Design one-way & two-way slabs per ACI 318-19 and IS 456:2000 — bending moment, shear, deflection checks with dual code comparison.
🏗️ Civil Construction Guide — By Engr. Muhammad BilalAdvertisement
| Check Parameter | Calculated | Permissible | Status |
|---|
| Location | Bar Size | Spacing | Area (mm²/m) |
|---|
| Description | Value |
|---|
| Parameter | IS 456:2000 | ACI 318-19 |
|---|---|---|
| Load Combination | 1.5(DL + LL) | 1.2DL + 1.6LL |
| Min Reinforcement (Slab) | 0.12% bD | 0.0018bh (Gr.60) |
| Strength Reduction (φ) | No φ factor | φ=0.9 flexure, 0.75 shear |
| Shear Strength | τc (Table 19) | φVc = φ×2√f'c×b×d |
| Deflection Limit | L/d ≤ 20–26 | L/240 to L/480 |
| Stress Block | Parabolic-rectangular | Whitney (β₁=0.85-0.65) |
| Max Bar Spacing | 3d or 300mm | 3h or 18" |
Advertisement
Our RCC Slab Design Calculator designs one-way and two-way slabs per IS 456:2000 and ACI 318-19. It calculates thickness, steel area, bar spacing, and performs shear & deflection checks with dual code comparison. Supports Simply Supported, Continuous, Fixed, and Cantilever conditions.
IS 456:2000: Factored Load = 1.5(DL+LL) | Moment M = α·w·L² | Ast = 0.5fck/fy[1-√(1-4.6R/fck)]bd | τc from Table 19 | L/d ≤ 20-26
ACI 318-19: Factored Load = 1.2DL+1.6LL | φ=0.9 (flexure), 0.75 (shear) | β₁ stress block | φVc = φ×2√f'c×b×d | L/240 to L/480
If Ly/Lx ≥ 2, it's a one-way slab (bends primarily in the short direction). If Ly/Lx < 2, it's a two-way slab (bends in both directions requiring reinforcement both ways).
IS 456 recommends L/28 to L/20 depending on support conditions. ACI 318 recommends L/24 to L/10. The calculator checks both codes.
ACI 318 typically requires thicker slabs due to lower L/d ratios and the φ strength reduction factor (0.9). IS 456 allows slightly thinner slabs.
Minimum 0.12% (IS 456) or 0.0018bh (ACI 318). Typical range is 0.3-0.5% for economical design. The calculator automatically ensures minimum steel requirements.