Deep beams calculator

Beam Size Calculator — IS 13920 Guidance (with reinforcement)

Geometry guide: D = L/12 to L/10, b ≈ D/1.5, and b ≥ 200 mm. Use this for a practical starting geometry. This tool visualizes reinforcement too.

Clear Span L (meters)

Preferred depth selection Auto (mid of L/12 & L/10) L/12 (shallower) L/10 (deeper) Custom depth (mm)

Custom overall depth D (mm)

Clear cover to reinforcement (mm) 20–25 mm typical; increase for severe exposure or larger bars.

Stirrup / link diameter (mm)

Main (longitudinal) bar diameter (mm) - choose predominant bottom bar

Minimum beam width allowed (mm) Do not design width less than this per your rule. Practical widths include 230/300/350/450 mm.

Width selection rule Width = D / 1.5 Fixed width (mm)

Fixed width b (mm)

Display & actions

Beam Cross-section (dynamic)

Drawing is illustrative, scaled to fit. Reinforcement shown: main longitudinal bars + stirrups/links.

Results

No calculation yet — press Calculate.

Engineer notes

• IS 13920:2016 is for ductile detailing — this tool provides geometry & visualization only. Run full checks per IS 456:2000 and IS 13920.
• Effective depth (d) = D - (clear cover + stirrup dia + 0.5 × main bar dia) — used for moment capacity checks.
• Check shear (Vc) and provide adequate stirrups; ensure development/anchorage lengths, lap details and links in plastic hinge zones per IS 13920.
• For T-beams, flange contribution and compression block influence required — this tool assumes a rectangular beam section.

Prepared as an engineering aid — not a substitute for full structural calculation and stamping by a licensed engineer.