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 |
| 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 | 96.605 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 kN−m |
