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ACI 318 Pile Design Verification

ACI-Verification-Books-Preview

Information presented on this page is intended to demonstrate the section design convergence of ACI 318-2014 provisions for pile foundations that can be achieved with SkyCiv. All examples are taken from the following books:

Book 1: Ruwan Rajapakse, Pile Design and Construction Rules of Thumb, 2016.
Book 2: American Concrete Institute, Designing Concrete Structures: Interaction Diagram for Concrete Columns, 2007.
Book 3: Hsiao, J. Kent (2012), Bending-Axis Effects on Load-Moment (P-M) Interaction Diagrams for Circular Concrete Columns Using a Limited Number of Longitudinal Reinforcing Bars, Electronic Journal of Structural Engineering 12(1)

 

Vertical Geotechnical Capacity

Book 1: Example 7.4.1 Compute the ultimate bearing capacity of the pile:

Details
Section
Diameter 500 mm
Length 10 m
Soil Properties
Unit Weight 17.3 kN/m3
Friction Angle 30 Degrees
Cohesion 0 KPa
Groundwater Table Not present

 

Results
Parameter Manual SkyCiv
Vertical Effective Pressure 173 kPa 173 kPa
Base Resistance term 713.3 kN 713.338 kN
Average Effective Vertical Stress 86.5 kPa 86.500 kPa
Shaft Frictional Resistance Term 703.5 kN 703.510 kN
Ultimate Bearing Capacity 1,416.8 kN 1,416.848 kN

 

Book 1: Example 7.4.2 Compute the ultimate bearing capacity of the pile:

Details
Section
Diameter 500 mm
Length 10 m
Soil Properties
Unit Weight 17.3 kN/m3
Friction Angle 30 Degrees
Cohesion 0 KPa
Groundwater Table 3 m

 

Results
Parameter Manual SkyCiv
Vertical Effective Pressure 104.33 kPa 104.330 kPa
Base Resistance term 430.19 kN 430.188 kN
Average Effective Vertical Stress
     0-3m 25.95 kPa 25.950 kPa
     3-10m 78.12 kPa 78.115 kPa
Shaft Frictional Resistance Term
     0-3m 63.32 kN 63.316 kN
     3-10m 444.72 kN 444.720 kN
Total Shaft Frictional Resistance Term 508.04 kN 508.036 kN
Ultimate Bearing Capacity 938.22 kN 938.224 kN

 

Book 1: Example 7.4.3 Compute the ultimate bearing capacity of the pile:

Details
Section
Diameter 500 mm
Length 12 m
Layer 1-Soil Properties
Thickness 5 m
Unit Weight 17.3 kN/m3
Friction Angle 30 Degrees
Cohesion 0 KPa
Groundwater Table Not present
Layer 2-Soil Properties
Thickness 7 m
Unit Weight 16.9 kN/m3
Friction Angle 32 Degrees
Cohesion 0 KPa
Groundwater Table Not present

 

Results
Parameter Manual SkyCiv
Vertical Effective Pressure 204.8 kPa 204.800 kPa
Base Resistance term 1,166.2 kN 1,166.159 kN
Layer 1: Average Effective Vertical Stress
     Layer 1 43.3 kPa 43.250 kPa
     Layer 2 145.7 kPa 145.650 kPa
Shaft Frictional Resistance Term
     Layer 1 176.1 kN 175.878 kN
     Layer 2 891.6 kN 891.295 kN
Ultimate Bearing Capacity 2,233.9 kN 2,233.332 kN

 

Book 1:  Example 7.4.4 Compute the ultimate bearing capacity of the pile:

Details
Section
Diameter 500 mm
Length 15 m
Layer 1-Soil Properties
Thickness 5 m
Unit Weight 17.3 kN/m3
Friction Angle 30 Degrees
Cohesion 0 KPa
Groundwater Table 3 m
Layer 2-Soil Properties
Thickness 7 m
Unit Weight 16.9 kN/m3
Friction Angle 32 Degrees
Cohesion 0 KPa

 

Results
Parameter Manual SkyCiv
Vertical Effective Pressure 137.9 kPa 137.780 kPa
Base Resistance term 785.2 kN 784.538 kN
Average Effective Vertical Stress
     0-3m 26 kPa 25.950 kPa
     3-5m 59.4 kPa 59.390 kPa
     5-15m 102.4 kPa 102.330 kPa
Shaft Frictional Resistance Term
     0-3m 63.4 kN 63.316 kN
     3-5m 96.6 kN 63.316 kN
     5-15m 895.2 kN 894.573 kN
Ultimate Bearing Capacity 1,840.4 kN 1,839.032 kN

 

Axial & Flexural Capacities

Book 2: Example E702 Compute the axial and flexural capacities, (ΦPN, ΦMN)

Details
Section
Cross-section Rectangular
Depth 12 in
Width 12 in
Reinforcement
Bar Diameter 4-#8
Materials
Concrete Strength 4,000 psi
Steel Yield Strength 60,000 psi

 

Results
Parameter Manual SkyCiv
Gross Area (Ag) 144 in2 144.0 in2
Steel Reinforcement Area (Ast) 3.16 in2 3.142 in2
ΦPN at Pure Compression 347.60 kips 347.055 kips
Neutral Axis Depth (c} 5.40 in 5.622 in
Equivalent Stress Block Depth (a} 4.590 in 4.779 in
Strain at Top Reinforcement 0.001612 0.00167
Stress at Top Reinforcement 46.75 ksi 48.316 ksi
Steel Force at Top Reinforcement 68.49 ksi 70.554 kips
Strain at Bottom Reinforcement 0.0022762 0.00207
Stress at Bottom Reinforcement 60 ksi 60 ksi
Steel Force at Bottom Reinforcement -94.80 ksi -94.248 kips
Force in Concrete 187.27 ksi 194.987 kips
ΦPN at Balanced condition 108.33 kips 112.324 kips
ΦMN at Balanced condition 70.97 kip-ft 69.990 kip−ft

 

Book 3: Example 1 Compute the axial and flexural capacities, (ΦPN, ΦMN)

Details
Section
Cross-section Round
Diameter 508 mm
Reinforcement
Bar Diameter 6-#10
Materials
Concrete Strength 20.7 MPa
Steel Yield Strength 414 MPa

 

Results
Parameter Manual SkyCiv
Gross Area (Ag) 202,682 mm2 202,682.992 mm2
Steel Reinforcement Area (Ast) 4,825.49 mm2 4,825.486 mm2
ΦPN at Pure Compression 2,850 kN 2,849.108 kN
Neutral Axis Depth (c} 263 mm 262.840 mm
Equivalent Stress Block Depth (a} 223.5 mm 223.414 mm
Strains on the reinforcements, εi
     ε1 0.00227 0.00227
     ε2 0.00119 0.00119
     ε3 -0.000984 -0.00098
     ε4 -0.00207 -0.00207
Stresses on the reinforcements, fsi
     fs1 414 MPa 414.0 MPa
     fs2 238 MPa 237.270  MPa
     fs3 -196.8 MPa -196.910  MPa
     fs4 -414 MPa -414.0 MPa
Forces on the reinforcements, Fi
     F1 325 kN 318.808  kN
     F2 361 kN 353.346  kN
     F3 -322 kN -316.729  kN
     F4 -339 kN -332.959  kN
Force in Concrete 1,510 kN 1,510.382 kN
ΦPN at Balanced condition 1,006.96 kN 1,005.293 kN
ΦMN at Balanced condition 248.62 kN-m 246.426 kNm
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