Concrete Beam

Rectangular beam flexure (phiMn) and one-way shear with stirrups (ACI 318-19).

Strength design (LRFD): enter factored demands (Pu, Mu, Vu from your load combinations). Results follow ACI 318-19; bar areas use standard ASTM sizes. Confirm detailing (development, spacing, ties) separately.

Design diagram — updates live with your inputs

Section

Web width bw (in)i

Overall depth h (in)i

Materials

Concrete f'c (psi)i

Steel fy (psi)i

Flexural Steel

Cover to bar c.l. (in)i To tension-bar centroid

Tension bari

Number of barsi

Shear Steel

Stirrup bari

Stirrup spacing s (in)i

Stirrup legsi 2 for a closed tie

Factored Demands

Factored moment Mu (kip-ft)i

Factored shear Vu (kip)i

ACI 318-19

Validation, assumptions & limitations Download validation report (PDF) ↗

This calculator is verified by 4 independent tests comparing its output against closed-form statics, NDS/SDPWS design-standard values and published worked examples. Full case-by-case results are in the PDF report.

Assumptions

Singly reinforced rectangular section; tension-controlled (phi=0.9).
Normalweight concrete (lambda = 1.0).
Vertical stirrups; Av = legs x bar area.

Limitations

No compression-steel or T-beam flange contribution.
Torsion and deep-beam behavior not covered.

Results are for preliminary design and must be confirmed by a licensed engineer against the current adopted code and project-specific conditions.