IQEG CALCULATION LAB
Single-bolt tension and shear
IQ-CAL-002 · Rev 0 Indicative · 11/11/2026 · Not a certificate
IQ Engineering Group · Sydney · IQ-CAL-002 · Single-bolt tension and shear · millimetres, kN, kNm, MPa unless noted
Inputs
AS/NZS 1252.1. 8.8/S snug, 8.8/TB, 8.8/TF. Snug, high strength, no specified pretension. TF slip uses Nti and kh = 1.
Glossary
- ns
- Number of shear planes. ns=2 doubles φVf. The elevation is always two plies — ns is a number, not a picture.
- As / An
- As is the tensile stress area (threads). An is the shank area πd²/4. Threads in the plane is the usual conservative assumption.
- φNtf
- AS 4100 tension capacity 0.80 fu As. kN.
- φVf
- AS 4100 shear 0.80 × 0.62 fu kr (As or An) ns. kN.
- kh
- Hole factor for TF slip. 1.00 standard, 0.85 oversize/short slot, 0.70 long slot.
One-bolt interaction
Static two-ply bearing joint. ns = 1 scales φVf only — the figure does not change. Hex on ply 1, nut on ply 2. Threads IN the shear plane (As). M20 8.8/S.
Notes
Worked example: M20 8.8/S, ns=1, threads in plane, N*=40 kN, V*=50 kN.
8.8/TF and 8.8/TB also require installation tension Nti — see IQ-CAL-008. No ply bearing in this revision.
φNtf = 0.80 As fuf. Vf = 0.62 fuf kr As|An ns. Interaction quadratic (4100) / linear (3990).
Grade 8.8 capacities — AS 4100 / AS 3990 (kN)
fu = 830 MPa · ns = 1. φ = 0.80. Highlighted row is the selected size. Threads-in uses As; shank uses An.
| Size | As | An | φNtf | φVf th | φVf sh | 3990 Nall | 3990 fv th | 3990 fv sh |
|---|---|---|---|---|---|---|---|---|
| M12 | 84.3 | 113.1 | 56.0 | 34.7 | 46.6 | 23.1 | 14.7 | 23.5 |
| M16 | 157 | 201.1 | 104.2 | 64.6 | 82.8 | 43.0 | 27.4 | 41.7 |
| M20 | 245 | 314.2 | 162.7 | 100.9 | 129.3 | 67.1 | 42.7 | 65.2 |
| M24 | 353 | 452.4 | 234.4 | 145.3 | 186.2 | 96.7 | 61.5 | 93.9 |
| M27 | 459 | 572.6 | 304.8 | 189.0 | 235.7 | 125.7 | 80.0 | 118.8 |
| M30 | 561 | 706.9 | 372.5 | 231.0 | 291.0 | 153.7 | 97.8 | 146.7 |
| M36 | 817 | 1017.9 | 542.5 | 336.3 | 419.0 | 223.8 | 142.4 | 211.2 |