Preliminary slab reinforcement sizing with code-based load factors (IS/ACI/EC2/NBC). Includes plan + moment diagram,
corner torsion toggle (two-way), and report export.
If “Auto”, αx & αy are estimated for preliminary use.
If required: torsion band = 0.2×Lx from corners (top+bottom, both directions).
Method used (quick)
• Self weight = 25 × (h/1000) kN/m²
• Ultimate (if service inputs):
IS/NBC: wu = 1.5(D+L)
ACI: wu = 1.2D + 1.6L
EC2: wu = 1.35G + 1.5Q
• One-way: Mu = wu·Lx²·k (k = 1/8 SS, 1/12 CONT, 1/2 CANT)
• Two-way: Mx = αx·wu·Lx², My = αy·wu·Lx²
• Steel per m: As ≈ Mu / (f · z), z≈0.9d, d = h - cover - φ/2
• Spacing: s ≈ 1000·Ab / As (rounded down so As_prov ≥ As_req)
Corner torsion (simplified):
If torsion required (corners held down):
both edges discontinuous: 0.75×As_main
one edge discontinuous: 0.375×As_main
both edges continuous: 0
Band = 0.2Lx; provide top+bottom, both directions.
Ready
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Enter inputs and compute to see reinforcement and diagrams.