Finite Bearing Capacity of RCC Cast in Place Pile

Thesis Paper

On

Finite Bearing Capacity of RCC Cast in Place Pile

Submitted by

For sub-soil investigation in mis project, standard penetration Test (SPT) has been executed with me permission of the authority. The most common for soil exploration in standard Penetration Test (SPT) in a borehole. This test is made by making use of a spilt spoon sampler. Which in connected to a strong of drill rods and is lowered into the bottom of the bonehole, which was drilled and cleaned in advice. The simplex in driven into me soid strata by making use of a drop weighting 63.5kg. The weight is allowed to fall freely from a height of 760mm on to an anvil fixed on the top of me drill rod. The number of blows required to penetrate from 150 to 450 mm depth is termed as SPT value or N-value.

1.1Objective

The process of indentifying the layers of deposits mat underline a proposed structure and their physical characteristics in generally referred to as subsurface exploration. The purpose of subsurface exploration is to obtain information mat will aid the foundation Engineer in-

a)Selecting the type and depth of foundation suitable for a given structure.

b)Evaluation the load-bearing capacity of a foundation.

1.2Approach

This theoretical research is based on three different memod; one is Meyenhof’s Alfa (α) and another one vesic memod.

1.4Organization of Thesis

This thesis is organized into chapters

Chapter 1 : This chapter describes the General, Objective, Approach and Organization of this thesis.

Chapter-2 : Literature Review

Ultimate static pile point capacity by Meyerhof memod. Alfa memod, vesic memod & pile skin friction capacity

Chapter 3 : Calcution of pile bearing capacity by different menod.

Chapter 4 : Result effect of different method of END bearing capacity both skin friction.

Chapter 5: Chapter describes the conclution.

2.2 For standard penetration test (SPT) data

Megan hot (195,1976) proposed

P pu = Ap (40n) Lb Ap (380 N) KN

Where, N= statistical avenge of me SPT NSS

number is a Zone of about 8B above to 3B below he pole point.

USE any applicable SPT N Correction given.

B= widen or diameter of pole pint

Lb = Pile Penetration deepen into Point –beating stratum.

Lb / B = avenge darn nation of point –into Point beaming station,

2.2 Vesic Memod :

Point beating Capacity

Ppu = Ap ( Nq Nq bq + 1y Bp Ng )

n = 1+2ko

Ko = 1+ sinq

Overbnunden pnessure,q = (sat-

dq= 1+0.247tan-1 L/B

pile Crossection Area, Ap=

D= Diameter

bearing capacity factor Nq

bearing capacity factor Ne

bearing capacity factor Ny

2.3 Alfa &Method

pile point bearing capacity:

ppu= 9 su Ap

pile crossection Area Ap= AD2

Avenage skin friction = Su

2.4 pile skin Resistance capacity:

CHAPTER -5

5.1 Concluation:

The overall muestingatin resolts of one site defines

Given Data

Depth SPT value

05’ 08

Pile length 40’ = 12.19m 10’ 08

Pile dia = 18”=0.4572m 15’ 07

• water table at GL 20’ 15
• Pile WH of level 1.5m below from G.L 25’ 18

30’ 25

35’ 30

40’ 40

Meyerhof’s Method

Pile point Capacity / END Bearing Capacity :

Pile crossection Area Ap =

=

= 0.164 Sq-m

= 1.5 m

Pile dia/width B = 18” = 0.4572 m

Overburden pressure, Po = (19-9.81) x 12.19

= 112.02 kv/m2

CN =

=

= 0.92

Average Energy ratio, = 1.14

Rod length correction, = 1.0

Sampler correction, = 0.8

Bore hole diameter (150mm) correction, = 1.05

N70 = Cn x N x x x x

= 0.92 x 40 x 1.14 x 1.0 x 0.8 x 1.05

= 35

Ppu = Ap 40 n

= 0.164 x 40 x 35 x

= 723 KN

Skin friction Resistance (Qs1) at EL 5’ ~10’

