Design - Piles Foundation Rock 661y42

GL dept h 11. 5 12. 6 13. 3 14. 2 15 16. 3 17. 1 18 19. 5

-

BH1 0 l ev el 11. 500 12. 600 13. 300 14. 200 15. 000 16. 300 17. 100 18. 000 19. 500

BH2 MP a uc s 1. 02 1. 96 7. 34 4. 21 5. 19 2. 42 1. 21 1. 08 1. 69

Ro c k l e v e l 11 - 11. 000 Wa t e r l e v e l 1. 7 - 1. 700

GL dept h 11. 3 12 13 14. 5 15. 3 16. 6 17. 5 18. 2 19. 6

Ro c k l e v e l 11 Wa t e r l e v e l 1. 8

0 l ev el - 11. 300 - 12. 000 - 13. 000 - 14. 500 - 15. 300 - 16. 600 - 17. 500 - 18. 200 - 19. 600

S haft m in T o e m in

GL dept h 11. 7 12. 9 13. 8 14. 5 15. 9 16. 8 17. 3 18 19. 5

-

BH3 0 l ev el 11. 700 12. 900 13. 800 14. 500 15. 900 16. 800 17. 300 18. 000 19. 500

- 1. 800 1990

980 1 .9 6

MP a uc s 0. 98 2. 61 4. 61 1. 35 1. 41 6. 31 1. 73 2. 16 4. 18

Ro c k l e v e l 11 - 11. 000 Wa t e r l e v e l 1. 65 - 1. 650

- 11. 000

1020

UC S

MP a uc s 2. 16 1. 99 4. 2 5. 61 1. 08 1. 86 0. 75 8. 31 1. 31

( f or ( f or

t oe l ev el t oe l ev el

980

- 1 2 m) - 1 2 m)

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PFP/040/09/04/A012

April 22, 2009

DESIGN CALCULATIONS OF 500 MM DIA PILES,

100 TONS (C) & 0 TONS (T)

CONTENTS: 1.0 GENERAL 2.0 PROPOSED PILE DETAILS 3.0 STRUCTURAL DESIGN CALCULATIONS OF THE PILE 3.1 MAXIMUM ALLAWABLE COMPRESSION LOAD 3.2 DESIGN REQUIREMENTS OF REINFORCEMENT

3.3 BENDING MOMENT CALCULATIONS IN PILE DUE TO H-FORCE & CONSTRUCTIONAL ALLOWANCES

3.4 STRESS IN CONCRETE 3.5 CHECK FOR CLEAR SPACING 3.6 CHECK FOR BOND LENGTH 3.7 CHECK FOR STEEL IN TENSION 3.8 CHECK FOR SPACING OF STIRRUPS 4.0 GEOTECHNICAL DESIGN CALCULATIONS OF THE PILE 4.1 RESUME OF SOIL DATA 4.2 TOTAL PILE CAPACITY 4.2.1 CAPACITY OF PILE IN ROCK LAYER 4.2.2 SHAFT FRICTIONAL RESISTANCE OF PILE IN SOIL ABOVE ROCK LAYER 4.3 CALCULATION OF SETTLEMENT OF PILE

4.3.1 SETTLEMENT OF PILE SHAFT 4.3.2 SETTLEMENT OF PILE CAUSED BY THE LOAD AT END BEARING 4.3.3 SETTLEMENT OF PILE CAUSED BY THE LOAD SUBMITTED ALONG THE PILE SHAFT

4.3.4 TOTAL PILE SETTLEMENT

1

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1.0 GENERAL Project

:

Villas - 63 CFA PILES

Location

:

Owner

:

Plot No. 98 – Sector Z 22 - MBZ City ABU DHABI ‫السيد محمد سالم سعيد محمد الحجري‬

PILING Contractor

:

‫بلى برنث للمقاوالت العامة‬

Consultants

:

‫مكتب التصميم العالمي لالستشارات الهندسية‬

References

:

BS 8110 : 1997 ; Structural use of Concrete BS 8004 : 1986 ; BS Code of practice for Foundations Charts for design of circular columns to BS 8110 Principles of Foundation Engineering - Braja M Das Pile Design and construction practice - M J Tomlinson, Third edition Elements of Soil Mechanics for Civil and Mining Engineers - By G N Smith Pressure Meter and Foundation Engineering - By F Baguelin, J F Jezequel, D H Shields

