Deep Foundation Design by BNBC-2020 PILE DESIGN INPUT DESIGN OUTPUT SUMMARY FOR SELECTED PILE LENGTH DESIGN OUTPUT SUMMARY FOR VARIOUS PILE LENGTH
Version: 1.0.0 User Guide and Calculation Method Selected Pile Length: L = 20 mTable1: Allowable/ Working Bearing Capacity for Different Pile Length Table2: Levels for Different Pile Length
GEOTECHNICAL INPUT 1 : GEOTECHNICAL PARAMETER AND SETTING [Required] ✔Note: Valid pile length range 3 m to 39 m SBCE Method Pile Length SPT N-Value Method Pile Length Pile Toe
depth from
EGL
Pile Toe
Level
Toe
Residing
Layer ID
Dig-out/Scour depth from EGL er = 3.000 [1] m Table1: Allowable Capacity for Selected Length Total
Capacity
End
Bearing
Skin
Friction Sparkline Sparkline Skin
Friction
End
Bearing
Total
Capacity
1 : SPT-Data [Required] ✔Water Table depth from EGL WT = 4.500 [2] m SBCE Method SPT N-value Method
Serial No. Depth from
EGL
Field SPT
Value Skin Friction (kN) 750 84.1% ― NA ― ― NA ― Qallow Qb.alw Qs.alw L Qs.alwN Qb.alwN QallowN L Ztoe Ltoe
Unit Weight Calculation Procedure: End Bearing (kN) 142 15.9% ― NA ― ― NA ― kN kN kN m kN kN kN m m m
di NMethod: Fixed value for all soil type [3] Allowable (kN) 892 ― NA ― 41 35 63 3 6.000 -2.000 Layer-1
m /0.3m Bulk Unit Weight: γ = 17 kN/m³ 48 39 10 5 5 8.000 -4.000 Layer-2
11.50 3 Saturated Unit Weight: γsat = 21 kN/m³ 55 41 14 7 7 10.000 -6.000 Layer-3
23.00 4 : Use Lab Test/ User define data (if available) 90 49 41 9 9 12.000 -8.000 Layer-3
34.50 5 33 66 -34 11 11 14.000 -10.000 Layer-4
46.00 8 Cohesion Calculation Procedure: 265 104 160 13 13 16.000 -12.000 Layer-4
57.50 5 Method: Using BNBC Equation [6.D.7] & [6.D.8] 493 123 369 15 15 18.000 -14.000 Layer-4
69.00 1 : Use Lab Test/ User define data (if available) 547 123 424 17 17 20.000 -16.000 Layer-5
710.50 4 Derived from (Su)l 784 142 642 19 19 22.000 -18.000 Layer-5
812.00 5 1013 156 857 21 21 24.000 -20.000 Layer-5
913.50 6 Frictional Angle Calculation Procedure: 1378 312 1066 23 23 26.000 -22.000 Layer-5
10 15.00 7 Method: BNBC Equation [6.D.6] 1605 341 1264 25 25 28.000 -24.000 Layer-5
11 16.50 11 : Use Lab Test/ User define data (if available) 1804 355 1449 27 27 30.000 -26.000 Layer-5
12 18.00 12 1949 331 1618 29 29 32.000 -28.000 Layer-5
13 19.50 14 PILE DESIGN PARAMETERS [Required] ✔2117 350 1767 31 31 34.000 -30.000 Layer-5
14 21.00 13 Foundation Type: Drilled Shaft 2267 374 1894 33 33 36.000 -32.000 Layer-5
15 22.50 15 Shape: Hexagon [4] 2345 350 1994 35 35 38.000 -34.000 Layer-5
16 24.00 15 Pile Diameter/Width B = 0.750 [5] m 2436 369 2067 37 37 40.000 -36.000 Layer-5
17 25.50 18 Pile top level from Datum Ltop = +1.000 [6]m 2516 407 2109 39 39 42.000 -38.000Layer-5
18 27.00 33 Group Efficiency Factor ξ = 1.00
19 28.50 36
20 30.00 38 2 : SPT INSTRUMENT DATA [Required] ✔Safety Factor Determination