Effective pile surface are, As =

=

= 2.15 sq-m

Overburden pressure, Po’ = (19-9.81) x 1.5

= 13.785 kn/m2

Cn =

= 2.63

Average Energy ratio, = 55/70 = 0.78

Rod length correction, = 0.75

Sampler connection, = 0.80

Bonehole diameter (150) correction, = 1.05

N55 = Cn x N x x x x

= 2.63 x 8 x .78 x 0.75 x 0.8 x 1.05

= 10.34

Qs1 = Asfs N55Xm= 1.0

= 2.15x10.34 = 1.0 x 10.34

= 22.28 kn = 10.34

Skin friction Resistance (Qs2) at EL 10’ ~15’

Effective pile surface are, As =

=

= 2.15 sq-m

Overburden pressure, Po’ = (19-9.81) x 3.0

= 27.57 kn/m2

Cn =

= 1.86

Average Energy ratio, = 55/70 = 0.78

Rod length correction, = 0.75

Sampler connection, = 0.80

Bonehole diameter (150) correction, = 1.05

N55 = Cn x N x n1 x n2 x n3 x n4

= 1.86 x 8 x0.78x 0.75 x 0.8 x 1.05

= 7.312

Qs2 = Asfs N55Xm= 1.0

= 2.15x7.312 = 1.0 x 7.312

= 15.721 kn = 7.312

Skin friction Resistance (Qs3) at EL 15’ ~20’

Effective pile surface are, As =

=

= 2.15 sq-m

Overburden pressure, Po’ = (19-9.81) x 4.57

= 41.998 kn/m2

Cn =

= 1.51

Average Energy ratio, = 55/70 = 0.78

Rod length correction, = 0.85

Sampler connection, = 0.80

Bonehole diameter (150) correction, = 1.05

N55 = Cn x N x x x x

= 1.51 x 7 x0.78x 0.85 x 0.8 x 1.05

= 5.89

Qs3 = Asfs N55Xm= 1.0

= 2.15x5.89 = 1.0 x 5.89

= 12.65 kn = 5.89

Skin friction Resistance (Qs4) at EL 20’ ~25’

Effective pile surface are, As =

=

= 2.15 sq-m

Overburden pressure, Po’ = (19-9.81) x 6.09

= 56.04 kn/m2

Cn =

= 1.307

Average Energy ratio, = 55/70 = 0.78

Rod length correction, = 0.95

Sampler connection, = 0.80

Bonehole diameter (150) correction, = 1.05

N55 = Cn x N x x x x

= 1.307 x 15 x0.78x 0.95 x 0.8 x 1.05

= 12.59

Qs4 = Asfs N55Xm= 1.0

= 2.15x12.59 = 1.0 x 12.59

= 27.06 kn = 12.59

Skin friction Resistance (Qs5) at EL25’ ~30’

Effective pile surface are, As =

=

= 2.15 sq-m

Overburden pressure, Po’ = (19-9.81) x 7.62

= 70.04 kn/m2

Cn =

= 1.17

Average Energy ratio, = 55/70 = 0.78

Rod length correction, = 1.0

Sampler connection, = 0.80

Bonehole diameter (150) correction, = 1.05

N55 = Cn x N x x x x

= 1.17x 18 x .78 x 1.0 x 0.8 x 1.05

= 13.78

Qs5 = Asfs N55Xm= 1.0

= 2.15x13.78 = 1.0 x 13.78

= 29.64 kn = 13.78

Skin friction Resistance (Qs6) at EL 30’ ~35’

Effective pile surface are, As =

=

= 2.15 sq-m

Overburden pressure, Po’ = (19-9.81) x 9.15

= 84.05 kn/m2

Cn =

= 1.06

Average Energy ratio, = 55/70 = 0.78

Rod length correction, = 1.0

Sampler connection, = 0.80

Bonehole diameter (150) correction, = 1.05

N55 = Cn x N x x x x

= 1.06 x 25 x .78 x 1.0 x 0.8 x 1.05

= 17.48

Qs6 = Asfs N55Xm= 1.0

= 2.15x17.48 = 1.0 x 17.48

= 37.58 kn = 17.48

Skin friction Resistance (Qs7) at EL 35’ ~40’