2.0 PROPOSED PILE DETAILS Pile Type

:

Pile Diameter

:

Design Capacity

:

Number of Piles

:

Pile Toe Level Pile length

: :

Cub Concrete Strength

:

Ground Level

Bored Piles Using CFA Method 500 mm (Nominal) 100 Tons (C) &

± 0.000 m

G.Lvl

750 mm max 1 m C.O.Lvl below platform

0 Tons (T)

63 Piles -8.60 m 8.60 m 40.00 N/mm

Reinforcement

:

Main Bars Links Cover

: : :

Tests

:

Nbr of Working test

:

2

Nbr of Integrity test

:

63

2

-7.6 m

Rock Lvl

-8.6 m

Toe Lvl

8.0m Steel Bars 6 No: 16 mm & fy = 8 mm @ 150mm & fy = 75 mm

460 N/mm2 250 N/mm2

Piles (1.5%) Piles (100.0%)

Note: All Dimensions are in mm unless otherwise noted C- Compression, S- Shear, T - Tension 2

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3.0 STRUCTURAL DESIGN CALCULATIONS OF THE PILE 3.1 Maximum allawble compression load: Allowing for eccentricity of loading due to deviations during construction, the ultimate axial load should not exceed the value of N given by: N = 0.4 fcu A c + 0.75 As fy (Eq 38 of BS 8110:1997) fcu = fy =

2 40 N/mm 2 460 N/mm

Ac =

,

As = , N = 3538488.9 N Or Load Factor : 1.4 Safe N = 252.75 TONS Hence the pile is structurally safe to carry the load

2 195143.1693 mm 2 1206.371579 mm

(Net Area)

353.85 TONS

100

3.2 Design Requirements of Reinforcement : BS 8004:1986 Art 7.4.2.5.4 refers OUT OF POSITION ALLOWED : OUT OF PLUMB ALLOWED : The reinforcement shall be designed for this Article requirement H-force on the Pile (5.0% of the Vertical Load) : Horizontal load from plumb on the pile : (Including construction allowances) B.M produced by eccentricity :

75 1:75 50.00 kN 13.33 kN 75.00 kN.m

3.3 Bending Moment calculations in Pile due to H-force and constructional allowances: Since the piles are restrained by the pilecaps and Tie Beams the pile head shall be considered to be restrained from rotational moment. Hence the moment on the pile occurs mainly due to horizontal force at the pile head. Total horizontal force on the pile head (Ultimate) H= 83.33 kN Elastic Analysis: Reese and Matlock have established a series of curves for normally consolidated and cohesionless soils for which the elastic modulus of the soil Es is assumed to increase from zero at the pile head in direct proportion to the depth assuming that the pile behaves as an elastic beam on a soil which also behaves elastically. Refer pages 219 to 223 of " Pile Design And Construction Practice by M J Tomlinson Third Edition; 1987 Using the fixed Pile head equation (6.58)

=

MF

FmHT

=

MF

= Bending Moment

Fm

= Bending Moment Coefficient from figure 6.39b = Stiffness Factor 5 = EI/nh = Reference: BS 8110:1997 Part 2, Table 7.2 = 28000 MN/m² or N/mm²

T E I nh T Zmax L Zmax

4 = 0.003067962 m = Coefficient of subgrade modulus variation

= = = = =

24 1.3 L/T Pile length 6.62

MN/m3



(Refer figure 6.20)

7

3

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Depth x (m) 0 1.3 2.6 3.9 5.2 6.5

T (m) 1.30 1.30 1.30 1.30 1.30 1.30

Z=x/T

Fm

0.00 1.00 2.00 3.00 4.00 5.00

-0.93 -0.05 0.25 0.17 0.05 0.00

MF =FmHT (kN.m) -100.75 -5.42 27.08 18.42 5.42 0.00

Therefore maximum bending moment on pile = Mmax = 75 318 mm 318 Then hs /h = 500

+

100.75

=

175.75 kN.m

hs =

=

0.64

For the Ultimate State Design apply a load factor of 1.4 for working load: 1.4 N M = 5.60 ; = 1.41 3 h h² From Chart 13 for design of circular columns to BS 8110 , for this condition: Area of Steel required Areq = (Asmin = 0.40%) 0.40% Area of Steel provided As

