Rebar Spacing Tool
Substitution & Safety Factor (FOS) Verification
SITE APPROVED
Safe Site Spacing
0
mm Center-to-Center (c/c)
Exact Mathematical:-
Provided Steel Area (Ast):-
Technical Calculation Logic
When changing rebar diameters on-site, the substituted arrangement must provide a cross-sectional area equal to or greater than the original structural design.
1. The Substitution Formula
S2 = S1 × (A2 / A1)
- S2: New Required Spacing
- A2: Area of New Rebar Diameter
- A1: Area of Original Rebar Diameter
2. IS 456:2000 Spacing Constraints
As per Clause 26.3.3, maximum spacing is restricted to control crack width, regardless of calculation results:
| Element Type | Maximum Allowed Spacing |
|---|---|
| Main Reinforcement (Slabs) | 3d or 300 mm (whichever is less) |
| Distribution Steel (Slabs) | 5d or 450 mm (whichever is less) |
3. Standard Steel Area Reference
| Dia (φ) | Area (mm²) | Weight (kg/m) |
|---|---|---|
| 8 mm | 50.26 | 0.395 |
| 10 mm | 78.54 | 0.617 |
| 12 mm | 113.10 | 0.888 |
| 16 mm | 201.06 | 1.580 |