Effective pile surface are, As =

=

= 2.15 sq-m

Overburden pressure, Po’ = (19-9.81) x 10.67

= 98.06 kn/m2

Cn =

=0.98

Average Energy ratio, = 55/70 = 0.78

Rod length correction, = 1.0

Sampler connection, = 0.80

Bonehole diameter (150) correction, = 1.05

N55 = Cn x N x x x x

= 1.06 x 30 x .78 x 1.0 x 0.8 x 1.05

= 19.42

Qs7 = Asfs N55Xm= 1.0

= 2.15x19.42 = 1.0 x 19.42

= 41.75 kn = 19.42

Skin friction Resistance (Qs8) at EL 40’ ~45’

Effective pile surface area, As =

=

= 2.15 sq-m

Overburden pressure, Po’ = (19-9.81) x 12.19

= 112.07 kn/m2

Cn =

= .924

Average Energy ratio, = 55/70 = 0.78

Rod length correction, = 1.0

Sampler connection, = 0.80

Bonehole diameter (150) correction, = 1.05

N55 = Cn x N x x x x

= .924 x 40 x .78 x 1.0 x 0.8 x 1.05

= 24.22

Qs8 = Asfs N55Xm= 1.0

= 2.15x24.22 = 1.0 x 24.22

= 37.58 kn = 24.22

Total skin friction resistance, Qs = 22.28+15.72

+ 12.65 + 27.06 + 29.64 + 37.58 + 41.75

+ 52.06 = 238.74 KN.

Pile Bearing capacity Qu = Ppu + Qs

= 723+238.74

= 961.74 Kn.

Let F.S = 3

Allowable bearing capacity =

= 320.58 KN

Chapter - 5

5.1 Conclusion:

The overall investigation results of the sitre defines that shallow & pile foundation is suitable for the best economic and structurally safe of the project.

Reference: Foundation Analysis and desine – j.e bowles, principles Foundation Engineering- Braja M.Das>, A Text B of soil Mechaices & foundation engineering. VNS Murphy > foundation design teng.> soil mechanics & foundation engineering – K.R Arona.

1

Given Data : Pile dia = 18” = 0.4572m

Pile length = 40’ = 12.19 m

1 / 2 / 3 / 4 / 5 / 6 / 7 / 8 / 9 / 10 / 11 / 12 / 13
Incensement ambedment length / SPT value / Over bunden Pressure connection Po’= / CN = / Average Energy ratio / Ro Length / sampler / Regonhone / N55=CN xN n1x n2x n3 xn4 / As = px / Xm / = xm N55 Colm = (11x9) / = As x fs
/ N / H (sat-w) / s / / / / / (KN)
5 / 8 / 13.785 / 2.63 / 0.78 / 0.75 / 0.8 / 1.05 / 10.34 / 2.15 / 1.0 / 10.34 / 22.28
10 / 8 / 27.57 / 1.86 / 0.98 / .75 / 0.8 / 1.05 / 7.312 / 2.15 / 1.0 / 7.312 / 15.721
15 / 7 / 41.998 / 1.51 / 0.78 / .85 / .8 / 1.05 / 5.89 / 2.15 / 1.0 / 5.89 / 12.65
20 / 15 / 56.04 / 1.307 / 0.78 / .95 / .8 / 1.05 / 12.59 / 2.15 / 1.0 / 12.59 / 27.06
25 / 18 / 70.04 / 1.17 / 0.78 / 1.0 / .8 / 1.05 / v / 2.15 / 1.0 / 13.78 / 29.64
30 / 25 / 84.05 / 1.06 / .78 / 1.0 / .8 / 1.05 / 17.48 / 2.15 / 1.0 / 17.48 / 37.58
35 / 30 / 98.06 / 0.98 / .78 / 1.0 / .8 / 1.05 / 19.42 / 2.15 / 19.42 / 41.75
40 / 40 / 112.07 / 0.924 / .78 / 10 / .8 / 1.05 / 24.22 / 2.15 / 24.22 / 52.06

1

Given Data Depth SPT value

05’ 08

Pile length 40’ = 12.19m 10’ 08

Pile dia = 18”=0.4572m 15’ 07

• water table at GL 20’ 15
• Pile WH of level 1.5m below from G.L 25’ 18

30’ 25

35’ 30

40’ 40

Method

Skin friction Resistance (Qs1) at EL 5’ ~10’or (1.5m~3.0m)

