B03 · Intermediate · 1–2 hours
BS 8110 — flanged (T/L) beam
Flanged beam in sagging: effective flange width, neutral axis in flange or web (3.4.4.5), span/depth.
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): 3.4.1.5 (effective flange width); 3.4.4.4; 3.4.4.5; Table 3.25 (flanged minimum steel); 3.12.6.1; 3.4.6, Tables 3.9–3.11; 3.12.11. | Withdrawn standard — education and legacy checks only (mapping awaiting checker verification) |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: Flexural design of a flanged beam with the flange in compression, deflection and bar spacing.
Model: Flange in compression. Neutral axis in flange → rectangular section width bf; else 3.4.4.5 eq. for βb ≥ 0.9.
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: bf ≤ bw + lz/5 (T) or bw + lz/10 (L); lz = span (simple) or 0.7·span (continuous) ; 0.9x ≤ hf: As = M/(fyd z), K = M/(bf d² fcu) ; 0.9x > hf: As = [M + 0.1 fcu bw d (0.45d − hf)]/[fyd (d − 0.5hf)], valid if M ≤ βf fcu bf d² ; βf = 0.45(hf/d)(1 − bw/bf)(1 − hf/2d) + 0.15 bw/bf
Clauses: 3.4.1.5 (effective flange width); 3.4.4.4; 3.4.4.5; Table 3.25 (flanged minimum steel); 3.12.6.1; 3.4.6, Tables 3.9–3.11; 3.12.11.
© 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 BS 8110 is WITHDRAWN (superseded by BS EN 1992-1-1 and, in Singapore, SS EN 1992-1-1).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: Hogging moments (flange in tension — design as rectangular beam of width bw with B02); Neutral axis in web with βb < 0.9, or needing compression steel — outside scope; Shear in flange/web junction, transverse flange steel
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.