Mandatory Checklist for Load Bearing Piles Foundation Design.

Designing the foundation for load-bearing piles involves considerations for soil conditions, structural loads, and the interaction between the piles and the surrounding soil. Below is a detailed checklist with explanations and examples for the design of a load-bearing piles foundation:

1. Site Investigation:

• Explanation: Conduct a thorough site investigation to understand soil conditions.
• Example: Perform soil tests (SPT, CPT) to determine soil properties, groundwater levels, and identify any weak or compressible soil layers.

2. Load Analysis:

• Explanation: Analyze and calculate loads acting on the piles.
• Example: Consider vertical loads from the structure, lateral loads from wind or seismic forces, and moments from uneven settlement.

3. Bearing Capacity:

• Explanation: Ensure that the soil bearing capacity is sufficient for the applied loads.
• Example: If the total vertical load is 500 kN and the allowable bearing capacity is 250 kN/pile, design the foundation with at least two piles to share the load.

4. Pile Type Selection:

• Explanation: Choose the appropriate pile type based on soil conditions and load requirements.
• Example: Select driven piles (concrete, steel, or timber) for cohesive soils and auger-cast piles for granular soils.

5. Pile Spacing and Arrangement:

• Explanation: Determine the optimal spacing and arrangement of piles for even load distribution.
• Example: Space the piles evenly to ensure uniform settlement and reduce the risk of differential settlement.

6. Pile Length:

• Explanation: Calculate the required length of the piles to reach load-bearing strata.
• Example: If the competent soil layer is at 10 meters below the ground surface, design piles with lengths exceeding 10 meters to ensure adequate embedment.

7. Pile Cap Design:

• Explanation: Design the pile cap to distribute loads to individual piles.
• Example: Include a reinforced concrete pile cap with appropriate dimensions and reinforcement to transfer loads from the structure to the piles.

8. Reinforcement:

• Explanation: Specify reinforcement in the piles and pile cap, if required.
• Example: Include reinforcing bars in the pile cap to enhance its tensile strength and improve overall stability.

9. Pile Installation:

• Explanation: Specify procedures for pile installation.
• Example: Use proper driving or drilling techniques and procedures to achieve the desired pile lengths and capacities.

10. Pile Load Testing:

• Explanation: Conduct load tests on selected piles to verify their capacity.
• Example: Apply incremental loads to test piles and compare the measured settlement to predicted settlement to confirm design assumptions.

11. Negative Skin Friction:

• Explanation: Account for negative skin friction in cohesive soils.
• Example: If piles are founded in clay, consider measures such as a shear key or vertical drains to mitigate negative skin friction effects.

12. Pile Group Effects:

• Explanation: Consider interactions between closely spaced piles in a group.
• Example: Account for pile group effects in the design to avoid excessive settlement or lateral deflection.

13. Construction Sequence:

• Explanation: Develop a construction sequence that ensures stability during and after construction.
• Example: Install piles, construct the pile cap, and then build the superstructure while monitoring for settlement or other issues.

14. Quality Control:

• Explanation: Implement quality control measures during construction.
• Example: Monitor pile installation for proper alignment and penetration, check reinforcement placement, and verify the dimensions of the pile cap.

15. Code Compliance:

• Explanation: Ensure compliance with local building codes and standards.
• Example: Adhere to relevant codes such as ACI 318 for concrete piles, ASTM standards for steel piles, or local geotechnical standards.

16. Professional Engineer Involvement:

• Explanation: Engage a qualified geotechnical and structural engineer to oversee the design.
• Example: Have licensed engineers review and approve the load-bearing piles foundation design to ensure it meets safety and code requirements.

17. Record Keeping:

• Explanation: Maintain detailed records of the load-bearing piles foundation design process.
• Example: Document all design calculations, soil test results, construction activities, and as-built drawings for future reference and audits.

By following this checklist, engineers can ensure a well-designed load-bearing piles foundation that effectively supports the structural loads, provides stability, and minimizes potential failure modes.