B14 · Advanced · 1–2 hours
BS 8110 — pile cap (2, 4, 5 or 6 piles)
Pile reactions with moments, bending at the column faces, beam shear with 2d/av enhancement within 3Ø strips, and punching (3.11.4).
Tool: Education preview · Lesson: In preparation · Example: Built awaiting check · Workbook: Not applicable · Assessment: Not started
Outstanding before release: Engineering checker to verify clause mapping against BS 8110-1 and sign off v0.1.0. Cross-checked against TCC RCC82 Pilecap Design (see evidence).
Sources
| Role | Source | Note |
|---|---|---|
| Primary | BS 8110-1:1997 (+A1–A3): 3.11.4.1 (bending theory), 3.11.4.2 (cap ULS loads), 3.11.4.3 (critical shear section and av), 3.11.4.4 (shear enhancement, 3Ø strips), 3.11.4.5 (punching), 3.4.4.4, 3.4.5.8, Table 3.8, Table 3.25, 3.12.11.2 | Withdrawn standard — education and legacy checks only (mapping awaiting checker verification) |
| Supporting | Cross-check reference: The Concrete Centre RCC82 Pilecap Design (external tool; not used in the implementation) | Comparison evidence only (mapping awaiting checker verification) |
"Primary" marks the governing clause for this exercise; "contextual" marks related clauses; "supporting" marks the design-method or data source outside the CDC. A CDC chapter mapping does not mean the CDC contains the equation used.
Prerequisites: B08 BS 8110 — pad foundation · Topics: Foundations, Reinforced concrete
Lesson
Lesson in preparation. No content is published until it has been written and reviewed.
Calculator
Purpose: Pile reactions, bending at the column faces, beam shear with enhancement near piles, and punching for a rectangular pile cap.
Model: Rigid cap; elastic pile group P = N/n + My·x/Σx² + Mx·y/Σy². Bending at each column face over the full cap width: M = Σ P (x − c/2 + tolerance) − cap self-weight. Shear on a section 20% of the pile diameter inside the pile face; vc enhanced by 2d/av (3.11.4.3–3.11.4.4), only within 3Ø strips centred on the piles. Punching at the column face, and at 1.5d where piles are more than 3Ø apart (3.11.4.5).
Units: N, mm, kN, kNm; stresses in N/mm² Ranges: fcu 25–50 N/mm²; fy 250 / 460 / 500; βb 0.7–1.0
Equations: Cap self-weight included in pile loads (1.4 at ULS) ; av = distance from column face to the section 0.2Ø inside the pile face ; vc,enh = vc × 2d/av ≤ min(0.8√fcu, 5) ; v at column face = N/(u0 d) ≤ min(0.8√fcu, 5)
Clauses: 3.11.4.1 (bending theory), 3.11.4.2 (cap ULS loads), 3.11.4.3 (critical shear section and av), 3.11.4.4 (shear enhancement, 3Ø strips), 3.11.4.5 (punching), 3.4.4.4, 3.4.5.8, Table 3.8, Table 3.25, 3.12.11.2
© 2026 QP Academy. Original calculation software implementing BS 8110-1:1997 (+A1, A2, A3). BS 8110 is WITHDRAWN (superseded by BS EN 1992-1-1 and, in Singapore, SS EN 1992-1-1). For education and for checking legacy designs only — not for new design submissions.
Not covered: 3-pile and other non-rectangular groups; eccentric columns; truss-analogy design; Horizontal loads, wind combinations, pile tension; Shear links in caps; mx about the line of a 2-pile cap (needs tie beams)
Version 0.1.0 Draft
EDUCATION PREVIEW — NOT YET INDEPENDENTLY CHECKED. Education preview: this calculator has not yet been independently checked by an engineer. Use for learning only — not for engineering use. Outputs are stamped and must not be used for engineering work.
Excel workbook
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Exercises
Assessment in preparation.