=

Proposed reinforcement: Main Bars, 6 Area = Links 8

0.61% Therefore safe

Nos, Dia: 16 0.61% of concrete mm @ 150

mm Therefore O.K. mm

3.4 Stress in Concrete: According to BS 8004:1986, Section 7.4.3.3.1 the working stress in compression should not exceed 25% of the characteristic concrete strength at 28 days; Working stress =

100 x p/4 x <

10000 500 ² 0.25 x fcu

= <

10

As an example of the foregoing calculations stresses, the Moment at 5.2 M = Nc M ± x s at 5.2 m = Ac I = =

5.53

1000 p/4

x x OR

3

10 250000 4.65

±

5.092958179

N/mm2

N/mm²

5.42 f

Therefore safe

kN.m

2 6

x 10 x 5.42 3067961576 x

N/mm²,

500 2

Which give sm =

5.09

As per BS 8004 Article 7.4.3.3.1: these stresses are < 0.25 fcu or

10 N/mm² From the above results it can be inferred that stressses in the concrete are acceptable

4

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3.5 Check for Clear Spacing: For 6 bars of 16 mm dia, c.c spacing = Therefore clear spacing is 150.50 mm Art 3.12.11.2.4 of BS 8110 (Part 1) : 1997 max clear spacing is 300 mm Thus 6 bars provided are adequate.

166.50

3.6 Check for Bond Length: Table 3.27 of BS 8110:1997 shows the following values of anchorages for various grades of concrete: Grade 30 35 40

Type 2 Deformed Bars 40 f 38 f 35 f

For fcu

=

40

Anchorage length We propose

N/mm²

= == 750

35

x 560 mm mm into the pile cap

16

3.7 Check for steel in tension: As = 1206.3716 mm² for 6 Bars, Dia Ultimate Tensile Force = 1206.37 x 437 = 527184.38 N = 52.718 Load Factor = 1.4 Allowable Tensile Force = 37.66 Tons >

16 mm (460 X 0.95 = 437) Tons 0 Tons

Therefore safe

3.8 Check for Spacing of Stirrups: From Table 3.8 BS 8110 (Part 1:1997) , for fcu = ds

=

40

N/mm² gm = 1.25

400.00 mm

Area of Reinforcement Provided = 1206.37 1/3 1/4 Shear Stress = vc 0.79 x (100 x A /(b x d)) x (400/d /gm = s s) 2 0.575 N/mm for concrete grade 25 1/3 = 0.575 [40/25] 0.673

= vc

=

Working Shear Stress in pile v =

83.33 p/4 x

3

x 10 500 ²

= v

mm2

N/mm2 for concrete grade 40

Hw

=

p/4 xf ²

= 0.424 N/mm²

(Ultimate)

As v < vc the permissible shear stress is more than the actual shear stress , No Shear reinforcement is not required. however we provide nominal

8 mm links @

150

mm

For this condition use the following equation: Minimum Shear reinforcement required = Asv  0.4 bv sv / 0.95 fyv Asv = 0.40 x 0.95 x

500 460

x

150

= <

68.650 100.53 mm²

mm² Therefore safe. 5

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4.0 GEOTECHNICAL DESIGN CALCULATIONS OF THE PILE: 4.1 RESUME OF SOIL DATA: : GULF LABORATORY Soil Report by : ± 0.000 m Platform Level Platform Level Cut-off Level

: max 1 m : below platform

Min UCS of shaft

:

1770

Cut-Off Level

kN/m²

: Min UCS at Toe 2175 kN/m² Zone of interest of reading for UCS Values at the Toe Level for End Bearing Capacity [25% from shaft (0.5D) & 75% from Toe (1.5D)] : Toe Level -8.60 m

