pondasi dalam 2

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DAYA DUKUNG FONDASI DALAM

TIANG PANCANG DAN TIANG BOR

Idrus Ir M.Sc IPM

PERHITUNGAN

PONDASI

Daya Dukung Aksial Pile

Daya Dukung Lateral PileAnalisis Group Pile

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Load Transfer Friksi

Load Transfer End Bearing

displacement

Friksi

0.4% Diameter Pile

displacement

EndBearing

6% Diameter Pile

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AXIAL LOAD TEST PILE #14

Lo

ad

(T

on

s)

Settlement (mm)

Friction(Elastic Zone)

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Settlement (mm)

AXIAL LOAD TEST FOR PILE #22L=45m, f=60 cm

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Rumus umum daya dukung aksial fondasi dalam:

Qult = Qs + Qp

Qs = Tahanan Geser Selimut TiangQp = Tahanan Ujung Tiang

DAYA DUKUNG AKSIAL

Qu = Qp + Qs

Qp

Qs =Σ2πr ∆l (α C)

+ Σ2πr ∆l (k σv tanδ)

.S.F

QQ u

all =

=Ap(c Nc +q Nq)

∆l

σv

κ σv

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Jenis HammerCara uji SPT

C (t/m2) = 2/3 N

N-SPT = Jumlah pukulan untuk memasukkan split spoon sedalam 30 cm

SPT (Standard Penetration Test)

Relationship between Cohesion and N-Value (Cohesive soil)

2/3 N

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Relationship between Angle of Internal Friction and N-Value (Sandy Soil)

Faktor Koreksi N – SPT Lapangan seusai dengan

Metoda Pelaksanaan Test:

Country

Hammer Type

Hammer Release

Estimated Rod Energy (%)

Correction Factor for 60% Rod Energy

Donut

Free Fall

78

78/60 = 1.30 Japan

Donut

Rope an Pulley with special throw release

67

67/60 = 1.12

Safety

Rope and Pulley

60

60/60 = 1.00 US

A

Donut

Rope and Pulley

45

45/60 = 0.75 Argentina

Donut

Rope and Pulley

45

45/60 = 0.75

Safety

Rope and Pulley

60

60/60 = 1.00 US

A

Donut

Rope and Pulley

45

45/60 = 0.75 Argentina

Donut

Rope and Pulley

45

45/60 = 0.75

Donut

Free Fall

60

60/60 = 1.00 China Donut

Rope and Pulley

50

50/60 = 0.83

Harga N free fall tidak perlu dikoreksi krn menjadi standard

Harga N rope and pulley harus dikalikan dengan 0.70

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CPT (Cone Penetration Test) atau Sondir CPT (Cone Penetration Test) atau Sondir

C= qc/(15 sampai 20) dalam kg/cm2

Tahanan Geser Selimut

Tanah Kohesif Tiang PancangTiang Bor

Tanah PasirTiang PancangTiang Bor

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Tahanan Geser Selimut Tiang :

1. Tahanan geser selimut tiang yang merupakan kontribusi dari Cohesi Tanah adalah:

Qs = αααα . Cu. Li. PDimana,αααα = Koefisien adhesi antara tanah dan tiangCu = Undrained CohesionLi = Panjang lapisan tanahp = keliling tiang

Tahanan Geser Selimut Tiang :

2. Tahanan geser selimut tiang yang merupakan kontribusi dari sudut geser dalam ( φφφφ) adalah:

Qs = fi.Li.pDimana,fi = tahanan geser selimut tiang per satuan luasfi = Ko . σσσσo’. Tan (2/3 . φφφφ)Li = Panjang lapisan tanahp = keliling tiang

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Faktor Adhesi (α) pada Tanah Kohesif untuk

“Tiang Pancang” :

1. API Metode - 2, 1986



2. Tomlinson, 1977 :Tergantung pada

kondisi tanah.

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“Tiang Bor” :

1. Reese and Wright, 1977 :Manurut Reese dan Wright koefisien αααα untuk bored pile adalah 0.55

2. Kulhawy, 1984( k N / m )

U n d r a in e d S h e a r in g R e s is t a n c e , s ( t s f )

Ad

hesio

n f

acto

r (

)

α

T o m l in s o n , 1 9 5 7 ( c o n c r e t e p ile s )

6 5 U 8 4 1 C lo a d t e s t s

= 0 . 2 1 + 0 .2 6 p / s ( < 1 )

u

α a u

S h a f t s in c o m p r e s s io n

S h a f t s in u p l i f t

2

D a t a g r o u p 1

D a t a g r o u p 2

D a t a g r o u p 3

D a t a g r o u p 3

D a t a g r o u p 2

D a t a g r o u p 1

Perbandingan Harga Faktor Adhesi (α) dari

Beberapa Metede pada Tanah Kohesif untuk

“Tiang Bor” :

0.00

0.20

0.40

0.60

0.80

1.00

1.20

0 50 100 150 200 250 300

S u (kN/m 2)

ad

he

sio

n f

ac

tor

Design =( Kulhawy + Reese)/2

Kulhawy

ReeseC ore Team

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“Tiang Bor” :

3. Reese and O’Neil, 1988 :

Undrained Shear Strength, Su

Value of α

< 2 tsf 2 – 3 tsf 3 – 4 tsf 4 – 5 tsf 5 – 6 tsf 6 – 7 tsf 7 – 8 tsf 8 – 9 tsf > 9 tsf

0.55 0.49 0.42 0.38 0.35 0.33 0.32 0.31

Treat as Rock

Tahanan Geser Selimut Tiang dari Tanah Berpasir

Menurut Naval Engineering Facilities Command:

1. Tiang Pancang :

Qs = 0.2 x (N SPT) x Li x p (ton)

2. Tiang Bor :

Qs = 0.1 x (N SPT) x Li x p (ton)

