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Header / coupling beam over an opening — conventional or diagonal reinforcement (ACI 18.10.7).

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

Geometry

Clear span ln (ft)i Opening width

Depth h (in)i

Width bw (in)i

Materials

Concrete f'c (psi)i

Steel fy (psi)i

Flexural Steel

Cover to bar c.l. (in)i

Tension bari

Number of barsi

Shear Steel

Stirrup bari

Stirrup spacing s (in)i

Stirrup legsi

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

ln/h = 3 here -> conventional beam design.
Same flexure/shear basis as the beam tool.

Limitations

Diagonal-reinforcement branch applies only to deep beams.
Joint and anchorage detailing confirmed separately.

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