B02 · Intermediate · 1–2 hours
BS 8110 — rectangular beam
Rectangular beam flexure including compression steel, span/depth with modification factors and bar spacing.
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): 3.4.4.4; Fig 2.2 (steel stress–strain); Table 3.25; 3.12.6.1; 3.4.6, Tables 3.9–3.11, eq 7–9; 3.12.11.1 (minimum spacing) and 3.12.11.2.4 (maximum clear spacing 47000/fs ≤ 300 mm). | Withdrawn standard — education and legacy checks only (mapping awaiting checker verification) |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: B01 BS 8110 — one-way solid slab · Topics: Reinforced concrete
Lesson
Lesson in preparation. No content is published until it has been written and reviewed.
Calculator
Purpose: Flexural design of a rectangular beam section including compression steel, deflection and bar spacing.
Model: Rectangular section, single layer of tension bars; compression steel where K > K′.
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: K ≤ K′: z = d[0.5 + √(0.25 − K/0.9)] ≤ 0.95d; As = M/(fyd z) ; K > K′: z from K′; x = (d − z)/0.45; fsc from strain 0.0035(x − d′)/x ; As′ = (K − K′)fcu b d²/(fsc (d − d′)) ; As = K′fcu b d²/(fyd z) + As′ fsc/fyd ; Comp MF = 1 + ρ′/(3 + ρ′) ≤ 1.5, ρ′ = 100As′prov/bd
Clauses: 3.4.4.4; Fig 2.2 (steel stress–strain); Table 3.25; 3.12.6.1; 3.4.6, Tables 3.9–3.11, eq 7–9; 3.12.11.1 (minimum spacing) and 3.12.11.2.4 (maximum clear spacing 47000/fs ≤ 300 mm).
© 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 BS 8110 is WITHDRAWN (superseded by BS EN 1992-1-1 and, in Singapore, SS EN 1992-1-1).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: Multiple layers of tension bars; Shear (use B04), torsion, anchorage/laps, curtailment, crack-width calculation; Analysis of moments (input is the design moment)
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.