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Tahanan Geser Selimut Tiang Bor pada Tanah

Berpasir �Rojiani, Duncan and Barker (1991)

= 0.11 N (t/m2)

= 0.28 N (t/m2)

(=27.5 t/m2)

=0.32 N (t/m2) N < 53

Z=depth below ground surface

0.20 N

Tahanan Ujung

Tanah C dan φ untuk dasar teori

Tanah LempungTiang PancangTiang Bor

Tanah PasirTiang PancangTiang Bor

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Tahanan Unjung Tiang

- φ dan Cu

Tahanan Ujung Tiang Pada Umunya dinyatakan sebagai

persamaan :

Qp = Ap (c Nc* + q’ Nq*)

Dimana,

Qp = Tahanan Ujung Ultimate

Ap = Luas Penampang Tiang

C = Undrained kohesi

q = Over Bourden Pressure

Nc, Nq= Faktor daya dukung.

Beberapa Motode Penentuan Faktor Daya Dukung

- φ dan Cu

1. Meyerhoff, 1976

0 10 20 30 40 45

2

1

4

6

810

20

40

60

80100

200

400

600

800

1000

an

d

Soil friction angle, Ø (deg)

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Beberapa Motode Penentuan Faktor Daya Dukung:

2. Vesic, 1977Nc = (Nq – 1) cot φφφφ

Dimana, Nq = f(Irr)Nq* = 4/3 ln (Irr + 1) + ππππ/2 +1

I rr = I r Nilai I r ditunjukkan pada tabel dibawah:

Soil type Ir Sand 70 – 150 Silts and clays (drained condition) 50 – 100 Clays (undrained condition) 100 – 200

- φφφφ dan Cu

Beberapa Motode Penentuan Faktor Daya Dukung:

3. Janbu, 1976

S oil fr ictio n ang le , Ø (deg)

0 10 20 30 40 4 51

2

4

6

8

10

20

40

60

80

1 00

2 00

4 00

6 00

8 0010 00

an

d

- φφφφ dan Cu

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Daya Dukung Ujung untuk Tanah Kohesif Cu

Tiang Pancang dan Tiang Bor:

Qp = 9 x Cu x Ap

Daya Dukung Ujung untuk Tanah Pasiran φφφφ

�Tiang Pancang :

Qp = 40 x N SPT x Ap

Dimana,N–SPT = (N1+N2)/2

N1= harga rata-rata N dari dasar ke 10-D keatasN2= harga rata-rata N dari dasar ke 4-D kebawah

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Nilai N – SPT Desain

adalah:

Ndesain = ½ (N1 +N2)

NILAI N – SPT UNTUK DESIGN TAHANAN UJUNG PADA TANAH PASIRAN φ :

D

(4 x D) dirata-rata untuk desain tahanan ujung = N2

(10 x D) dirata-rata untuk desain tahanan ujung = N1

Ground Sur face

Tiang Pancang

Daya Dukung Ujung untuk Tanah Pasiran Tiang BorTiang BorTiang BorTiang Bor

=7 N (t/m2)

=400 (t/m2)

qp = 7 N (t/m2) < 400 (t/m2)

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Daya Dukung Ujung Tiang Bor Tanah Pasiran φ:

Qb = σ σ σ σv.Nq.Ab

Kulhawy, 1983

DAYA DUKUNG AKSIAL

Qu = Qp + Qs

Qp

Qs =Σ2πr ∆l (α C)

+ Σ2πr ∆l (k σv tanδ)

.S.F

QQ u

all =

=Ap(c Nc +q Nq)

∆l

σv

κ σv

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Summary

τ

qp

Clay Sand

Pancang PancangTiang Bor Tiang Bor

αααα C αααα C

Untuk PancangAPI

Untuk Tiang BorKulhawy, 84Reese, 88

0.2 N

(Meyerhof)

0.2 N

(Rata2 antaraMeyerhof, 76 danReese+Wright, 77)

9999 C40 N

< 1600 t/m2

N=(N1+N2)/2

7 N (t/m2) < 400 (t/m2)

(Reese+Wrihgt, 77) (Meyerhof)

Pult = 2πr Σ ∆l τ + πr2 qp



1. API Metode - 2, 1986

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“Tiang Bor” :

1. Reese and Wright, 1977 :Manurut Reese dan Wright koefisien αααα untuk bored pile adalah 0.55

2. Kulhawy, 1984( k N / m )

U n d r a in e d S h e a r in g R e s is t a n c e , s ( t s f )

Ad

hesio

n f

acto

r (

)

α

T o m l in s o n , 1 9 5 7 ( c o n c r e t e p ile s )

6 5 U 8 4 1 C lo a d t e s t s

= 0 . 2 1 + 0 .2 6 p / s ( < 1 )

u

α a u

S h a f t s in c o m p r e s s io n

S h a f t s in u p l i f t

2

D a t a g r o u p 1

D a t a g r o u p 2

D a t a g r o u p 3

D a t a g r o u p 3

D a t a g r o u p 2

D a t a g r o u p 1

D

(4 x D)dirata-rata untukdesain tahanan ujung = N2

(10 x D)dirata-rata untukdesain tahanan ujung = N1

Ground Surface

Tiang Pancang

Ndesain = ½ (N1 +N2)

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SF Criterion Based on Canadian Foundation Engineering Manual (1992)

SF Criterion Based on Tomlinson (1977)

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Lensa Pada Group Tiang:

(Tomlinson, 1977)

Ketebalan Lapisan Tanah Yang Harus Diperhitungkan Dalam

Perhitungan Daya Dukung :

3-4B

a=4B

b=6-8 B

Minimal kedalaman penyelidikan tanah adalah sampai 4 diameter tiang (atau 5 m) dibawah dasar pondasi

