Timber · Columns & studs
Timber tension member calculator
Tension capacity parallel to grain on the net area after holes.
Standard: AS 1720.1 Cl 3.4
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 |
|---|---|---|
| Breadth | 45 | mm |
| Depth | 140 | mm |
| Holes across section | 1 | |
| Hole diameter | 14 | mm |
| Characteristic tension f′t | 11 | MPa |
| Capacity factor φ | 0.85 cat 2 | |
| Duration k1 | 0.8 (5 months) | |
| Moisture k4 | 1 | |
| Temperature k6 | 1 | |
| Design tension | 25 | kN |
Worked example — results
| Result | Value | Unit |
|---|---|---|
| Net area | 5,670 | mm² |
| φNt = φ k1 k4 k6 f′t An | 42.41 | kN |
- ✓ N* ≤ φNt
Method, formulas and assumptions
- Net area = (140-1*14)*45 = 5670 mm²
- φNt = φ k1 k4 k6 f′t An = 0.85*0.8*1*1*11*5670/1000 = 42.412 kN
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For preliminary design and education. Check every result against the current standard and your own engineering judgement before use.