21 31.50 37 Hammer Type & release Mechanism: Automatic - Trip Structure Type & Design Life: Temporary [<25 yr]
22 33.00 35 Borehole Diameter: 150 mm Construction Quality: Very Poor Control
23 34.50 37 Sampling Method: Sampler without liner Code Spacified Safety Factor : SF = 2.8
24 36.00 39 Rod Length: 6 m – 10 m : Ignore Skin Friction (End Bearing Pile behavior)
25 37.50 40 : Ignore End Bearing (Floating Pile behavior)
26 39.00 37 3 : SOIL CLASSIFICATION DATA [Required] ✔
27 40.50 39 Existing Ground Level (EGL) from reference datum: EGL = +4.000 [7] m
28 42.00 42 Soil Layer
ID
Layer Levels from
Datum
Layer Depth from EGL Soil Layer
Thickness
Soil Group Symbol & Group Name
[ BNBC section 3.5.3 and ASTM D 2487 ]
29 43.50 44
30 Top Level Bottom
Level
Top Bottom DESIGN CALCULATION FOR SELECTED PILE LENGTH
31 S't S'b Δs
32 mmmmm Table 1: Foundation Geometry Table 2: SPT Correction Factor
33 Layer-1 +4.000 +0.750 0 3.250 3.250 ML - Silt Foundation Type: Drilled Shaft Hammer efficiency EH = 0.7
34 Layer-2 +0.750 -3.000 3.250 7.000 3.750 CH - Fat clay Cross section shape: Round Borehole diameter correction CB = 1.05
35 Layer-3 -3.000 -5.000 7.000 9.000 2.000 ML - Silt Pile section perimeter peri = 2.356m Sampler correction CS = 1.2
36 Layer-4 -5.000 -8.750 9.000 12.750 3.750 ML - Silt Pile base area Ab = 0.442m² Rod length correction CR = 0.95
37 Layer-5 -8.750 -14.750 12.750 18.750 6.000 SM - Silty sand Pile length L = 20.000 m EH*CB*CS*CR/0.60 = 1.3965
38 Layer-6 -14.750 -39.750 18.750 43.750 25.000 SP - Poorly graded sand Pile toe level Ltoe = -19.000 m
39 Layer-7
40 Layer-8 Table 3: Effective Overburden Stress Table 4: Geotechnical Parameters for Design Calculation
41 Layer-9 Depth from
EGL
Effective
Overburde
n Stress
Remark Soil Layer
ID
Soil Symbol
& Description
Soil Type Layer Depth from EGL
after Scour/Cut Out
SPT Value Correction Soil Parameters for Design
42 Layer-10 SPT Correction Overburden Stress Correction Wet Unit weight Saturated Unit weight Plasticity
Index
Cohesion [Cohesive Soil] Frictional Angle [Granular Soil]
43 Layer-11 z σ'v , σ'z Average of
Field N-
Values in
Soil Layer
Corrected
N-Value for
Field
Procedure
s
Soil Layer
Mid-depth
from EGL
Effective
Stress at
Mid-height
Overburde
n Stress
Correction
Factor
Overburde
n pressure
Corrected
N-Value
Lab Test/
User Value
Correlation
/Table
Design
Value
Lab Test/
User Value
Correlation
/Table
Design
Value
Lab Test/ User Value Correlation/ Table Design
Value
Lab Test/
User Value
Correlation/ Table Design
Value
44 Layer-12 m kPa Lab Test/
User Value
45 Layer-13 3.000 0.00 DU Top Bottom Tomlinson
and
Coduto
Table
Tomlinson
and
Coduto
Table
Derived
from UC
Test [ by
(qu)l ]
Derived
from DS
Test [ by
(Su)l ]
BNBC Eq.
(6.D.7 & 6.
D.8)
BNBC
Table 6.D.7
BNBC Eq.
(6.D.5)
BNBC Eq.