3-4B

a=4B

b=6-8 B

3-4B3-4B

a=4B

b=6-8 B

Minimal kedalaman penyelidikan tanah adalah sampai 4 diameter tiang (atau 5 m) dibawah dasar pondasi

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Cross section of Soil Investigation

28.20

R1

32.20

R2

36.95

R5

36.9738.2038.20

R5 R5

38.20

R5 R2 R1

38

20

2221

78

4488

47

21

29

2734

24

1918

27

3224

23

22

41

25

1921

BT-2

18

20

33

22

22

24

19

18

17

18

50

37

BH-201

3

10

5

31.0036.95

R1 R3R2

38.20 38.2031.00

R4R4

43.20

R5R3

38.20 36.95

R2R5

38.20

R1

66

32

26

30

16

80

88

36

29

27

50

3334

45

912

32

54

62

60

39

33

50

18

26

21

90

8

6

10

10

6

BT-1

Proposed Additional Soil Investigation

Proposed Additional Soil Investigation

BH-201 BT-02

BT-01BH-202

Qult = 1610 ton

East Side (STA 1+050)

45m

Bored Pile Diameter 1,5m, panjang 45m

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Very stiff

Very stiff

Very stiff

Soft

Hard

Hard

Dense

Dense

Axial Capacity of Single Bored PileBased on Data at Sta 1+050

Positive Qbαααα Cu As or 0.2N As (Ton)

1 0.0 - 2.0 2.02 2.0 - 6.0 4.0 Clayey Silts 3 2.0 0.80 1.6 30.8 31 77.3 108.1 433 6.0 - 9.0 3.0 Clayey Sand 10 25 4.0 14.1 45 218.8 263.7 1054 9.0 - 11.5 2.5 Clayey Sand 37 30 14.8 43.6 88 618.5 707.0 2835 11.5 - 12.5 1.0 Sandstone 80 40 20.0 23.6 112 356.9 468.9 1886 12.5 - 15.0 2.5 Clayey Silts 33 22.4 0.46 10.3 121.6 234 237.9 471.6 1897 15.0 - 19.0 4.0 Clayey Silts 22 15.0 0.49 7.3 137.5 371 162.2 533.4 2138 19.0 - 22.0 3.0 Silty Clay 15 10.2 0.53 5.4 75.9 447 299.2 746.2 2989 22.0 - 30.0 8.0 Silty Clay 21 14.3 0.49 7.0 264.6 712 302.8 1014.4 40610 30.0 - 32.0 2.0 Silty Clay 39 26.5 0.45 12.0 112.9 824 245.1 1069.6 42811 32.0 - 33.0 1.0 Silty Clay 23 15.6 0.48 7.6 35.7 860 248.7 1108.9 44412 33.0 - 34.0 1.0 Silty Clay 22 15.0 0.49 7.3 34.4 895 270.4 1164.9 46613 34.0 - 35.0 1.0 Silty Clay 23 15.6 0.48 7.6 35.7 930 288.4 1218.6 48714 35.0 - 36.0 1.0 Silty Clay 24 16.3 0.48 7.8 37.0 967 299.2 1266.4 50715 36.0 - 37.0 1.0 Silty Clay 28 19.0 0.47 8.9 42.2 1009 274.0 1283.3 51316 37.0 - 38.0 1.0 Silty Clay 28 19.0 0.47 8.9 42.2 1051 259.6 1311.0 52417 38.0 - 39.0 1.0 Silty Clay 27 18.4 0.47 8.7 40.9 1092 227.1 1319.4 52818 39.0 - 40.0 1.0 Silty Clay 21 14.3 0.49 7.0 33.1 1125 237.9 1363.3 54519 40.0 - 41.0 1.0 Silty Clay 21 14.3 0.49 7.0 33.1 1158 248.7 1407.2 56320 41.0 - 42.0 1.0 Silty Clay 23 15.6 0.48 7.6 35.7 1194 302.8 1497.0 59921 42.0 45.0 3.0 Silty Clay 28 19.0 0.47 8.9 126.5 1321 254.2 1574.8 63022 45.0 - 47.0 2.0 Silty Clay 28 19.0 0.47 8.9 84.3 1405 205.5 1610.4 64423 47.0 - 50.0 3.0 Silty Clay 19 12.9 0.50 6.5 91.4 1496 227.1 1723.5 68924 50.0 - 55.5 5.5 Silty Clay 21 14.3 0.49 7.0 181.9 1678 1618.5 3296.8 131925 55.5 - 60.5 5.0 Silty sand 60 40 20.0 116.6 1795 1618.5 3413.4 1365

No. DepthTebal

Lapisan (m)Deskripsi Qult (Ton)

Qall (ton) SF = 2.5

Pile Cap

Skin Friction (ton)Kumulatif

Friction (ton)

End Bearing (ton)ααααN-SPT c (t/m2) φφφφ

Unit Skin Frinction

(t/m2)

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Medium stiff

Stiff

Hard

Very Hard

Hard

Very stiff

Dense

Dense

Axial Capacity of Single Bored PileBased on Data at Sta 0+490

Flyover CirebonSkin Friction (ton)

Positive Qbαααα Cu As or 0.2N As (Ton)

