mohamed kamal ver 24 (1)

الرحيـــــــــــم الرحمـــــن الله بسم

لله الحــــمـــــداّله على و محمــد سيدنا الله، رسول على السالم و الصالة و

وااله من و صحبه .و

Faculty of Engineering Port Said University Department of Civil Engineering

SUEZ CANAL UNIVERSITYFACULTY OF ENGINEERINGCIVIL ENGINEERING DEPT.

2013

Analysis of Piled Foundations Using International Codes

Eng. Mohamed Ahmed KamalB.Sc. in Civil Engineering 2004

The General Authority for Port-Said Ports

Supervised by

Prof. Mohamed Mosad El-Gendy

Dr. Ibrahim Ahmed El-Araby

Professor of Geotechnical Engineering and Foundations, Vice Dean of Environmental

Affairs, Faculty of EngineeringPort Said University

Associate Professor Faculty of Engineering

Port Said University

باستخدام الخازوقية االساسات تحليلالعالمية االكواد

Approval committee

Prof. Nagwa Ragab EL-Sakhawy

Prof. Hassan Mohamed HassanProfessor of Foundations and Soil MechanicsFaculty of Engineering, EL-Zagazig University

Professor of Concrete StructuresHead of Civil Engineering Department

Faculty of Engineering, Port Said University

Presentation Steps

Port-Said Univeresty 2013

Port-Said University 2013

IntroductionLiterature Review

Analysis of single pile

Numerical model

Case studies of piled raft

Conclusions

Introduction

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Advantage of a piled raft foundation

Reduction of settlement

Economic saving

Improve foundation supporting

piled raft system recently used widely

Residential constructions

Industrial constructions

Engineering constructions



Conclusions

Introduction

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Capacity of piled raft foundation

Pile

Pile

Pile

Raft

Pile – Raft interaction

Pile – Pile interaction

Raft – Soil interaction

Raft– Pile interaction


Numerical model



Conclusions

Introduction

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The aims of this study:1. Comparison of large diameter bored piles

behavior acc. to 3 international codes in addition to EGY. code with pile load-test results.

2. Comparison of single pile behavior of the Egyptian code with international codes.

3. Proposal of a simplified L-S model for a single pile based on code predictions

4. Evaluation of the performance of the numerical model for piled raft analysis depending on ELPLA, by the comparison with field measurements for 10 realistic case histories.


Numerical model



Conclusions

Introduction

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To reach the objectives of this study:1. Analysis of the estimated results for 38 pile load

tests collected from projects and previous research in Port-Said and North Delta regions.

2. The ultimate capacities were determined using the 4 different codes.

3. Statistical analyses were conducted to evaluate the codes methodologies.

4. Based on these analyses, an empirical hyperbolic load-settlement (L-S) is proposed.

5. 10 case histories of piled-raft are analyzed and comparisons are given for both the settlement and pile sharing ratio to evaluate the piled-raft analysis method depending on single pile L-S models.


Numerical model



Conclusions

Literature Review

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Harraz et al (2005) compared the results of empirical skin friction data using different methods in AASHTO to measured results and concluded that empirical methods results greater than the estimated values


Numerical model



Conclusions

Literature Review

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Hossain et al 2008 presented a case studies of drilled shaft constructed in Mid-Atlantic in USA and concluded that some empirical methods are over predicted while others are under predicted recommended in AASHTO


Numerical model



Conclusions

Literature Review

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Amr M. Radwan et al. (2007) presented a new suggested approach for design of large diameter bored piles resting on cohesionless soils.


Numerical model



Conclusions

Literature Review

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Amr M. Radwan et al. (2007) presented a new suggested approach for design of large diameter bored piles resting on cohesionless soils.Mobarak (2010) studied a pile cap connected by tie girders as an alternative pile foundation system in Port-Said.


Numerical model



Conclusions

Literature Review

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Amr M. Radwan et al. (2007) presented a new suggested approach for design of large diameter bored piles resting on cohesionless soils.Mobarak (2010) studied a pile cap connected by tie girders as an alternative pile foundation system in Port-Said.

El- Laban (2011) presented some comparative studies to study the behavior of piled rafts constructed in Port-Said.