Rock Level Toe Level

Length of Piles: It should be emphasized that the length of pile assumed in these calculations is based on Lower cut-off levels, Loadings and results of tests run on a few boreholes carried out by a third party. At any rate such information contained in the Boreholes results affecting the design may not be exactly representative of the whole area and particularly that the hard strata reported may differ from pile location to the other. The length of pile(s) shall be determined on site while boring by our supervisor on site as he is the best judge of the soil conditions because he watching every bore all the time.Of course the attention of the Engineer's Representative shall be drawn to each case as it arises and a decision taken regarding where to found the pile in each case. 4.2 Total Pile Capacity : 4.2.1 Pile Capacity in Rock Layer : Taking the worst case, Rock Level : -7.60 m UCS of rock at Toe of Pile : -8.60 m 2175 kN/m² UCS in Rock Socket : 1770 kN/m² Length of Rock Socket : 1 m Ultimate Bearing Capacity of Pile Qu _ a. 1st assumption: Reference: Braja M Das (Principles of Foundation Engineering - Pages 487 - 504) - Estimation of shaft & end bearing according to TERZAGHI which can be calculated as follows: Qu = Qb + Qs = Ab qb +As qs = Ab (1.3 C Nc + Nq s'v0 + 0.3 g' D Ng) + 1/2 Ks s'v0 tand As Ab = Pile base area

= 196349.5 mm² C = Cohesion at base = ½ quc of UCS of Rock (but less than 0.46) =

0.46 N/mm²

(see annex - page 6 for Mudstone - to be at the safe side since the soil report give a higher value, we adopt 0.46 N/mm 2) Nc , Ng & Nq = Dimensionless Bearing Capacity Factors depneding of f (Tomlinson,3rd ed page 123) Nc = 40 Nq = 20 f = Angle of friction at the base pile level = 30  s'v0 = Effective overburden pressure at base pile level = g' = Average Effective unit weight of shaft pile in rock = D = Diameter of Piles = 500 mm

Ng = 20 (see annex - page 4) (see annex - pages 6 & 7 to take an idea) 76.00 kN/m² , 3 9.00 kN/m , (see annex - page 3 to take an idea)

As = Area of Socket friction in rock

= 1570796.327 mm² Ks = Coefficient of the horizontal soil stress; d = Pile/Soil friction angle Ks = K0 = (1-sinf) = 0.500 (Pile Design and construction practice - M J Tomlinson, tand = qb =

tanf 25467

=

0.577 &

Third edition: Cast-in-place; concrete/sand) qs =

2 10.96965511 kN/m

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Qb =

196349.54 x

Qs =

1570796.3 x

25.467 = 0.01096966 = Qu =

5000433.757 N

99.66%

17231.09396 N 5017664.851 N =

0.34% 501.77 Tons 6

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b. 2nd assumption: (Reference: Tomlinson's "Pile Design and Construction" Pages 131 - 136 Unit end bearing according to Tomlinson can be calculated as follows: qb = 2 Nf quc (4.26) Where Nf = tan² (45 + f/2) For UCS of f = Nf = 3.00 ; 30 °, qb = 2 x 3.00 x 2175

2175 kN/m² ; = =

13050.00 kN/m² 13.05 N/mm²

Shaft Frictional Resistance of Pile in Rock according to Tomlinson (After Williams & Pells): qs = ab quc Where, a = Rock Socket Reduction factor = 0.28 ; b = Rock Socket correction factor = 0.65 ; (Dependent on Mass factor/RQD) Average RQD < 50% quc = 1.770 N/mm² (Average UCS Value) qs = 0.28 x 0.650 x 1.770 = 0.322 N/mm² Shaft Frictional Resistance of Pile in Rock according to according to Tomlinson (After Rosenberg & Journeaux) : ;b= qs = ab quc ; a = 0.20 1.00 ; qs =

0.2

x

1

x

1770

=

0.35 N/mm²

From the above comparative calculations it can be inferred that the minimum values are: qb = qs = ; 13.05 N/mm² 0.32 N/mm² Therefore Qb = 196349.54 Qs = 1570796.3

x

13.05

=

2562361.508 N

83.51%

x

0.32 Qu

= =

506016.3287 N 3068377.837 N =

16.49% 306.84 Tons

From the above comparative calculations it can be inferred that the minimum value for bearing in rock is: Qu = 306.84 Tons 4.2.2 Shaft Frictional Resistance of Pile in Soil above Rock Layer: Friction angle of shaft in the Soil Layer : Length of Pile shaft in Soil Layer - 1m for Cap Pile : Qs (S) = As qs = 1/2 Ks s'v0 tand As

