B05 · Advanced · 1–2 hours
BS 8110 — short column (N + M)
Symmetrically reinforced rectangular short column under axial load and uniaxial moment, by strain compatibility.
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 a copy of BS 8110-1:1997 (+A3) and sign off v0.1.0. Cross-checked against TCC RCC11 v4.0 (see evidence).
Sources
| Role | Source | Note |
|---|---|---|
| Primary | BS 8110-1:1997 (+A1–A3): 3.8.1.3 (short column: le/h < 15 braced, < 10 unbraced); 3.8.2.4 (minimum eccentricity min(0.05h, 20 mm)); 3.4.4.1 / Fig 2.1–2.2 (section analysis); 3.12.5.2 (minimum 0.4%); 3.12.6.2 (maximum 6% vertically cast); 3.12.7.1 (links ≥ Ø/4, spacing ≤ 12Ø). | Withdrawn standard — education and legacy checks only (mapping awaiting checker verification) |
| Supporting | Cross-check reference: The Concrete Centre RCC11 Element Design v4.0 (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: B02 BS 8110 — rectangular beam · Topics: Reinforced concrete
Lesson
Lesson in preparation. No content is published until it has been written and reviewed.
Calculator
Purpose: Area of reinforcement for a short column section under N and M by strain compatibility.
Model: Symmetric reinforcement As on each of the two faces parallel to the bending axis; side bars ignored. Section analysis: N = 0.67fcu b dc/γm + As(fsc − fst); M about centroid; dc = min(0.9x, h).
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: M_design = max(M, N · emin) ; εsc = 0.0035(x − d′)/x; εst = 0.0035(d − x)/x; f = Es ε ≤ fy/γs ; Solve for the smallest As per face whose N–M section capacity encloses (N, M_design)
Clauses: 3.8.1.3 (short column: le/h < 15 braced, < 10 unbraced); 3.8.2.4 (minimum eccentricity min(0.05h, 20 mm)); 3.4.4.1 / Fig 2.1–2.2 (section analysis); 3.12.5.2 (minimum 0.4%); 3.12.6.2 (maximum 6% vertically cast); 3.12.7.1 (links ≥ Ø/4, spacing ≤ 12Ø).
© 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 BS 8110 is WITHDRAWN (superseded by BS EN 1992-1-1 and, in Singapore, SS EN 1992-1-1).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: Slender columns (additional moments, 3.8.3) — outside scope; Biaxial bending (3.8.4.5); Circular columns, unsymmetric reinforcement, side bars; Shear in columns
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
The workbook is available with the calculator once this version is released.
Exercises
Assessment in preparation.