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Pile Capacity Check

This document provides information on pile design calculations for 4 boreholes (BH-01 through BH-04) with varying pile lengths and soil properties. The calculations determine the ultimate bearing capacity (Qu) of piles considering point resistance (Rb) and skin friction (Rs) values. Rb and Rs are calculated for different pile lengths and compared to the allowable bearing capacity (Qu(allow)) with factors of safety (FOS) of 2.5.

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Mohammad Munazir Ali
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309 views7 pages

Pile Capacity Check

This document provides information on pile design calculations for 4 boreholes (BH-01 through BH-04) with varying pile lengths and soil properties. The calculations determine the ultimate bearing capacity (Qu) of piles considering point resistance (Rb) and skin friction (Rs) values. Rb and Rs are calculated for different pile lengths and compared to the allowable bearing capacity (Qu(allow)) with factors of safety (FOS) of 2.5.

Uploaded by

Mohammad Munazir Ali
Copyright
© Attribution Non-Commercial (BY-NC)
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as XLSX, PDF, TXT or read online on Scribd
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Daimeter of pile (D) = Effective pile length from bottom of pile cap = Height of GL from bottom of pile cap

= Depth of water table from GL = Depth 0-0m 0 - 15 m Total = Depth 0-0m 0 - 15 m Total = Depth 0-0m 0 - 15 m Total = Length 0.00 15.00 15.00 Length 0.00 15.00 15.00 Length 0.00 15.00 15.00 BH-01 BH-02 BH-03 BH-04

1.20 15.00 2.30 2.30

m m m m

Average Dry density Submerged density

1.87 t/m^3 0.87 t/m^3

BH-01

BH-02

BH-03

BH-04

Average f f

35.0 degrees 35.0 degrees

BH-01

BH-02

BH-03

BH-04

Average c c

0 t/m^2 2 t/m^2

Qu(ultimate) = Ap*(0.5 * D * g * Ng + Pd * Nq) + Sum (K i to d * Pdi * tand * Asi) + Ap * (c * Nc) + a * Ci * Asi Cross sectional area of pile (Ap) = Unit weight of soil above water table = Effective unit weight at soil at pile toe = Cohesion at pile toe = For f = 35 degrees Nc = Overburden pressure at bottom of pile cap (Pd0) = Overburden pressure (Pd1) = Overburden pressure (Pd2) = Total overburden pressure (Pd) = 1.1304 1.87 0.87 2.00 33.3 4.301 4.30 13.05 17.35 m^2 t/m^3 t/m^3 t/m^2 t/m^2 t/m^2 t/m^2 t/m^2

Nq =

Ng =

48.03

Point resistant (Rb) = Ap*(0.5 * D * g * Ng + Pd * Nq) + Ap * (c * Nc) d=f tan d = Adopt value of K = 1.00 & a= 0.40 Average Ci = As1 = As2 = As = As1 + As2 Average overburden pressure for upper part of pile = Average overburden pressure for lower part of pile = Skin friction resistant (fs1) = Skin friction resistant (fs2) = Total skin friction resistant (Rs) = a * Ci * Asi + Sum (K i to d * Pdi * tand * Asi) Total bearing resistant (Rb + Rs) = Allowable bearing resistant Qu(allow.) = FOS = 2.5

701.82 t

0.700 2.00 0.00 56.55 56.55 4.30 10.83 0.00 428.66

t/m^2 m^2 m^2 m^2 t/m^2 t/m^2 t t

473.90 t

1175.72 t (A) Ratio=Rs/Rb 470.29 t

0.6752

Limiting the overburden pressure upto 20 times of dia. of pile, i.e. Actual length of pile provided = and assuming water table reach the GL, Hence gsubmerged = Maximum overburden pressure = d=f tan d = Adopt value of K = 1.00 & As = Total skin friction resistant (Rs) = a * Ci * Asi + Sum (K i to d * Pdi * tand * Asi) Total bearing resistant (Rb + Rs) = Allowable bearing resistant Qu(allow.) = Also ignoring the Ng effect in point bearing, Total bearing resistant (Rb + Rs) = Allowable bearing resistant Qu(allow.) = Uplift resistant = Skin resistant of pile/2 FOS = 2.5 FOS = 2.5 FOS = 2.5 Rb =