1 0.0 - 3.0 3.0 Clayey Silts 8 5.2 0.55 40.1 40 82.7 122.8

2 3.0 - 6.0 3.0 Clayey Silts 8 5.2 0.55 40.1 80 82.7 162.8

3 6.0 - 9.0 3.0 Clayey Silts 8 5.2 0.55 40.1 120 103.4 223.6

4 9.0 - 11.6 2.6 Clayey Silts 12 7.8 0.49 47.0 167 737.8 905.0

5 11.6 - 12.9 1.3 Tuffaceous Sand 90 35 30.6 198 450.8 648.7

6 12.9 - 17.0 4.1 Silty Sand 22 30 42.5 240 320.5 560.8

7 17.0 - 24.0 7.0 Silty Clay 31 20.2 0.43 284.2 525 620.3 1144.8

8 24.0 - 30.2 6.2 Tuffaceous Silt 60 39.0 0.41 460.9 985 408.3 1393.8

9 30.2 - 31.0 0.9 Tuffaceous Silt 45 29.3 0.41 48.6 1034 389.4 1423.4

10 31.0 - 32.0 1.0 Tuffaceous Silt 34 22.1 0.42 44.1 1078 351.5 1429.7

11 32.0 - 33.0 1.0 Tuffaceous Silt 34 22.1 0.42 44.1 1122 351.5 1473.8

12 33.0 - 34.0 1.0 Tuffaceous Silt 33 21.5 0.43 43.0 1165 341.1 1506.4

13 34.0 - 35.0 1.0 Tuffaceous Silt 33 21.5 0.43 43.0 1208 341.1 1549.4

14 35.0 - 36.0 1.0 Tuffaceous Silt 34 22.1 0.42 44.1 1252 351.5 1603.9

15 36.0 - 37.0 1.0 Tuffaceous Silt 36 23.4 0.42 46.5 1299 372.2 1671.1

16 37.0 - 38.0 1.0 Tuffaceous Silt 38 24.7 0.42 48.9 1348 392.8 1740.7

17 38.0 - 39.0 1.0 Tuffaceous Silt 27 17.6 0.43 35.9 1384 279.1 1662.8

18 39.0 - 40.0 1.0 Tuffaceous Silt 29 18.9 0.43 38.2 1422 299.8 1721.7

19 40.0 - 41.0 1.0 Tuffaceous Silt 29 18.9 0.43 38.2 1460 299.8 1759.9

20 41.0 - 42.6 1.6 Tuffaceous Silt 30 19.5 0.43 63.1 1523 237.8 1761.0

21 42.6 - 46.0 3.4 Tuffaceous Silt 23 15.0 0.44 105.8 1629 237.8 1866.8

22 46.0 - 46.0 0.0 Tuffaceous Silt 23 15.0 0.44 0.0 1629 620.3 2249.3

N-SPT c (t/m2) φφφφ ααααNo. DepthTebal

Lapisan (m)Deskripsi Kumulatif

Friction (ton)Qult (Ton)

End Bearing (ton)

2.41.0

45.0

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29 25 15 0.5 7.5 112.5 108 175 242

27 20 12 0.5 6.0 30 144 210 300

314 430

Prediksi Daya Dukung Tiang PancangTambak Lorok

rope and pulley (bukan free falling)

Based on Bored P-0 1.20

Skin Friction End Bearing

0.01 0.0 - 1.0 1.0 Silty Gravel 0 0.0 1.00 0.0 0 0 02 1.0 - 2.0 1.0 Silty Gravel 0 0.0 1.00 0.0 0 0 03 2.0 - 3.0 1.0 Silty sandy clay 5 3.0 0.80 9.0 9 31 404 3.0 - 4.0 1.0 Silty sandy clay 5 3.0 0.80 9.0 18 31 495 4.0 - 5.0 1.0 Silty sandy clay 7 4.2 0.62 9.8 28 43 716 5.0 - 6.0 1.0 Silty sandy clay 11 6.6 0.26 6.5 34 67 1027 6.0 - 7.0 1.0 Silty sandy clay 11 6.6 0.26 6.5 41 67 1088 7.0 - 8.0 1.0 Medium - Stiff clay 6 3.6 0.71 9.6 50 37 879 8.0 - 9.0 1.0 Medium - Stiff clay 20 12.0 0.40 18.1 69 122 19110 9.0 - 10.0 1.0 Tuffaceous 20 12.0 0.40 18.1 87 122 20911 10.0 - 11.0 1.0 Tuffaceous 31 18.6 0.40 28.0 115 189 30414 11.0 - 12.0 1.0 Tuffaceous 60 36.0 0.40 54.3 169 366 53515 12.0 - 13.0 1.0 Tuffaceous 60 36.0 0.40 54.3 223 366 59016 13.0 - 14.0 1.0 Tuffaceous 37 22.2 0.40 33.5 257 226 48317 14.0 - 15.0 1.0 Tuffaceous 48 28.8 0.40 43.4 300 293 59318 15.0 - 16.0 1.0 Tuffaceous 51 30.6 0.40 46.1 346 311 65819 16.0 - 17.0 1.0 Tuffaceous Silty sand with Gravel 51 30.6 0.40 46.1 392 311 70420 17.0 - 18.0 1.0 Tuffaceous Silty sand with Gravel 57 34.2 0.40 51.6 444 348 79221 18.0 - 19.0 1.0 Tuffaceous Silty sand with Gravel 62 37.2 0.40 56.1 500 379 87922 19.0 - 20.0 1.0 Tuffaceous Silty sand with Gravel 62 37.2 0.40 56.1 556 379 93523 20.0 - 21.0 1.0 Tuffaceous Silty sand with Gravel 54 32.4 0.40 48.9 605 330 93524 21.0 - 22.0 1.0 Tuffaceous Silty sand with Gravel 54 32.4 0.40 48.9 654 330 98425 22.0 - 23.0 1.0 Tuffaceous Silty sand with Gravel 60 36.0 0.40 54.3 708 366 107526 23.0 - 24.0 1.0 Tuffaceous Silty sand with Gravel 60 36.0 0.40 54.3 763 366 112927 24.0 - 25.0 1.0 Tuffaceous Silty sand with Gravel 51 30.6 0.40 46.1 809 311 112028 25.0 - 26.0 1.0 Tuffaceous Silty sand with Gravel 51 30.6 0.40 46.1 855 311 116629 26.0 - 27.0 1.0 Tuffaceous Silty sand with Gravel 39 23.4 0.40 35.3 890 238 112830 27.0 - 28.0 1.0 Tuffaceous silt very stiff 39 23.4 0.40 35.3 925 238 116431 28.0 - 29.0 1.0 Tuffaceous silt very stiff 47 28.2 0.40 42.5 968 287 125532 29.0 - 30.0 1.0 Tuffaceous silt very stiff 47 28.2 0.40 42.5 1010 287 129733 30.0 - 31.0 1.0 Gravel with sand noncemented 60 12 45.2 1056 452 150834 31.0 - 32.0 1.0 Gravel with sand noncemented 60 12 45.2 1101 452 155335 32.0 - 33.0 1.0 Tuffaceous silty sand very stiff 30 18.0 0.40 27.1 1128 183 131136 33.0 - 34.0 1.0 Tuffaceous silty sand very stiff 35 21.0 0.40 31.7 1160 214 137337 34.0 - 35.0 1.0 Tuffaceous silty sand very stiff 35 21.0 0.40 31.7 1191 214 140538 35.0 - 36.0 1.0 Tuffaceous silty sand very stiff 42 25.2 0.40 38.0 1229 257 1486

