DESIGN SOFTWARE
Flexural Design & Analysis
Singly-reinforced rectangular sections per ACI 318-25. Design the steel from a given Mu, or check the capacity φMn of a placed section — with cross-section and strain diagrams. Metric units (m, MPa, kN·m, cm²).
TERCERO TABLADA
Civil & Structural Engineering Inc.
FLEXURAL DESIGN (singly reinforced)ACI 318-25
1 · Inputs
1.0 m for walls/slabs
Gr.60 = 420
from 1.2D + 1.6L
d = h − r = 0.470 m · β1 = 0.850
2–4 · Required steel
| Rn = Mu/(0.9·b·d²) | 4.024 MPa | |
| ρ required | 0.01101 | (0.85f′c/fy)(1−√(1−2Rn/0.85f′c)) |
| ρmin = 1.4/fy | 0.00333 | ACI 9.6.1.2 |
| ρmin alt = (4/3)·ρ | 0.01467 | ACI 9.6.1.3 (lesser governs) |
| ρmax (εt = 0.005) | 0.01355 | keeps φ = 0.90 |
| ρ design = max(ρ, ρmin) | 0.01101 | |
| As required = ρ·b·d | 12.93 cm² | |
| Ductile? (ρ ≤ ρmax) | Yes |
5 · Pick commercial bars
6 · Verify the placed steel
| As placed ≥ required? | Yes | |
| a (stress block) = As·fy/(0.85f′c·b) | 143.1 mm | |
| c (neutral axis) = a/β1 | 168.3 mm | |
| εt = (d−c)/c · 0.003 | 0.0054 | ≥ 0.004 to accept |
| φ (transition, capped) | 0.900 | Table 21.2.2 |
| Mn = b·d²·fy·ρ(1−ρfy/1.7f′c) | 254.44 kN·m | |
| φMn (capacity) | 228.99 kN·m | vs Mu = 200.00 |