15.00 15.00 0.87 13.05 0.700 56.55 303.60

m m t/m^3 t/m^2 m^2 t

1005.42 t (B) Ratio=Rs/Rb 402.17 t 491.23 t 794.83 t (C ) Ratio=Rs/Rb 317.93 t -60.72 t

0.4326

0.6180

Daimeter of pile (D) = Effective pile length from bottom of pile cap = Height of GL from bottom of pile cap = Depth of water table from GL = Depth 0-0m 0 - 20 m Total = Depth 0-0m 0 - 20 m Total = Depth 0-0m 0 - 20 m Total = Length 0.00 20.00 20.00 Length 0.00 20.00 20.00 Length 0.00 20.00 20.00 BH-01 BH-02 BH-03 BH-04

1.20 20.00 2.30 2.30

m m m m

Average Dry density Submerged density

1.87 t/m^3 0.87 t/m^3

BH-01

BH-02

BH-03

BH-04

Average f f

33.0 degrees 33.0 degrees

BH-01

BH-02

BH-03

BH-04

Average c c

0 t/m^2 2 t/m^2

Qu(ultimate) = Ap*(0.5 * D * g * Ng + Pd * Nq) + Sum (K i to d * Pdi * tand * Asi) + Ap * (c * Nc) + a * Ci * Asi Cross sectional area of pile (Ap) = Unit weight of soil above water table = Effective unit weight at soil at pile toe = Cohesion at pile toe = For f = 33 degrees Nc = Overburden pressure at bottom of pile cap (Pd0) = Overburden pressure (Pd1) = Overburden pressure (Pd2) = Total overburden pressure (Pd) = 1.1304 1.87 0.87 2.00 27.34 4.301 4.30 17.40 21.70 m^2 t/m^3 t/m^3 t/m^2 t/m^2 t/m^2 t/m^2 t/m^2

Nq =

Ng =

37.77

Point resistant (Rb) = Ap*(0.5 * D * g * Ng + Pd * Nq) + Ap * (c * Nc) d=f tan d = Adopt value of K = 1.00 & a= 0.40 Average Ci = As1 = As2 = As = As1 + As2 Average overburden pressure for upper part of pile = Average overburden pressure for lower part of pile = Skin friction resistant (fs1) = Skin friction resistant (fs2) = Total skin friction resistant (Rs) = a * Ci * Asi + Sum (K i to d * Pdi * tand * Asi) Total bearing resistant (Rb + Rs) = Allowable bearing resistant Qu(allow.) = FOS = 2.5

713.31 t

0.649 2.00 0.00 75.40 75.40 4.30 13.00 0.00 636.58

t/m^2 m^2 m^2 m^2 t/m^2 t/m^2 t t

696.90 t

1410.21 t (A) Ratio=Rs/Rb 564.08 t

0.9770

Limiting the overburden pressure upto 20 times of dia. of pile, i.e. Actual length of pile provided = and assuming water table reach the GL, Hence gsubmerged = Maximum overburden pressure = d=f tan d = Adopt value of K = 1.00 & As = Total skin friction resistant (Rs) = a * Ci * Asi + Sum (K i to d * Pdi * tand * Asi) Total bearing resistant (Rb + Rs) = Allowable bearing resistant Qu(allow.) = Also ignoring the Ng effect in point bearing, Total bearing resistant (Rb + Rs) = Allowable bearing resistant Qu(allow.) = Uplift resistant = Skin resistant of pile/2 FOS = 2.5 FOS = 2.5 FOS = 2.5 Rb =