Numerical model



Numerical modelCase studies of piled raft

Conclusions


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38 case studies of bored pile load test

Port said Damietta, El-Mansoura

East, Central Delta

Cairo, El-Giza0

2

4

6

8

10

12

14

16

Freq

uenc

y

0.8 1.00 , 1.08 1.20

5

10

15

20

25

Freq

uenc

y

Site location Pile diameter [m]

Pile Length [m] Borehole log.

0 10 20 30 40 50 60 70

Case no.2 Case no.6

Fill

Soft clay

Stiff clay

Dense sand

V. Dense sand

Case no.16

Loose sand

Case no.33

Dep

th

16 - 20 20 - 30 30 - 40 40 - 50 50 - 700

2

4

6

8

10

12

14

Freq

uenc

y


Case studies of piled raftConclusions


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Pile Load Test

0 200 400 600 800 10000

2

4

6

8

10

12

14

16

18

Load [MN]

Settl

emen

t [m

m]

load-settlement curve for case history no. (18)

Modified Chin method (1970)

0 2 4 6 8 10 12 14 16 180.000

0.002

0.004

0.006

0.008

0.010

0.012

0.014

0.016

0.018

f(x) = 0.000619378747013515 x + 0.00545211754486284R² = 0.919837446797783

Settlement X [mm]

Sett.

/Loa

d Y

[mm

/ton]


Numerical model




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Code estimation of single pile capacityEgyptian code ECP202 (2005)

German code DIN 4014 (1990)

AASHTO (2005)

French code (1993)

Side Resistance

Tip Resistance

Total Resistance

Settlement [mm]

Load

[MN

]

Qb

QS

1 s

ni

ibT QQQ


Numerical model




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DIN 4014 (1990)

AASHTO (2005)

French code (1993)

1- Estimations for SPT and Cu 2- Determine ultimate skin friction and tip resistance

No. of bowls of SPT

Depth below ground level [m]

Skin friction resistance [kN/m2]

Less than 10 - 0

10.00 - 20.000.00-2.00 02.00-5.00 3

> 5.00 5

20.00 - 30.000.00-2.00 02.00-7.50 4.5

> 5.00 7.5

> 30.000.00-2.00 0

2.00-10.00 6>10.00 10

Type of soil qs/N30 [MN/m2]

Fine to medium or slightly silty sand 0.3 to 0.4

sand or slightly gravelly sand 0.5 to 0.6

Gap-graded sand 0.5 to 1.01.0 2.0

1.0

Rsd

/ R

s

0zt / D (%)

0

5.0 10.0zt / D (%)

1.0

Rpd

/ R

p

0

0


Numerical model

unit skin friction settlement curve

unit end bearing settlement curve




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DIN 4014 (1990)

AASHTO (2005)

French code

Total resistanceSkin resistanceTip resistance

0 2 4 6 8 10 120

400

800

1200

Settlement S [cm]

Load

Q [M

N]

0 2 4 6 8 10 120

400

800

1200

Settlement S [cm]

Load

Q [M

N]

0 2 4 6 8 10 120

400

800

1200

Settlement S [cm]

Load

Q [M

N]

0 2 4 6 8 10 120

400

800

1200

Settlement S [cm]

Load

Q [M

N]

Case no. 18


Numerical model

0 2 4 6 8 10 120

400

800

1200

Settlement S [cm]

Load

Q [M

N]




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Code estimation of single pile capacityEgyptian code ECP202 (2005) DIN 4014 (1990)

AASHTO (2005) French code

Total resistanceSkin resistanceTip resistance

0 2 4 6 8 10 120

400

800

1200

Settlement S [cm]

Load

Q [M

N]

0 2 4 6 8 10 120

400

800

1200

Settlement S [cm]

Load

Q [M

N]

0 2 4 6 8 10 120

400

800

1200

Settlement S [cm]

Load

Q [M

N]

0 2 4 6 8 10 120

400

800

1200

Egyptian Code DIN 4014 AASHTO French Code

Settlement S [cm]

Load

Q [M

N]

All codes load-settlement curve for case history no. (18)


Numerical model




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Code estimation of single pile capacity

