Bolt Database & Calculator
ISO metric bolt database (M6–M48) with grades 4.6, 8.8, 10.9, 12.9 — plus tensile, shear, torque and bolt-group calculators.
🔩 Bolt Database
⚙ Capacity Calculator
🔧 Torque Calculator
📐 Bolt Group
| Size | Grade | Std | d (mm) | Pitch (mm) | As (mm²) | Anom (mm²) | fub (MPa) | fyb (MPa) | Ft,Rd (kN) | Fv,Rd (kN) |
|---|
Ft,Rd = 0.9 × fub × As / γM2 (γM2=1.25, EN 1993-1-8). Fv,Rd = 0.6 × fub × As / γM2 (single shear, threads in shear plane). Reference only — verify against project-specific code requirements.
🔩 Bolt Tensile Capacity
Design tensile resistance Ft,Rd
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Characteristic tensile capacity
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Formula: Ft,Rd = 0.9 × fub × As / γM2 — EN 1993-1-8 §3.6.1(1)
⚡ Bolt Shear Capacity
Design shear resistance Fv,Rd
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Per shear plane
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Formula: Fv,Rd = αv × fub × As / γM2 — EN 1993-1-8 §3.6.1(1)
🔧 Tightening Torque Calculator
Tightening torque T
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Torque (N·m)
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T = K × d × Fp — where K is the nut factor, d in metres, Fp in kN. Always use a calibrated torque wrench. Consult connection design engineer for critical joints.
📖 Standard Preload Values
EN 1993-1-8 Table 3.4 — Design preload Fp,C = 0.7 × fub × As
| Size | Grade 8.8 Fp,C (kN) | Grade 10.9 Fp,C (kN) |
|---|
📐 Bolt Group — Force Distribution
Direct shear per bolt
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Maximum bolt force (V + M combined)
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Utilisation ratio
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Result
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Simplified linear elastic method — assumes equal load distribution for direct shear. Moment component calculated for in-line bolt arrangement. For eccentric connections use the elastic vector method (full FEA or design tables).
🔖 Minimum Spacing Reference
EN 1993-1-8 Table 3.3 minimum distances
| Dimension | EN 1993-1-8 | For M20 |
|---|---|---|
| End dist. e1 | ≥ 1.2 d0 | ≥ 26.4 mm |
| Edge dist. e2 | ≥ 1.2 d0 | ≥ 26.4 mm |
| Bolt pitch p1 | ≥ 2.2 d0 | ≥ 48.4 mm |
| Bolt spacing p2 | ≥ 2.4 d0 | ≥ 52.8 mm |
| Max pitch (inner) | ≤ min(14t, 200) mm | — |
| Max end dist. | ≤ 4t + 40 mm | — |
d0 = hole diameter = d + 2mm (M12–M14) or d + 3mm (M16+). t = plate thickness.