Overburden pressure, Po’ = (sat-w)

= (19-9.81) x 1.5

= 13.785 Kn/m2

Su =

From and Su relationship (Bowles Curve)

= 1.085

Su = 1.085 x 6.90 = 7.48 kpa

Effective pile surface area As, = p x

Qs1 =As

= 7.48 x 2.12

= 16.082 KN

Element / Depth
m / Kpa / Su
Kpa / /
Kpa /
KN
1 / 1.5 / 13.785 / 6.90 / 1.085 / 7.48 / 16.082
2 / 3.0 / 27.57 / 13.785 / 1.05 / 14.47 / 31.11
3 / 4.57 / 42.02 / 21.01 / 1.04 / 21.85 / 46.97
4 / 6.1 / 56.03 / 28.01 / 1.02 / 28.57 / 61.44
5 / 7.62 / 70.04 / 35.02 / 0.98 / 34.32 / 73.79
6 / 9.14 / 84.05 / 42.03 / 0.96 / 40.34 / 86.74
7 / 10.67 / 98.06 / 49.03 / 0.95 / 46.58 / 100.14
8 / 12.19 / 112.07 / 56.04 / .94 / 52.67 / 113.25
Total Skin friction Qs = / 529.52 Kn

Pile point bearing capacity / END Bearing capacity:

Average =Su=

=31.49

Ppu = 9Su Ap Ap =

= 9x31.49x.164 =

= 46.47 KN = 0.164 sq.m

Total pile bearing capacity Pu = Ppu+Qs

= 46.47 + 529.52

= 575.99 Kv

Allowable bearing capacity =

Let F.S = 3 =

= 191.99 KN

Given Data:

Depth SPT Value

• Water Table at GL 05′ 08
• Pile Cut of level 1.5m below from G.L 10′ 08

15′ 07

20′ 15

25′ 18

30′ 25

35’ 30

VESIC Method: 40’ 40

Point bearing capacity /END bearing Capacity:

Ppu = Ap (

n = Ko = 1-sin

=0638 = 1- sin 32.8

= 0.458

Overburden pressure, = (sat-w)H

= (19-9.81) x12.19

= 112.07 Kn/m2

(L/B = )

= 1.38

Pile crossection Area , Ap =

=

= 0.164 Sq-m

bearing capacity factor,(Table 16-2, Page 895)

bearing capacity factor,(Table 16-2, Page 895)

bearing capacity factor, Ny = 22.4 (Table 44 Page 223)

Y’ = (19-9.81) = 9.19 Kn/m2

Ppu = Ap (

=0.164 (0.638 x 112.07 x 51.02 x 1.38 + ½ x 9.19 x 0.4872 x 22.4)

= 833.32 KN.

Skin friction Renistance By VESIC Memod

= x u (10) 1.54 dr4--- Kpa-----(16-16)

Dr= 25.Po-0.12 N600.46...... (3-8a)

Skin friction Resistance (Qs1) at EL 5’ ~10’

Effective pile surface are, As =

=

= 2.15 sq-m

Overburden pressure, Po’ = (19-9.81) x 1.5

= 13.785 kn/m2

Cn =

=2.63

Average Energy ratio, = 60/70 = 0.85

Rod length correction, = 0.75

Sampler connection, = 0.80

Bonehole diameter (150) correction, = 1.05

N60 = Cn x N x x x x

= 2.63 x 8x 0.85 x 0.75 x 0.8 x 1.05

= 11.26

Dr = 25 x Po-.12

= 25 x 13.785-0.12 (11.26)0.46

= 25 x 0.72 x 3.04

= 54.82 %

= 0.54

Qs1 = Asfs fs = Xu101.54 Dr4 Xu= 2.5

= 2.15x3.45 = 2.5

= 7.43 kn = 3.45

Skin friction Resistance (Qs2) at EL 10’ ~15’