Statistical analysis of results

A. Comparison of total ultimate pile resistance

B. Comparison of separate components of resistance

- Tip resistance- Skin resistance ( Sand and clay skin resistance)


Numerical model




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Comparison of total ultimate pile resistant1. Normal probability distribution

0 5 10 15 20 25 300

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16Egyptian CodeDIN 4014AASHTOFrench CodeModified Chin Method

Ultimate pile capacity [MN]

Prop

abili

ty d

ensit

y fu

nctio

nMethodµ σ

C.O.V[MN] [MN]

ECP202 7.71 2.81 0.36DIN4014 9.82 3.84 0.39AASHTO 9.73 4.14 0.43French code 7.54 3.24 0.43Chin's method 8.64 4.91 0.57

Method µp/µm

[%]ECP202 89.20DIN4014 113.60AASHTO 112.50French code 87.30


Numerical model




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2. Best fit regression analysis Egyptian code ECP202 (2005)

0 500 1000 1500 2000 2500 30000

500

1000

1500

2000

2500

3000

f(x) = 1.16371324554537 xR² = 0.92601299910858

Predicted load (Qu)p [MN]

Estim

ated

load

(Qu)

m [M

N]

AASHTO (2005)DIN 4014French code

0 500 1000 1500 2000 2500 30000

500

1000

1500

2000

2500

3000

f(x) = 0.904133234767697 xR² = 0.921657779727726


Estim

ated

load

(Qu)

m [M

N]

0 500 1000 1500 2000 2500 30000

500

1000

1500

2000

2500

3000

f(x) = 0.907166343350402 xR² = 0.932580970619128


Estim

ated

load

(Qu)

m [M

N]

0 500 1000 1500 2000 2500 30000

500

1000

1500

2000

2500

3000

f(x) = 1.15601551437052 xR² = 0.910311641970856


Estim

ated

load

(Qu)

m [M

N]

Methodology Qup / Qum R2

Egyptian code 0.86 0.69DIN 4014 1.11 0.67AASHTO 1.11 0.72French Code. 0.86 0.63

Summary of regression analysis

Comparison of total ultimate pile resistant


Numerical model



Analysis of single pilePort-Said University 2013

Comparison of separate components of resistance

Contribution of predicted resistances using ECP202

0

10

20

30

40

50

60

70

80

90

100Sand Skin Resistance Clay Skin Resistance Tip Resistance

Case no.

Pred

icte

d re

sist

ance

con

trib

ution

[%] Sand skin resistance (average: 43%)

Tip resistance (average: 33%)

Clay skin resistance (average: 24%)

Contribution of predicted resistances using DIN 4014

Contribution of predicted resistances using AASHTO Contribution of predicted resistances using French code

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 370

10

20

30

40

50

60

70

80

90


Case no.

Pred

icte

d re

sist

ance

con

trib

ution

[%]

Sand skin Resistance (average: 48%)

Tip Resistance (average: 29%)

Clay skin Resistance (average: 23%)

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 370

102030405060708090


Case no.

Pred

icte

d re

sist

ance

con

trib

ution

[%]




1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 370

102030405060708090


Case no.

Pred

icte

d re

sist

ance

con

trib

ution

[%]




International codes

Separate resistance components [%]

Tip resistance

Skin resistance

Total Clay Sand

ECP202 33 67 24 43DIN4014 29 71 23 48AASHTO 25 75 26 49French code 32 68 15 53

Average contribution of components resistance


Numerical model




Code over estimation of ultimate pile capacity

9 12 19 24 25 26 30 320

200

400

600

800

1,000

1,200

1,400

1,600Egyptian Code French code 1993 Modified Chin Method

Case Studies

Ulti

mat

e C

apac

ity [M

N]

9 12 19 24 25 26 30 320

200

400

600

800

1,000

1,200

1,400

1,600Din 4014 ASSHTO Modified Chin Method

Case Studies

Ultim

ate

Capa

city

[MN

]

Increasing of Egyptian and French codes prediction values Increasing of DIN 4014 and AASHTO prediction values

Code Egyptian code DIN 4014 AASHTO French codeOver prediction [%] 34 67 58 37


Numerical model




Comparison of ECP 202 with other international codes

International CodesEgyptian Code Results [%]