(6.D.6)
46 Layer-14 3.250 2.80
47 Layer-15 4.500 24.84 WT
48 Note: Maximum Bore-hole Depth from EGL: 43.500 m 7.000 43.66 St Sb N N60 Zm σ'v CN (N1)60 (γ)l γ (γsat)l γsat PI Su φ
49 9.000 77.66 m m m kPa kN/m³ kN/m³ kN/m³ kN/m³ kN/m³ kN/m³ % kPa kPa kPa kPa kPa degree degree degree degree
50 4 : LABORATORY TEST /USER DEFINED DATA [Optional] ✔12.750 145.93 Layer-1 ML - Silt Cohesive 3.000 3.250 4.0 5.6 3.125 1.40 2.000 11.2 14.50 17.00 16.50 21.00 34.9 25.0 34.9 ― NA ― ― NA ― ― NA ―
51 Soil
Sample
Depth from
EGL
Plasticity
Index
Specific
Gravity
Moisture
Content
Dry Density Undrained
Shear
Strength
Unconf.
Compr.
Strength
Frictional
Angle
Wet/Bulk
Unit
Weight
Saturated
Unit
Weight
18.750 247.93 Layer-2 CH - Fat clay Cohesive 3.250 7.000 6.5 9.1 5.125 29.55 1.410 12.8 17.63 15.00 17.63 17.33 15.25 17.33 23.0 94.3 23.9 56.7 40.6 23.9 30.0 ― NA ― ― NA ― ― NA ―
52 23.000 316.72 Toe Level Layer-3 ML - Silt Cohesive 7.000 9.000 3.0 4.2 8.000 60.66 1.169 4.9 14.50 17.00 16.50 21.00 26.2 18.8 26.2 ― NA ― ― NA ― ― NA ―
53 43.750 652.56 Layer-4 ML - Silt Cohesive 9.000 12.750 3.3 4.7 10.875 111.80 0.965 4.5 18.21 14.50 18.21 18.93 16.50 18.93 25.0 29.1 20.8 29.1 ― NA ― ― NA ― ― NA ―
54 PI Gs w ρ
𝑑
(Su)l (qu)l (φ)l (γ)l (γsat)l Layer-5 SM - Silty sand Granular 12.750 18.750 9.0 12.6 15.750 196.93 0.775 9.7 16.75 17.00 19.75 21.00 3.5 ― NA ― ― NA ― ― NA ― 38.7 29.9 29.0 29.0
55 m % % kg/m³ kPa kPa degree kN/m³ kN/m³ Layer-6 SP - Poorly graded sand Granular 18.750 43.750 31.3 43.7 31.250 450.25 0.499 21.8 16.19 17.25 16.19 19.05 20.00 19.05 30.4 ― NA ― ― NA ― ― NA ― 30.0 33.5 35.9 35.9
56 2.23 16 2.66 30.5
57 3.75 23 2.66 46.2 1230 188.6 17.63 17.33
58 6.23 23.9 30
59 9.23 25 2.66 24.6 1490 18.21 18.93
60 16.73 3.5 38.7
61 27.23 2.66 9.3 1510 16.19 19.05
62 31.73 30.4 30
63
64
65
66 Table 5: Bearing Capacity Parameters Table 6: Safety Factor
67 Bearing capacity factor Nc = 9 for SBCE Method SF(SBCE) = 2.8
68 Drilled shaft capacity factor ω1 = 0.0015 for SPT Method SF(SPT) = 3.5
69
70 Table7: Pile Resistance Calculation
Soil layer
ID
Soil symbol
& Description
Soil Type Soil Parameter for
Design
Skin Frictional Resistance Calculation End Bearing Resistance Calculation
Layer Depth from EGL
Contributing Skin
Resistance
Layer
Thickness
for Skin
Friction
Resistance
SPT Correction Adhesion
factor
Effective Stress Calculation Friction
factor due
to
overburde
n
Unit Skin Friction Layer Depth from EGL
Contribution Base
Resistance
Layer
Thickness
for End
Bearing
Resistance
SPT Correction Bearing
capacity
factors
Capacity Modification
Factor [ only for Drilled
Shaft ]
Unit End Bearing
Unit Conversion Undrained