36.0 6.6 ; Where

s'v0 = Effective overburden pressure at the base of soil level =

76.00 kN/m² ,

Ks = Coefficient of the horizontal soil stress;

d = Pile/Soil friction angle

As = Area of Socket friction

10367255.76 mm²

qs = 1/2 Ks s'v0 tand As ; (1-sinf) = tand = tanf =

Ks = K0 =

qs Qs (S) =

=

11.38 0.0113807 x

=

Where 0.412 0.727

 see annex - page 1) m

:

(Pile Design and construction practice - M J Tomlinson, Third edition: Cast-in-place; concrete/sand)

kN/m² 10367255.8 =

117986.4068 N =

Therefore, the total capacity of the pile is : Qu =

11.79864068 Tons 318.64 Tons 7

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In compression : F.S = 3 In Tension : Qu = Qs F.S =

Qallow

;

= 2.5

51 Qallow

;

= >

106.21 Tons 100 Tons

Tons

; Therefore safe

; The weight of pile is not considered

=

24.96 Tons

4.3 Calculation of Settlement of Pile : Reference: "Principles of Foundation Engineering", second edition by Braja M Das. Nomenclature: S = Total pile settlement = S1 + S2 + S3 S1 = Settlement of pile shaft S2 = Settlement of pile caused by the load at end bearing S3 = Settlement of pile caused by the load transmitted along the pile shaft 4.3.1 Settlement of Pile shaft : Settlement of pile shaft = S1 =

(Qwp + x Qws )L Ap Ep

Qwp = load carried by end bearing under working load condition =

376 kN

Qws = load carried by shaft friction under working load condition =

624 kN

Ap = area of pile cross section L = Length of the pile from cut-off level Ep = Young's modulus of the pile material Skin Friction resistance Distribution factor " x " x = 0.5 for uniform & parabolic ; x = 0.67 for triangular Settlement of pile shaft = S1

= = = = (Vesic, 1977) =

196349.54 mm² 7600.00 mm 28 kN/mm² 0.5 0.952 mm

4.3.2 Settlement of pile caused by the load at end bearing : S2

=

qwp D

x (1 - ms² ) Iwp

Es D = diameter of pile qwp = point load per unit area at pile point

= =

500.0 mm 1914.95 kN/m²

Es

= Young's modulus of rock at pile tip (see annex - pages 7, 9 & 10) =

µs

= Poisson's ratio of soil

Iwp = influence factor

350000 kN/m²

=

0.30 (see annex - page 11)

=

0.88

S2 = Settlement of pile caused by the load at end bearing =

2.19 mm

4.3.3 Settlement of pile caused by the load transmitted along the pile shaft : S3 =

Qws pLe

p Le

x

D Es

x

2

(1- µS ) Iws

= perimeter of the pile = embedded length of pile

Iws = influence factor

= =

1570.80 mm 1.00 m

= 2 + 0.35  Le / D (Vessic, 1977) =

3.36 mm

S3 =

1.74 mm

4.3.4 Total pile settlement : Total settlement anticipated = S = S1 + S2 + S3 =

4.88 mm

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The above figures, it must be appreciated, are calculated using data available from the soil report and the actual conditions may vary taking into consideration the practical aspects and limitations of the piling operation. We cannot predict residual settlements as these should better be left to the actual testing of piles. 8

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PILE DESIGN JOB NUMBER:

PFP/040/09/04/A012

PROJECT:

Villas - 63 CFA PILES

LOCATION:

Plot No. 98 – Sector Z 22 - MBZ City ABU DHABI

OWNER:

‫السيد محمد سالم سعيد محمد الحجري‬

CONSULTANT:

‫مكتب التصميم العالمي لالستشارات الهندسية‬

CONTRACTOR:

‫بلى برنث للمقاوالت العامة‬

PHEONIX FOUNDATION PILING LLC Tel: + 971 2 582508 Phoenix Foundation Piling LLC

Fax: +971 2 5825184 E-mail: [email protected]

P.O. Box: 40287 - Abu Dhabi

Mob: + 971 50 96 76 136

ANNEXES Construction & Trading Licenses Soil Report & References Sheets Drawings