Structural design of pile caps

What the tool calculates

• Tie reinforcement calculated from the design actions and strut geometry
• Compressive stress checks in the struts, using the adopted model's limits
• Recommended strut angle between 45° and 55°
• Checks at the column and pile

What you enter

• Number and arrangement of piles
• Column load and pile cap geometry
• Concrete fck and steel fyd

What you receive

• Tie reinforcement
• Strut stress and crushing check
• Adopted strut angle

References and limits of applicability

• ABNT NBR 6118:2023 — Design of concrete structures, §22.7 (struts and ties)
• Blévot & Frémy (1967) — classical strut-and-tie model for pile caps

Checks and considerations

• Strut angle outside the recommended range (45°–55°)
• Strut stress above the k·fcd limit

How it works

The model transfers the column load to the piles through compression struts balanced by tension ties. Design considers the geometry and compression limits at the column and pile regions. The support arrangement, anchorage and limitations of the adopted coefficients must be checked as part of the design.

Example of use

To compare pile arrangements beneath a column, enter the load and support layout. Adjust the pile cap geometry and review strut angles, tie reinforcement and compression checks before preparing the member details.

Generated documents

These documents are assembled within your project using data from the corresponding tools.

• Foundation calculation report — Combine the project's SPT logs, bearing capacity calculations and structural designs for piles, pile caps, footings and belled caissons in one PDF. The document consolidates selected items; technical checks remain within each tool.
• Structural calculation report — Combine the project's saved structural results in one PDF, with the selected calculations and their references, including NBR 6118:2023 for concrete members. Check the standards applicable to each member before issuing the document; consolidation does not replace design review.
• Concrete, formwork and reinforcement quantities — Determine concrete volumes, formwork areas and steel masses from the structural designs of piles, pile caps, footings and belled caissons, with recalculation of the members and reference to NBR 7480 for mass per unit length. Review quantities, allowances for waste and assumptions; export to PDF, Word, Excel/XML (.xls), XML or DXF. Pricing is not included.