Maximum end bearing 400 ton/m2

N-SPT c (t/m2) ττττααααα α α α Cu As or

0.2N As

KsNo. DepthTebal

Lapisan (m)

Deskripsi

C N atau qNq Ap

Meyerhof

Kumulatif Friction (ton)

Qult (Ton)

Bored Pile Kiara Condong

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Pelaksanaan Bored Pile


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Slurry Method

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Casing Method

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Method Statement of Bored Pile

Casing Installation Drilling Process Cleaning at Final Depth

Reinforcement Installation

Pouring Concrete Temporary CasingRemoval

Bored Piling Method of Works

Drilling tools

Auger Cleaning bucket

Underreamer

Roller bit core barrel

Drill Bucket

Round shank Core BarrelTapered rock auger

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Sambungan Tiang Pancang

Sambungan Tiang Pancang

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Spesifikasiend bearing = 1 in/ 10 blows

Final Set = ? In/10 blows

Analisis Daya Dukung Berdasarkan Persamaan

Gelombang

A = cross-sectional area of pile Cm = relative displacement between two

adjacent pile elements

D?m = element displacement two time intervals back m

D?m = element displacement in preceding time interval DT m

Dm = current element displacement

DT = time interval (At on Error! Reference source not found.c) E = modulus of elasticity of pile material Fm = element force = Cm Km Fam = unbalanced force in element causing acceleration (F = ma)

g = gravitation constant J = damping constant, use Js for side

value, Jp = point value Km = element springs = AE/L for pile

segments K?m = soil springs = R/quake

L = length of pile element Rm = side or point resistance including

damping effects R?m = amount of estimated Pu on each

element including the point j for 100

m percent of Pu on point R3 through R11 of Error! Reference source not found.b are zero and R12 = Pu

t = current instant in time = number of iterations x DT

v = velocity of element m at DT

v?m = velocity of element m at DT - 1 Wm = weight of pile segment m

03/03/2012

34

Formula Dinamik ENR

CS

hWQu R

+⋅=

atau

CS

HEQu E

+= .

dimana:

Qu : Kapasitas daya dukung ultimateWR : Berat ram (kN)h : Tinggi jatuh ram (cm)S : Penetrasi tiang untuk setiap pukulan(m/blow)C : konstanta, untuk drop hammer = 2.54 cm, untuk steam hammer = 0.254 cmAngka keamanan yang direkomendasikan adalah 6.

Modified New ENR (recommended)

++

+=

PR

pRR

WW

WnW

CS

hWEQu

2..

dimana:

E : Efisiensi hammer C : 0.254 cm untuk unit S dan h dalam centimeter Wp : Berat tiang

n : koefisien restitusi antara ram dan pile cap Angka keamanan yang direkomendasikan adalah 6.

03/03/2012

35

Harga Efisiensi Hammer (E)dan Koef. Restitusi (n)

Tipe Hammer Efficiency, E

Single and Double acting hammer 0.7 – 0.8

Diesel Hammer 0.8 – 0.9 Drop Hammer 0.7 – 0.9

Pile Material Coefficient of restitution, n

Cast iron hammer and concrette pile (whitout cap) 0.4 – 0.5

Wood cushion on steel pile 0.3 – 0.4 Wooden pile 0.25 – 0.3

Michigan State Highway Commission

++

+=

PR

pRE

WW

WnW

CS

HQu

25.2

dimana:

HE : Rated hammer energy (from the factory) C : 0.254 cm Angka keamanan yang direkomendasikan adalah 6.

03/03/2012

36

Dannish’s Formula

+=

pp

E

E

EA

LHES

HEQu

..2

..

.

dimana:

Ep : Modulus Young dari material tiang

L : Panjang tiang Ap : Luas penampang tiang Angka keamanan yang direkomendasikan bervariasi dari 3 hingga 6.

Analisis Daya Dukung Berdasarkan Persamaan Gelombang

A = cross-sectional area of pile Cm = relative displacement between two

adjacent pile elements

D?m = element displacement two time intervals back m

D?m = element displacement in preceding time interval DT m

Dm = current element displacement

DT = time interval (At on Error!

Reference source not found.c) E = modulus of elasticity of pile material Fm = element force = Cm Km

Fam = unbalanced force in element causing acceleration (F = ma)

g = gravitation constant J = damping constant, use Js for side

value, Jp = point value

Km = element springs = AE/L for pile segments

K?m = soil springs = R/quake

L = length of pile element Rm = side or point resistance including

damping effects R?m = amount of estimated Pu on each

element including the point j for 100

m percent of Pu on point R3 through

R11 of Error! Reference source not found.b are zero and R12 = Pu

t = current instant in time = number of

iterations x DT v = velocity of element m at DT

v?m = velocity of element m at DT - 1 Wm = weight of pile segment m

03/03/2012

37

Contoh Perhitungan

Diameter PC Spun Pile : 400 mmBerat Tiang Per m : 200 kgBerat hammer pemancang : 3,45 (K – 35)Tinggi Jatuh : 1,60 mDaya Dukung Ultimate yang diinginkan : 210 ton.Daya Dukung Ijin yang diinginkan : 50 ton.

