Inputs
Geometry
m
m (perp.)
mm
Loads
kPa
kPa
Materials
MPa
MPa
mm
System
0 if no beams
Reinforcement
Method & assumptions
- wu = 1.2 D + 1.6 L (kPa).
- M0 = wu · ℓ2 · ℓn² / 8.
- Interior span: 0.65 M0 negative @ supports, 0.35 M0 positive @ midspan.
- Exterior span (no edge beam): exterior neg = 0.26, positive = 0.52, interior neg = 0.70 of M0.
- Column strip width = 0.5 · min(ℓ1, ℓ2) total (0.25 each side of column line).
- Min thickness h: per ACI 318-19 Table 8.3.1.1, adjusted for fy.
- Flexure design: ρ = (0.85 f'c / fy)·[1 − √(1 − 2 Rn / (0.85 f'c))], Rn = Mu / (φ b d²), φ = 0.9.
- As,min = 0.0018 b h (Grade 60); max spacing = min(2 h, 450 mm) per ACI 8.7.2.2.
- DDM applicability: 3+ spans, ratio ≤ 2, LL ≤ 2 DL, gravity uniform loads only.
Results (per design direction strip)
Min thickness hmin (≈)—
Effective depth d—
Factored Load wu—
Total Static Moment M0—
Column Strip Width—
Middle Strip Width—
As,min per metre—
Max spacing smax—
Moment Distribution
| Section | Total (kN·m) | Col. Strip | Mid Strip |
|---|
Reinforcement Design (As per metre of strip)
| Section | Strip | Mu/m (kN·m/m) | As,req (mm²/m) | Spacing (mm) |
|---|