20.00 20.00 0.87 17.4 0.649 75.40 486.31

m m t/m^3 t/m^2 m^2 t

1199.61 t (B) Ratio=Rs/Rb 479.85 t 537.75 t 1024.06 t (C ) Ratio=Rs/Rb 409.62 t -97.26 t

0.6818

0.9043

Daimeter of pile (D) = Effective pile length from bottom of pile cap = Height of GL from bottom of pile cap = Depth of water table from GL = Depth 0-0m 0 - 25 m Total = Depth 0-0m 0 - 25 m Total = Depth 0-0m 0 - 25 m Total = Length 0.00 25.00 25.00 Length 0.00 25.00 25.00 Length 0.00 25.00 25.00 BH-01 BH-02 BH-03 BH-04

1.20 25.00 2.30 2.30

m m m m

Average Dry density Submerged density

1.87 t/m^3 0.87 t/m^3

BH-01

BH-02

BH-03

BH-04

Average f f

33.0 degrees 33.0 degrees

BH-01

BH-02

BH-03

BH-04

Average c c

0 t/m^2 2 t/m^2

Qu(ultimate) = Ap*(0.5 * D * g * Ng + Pd * Nq) + Sum (K i to d * Pdi * tand * Asi) + Ap * (c * Nc) + a * Ci * Asi Cross sectional area of pile (Ap) = Unit weight of soil above water table = Effective unit weight at soil at pile toe = Cohesion at pile toe = For f = 33 degrees Nc = Overburden pressure at bottom of pile cap (Pd0) = Overburden pressure (Pd1) = Overburden pressure (Pd2) = Total overburden pressure (Pd) = 1.1304 1.87 0.87 2.00 27.34 4.301 4.30 21.75 26.05 m^2 t/m^3 t/m^3 t/m^2 t/m^2 t/m^2 t/m^2 t/m^2

Nq =

Ng =

37.77

Point resistant (Rb) = Ap*(0.5 * D * g * Ng + Pd * Nq) + Ap * (c * Nc) d=f tan d = Adopt value of K = 1.00 & a= 0.40 Average Ci = As1 = As2 = As = As1 + As2 Average overburden pressure for upper part of pile = Average overburden pressure for lower part of pile = Skin friction resistant (fs1) = Skin friction resistant (fs2) = Total skin friction resistant (Rs) = a * Ci * Asi + Sum (K i to d * Pdi * tand * Asi) Total bearing resistant (Rb + Rs) = Allowable bearing resistant Qu(allow.) = FOS = 2.5

847.74 t

0.649 2.00 0.00 94.25 94.25 4.30 15.18 0.00 928.85

t/m^2 m^2 m^2 m^2 t/m^2 t/m^2 t t

1004.25 t

1851.99 t (A) Ratio=Rs/Rb 740.80 t

1.1846

Limiting the overburden pressure upto 20 times of dia. of pile, i.e. Actual length of pile provided = and assuming water table reach the GL, Hence gsubmerged = Maximum overburden pressure = d=f tan d = Adopt value of K = 1.00 & As = Total skin friction resistant (Rs) = a * Ci * Asi + Sum (K i to d * Pdi * tand * Asi) Total bearing resistant (Rb + Rs) = Allowable bearing resistant Qu(allow.) = Also ignoring the Ng effect in point bearing, Total bearing resistant (Rb + Rs) = Allowable bearing resistant Qu(allow.) = Uplift resistant = Skin resistant of pile/2 FOS = 2.5 FOS = 2.5 FOS = 2.5 Rb =

25.00 25.00 0.87 21.75 0.649 94.25 741.01

m m t/m^3 t/m^2 m^2 t

1588.75 t (B) Ratio=Rs/Rb 635.50 t 672.19 t 1413.19 t (C ) Ratio=Rs/Rb 565.28 t -148.20 t

0.8741

1.1024

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