Perhitungan Final set :

SF = 6 �� ultimated bearing Capacity = 300 ton.

Contoh Perhitungan

1. Menggunakan Modified ENR Formula

pR

pRRu WW

WnW

CS

WEQ

++

×+

=2

.

cms

s

s

S

xs

S

x

248,0

)08,523(2106

82,119,5342106

783.102,782,11

300

)02,7()254.0(

82,11300

6,342,3

6,35.042,3

254.0

42,38,0300

2

−=−=

=++

=

+=

++×

+=

Final Set adalah 0,248 cm/blow �� 2,48 cm/10 blows.

03/03/2012

38

Contoh Perhitungan

2. Menggunakan formula dari Michigan state Highway Commision (1965)


pR

pREu WW

WnW

CS

HQ

++

×+×=

25.2

cms

s

ss

s

S

2258,0

)74,67(300

461,82,76300254.0

461,8300

6154.0254.0

75.13300

6,342,3

6,35,042,3

254.0

5,55.2300

2

−=−=

=++

=

×+

=

++×

+×=

Contoh Perhitungan

3. Menggunakan formula Danish


pp

E

Eu

EA

LHES

HEQ

.2

..+

=

blowcms

s

sS

S

S

/03,0

025,9300

75,2775,113000392.075,2

300

321300095,4

75,2300

10.1,20765,02185,55,0

5,55.0300

7

=−=

=++

=

+=

××××+

×=

03/03/2012

39

UJI BEBAN STATIS DAN

INTERPRETASINYA

Uji Beban :� Uji beban pendahuluan (preliminaries test )

dengan instrumentasi sampai kegagalan� Uji beban pembuktian (proof test )

Sampai 200% beban rencana, 100% atau kurang

Uji Beban Statis dan Interpretasinya (1)

Uji Beban :� Slow �� Slow maintained test (cyclic)� Quick : Quick maintained load

Constant rate of penetration (CRP)

Prinsip Interpretasi :� Batas penurunan� Rate of settlement (kecepatan penurunan)� Kegagalan didefinisikan dari bentuk kurva load & deformation

Uji Beban Tiang (tekan)

03/03/2012

40

Uji Beban Statis dan Interpretasinya (2)

Interpretasi uji beban :�Cara Davisson�Cara Mazurkiewics�Cara Chin

Kurva load vs settlement uji beban siklik

0

5

10

15

20

25

30

350 200 400 600 800 1000 1200 1400 1600

APPLIED LOAD (TONS)

SE

TT

LE

ME

NT

(M

M)

Cycle 1 Cycle 2 Cylce 3Cylce 4 Cycle 5 Cycle 6

03/03/2012

41

0

5

10

15

20

25

30

35

0 200 400 600 800 1000 1200 1400 1600

APPLIED LOAD (TONS)

SE

TT

LE

ME

NT

(M

M)

Cara Davisson

Metode Davisson

EA

QLe =δ

12015,0

Dx += inch

dimana �e = penurunan elastis Q = beban uji yang diberikan L = panjang tiang A = luas penampang tiang E = modulus elastisitas tiang

XQult = 1415 ton

Cara Mazurkiewics

03/03/2012

42

y = 0.0006x + 0.0036

0

0.005

0.01

0.015

0.02

0.025

0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00

SETTLEMENT (mm)

SE

TT

LE

ME

NT

/LO

AD

(m

m/t

on

)Cara Chin

Metode Chin

21 CCQ

+⋅= δδ

1

1

CQu =

Qu koreksi = 0,8 Qu

1/Qult = 0,0006 Qult = 1666,67 ton Faktor reduksi = 20 % Qult koreksi = 1333 ton

C2

0

5

10

15

20

25

0 200 400 600 800 1000 1200 1400 1600

Loads (ton)

Set

tlem

ent

(mm

)

Cara Davisson untuk cylce ke-6

Qult = 1505 ton

03/03/2012

43

Cara Chin untuk cycle ke-6

y = 0.0005x + 0.0036

0

0.002

0.004

0.006

0.008

0.01

0.012

0.014

0.016

0.018

0 5 10 15 20 25

Settlement (mm)

Set

tlem

ent/

Lo

ad (

mm

/to

n)

1/Qult = 0,0005 Qult = 2000 ton Faktor reduksi = 20 % Qult koreksi = 1600 ton

NEGATIVE SKIN FRICTION :�Terjadi kondisi dimana Pondasi direncanakan akan dipancang sampai

lapisan tanah keras sementara tanah di atasnya adalah lapisan kompresibel,

yang di atasnya terdapat timbunan. Tanah kompresibel ini akan mengalami

konsolidasi akibat adanya pertambahan beban timbunan. Selama proses

konsolidasi ini tanah akan bergerak relatif terhadap tiang. Sehingga,

menghasilkan tahanan geser ke bawah di sekeliling tiang

03/03/2012

44

NEGATIVE SKIN FRICTION :

Daerah Negative Skin Friction

Fill material

Soft soil,Consolidating soil

Bearing soil

03/03/2012

45

METODA PERHITUNGAN NEGATIVE SKIN FRICTION :� Negative Skin Friction pada Kondisi Un-Drained :

dimana,

α = faktor adhesi

Cu = undrained shear strength dari nilai N – SPT

Ks = Koeffisien lateral earth pressure.