Tip resistance

Skin resistance Total resistance

Sample [%]Clay Sand Total

DIN 4014 85 67-100 39-93 54-100 67-88 92AASHTO 104 52-86 37-100 59-94 66-91 85French Code 103 100-300 50-101 76-123 89-116 85

Egyptian code prediction for weak cohesive end bearing layers


Numerical model

Type of pile resistance

Predicted ultimate load [MN]

Case No. 1 Case No. 8ECP 202

Din 4014 AASHTO French

code ECP 202

Din 4014 AASHTO French

code Skin resistance 3.41 3.14 2.86 3.04 3.92 4.21 3.15 2

Tip resistance 1.1 0.23 0.26 0.25 1.1 0.2 0.23 0.25Total 4.51 3.37 3.11 3.29 5.02 4.41 3.37 2.25




Proposed modified load-settlement curve

11 = u

uQQ S CS

Qu = Ultimate load predicted by codeSu = Ultimate settlement recommended by code

8.66 For (Egyptian and French codes)11.00 For (DIN 4014 and AASHTO)

C =


Numerical model

0 10 20 30 40 50 60 70 80 90 1000

200

400

600

800

1000

Egyptian Code

DIN 4014

AASHTO

French Code

Proposed model

Settlement S [mm]

Load

Q [M

N]



Mathematical modelCase studies of piled raft

Conclusions

Mathematical modelPort-Said University 2013

Soil modelThe numerical study of this chapter was carried out by the program ELPLA

(ELASTIC PLATE)

Modulus of compressibility method

1- For elastic piled raft.2- For rigid piled raft.3- For rigid freestanding piled raft.



Mathematical modelPort-Said University 2013

Theory of piled raft foundation

1- Nonlinear analysis of piled raft using ECP 202 (NPRE)2- Nonlinear analysis of piled raft using DIN 4014 (NPRD)3- Nonlinear analysis of piled raft using AASHTO (NPRA)4- Nonlinear analysis of piled raft using French code (NPRF)5- Nonlinear analysis of piled raft using modified AASHTO (NPRM1)6- Nonlinear analysis of piled raft using modified ECP 202 (NPRM2)


Mathematical model

Nonlinear analysis of piled raft



Numerical modelPort-Said University 2013


Numerical model

Nonlinear analysis of piled raft In the present analysis of a piled-raft system, it is assumed that the settlement along the entire length of the pile is the same as the pile tip settlement

Pile

load

Qp

[kN

]

Sg = 0.1 D

D = Pile shaft diameter

Srg = 0.5 Qrg + 0.5 = 3

Qrg = Ultimate skin force [MN]

Self-settlement Sp [m]

Empirical pile resistance curve

0.2 Sg 0.3Sg Sg = 0.1D Sp i

Qp i

k i

Srg

k i (o)

Qt 1

Pile

load

Qp

[kN

]

Sg = 0.1 D

D = Pile shaft diameter

Srg = 0.5 Qrg + 0.5 = 3

Qrg = Ultimate skin force [MN]

Self-settlement Sp [m]

Proposed pile resistance curve

0.2 Sg 0.3Sg Sg = 0.1D Sp i

Qp i

k i

Srg

k i (o)

Qt 1

1- Self-settlement of the pile Spi [m]

DIN 4014 load-settlement curve Proposed load-settlement model





Numerical model

Nonlinear analysis of piled raft 2- Pile-pile interaction

Ground surface

Pile j

r

Pile i

Sbs k, j

Qb j

Element 1

c

c

Sbs m, j Uniform settlement Sbs i, j

Sbs i, j

Element k

Element m

Sbs 1, j

Δ l

dz

z

l i

z 1

z 2

dc

T

dz

Ground surface

Pile j

Δ l

Pile i

Sss k, j

T=Qs j / l j

Element 1

c

c

Sss m, j Uniform settlement Sss i, j

Sss i, j

Element k

Element m

Sss 1, j

c 1

c 2

z

l j l i

z 1

z 2

r

d j

Settlement in a pile element due to a skin force on pile j Settlement in a pile element due to a tip force on pile j





Numerical model

Nonlinear analysis of piled raft 4- Pile-raft interaction

Settlement in a pile element k due to a contact forceSettlement in a node i due to a tip force on the base of pile j

