Table 2.3)
Tip resistance Q = 185.05 kip Q = q X Area of pile
Weight of pile W= 179.93 kip
Total capacity Q = 1106.93 kip (Equation 2.30)
4924 kN
Soil SPTZi
(ft)γ'
lb/cftγ'Zi (ksf)
βi
2 4.92 0.23 1.207 9.84 0.47 1.086 14.8 0.70 0.9812 19.7 0.94 0.9010 24.6 1.17 0.838 29.5 1.41 0.77
Silty 8 34.4 1.64 0.71Sand 9 39.4 47.60 1.87 0.65
18 44.3 2.11 0.607 49.2 2.34 0.5511 54.1 2.58 0.5115 59 2.81 0.4618 64 3.04 0.4210 68.9 3.28 0.3816 73.8 3.51 0.3416 78.7 3.75 0.3024 83.6 3.98 0.2724 88.6 0.00 0.23
131
SL No : 4 (Bored pile) Method
: AASHTO(2002)
Site
: Mogbazar Fly over, Dhaka Pile ID : TP-2 Pile diameter : 1.2 m Length : 29.5m
Soil Profile and properties Bore Hole Data of BH-43
Adhesion factor α = 0.55 (Table 2.2)
Un-drained shear
strength
s = 2.53 ksf [N(avg)/5]
Skin friction Q =
=
373.11 kip (Clay)+892 kip (Sand)
1265 kip
(Equation 2.31 &
2.32)
Unit end bearing q = 27 ksf (Table 2.3)
Tip resistance Q = 338 kip Q = q X Area of pile
Weight of pile W= 179.93 kip
Total capacity Q = 1423 kip (Equation 2.30)
6328 kN
Soil SPTZi
(ft)γ'
lb/cftγ'Zi (ksf)
βi
15 6.56
Clay 12 19.7 47.60
11 26.2
12 32.8 1.56 0.73
19 39.4 1.87 0.65
20 45.9 2.19 0.59
23 52.5 2.50 0.52
Sand 20 59 47.60 2.81 0.46
22 65.6 3.12 0.41
27 72.2 3.43 0.35
30 78.7 3.75 0.30
29 88.6 4.22 0.23
22 98.4 4.68 0.16
132
SL No : 5 (Bored pile) Method
: AASHTO(2002)
Site
: Mogbazar Fly over, Dhaka Pile ID : P-114 Pile diameter : 1.5 m Length : 44m
Soil Profile and properties Bore Hole Data of BH-43
Adhesion factor α= 0.55 (Table 2.2)
Un-drained shear
strength
s = 2.53 ksf [N(avg)/5]
Skin friction Q =
=
574 kip (Clay)+1452 kip (Sand)
2026 kip
(Equation 2.31 & 2.32)
Unit end bearing q = 29 ksf (Table 2.3)
Tip resistance Q = 562 kip Q = q X Area of pile
Weight of pile W= 130 kip
Total capacity Q = 2458 kip (Equation 2.30)
10936 kN
Soil SPTZi
(ft)γ'
lb/cftγ'Zi (ksf)
βi
15 6.56
Clay 12 19.7 47.60
11 26.2
12 32.8 1.56 0.73
19 39.4 1.87 0.65
20 45.9 2.19 0.59
23 52.5 2.50 0.52
Sand 20 59 47.60 2.81 0.46
22 65.6 3.12 0.41
27 72.2 3.43 0.35
30 78.7 3.75 0.30
29 88.6 4.22 0.23
22 98.4 4.68 0.16
28 108 5.15 0.10
28 121 5.78 0.01
27 131 6.25 0.00
27 144 6.87 0.00
133
SL No : 6 (Bored pile) Method
: AASHTO(2002)
Site
: Mogbazar Fly over, Dhaka Pile ID : P-180 Pile diameter : 1.2 m Length : 44m
Soil Profile and properties Bore Hole Data of BH-43
Adhesion factor α = 0.55 (Table 2.2)
Un-drained shear
strength
s = 2.53 ksf [N(avg)/5]
Skin friction Q =
=
459.21 kip (Clay)+1162 kip (Sand)
1621 kip
(Equation 2.32)
Unit end bearing q = 29 ksf (Table 2.3)
Tip resistance Q = 360 kip Q = q X Area of pile
Weight of pile W= 180 kip
Total capacity Q = 1801 kip (Equation 2.30)
8009 kN
Soil SPT Zi (ft)γ'
lb/cftγ'Zi (ksf)
βi
15 6.56Clay 12 19.68 47.60
11 26.2412 32.8 1.56 0.7319 39.36 1.87 0.6520 45.92 2.19 0.5923 52.48 2.50 0.52
Sand 20 59.04 47.60 2.81 0.4622 65.6 3.12 0.4127 72.16 3.43 0.3530 78.72 3.75 0.3029 88.56 4.22 0.2322 98.4 4.68 0.1628 108.24 5.15 0.1028 121.36 5.78 0.0127 131.2 6.25 0.0027 144.32 6.87 0.00
134
SL No : 7 (Bored pile) Method
: AASHTO(2002)
Site
: Dhaka Road Research Lab Pile ID : P1 Pile diameter : 1.2 m Length : 44m
