Steel · Connections: bolts & welds
Column cap plate & beam web bearing calculator
Beam sitting on a column cap plate: stiff bearing length with dispersion through flange and plate, web yield, and cap plate weld to the column.
Standard: AS 4100 Cl 5.13 (web bearing yield) · 9.7 welds
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 |
|---|---|---|
| Beam reaction R* | 450 | kN |
| Stiff bearing (column flange/plate length) | 150 | mm |
| Cap plate thickness | 20 | mm |
| Beam flange thickness | 12.8 | mm |
| Beam web thickness | 7.8 | mm |
| Beam web fy | 320 | MPa |
| Cap plate weld length (perimeter) | 900 | mm |
| Weld leg | 6 | mm |
| Weld category | SP (φ = 0.8) |
Worked example — results
| Result | Value | Unit |
|---|---|---|
| Bearing width bs + 5 tf + 2 tp | 254.0 | mm |
| φRby = 0.9·1.25 bbf tw fy | 713.2 | kN |
| Weld capacity | 898.1 | kN |
- ✓ Beam web bearing yield
- ✓ Cap plate welds (if not in direct bearing)
Method, formulas and assumptions
- Bearing width bs + 5 tf + 2 tp = 150+5*12.8+2*20 = 254 mm
- φRby = 0.9·1.25 bbf tw fy = 0.9*1.25*254*7.8*320/1000 = 713.23 kN
- Weld capacity = IF(1=1,0.8,0.6)*0.6*490*6/SQRT(2)*900/1000 = 898.08 kN
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For preliminary design and education. Check every result against the current standard and your own engineering judgement before use.