Effective pile surface are, As =

=

= 2.15 sq-m

Overburden pressure, Po’ = (19-9.81) x 3.0

= 27.57 kn/m2

Cn =

=1.86

Average Energy ratio, = 60/70 = 0.85

Rod length correction, = 0.75

Sampler connection, = 0.80

Bonehole diameter (150) correction, = 1.05

N60 = Cn x N x x x x

= 1.86 x 8x 0.85 x 0.75 x 0.8 x 1.05

= 7.968

Dr = 25 x Po-.12

= 25 x 27.57-0.12 (7.968)0.46

= 25 x 0.67 x 2.59

= 43.51 %

= 0.43

Qs2 = Asfs fs = Xu101.54 Dr4 Xu= 2.5

= 2.15x2.82 = 2.5

= 6.06 kn = 2.82

Skin friction Resistance (Qs3) at EL 15’ ~20’

Effective pile surface are, As =

=

= 2.15 sq-m

Overburden pressure, Po’ = (19-9.81) x 4.57

= 41.998 kn/m2

Cn =

=1.51

Average Energy ratio, = 60/70 = 0.85

Rod length correction, = 0.85

Sampler connection, = 0.80

Bonehole diameter (150) correction, = 1.05

N60 = Cn x N x x x x

= 1.51 x 7x 0.85 x 0.85 x 0.8 x 1.05

= 6.41

Dr = 25 x Po-.12

= 25 x( 41.998)-0.12 (6.41)0.46

= 25 x 0..63 x 2.35

= 37.51 %

= 0.37

Qs3 = Asfs fs = Xu101.54 Dr4 Xu= 2.5

= 2.15x2.76 = 2.5

= 5.95 kn = 2.76

Skin friction Resistance (Qs4) at EL 20’ ~25’

Effective pile surface are, As =

=

= 2.15 sq-m

Overburden pressure, Po’ = (19-9.81) x 6.09

= 56.04 kn/m2

Cn =

=1.037

Average Energy ratio, = 60/70 = 0.85

Rod length correction, = 0.95

Sampler connection, = 0.80

Bonehole diameter (150) correction, = 1.05

N60 = Cn x N x x x x

= 1.037 x 15x 0.85 x 0.95 x 0.8 x 1.05

= 13.29

Dr = 25 x Po-.12

= 25 x( 56.04)-0.12 (13.29)0.46

= 25 x 0..61 x 3.28

= 50.12 %

= 0.50

Qs4 = Asfs fs = Xu101.54 Dr4 Xu= 2.5

= 2.15x3.12 = 2.5

= 6.70 kn = 3.12

Skin friction Resistance (Qs5) at EL25’ ~30’

Effective pile surface are, As =

=

= 2.15 sq-m

Overburden pressure, Po’ = (19-9.81) x 7.62

= 70.04 kn/m2

Cn =

= 1.17

Average Energy ratio, = 60/70 = 0.85

Rod length correction, = 1.0

Sampler connection, = 0.80

Bonehole diameter (150) correction, = 1.05

N60 = Cn x N x x x x

= 1.17x 18 x .85 x 1.0 x 0.8 x 1.05

= 15.03

Dr = 25 x Po-.12

= 25 x( 70.04)-0.12 (15.03)0.46

= 25 x 0.60x 3.48

= 52.2%

= 0.52

Qs5 = Asfs fs = Xu101.54 Dr4 Xu= 2.5

= 2.15x3.24 = 2.5

= 6.96 kn = 3.24

Skin friction Resistance (Qs6) at EL 30’ ~35’

Effective pile surface are, As =

=

= 2.15 sq-m

Overburden pressure, Po’ = (19-9.81) x 9.15

= 84.05 kn/m2

Cn =

= 1.06

Average Energy ratio, = 60/70 = 0.85

Rod length correction, = 1.0

Sampler connection, = 0.80

Bonehole diameter (150) correction, = 1.05

N60 = Cn x N x x x x

= 1.06 x 25 x .85 x 1.0 x 0.8 x 1.05

= 18.92

Dr = 25 x Po-.12

= 25 x( 84.05)-0.12 (18.92)0.46

= 25 x 0.58x 3.86

= 56.07%

= 0.56

Qs6 = Asfs fs = Xu101.54 Dr4 Xu= 2.5

= 2.15x3.54 = 2.5

= 7.61 kn = 3.54

Skin friction Resistance (Qs7) at EL 35’ ~40’