Soil Profile and properties Bore Hole Data of BH-1
Adhesion factor α= 0.55 (Table 2.2)
Un-drained shear strength s = 2.2 ksf [N(avg)/5]
Skin friction Q =
=
124.6 kip (Clay)+519 kip (Sand)
644 kip
(Equation 2.31 &
2.32)
Unit end bearing q = 25 ksf (Table 2.3)
Tip resistance Q = 219 kip Q = q X Area of pile
Weight of pile W= 97 kip
Total capacity Q = 766 kip (Equation 2.30)
3406 kN
Soil SPT Zi (ft)γ'
lb/cftγ'Zi (ksf)
βi
7 4.92
12 9.84 47.60
Clay 7 14.76
13 19.68
16 24.6
27 29.52
26 34.44 1.64 0.71
Sand 19 39.36 47.60 1.87 0.65
23 44.28 2.11 0.60
22 49.2 2.34 0.55
22 54.12 2.58 0.51
23 59.04 2.81 0.46
21 63.96 3.04 0.42
12 68.88 3.28 0.38
14 73.8 3.51 0.34
135
SL No : 8 (Bored pile) Method
: AASHTO(2002)
Site
: Dhaka Road Research Lab Pile ID : P2 Pile diameter : 1.2 m Length : 44m
Soil Profile and properties Bore Hole Data of BH-1
Adhesion factor α= 0.55 (Table 2.2)
Un-drained shear
strength
s = 2.2 ksf [N(avg)/5]
Skin friction Q =
=
124.62 kip (Clay)+580 kip (Sand)
705 kip
(Equation 2.31 & 2.32)
Unit end bearing q = 27 ksf (Table 2.3)
Tip resistance Q = 233 kip Q = q X Area of pile
Weight of pile W= 122 kip
Total capacity Q = 816 kip (Equation 2.30)
3630 kN
Soil SPTZi
(ft)γ'
lb/cftγ'Zi (ksf) βi
7 4.9212 9.84 47.60
Clay 7 14.813 19.716 24.627 29.5 1.41 0.7726 34.4 1.64 0.71
Sand 19 39.4 47.60 1.87 0.6523 44.3 2.11 0.6022 49.2 2.34 0.5522 54.1 2.58 0.5123 59 2.81 0.4621 64 3.04 0.4212 68.9 3.28 0.3814 73.8 3.51 0.3424 78.7 0.00 0.3027 83.6 0.00 0.2726 88.6 0.00 0.2326 93.5 0.00 0.19
136
SL No : 9 (Bored pile) Method
: AASHTO(2002)
Site
: Zinzira-Nawabganj (Bridge LRP) Pile ID : P3 Pile diameter : 1 m Length : 23.7m
Soil Profile and properties Bore Hole Data of BH-1
Adhesion factor α= 0.55 (Table 2.2)
Un-drained shear
strength
s = 1.28 ksf [N(avg)/5]
Skin friction Q =
=
109 kip (Clay)+639 kip (Sand)
748 kip
(Equation 2.31 & 2.32)
Unit end bearing q = 24 ksf (Table 2.3)
Tip resistance Q = 212 kip Q = q X Area of pile
Weight of pile W= 109 kip
Total capacity Q = 816 kip (Equation 2.30)
3784 kN
Soil SPT Zi (ft)γ'
lb/cftγ'Zi (ksf)
βi
Rubish 5 4.9211 9.84 47.60
Clay 3 14.765 19.687 24.66 29.5223 34.44 1.64 0.71
Sand 25 39.36 47.60 1.87 0.6524 44.28 2.11 0.6031 49.2 2.34 0.5524 54.12 2.58 0.5129 59.04 2.81 0.4629 63.96 3.04 0.4228 68.88 3.28 0.3828 73.8 3.51 0.3427 78.72 3.75 0.3027 83.64 3.98 0.27
137
SL No : 10 (Bored pile) Method
: AASHTO(2002)
Site
: Zinzira-Nawabganj (Bridge LRP) Pile ID : P4 Pile diameter : 1 m Length : 23.7m
Soil Profile and properties Bore Hole Data of BH-1
Adhesion factor α= 0.55 (Table 2.2)
Un-drained shear
strength
s = 1.2 ksf [N(avg)/5]
Skin friction Q =
=
102 kip (Clay)+639 kip (Sand)
741 kip
(Equation 2.31 & 2.32)
Unit end bearing q = 27 ksf (Table 2.3)
Tip resistance Q = 235 kip Q = q X Area of pile
Weight of pile W= 109 kip
Total capacity Q = 866 kip (Equation 2.30)
3854 kN
Soil SPT Zi (ft)γ'
lb/cftγ'Zi (ksf)
βi
3 4.92Clay 2 9.84 47.60
4 14.764 19.688 24.615 29.5220 34.44 1.64 0.71
Sand 21 39.36 47.60 1.87 0.6524 44.28 2.11 0.6022 49.2 2.34 0.5523 54.12 2.58 0.5117 59.04 2.81 0.4624 63.96 3.04 0.4222 68.88 3.28 0.3820 73.8 3.51 0.3427 78.72 3.75 0.3027 83.64 3.98 0.27