📋 Input Parameters
📐 Section Geometry
| Width of Column B | mm | |
| Depth of Column D | mm | |
| Effective Length — about B-B axis (lex) | m | |
| Effective Length — about D-D axis (ley) | m |
🔩 Reinforcement
| Primary Bar Diameter (φ₁) | mm | |
| No. of Primary Bars (n₁) | — | |
| Secondary Bar Diameter (φ₂) | mm | |
| No. of Secondary Bars (n₂) | — | |
| Bars on each D-face incl. corners — C₈ | — | |
| Bars on each B-face incl. corners — C₉ | — | |
| Nominal Clear Cover to Ties | mm | |
| Tie Bar Diameter (φt) | mm | |
🧱 Materials
| Concrete Grade (fck) | MPa | |
| Steel Grade (fy) | MPa |
⚡ Applied Loads (Factored)
| Axial Load Pu | kN | |
| Mux — Moment about B-B axis | kNm | |
| Muy — Moment about D-D axis | kNm |
📊 Design Summary
| Section B × D | — | mm |
| Factored Load Pu | — | kN |
| Steel Area Asc provided | — | mm² |
| Minimum Asc (0.8% Ag) | — | mm² |
| Effective Cover d′ (= c + φt + φ/2) | — | mm |
| Reinforcement Details | — | |
| Tie Bar & Pitch | — | |
| Clear Spacing along B / along D | — | mm |
| Design Mux / Muy (with slenderness) | — | kNm |
| Mux1 / Muy1 uniaxial capacity at Pu | — | kNm |
| Biaxial Interaction Ratio (≤ 1.0) | — | — |
⬛ Cross-Section & Reinforcement Layout
B = horizontal · D = verticalMain bars
Lateral ties
Effective cover zone
Nominal cover limit
⚡ Derived Properties & Uniaxial Capacity
| Parameter | Value | Unit |
|---|---|---|
| Total bars (n₁+n₂) | — | — |
| Total Asc | — | mm² |
| Eff. cover d′ = c+φt+φ/2 | — | mm |
| Puz = 0.45fckAg+0.75fyAsc | — | kN |
| Pu/Puz | — | — |
| αn exponent (IS 456 Cl 39.6) | — | — |
| Mux1 capacity (about B-B, X₁=D) | — | kNm |
| Muy1 capacity (about D-D, X₁=B) | — | kNm |
| Pb balanced (B-B axis) | — | kN |
| Pb balanced (D-D axis) | — | kN |
📐 Slenderness & Design Moments (IS 456 Cl 39.7)
| Parameter | B-B axis | D-D axis | Unit |
|---|---|---|---|
| Effective length Le | — | — | m |
| Slenderness le/D or le/B | — | — | — |
| Column type | — | — | — |
| Min eccentricity emin | — | — | mm |
| Mecc = Pu·emin | — | — | kNm |
| Reduction factor Ca | — | — | — |
| Madd (slenderness moment) | — | — | kNm |
| Mu,des (governing) | — | — | kNm |
📖 SP:16 Normalised Parameters
| Parameter | Value |
|---|---|
| Pu / (fck·B·D) | — |
| Mux,des / (fck·B·D²) | — |
| Muy,des / (fck·D·B²) | — |
🔄 Biaxial Interaction — Bresler's Formula (IS 456 Cl 39.6)
| Parameter | Value | Remark |
|---|---|---|
| Mux,des / Mux1 | — | B-B axis demand ratio |
| Muy,des / Muy1 | — | D-D axis demand ratio |
| Interaction = (rBB)^α + (rDD)^α | — | — |
📈 P-M Interaction Diagram (IS 456:2000)
✅ Codal Checks — IS 456:2000
| Check & IS 456 Reference | Provided | Limit | Result |
|---|---|---|---|
| Enter inputs to evaluate | |||
Engineering Disclaimer — IS 456:2000 : This tool implements the Limit State Method for rectangular RC columns under biaxial bending, braced frame assumption. Effective cover = clear cover to tie face + tie dia + ½ main bar dia (IS 456 Annex B). Slenderness ratios: lex/D and ley/B per IS 456 Cl 25.1.2. Additional moments per Cl 39.7.1 with Cₐ reduction factor per Cl 39.7.1.1. Biaxial interaction by Bresler's formula, Cl 39.6. Steel stress-strain per IS 456 Annex B (Fe 500 non-linear; Fe 415/Fe 550 simplified E-PP model). Results are indicative only and must be verified by a licensed structural engineer before use in construction documents.