Steel · Connections: moment & splices
Portal knee: column web panel zone calculator
Shear in the column web panel from the rafter moment; diagonal stiffener area required if the web is overstressed.
Standard: AS 4100 Cl 5.11 (web shear) · rigid knee practice
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 |
|---|---|---|
| Knee moment M* | 320 | kNm |
| Rafter (haunch) depth at column face | 700 | mm |
| Column shear above panel | 40 | kN |
| Column depth | 460 | mm |
| Column web thickness | 9.1 | mm |
| Column web fy | 320 | MPa |
| Stiffener fy | 300 | MPa |
| Diagonal stiffener area provided | 2000 | mm² |
Worked example — results
| Result | Value | Unit |
|---|---|---|
| Panel shear M/db − Vc | 417.1 | kN |
| φVw = 0.9·0.6 fy dc tw | 723.3 | kN |
| Diagonal angle | 56.69 | ° |
| Diagonal stiffener area (Vp − φVw)/(φ fys cos θ) | 0.000 | mm² |
- ✓ Panel adequate (web or with stiffener)
Method, formulas and assumptions
- Panel shear M/db − Vc = 320*1000/700-40 = 417.14 kN
- φVw = 0.9·0.6 fy dc tw = 0.9*0.6*320*460*9.1/1000 = 723.34 kN
- Diagonal angle = DEGREES(ATAN(700/460)) = 56.689 °
- Diagonal stiffener area (Vp − φVw)/(φ fys cos θ) = MAX(0,(417.14-723.34)*1000/(0.9*300*COS(RADIANS(56.689)))) = 0 mm²
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For preliminary design and education. Check every result against the current standard and your own engineering judgement before use.