Ground surface

Node j

r

Pile i

Srs k, j

Qr j

Element 1

c

c

Srs m, j Uniform settlement Srs i, j

Srs i, j

Element k

Element m

Srs 1, j

Δ l

dz

z

l i

z 1

z 2

Ground surface

Pile j

r

Node i

Qbj

c

c

zWbi, j

3- Raft-pile interaction





Numerical model

Nonlinear analysis of piled raft

Settlement in a pile element due to a skin force on pile j

τ s j

Pile j qb j

pile n p

p P 1 P 2

a) Piled raft

pile 1

Ground surface

node 1 Qr 1

node n r Qr nr

1 1

3 4

2

1

3 2

4

Pile-pile interaction Pile-soil interaction

Pile-raft interaction Raft-soil interaction

Ground surface

Q i

N

S 1 S i

Ground surface

c) Soil settlement

b) Equivalent statical system

node n node 1 Q 1 Q n

w o

S n

e x

θ y

C.L.

The settlement can be defined by the rigid body translation wo at the center of the raft, and two rotations θx and θy around the x and y axes.



Case studies of piled raftPort-Said University 2013

London

Frankfurt

Japan

Poland1

25

2

Messeturm

Torhaus

Japan center

West-end 1

Skyper

Stonebridge

Dash-wood

FORTY-SEVEN-STORY RESIDENTIAL TOWER

Eleven-STORY Office building

Liquid Gas Terminal


Numerical model




Case studies of piled raftAnalysis of single pile

Numerical model

256.5 m

450 m2

3500 m24600 m2

6.27 m

50.0 m

1880 MN

156 MN400 MN

Raft areaPile lengthTotal building load

Building height

130 m

43 m

15 m

Measured values

S [cm] 14.4 12 2.9 3.1 12 5 3.1 1 1.8 1.8

B [%] 40 50 82 - 64 - 100 54 100 -





Numerical model

B1

T

5.00

E = 22900[kN /m2 ],F hi = 20[°]W = 22900[kN /m2],C = 200[kN /m2]Gam = 20[kN /m3],N ue = 0 .3[- ]

T

10 .00


T

20 .00


T

25 .00


T

40 .00

E = 110000[kN /m2],F hi = 20[°]W = 110000[kN /m2],C = 200[kN /m2]Gam = 10[kN /m3],N ue = 0 .3[- ]

T

60 .00

E = 157000[kN /m2],F hi = 20[°]W = 157000[kN /m2],C = 200[kN /m2]Gam = 10[kN /m3],N ue = 0 .3[- ]

GW 5.00

0 30 60 90 120 1500

200

400

600

800

1000

1200

1400

1600

1800Egyptian Code DIN 4014 AASHTOFrench Code MLSC1 MLSC2

Settlement S [mm]

Load

Q [M

N]





Numerical model

15798.0 15798.0 15798.0 15798.0

15798.0

15798.0

15798.0

15798.0

15798.015798.015798.0

15798.0

15798.0

15798.0

15798.0

15798.0

15798.015798.0

15798.052.0

100.0

93.0

1700.01293.0

98.0

506.0

P [ kN ]

p [ kN /m 2]

Method (8) (Layered soil model)Rigid piled raft foundation

Loads





Numerical model

2. 05 [c m]

2. 21 [c m]

2. 37 [c m]

2. 53 [c m]

2. 69 [c m]

2. 85 [c m]

3. 01 [c m]

3. 17 [c m]

3. 33 [c m]

3. 49 [c m]

3. 65 [c m]

3. 81 [c m]

3. 97 [c m]


Settlements [cm]Max. s = 3.99 at node 75, Min. s = 1.97 at node 2





Numerical model

5624.7 5133.9 4859.0 4704.8

5754.15831.16254.1

6161.56064.7 5078.76031.8

6253.9 6453.6 5437.76297.66380.2

6890.26826.86622.6 5909.0

6620.2 6919.4

7103.1 6738.97741.6 7532.4 7578.5

7156.4 7340.7 7514.37460.8

7473.47496.8 8348.5 8007.7 8187.6

8377.87955.3 8637.3 8805.2

8264.0 8690.49625.5

8812.69115.2 9547.7

-v e S up por t r eac ti ons V

+v e S up por t r eac ti ons V0 67 37. 9 [kN ]


