Steel · Members & beams
Steel angle lintel calculator
Equal-angle lintel over a masonry opening with triangular (arching) or full masonry load.
Standard: AS 4100 (elastic) · AS 3700 masonry arching (60° triangle)
Inputs in the worked example
The live calculator starts with these values; change any of them and every result, check and diagram updates instantly.
| Input | Value | Unit |
|---|---|---|
| Clear span | 2.1 | m |
| Angle leg b | 100 | mm |
| Angle thickness t | 8 | mm |
| Masonry height above lintel | 1.2 | m |
| Load model | 60° triangle (arching) | |
| Masonry density | 19 | kN/m³ |
| Leaf thickness | 0.11 | m |
| Other live load | 0 | kN/m |
| fy | 300 | MPa |
Worked example — results
| Result | Value | Unit |
|---|---|---|
| Angle area / mass | 1,536 mm² / 12.1 | kg/m |
| I / Z (vertical leg) | 1.482 ×10⁶ / 20.6 ×10³ | mm⁴ / mm³ |
| Masonry load | 2.00 | kN |
| M* | 0.916 | kNm |
| φMs (elastic, no LTB) | 5.55 | kNm |
| Deflection (masonry, G) | 1.04 | mm |
| Limit span/500 | 4.2 | mm |
- ✓ M* ≤ φMs
- ✓ Deflection ≤ span/500
- ✓ Bearing length ≥ 100–150 mm each end (detail)
Method, formulas and assumptions
- Triangle load: W = ½·L·h·γ·t with h = min(height, L·sin60/2·…); M = WL/6
- Full load: M = wL²/8
- Elastic Z about the axis parallel to the horizontal leg; torsion from eccentric masonry and LTB ignored (restrained by masonry)
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For preliminary design and education. Check every result against the current standard and your own engineering judgement before use.