Effective pile surface are, As =

=

= 2.15 sq-m

Overburden pressure, Po’ = (19-9.81) x 10.67

= 98.06 kn/m2

Cn =

=0.98

Average Energy ratio, = 55/70 = 0.78

Rod length correction, = 1.0

Sampler connection, = 0.80

Bonehole diameter (150) correction, = 1.05

N60 = Cn x N x x x x

= 1.06 x 30 x .85 x 1.0 x 0.8 x 1.05

= 20.99

Dr = 25 x Po-.12

= 25 x( 98.06)-0.12 (20.99)0.46

= 25 x 0.57x 4.05

= 57.8%

= 0.57

Qs7 = Asfs fs = Xu101.54 Dr4 Xu= 2.5

= 2.15x3.63 = 2.5

= 7.82 kn = 3.63

Skin friction Resistance (Qs8) at EL 40’ ~45’

Effective pile surface area, As =

=

= 2.15 sq-m

Overburden pressure, Po’ = (19-9.81) x 12.19

= 112.07 kn/m2

Cn =

= .924

Average Energy ratio, = 55/70 = 0.78

Rod length correction, = 1.0

Sampler connection, = 0.80

Bonehole diameter (150) correction, = 1.05

N60 = Cn x N x x x x

= .924 x 40 x .85 x 1.0 x 0.8 x 1.05

= 26.38

Dr = 25 x Po-.12

= 25 x( 112.07)-0.12 (26.38)0.46

= 25 x 0.56x 4.5

= 63.08%

= 0.63

Qs8 = Asfs fs = Xu101.54 Dr4 Xu= 2.5

= 2.15x4.37 = 2.5

= 9.39 kn = 4.37

Total Skin friction Resistance

= 7.43 + 6.06 + 5.95 + 6.70+ 6.96 + 7.61 + 7.82 + 9.93 = 57.92 KN

Total piple bearing Capacity

Qu = Ppu +QS

= 833.32 + 57.92

= 891.24

Let F.S = 3

Allowable bearing capacity =

1

Pile length = 40’ = 12.19 m

Pile Dia = 18” = 0.4572m

1 / 2 / 3 / 4 / 5 / 6 / 7 / 8 / 9 / 10 / 11 / 12 / 13
Incensement ambedment length / SPT value N / over bunden Pressure Po’= () x / CN = / / / / / N60=CN N xx x x / Dr = / As= P x / fs = Xu101.54 Dr4 / Skin friction Asfs
1.5 / 8 / 13.785 / 2.63 / 0.85 / .75 / 0.8 / 1.05 / 11.26 / 0.4 / 2.15 / 3.45 / 7.43
3.0 / 8 / 27.57 / 1.86 / 0.85 / .75 / 0.8 / 1.05 / 7.968 / 0.43 / 2.15 / 2.82 / 6.06
4.57 / 7 / 41.998 / 1.51 / 0.85 / 0.85 / 0.8 / 1.05 / 6.41 / 0.37 / 2.15 / 2.70 / 5.95
6.09 / 15 / 56.4 / 1.307 / 0.85 / 0.95 / 0.8 / 1.05 / 13.29 / 0.5 / 2.15 / 3.12 / 6.70
7.62 / 18 / 70.04 / 1.17 / 0.85 / 1.0 / 0.8 / 1.05 / 15.03 / 0.52 / 2.15 / 3.24 / 6.96
9.15 / 25 / 84.05 / 1.06 / 0.85 / 1.0 / 0.8 / 1.05 / 18.92 / 0.50 / 2.15 / 3.54 / 7.61
10.67 / 30 / 98.06 / 0.98 / 0.85 / 1.0 / 0.8 / 1.05 / 20.99 / 0.57 / 2.15 / 3.63 / 7.82
12.19 / 40 / 112.07 / 0.924 / 0.85 / 1.0 / 0.8 / 1.05 / 26.38 / 0.63 / 2.15 / 4.37 / 9.39

Pile point/END Bearing capacity KN

Skin Function Resistance KN