Shear
Strength
Angle of
Internal
Fiction
Average of
N-Values
of Soil
Layer
Hammer
Corrected
N-Value
Mid Depth
Soil Layer
from EGL
Effective
Stress at
Mid Depth
Critical
Depth from
EGL after
Dig-out
Effective
Stress at
Critical
Depth
Average of
N-Values
of Soil
Layer
Hammer
Corrected
N-Value
1 kN/m³ = 101.97 kg/m³ by Static
Bearing
Capacity
Equation
by SPT N-
Value
by Static
Bearing
Capacity
Equation
by SPT N-
Value
Top Level Bottom
Level
Abbreviation
BNBC = Bangladesh National Building Code Cu, Su φ (Zt)s (Zb)s ΔZs N N60 α Zm σ'z Dc σ'zc β fs fsN (Zt)b (Zb)b ΔZb N N60 Nq ω2 Fr fb fbN
DU = Dig out /Scour depth kPa degree m m m m kPa m kPa kPa kPa m m m kPa
EGL = Existing Ground Level Layer-1 ML - Silt Cohesive 34.9 ― NA ― ― NC ― ― NC ― ― NC ― ― NC ― ― NC ― ― NC ― ― NC ― ― NC ― ― NC ― ― NC ― ― NC ― ― NC ― ― NC ― ― NI ― ― NI ― ― NI ― ― NI ― ― NI ― ― NI ― ― NI ― ― NI ― ― NI ― ― NI ―
NA = Not Applicable Layer-2 CH - Fat clay Cohesive 23.9 ― NA ― 4.750 7.000 2.250 8.0 11.2 0.550 ― NA ― ― NA ― ― NA ― ― NA ― ― NA ― 13.15 ― NA ― ― NI ― ― NI ― ― NI ― ― NI ― ― NI ― ― NI ― ― NI ― ― NI ― ― NI ― ― NI ―
NC = Non-Contributing zone for skin friction Layer-3 ML - Silt Cohesive 26.2 ― NA ― 8.500 9.000 0.500 1.0 1.4 0.550 ― NA ― ― NA ― ― NA ― ― NA ― ― NA ― 14.40 ― NA ― ― NI ― ― NI ― ― NI ― ― NI ― ― NI ― ― NI ― ― NI ― ― NI ― ― NI ― ― NI ―
NI = Non-Influenced zone for end bearing Layer-4 ML - Silt Cohesive 29.1 ― NA ― 10.500 12.750 2.250 4.5 6.3 0.550 ― NA ― ― NA ― ― NA ― ― NA ― ― NA ― 16.00― NA ― ― NI ― ― NI ― ― NI ― ― NI ― ― NI ― ― NI ― ― NI ― ― NI ― ― NI ― ― NI ―
SBCE = Static Bearing Capacity Equation Layer-5 SM - Silty sand Granular ― NA ― 29.0 14.250 18.750 4.500 10.0 14.0 ― NA ― 16.500 209.68 ― NA ― ― NA ― 0.594 124.63 ― NA ― ― NI ― ― NI ― ― NI ― ― NI ― ― NI ― ― NI ― ― NI ― ― NI ― ― NI ― ― NI ―
SPT = Standard Penetration Test Layer-6 SP - Poorly graded sand Granular ― NA ― 35.9 20.250 22.250 2.000 13.0 18.2 ― NA ― 21.250 288.40 ― NA ― ― NA ― 0.447 128.93 ― NA ― 23 24.5 1.500 15.0 20.9 86.65 ― NA ― ― NA ― 900.00 ― NA ―
UC = Unconfined Compression
US = Undrained Shear
WT = Water Table depth
Sum = 11.500 Sum product = 891.50 0.00 Sum = 1.500 Weighted Average = 900.00 #VALUE!
Table 8: Axial Bearing Capacity
Method Static Bearing Capacity Equation Method SPT N-Value Method
Ultimate Capacity Allowable Capacity Ultimate Capacity Allowable Capacity
Skin Friction Qs = 2101 kPa Qs.alw = 750kPa Qs =― NA ― kPa Qs.alw.N = ― NA ― kPa
End Bearing
Qb = 398 kPa Qb.alw = 142 kPa Qb =― NA ― kPa Qb.alw.N = ― NA ― kPa
Total Capacity Qult = 2498 kPa Qallow = 892 kPa Qult = ― NA ― kPa Qallow.N =― NA ― kPa