Support reactions V [kN]Max. V = 9625.5 at node 925, Min. V = 4704.8 at node 140, Sum = 325621.2





Numerical model

Case historyMeasured settlement

[cm]

Predicted settlement [cm] P / M ratio

NPRE NPRD NPRA NPRF NPRM1 NPRM2 best worst

1 Messeturm 14.40 17.29 15.37 10.83 15.92 12.07 16.01 1.07 0.752 Westend 1 12.00 12.71 11.38 9.96 12.13 11.22 12.07 1.01 0.833 47 story res. tower 2.90 4.44 3.63 3.66 3.98 3.46 4.13 1.19 1.534 Skyper tower 3.10 3.52 3.09 2.86 3.33 3.35 3.35 0.99 1.145 Torhaus 12.40 11.52 11.84 7.69 9.11 8.52 10.11 0.95 0.626 Japan center 5.00 4.56 4.33 3.34 4.24 3.89 4.34 0.91 0.677 Dashwood house 3.30 2.84 2.95 2.44 2.75 2.74 2.76 0.89 0.748 Eleven story building 1.00 1.41 1.31 1.43 1.43 1.37 1.40 1.31 1.439 Stonebridge Tower. 1.80 1.66 2.10 1.72 1.92 1.87 1.93 1.04 1.1710 Liquid Gas Terminal. 1.80 3.23 3.19 3.13 3.24 3.24 3.14 1.74 1.79





Numerical model

Case historyMeasured

bearing factor [%]

Predicted bearing factor [%] P / M ratio

NPRE NPRD NPRA NPRF NPRM1 NPRM2 best worst

1 Messeturm 40% 32% 40% 59% 38% 54% 37% 1. 00 0.82

2 Westend 1 50% 26% 34% 43% 30% 35% 30% 0.86 0.52

3 47 story res. tower 82% 58% 61% 61% 60% 62% 59% 0.76 0.71

4 Skyper tower - 44% 50% 52% 46% 46% 46% - -

5 Torhaus 64% 49% 65% 69% 62% 66% 56% 1.02 0.77

6 Japan center - 17% 20% 32% 21% 25% 20% - -

7 Dashwood house 100% 100% 100% 100% 100% 100% 100% 1.00 1.00

8 Eleven story building 54% 33% 37% 33% 33% 35% 34% 0.69 0.61

9 Stonebridge Tower. 100% 100% 100% 100% 100% 100% 100% 1.00 1.00

10 Stonebridge Tower. - 67% 67% 67% 67% 67% 67% 67% 67%



ConclusionsPort-Said University 2013

Single bored pile

1. Performance of each of the four codes under consideration is as good as the others within (-)14 [%] (Egyptian and French Codes) to (+)11 [%] (DIN 4014 and AASHTO) from the ultimate load computed by the modified Chin method.

2. In general, the average predicted ultimate tip resistance contribution was found to be 25 [%] to 33 [%] of the total ultimate pile resistance.


Mathematical model




Single bored pile

3. The ultimate capacity predicted by Egyptian code was greater than the other codes for soft clay base bearing soils; because of ignoring the actual properties of clay at the toe by the code.

4. The pile load test is an irreplaceable process for determining the ultimate capacity of large diameter bored piles.


Mathematical model




Single bored pile

5. A simplified load-settlement curve presented using code prediction for the ultimate bearing capacity to estimate the pile settlement.


Mathematical model




Piled raft

1. The maximum variance between the 4 codes was about 34 [%] from the measured values.

2. The modulus of compressibility method for the pile group is valid for deep foundation systems with small piles distance.

3. The results of the proposed P-S curve are not only in a good agreement with the code results but also But also improves the code performance worth up to 11 [%].


Mathematical model




Piled raft

4. The results of the ELPLA methods are not only in a good agreement with the measured results but also can accept any empirical load-settlement relation from any code to predict the analysis of piled raft system


Mathematical model

[email protected]

رب لله الحمد والعالمين

mohamed kamal ver 24 (1)

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