δ = interface sudut geser dalam antar tiang dan tanah.

σv = effective overbourden pressure.

Prakash dan Sharma, 1990

( )zKsCu

P

vdiameterpile

LbLcLfx

LcLfxutseareafriction

∆Σ+Σ=

Ψ= ∑++=

+=

δσαπφ

τ

tan5,0

lim

tanah lempung tanah pasir

03/03/2012

46

METODA PERHITUNGAN NEGATIVE SKIN FRICTION :� Negative Skin Friction pada Kondisi Drained :

dimana,

σo’ = Effective vertical stress at depth z

f = pile diameter

Le = panjang effective dari lapisan yang terkonsolidasi yang menimbulkannegative skin friction. Lc = 0.75 Le

No = Non dimensional factor.

∫

∫+=

=

+=

=

∆××××=

∆×××=

LeLfz

z

LeLfz

z

negatif

zRN

zRQf

0

00

0

)(

πσ

πτ


METODA PERHITUNGAN NEGATIVE SKIN FRICTION :

� Non – dimensional factor (No):


Soil Type No

a. Uncoated Pile

- Sand 0.35 – 0.50

- Silt 0.25 – 0.35

- Clay 0.20 – 0.25

b. Coated Pile with Bitumen SL pile : τ = 0.2 ton/m2

� Alternative Pelapisan Bitument :

- Untuk mengurangi pengaruh terjadinya konsolidasi tanah lunak akibat timbunan

di atasnya bisa diupayakan dengan melakukan pelapisan bitument asphalt pada

tiang pancang sebelum dilakukan pemancangan.

- Pelapisan bitument dilakukan sepanjang lapisan lunak yang mengalami konsoli-

dasi.

- Dengan pelapisan bitument tersebut, negative skin friction yang terjadi bisa di-

minimasi.

03/03/2012

47

KAPASITAS IJIN TIANG YANG MENGALAMI NEGATIVE

SKIN FRICTION (NSF):


SF

NSFultimateijin

−= σσ

atau

NSFSFultimate

ijin −= σσ

� SF berkisar antara 2,0 – 3,0

03/03/2012

48

Pile Group Efficiency

Salah satu perilaku tiang group adalah ada group efficincy yang Berhubunan dengan parak tiang tunggal dalam group tiang:

(Nav Doc, September 1986)

03/03/2012

49

Pile Group Efficiency• CONVERSE – LABARRE FORMULA• (n-1)m + (m-1)n• Ŋ = 1 - ξ { ------------------------- } / 90• m n

• Ŋ = Factor Effisiensi Group• ξ = arc tan d/s (in degree)• m = jumlah baris• n = jumlah pile pada satu baris• d = diameter tiang • s = jarak antara tiang ke tiang

• l

m = 2 , n = 3 , d= 30 cm s=120 cm

ξ = arc tan 30/120

s

Transfer beban pada Group Tiang:

(Tomlinso, 1977)

03/03/2012

50

Settlement Analysis

Consolidation Settlement

03/03/2012

51

∆σ

Seluruh dipikul air

∆σ Seluruh dipikul Tanah

∆σ

∆σ∆σ

U + ∆σ U

S

pegas(tanah)

kecepatan air ditentukan permeabilitas

air

0 0

∆σ 0

PEMODELAN KONSOLIDASI PRIMER

Akibat pertambahan beban � kenaikan tekanan air pori

Keluarnya air dari pori � tekanan air pori kembali lagi (tanah settle)

Kurva Test Konsolidasi

03/03/2012

52

Persamaan untuk Menghitung Penurunan Konsolidasi (Normally Consolidated Clay)

o

avo

o

cc

p

p∆plog

e1

HC

++

Dimana,

p0 = tekanan efektif akibat berat sendiri

∆∆∆∆pav = tambahan tekanan efektif akibat beban diatas lapisan kompresible

e0 = initial void ratio

Cc = compression index

Hc = tebal lapisan lempung

Calculation of Settlement (STA 0+490)

γ γ γ γ ' σσσσ'b σσσσ'm ∆σ∆σ∆σ∆σ σσσσ1 =σσσσo+∆∆∆∆s Cc eo ∆∆∆∆s

(t/m3) (t/m

2) (t/m

2) (t/m

2) (t/m

2) (m)

1 0.0 - 3.0 3.02 3.0 - 6.0 3.03 6.0 - 9.0 3.04 9.0 - 11.6 2.65 11.6 - 12.9 1.36 12.9 - 17.0 4.17 17.0 - 24.0 7.08 24.0 - 26.5 2.5

9 26.5 30.0 3.510 30.0 - 33.0 3.0 0.7 2.1 1.1 4.04 5.1 0.05 0.6 0.0611 33.0 - 36.0 3.0 0.7 4.2 3.2 3.03 6.2 0.05 0.6 0.0312 36.0 - 39.0 3.0 0.7 6.3 5.3 2.36 7.6 0.05 0.6 0.0213 39.0 - 42.0 3.0 0.7 8.4 7.4 1.89 9.2 0.05 0.6 0.0114 42.0 - 44.0 2.0 0.7 9.8 9.1 1.65 10.8 0.07 0.55 0.0115 44.0 - 46.0 2.0 0.7 11.2 10.5 1.46 12.0 0.07 0.55 0.01

0.13AB Value Correction 0.7

0.09

No. DepthTebal

Lapisan (m)

Settlement (m)

Settlement (m)

31.5x0.7=22.0534.5x0.7=24.1537.5x0.7=26.2540.5x0.7=28.3543.0x0.7=30.1045.0x0.7=31.50

σσσσo”

