RC Section Designer

Interactive reinforced concrete section analysis with N-M interaction, biaxial capacity, moment-curvature and code checks.

Design Code

Units

Geometry

Section shape

Width b ?mm

Depth h ?mm

Cover d' ?mm

50 mm

Materials

Concrete strength f'c ?MPa

Steel yield fy ?MPa

Steel ratio ρ ?%

3.0 %

Bar diameter ?mm

Ø20 mm

Applied Forces (ULS)

Axial N* ?kN

Moment M* ?kNm

Shear V* ?kN

SLS moment ?kNm

Y-axis My* ?kNm

Section Preview 300 × 400 mm

M – N Interaction Diagram ACI 318 · φ factors applied

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Compression-controlled Tension-controlled Balanced point Design point (N*, M*)

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φPn max

—

Compression cap

Balanced N

—

At balanced point

Balanced M

—

At balanced point

Pure bending φMn

—

Zero axial

Biaxial Bending Failure Surface Mx–My at constant N levels

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Moment – Curvature Diagram Fiber model · Nominal moments · No φ factor

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Yield Moment

—

First yield

Yield Curvature

—

×10⁻⁶ rad/mm

Ultimate Moment

—

At failure

Ductility μ

—

ϕu / ϕy

Not run

ULS Flexure + Axial

—

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Not run

Shear Capacity φVc

—

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Not run

SLS Crack Width wk

—

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Not run

Reinforcement Limits

—

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