RC Column Design (Axial + Uniaxial Moment)

Select a code, enter factored/ultimate load effects (Pu, Mu), section & materials. Output gives required longitudinal steel and a P–M interaction curve for the suggested bar arrangement.

Design standard / practice

NBC Nepal practice is often aligned with IS/NBC detailing; this tool focuses on Pu–Mu capacity & steel sizing (uniaxial model).

Load sample

Column width b (mm)

Depth D (mm) (bending direction)

D is the section depth in the direction of Mu.

Clear cover (mm)

Preferred main bar dia (mm)

Concrete strength (MPa)

Steel strength (MPa)

Pu (kN) (factored axial compression)

Mu (kN·m) (factored moment)

Effective length Le (m) (optional)

Used only for a slenderness screening message.

ACI confinement (only for ACI)

Affects ϕ(min) and axial cap (ACI).

Method used (quick)

- Uniaxial P–M interaction is generated by strain-compatibility with an equivalent rectangular concrete block. - Symmetric reinforcement model: Ast split equally on two opposite faces (compression/tension faces). - Required Ast is found by binary search between code min/max steel limits until Mu ≤ Mcap at Pu. - ACI: ϕ varies with tensile strain; design axial cap applied.

Ready

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Enter inputs to compute required steel and interaction check.

Required Ast	—
Steel ratio ρ	—
M capacity at Pu (Mcap)	—
Utilization (Mu / Mcap)	—
Suggested bars (preferred dia)	—
Min/Max steel limits (code)	—
Slenderness screening	—

Intended for preliminary design / quick check. Final design should include detailing rules, biaxial effects (if any), second-order effects, and full code compliance.

Step-by-step solution (auto-generated) + Export

Step-by-step solution

Compute to populate the step-by-step solution.