26.0927.1828.6130.2431.7532.96

0.0070.0050.0040.0030.0020.0020.023

03/03/2012

53

Contoh-Contoh Pemilihan Jenis Pondasi

Location of Soil Investigation

S-3

S-1

S-2

S-4

S-5

S-6

03/03/2012

54

Soil ProfileBH 1.0 (EL+0.473) BH 1.1 (EL+0.582) BH 1.2 (EL+1.895)

BH 1.0 (EL+0.473) BH 1.1 (EL+0.582) BH 1.2 (EL+1.895) BH 1.3 (EL+0.942) BH 1.4 (EL+0.415)

SPUN PILE PENETRATIONWITHOUT PRE-AUGER

SPUN PILE PENETRATIONWITH PRE-AUGER

PIPE PILE PENETRATION

ESTIMATED MAXIMUM

ESTIMATED MAXIMUM

ESTIMATED MAXIMUM STEEL

(Ø = 600 mm, thickness = 140 mm)

Figure 8 - Estimated Maximum Length of Pile Penetration (Tank-1)Maximum penetration for precast concrete pile

Without preauger

With preauger

03/03/2012

55


WITHOUT PRE-AUGERSPUN PILE PENETRATIONESTIMATED MAXIMUM

ESTIMATED MAXIMUMSPUN PILE PENETRATIONWITH PRE-AUGER

ESTIMATED MAXIMUM STEELPIPE PILE PENETRATION(Ø = 600 mm,thickness = 140 mm)

Figure 9 - Estimated Maximum Length of Pile Penetration (Tank-2)





ESTIMATED MAXIMUM

ESTIMATED MAXIMUM




Maximum penetration for steel pipe pileRecommended thickness 16 mm


WITHOUT PRE-AUGERSPUN PILE PENETRATIONESTIMATED MAXIMUM

ESTIMATED MAXIMUMSPUN PILE PENETRATIONWITH PRE-AUGER

ESTIMATED MAXIMUM STEELPIPE PILE PENETRATION(Ø = 600 mm,thickness = 140 mm)






ESTIMATED MAXIMUM

ESTIMATED MAXIMUM



Figure 8 - Estimated Maximum Length of Pile Penetration (Tank-1)Recommended foundation for large tension load

Bored pile

03/03/2012

56

PEMANCANGAN

Pemancangan menggunakan Pontoon Hammer dng minimum energy 6 ton.m

-16 lws

-12 lws

URUTAN PEMANCANGAN DAN ANCHORING

1 2 3 4 5

Pemancangan sampai batas maksimal yang dapat ditembus (5.0 m) menggunakan minimal K-60

•Pembersihan tanah / kotoran didalam pipa

•Pemboran tanah dalam pipa untuk anchor

•Pemasangan Ground anchor

•Grouting & Curing

•Penegangan kabel untuk kelurusan

•Pengecoran isi dalam tiang dengan menggunakan tremi, bucket cor diangkat menggunakan crane

•Pengecoran plat form dan curing

• Stresing kabel

•Pengecoran kepala anchor.

03/03/2012

57

5.0

0 m

5.0

0 m

6.30 m 5.00 m

7.00 m

DAMPAK PENGGALIAN TERHADAP

KESTABILAN TANAH

HASIL-HASIL PENYELIDIKAN TANAH (BH-355)

B.04

mixed with fines material

gravels & boulders andesite

KETERANGAN :

: Collovial deposit

B.03BH-355

B.05BH-355

G.W.L

TO JAKARTA

BH-355B.02

: Siltstone / claystone

G.W.L

0

1

3

5

10 M

G.W.L

BH-355

TO BANDUNG

B.01BH-355

z = 3.00 – 3.60

m

qu = 1.71

kg/cm2

c = 0.082

kg/cm2

φ = 80

qc = 5 kg/cm2

z = 3.50 – 4.00

m

qu = 1.1 kg/cm2

c = 0.482

kg/cm2

φ = 230

qc = 25 kg/cm2

03/03/2012

58

TIPIKAL BENTUK PIER

Tampak Atas

Tampak Samping Tampak Depan

Transfer beban pada Group Tiang:

(Tomlinso, 1977)

03/03/2012

59

Berikut ini adalah jarak Pile agar effiency group

menjadi optimal :

(Tomlinson, 1977)

Berikut ini adalah jarak Pile agar effiency group

menjadi optimal :

(Tomlinson, 1977)

03/03/2012

60

P existing tunggal pada Pile Group

8

2

4 5 6

7

1

9

3

X

Y

My

Mx

X

Y

P existing tunggal pada Pile Group

P Group My . X Mx . Y

P singgle = --------------- + --------------------- + -----------------

N Σ X 2 Σ Y 2

P Singgle = Gaya Aksial yang bekerja pada tiang tunggal di koord ( x , y )

P Group = Gaya Aksil yang bekerja pada Pile Group

N = Jumlah Tiang pada Pile Group

My = Momen yang bekerja pada Pile Group arah sumbu y

Mx = Momen yang bekerja pada Pile Group arah sumbu x

X & Y = Koordinat P singgle yang akan dicari Gayanya

Σ X 2 & Σ Y 2 = Jumlah dari jarak koordinat kwadrat sumbu x dan sumbu y

03/03/2012

61

Pile No Sum P/n Xi Yi My X/Σxi2 Mx Y/Σyi2 Force Ext.

ton cm cm ton

1 23.6988 -400 400 -13.2124 0.3900 10.8763

2 23.6988 0 400 0.0000 0.3900 24.0888

3 23.6988 400 400 13.2124 0.3900 37.3012

4 23.6988 -400 0 -13.2124 0.0000 10.4864

5 23.6988 0 0 0.0000 0.0000 23.6988

6 23.6988 400 0 13.2124 0.0000 36.9112

7 23.6988 -400 -400 -13.2124 -0.3900 10.0964

8 23.6988 0 -400 0.0000 -0.3900 23.3088

9 23.6988 400 -400 13.2124 -0.3900 36.5213

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