Mandatory Checklist for Anchored Retaining Wall Foundation Design.

Designing the foundation for an anchored retaining wall involves considerations for stability, bearing capacity, and soil-structure interaction. Below is a detailed checklist with explanations and examples for the design of an anchored retaining wall foundation:

1. Site Investigation:

Explanation: Conduct a thorough site investigation to understand soil conditions.
Example: Perform soil tests (SPT, CPT) to determine soil properties, bearing capacity, and potential sliding or settlement.

2. Load Analysis:

Explanation: Analyze and calculate loads acting on the anchored retaining wall.
Example: Consider the weight of the wall, backfill soil pressure, surcharge loads, water pressure, and seismic loads to determine the total lateral load.

3. Bearing Capacity:

Explanation: Ensure that the soil bearing capacity is sufficient for the applied loads.
Example: If the total lateral load is 180 kN/m and the soil bearing capacity is 250 kN/m², the foundation is considered suitable.

4. Sliding Stability:

Explanation: Check and ensure the foundation resists sliding.
Example: Calculate the sliding force and compare it to the resisting force provided by the foundation. Use appropriate safety factors.

5. Overturning Stability:

Explanation: Verify the foundation’s resistance to overturning.
Example: Assess the moments and forces acting on the anchored wall and ensure they are counteracted by the resisting moments and forces provided by the foundation.

6. Foundation Geometry:

Explanation: Determine the appropriate dimensions and shape of the foundation.
Example: Design a trapezoidal or rectangular foundation with dimensions that distribute the loads evenly along the length of the anchored wall.

7. Reinforcement:

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

8. Foundation Depth:

Explanation: Determine the optimal foundation depth for stability.
Example: Increase the foundation depth if weak or compressible soil layers are present near the surface.

9. Toe and Heel Details:

Explanation: Address toe and heel details to enhance stability.
Example: Extend the foundation in the direction of potential sliding (toe) and provide a keying-in detail to resist sliding.

10. Drainage:

Explanation: Implement drainage measures to reduce hydrostatic pressure.
Example: Install drainage pipes behind the anchored wall to relieve water pressure and prevent water accumulation.

11. Backfill Compaction:

Explanation: Specify compaction requirements for the backfill soil.
Example: Compaction should be done in lifts with specified moisture content to achieve adequate density.

12. Anchor Connection:

Explanation: Detail the connection between the foundation and anchors.
Example: Ensure that the anchors are securely attached to the foundation using appropriate connectors.

13. Anchor Design:

Explanation: Design the anchors to resist tensile forces.
Example: Calculate the required anchor length and embedment depth based on the wall geometry, soil properties, and applied loads.

14. Construction Sequence:

Explanation: Develop a construction sequence that ensures stability during and after construction.
Example: Excavate, place and compact the foundation material, construct the anchored wall, and ensure proper compaction of the backfill.

15. Quality Control:

Explanation: Implement quality control measures during construction.
Example: Monitor the compaction of backfill, check reinforcement placement, and verify the dimensions of the foundation.

16. Code Compliance:

Explanation: Ensure compliance with local building codes and standards.
Example: Adhere to relevant codes such as AASHTO LRFD Bridge Design Specifications or local geotechnical standards.

17. Professional Engineer Involvement:

Explanation: Engage a qualified geotechnical and structural engineer to oversee the design.
Example: Have licensed engineers review and approve the anchored retaining wall foundation design to ensure it meets safety and code requirements.

18. Record Keeping:

Explanation: Maintain detailed records of the anchored retaining wall 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 anchored retaining wall foundation that effectively resists lateral loads, provides stability, and minimizes potential failure modes.