1 Bolt Selection
Bolt Type & Size
bolt diameter d
245
mm²
tensile stress area
Bolt Class
per EN 1993-1-8 §3 Table 3.1
900
N/mm²
yield strength
1000
N/mm²
ultimate tensile strength
2 Partial Safety Factors
3 Bolt Design Strength & Tension Resistance
Design Yield Strength
fyd
= fyb / γM2
=
720.00
N/mm²
Design Tension Resistance
Ft,Rd
= fyd · As
=
176.40
kN
4 Bolt Design Preload — EN 1993-1-8 §3.6.1
Fp,Cd
= 0.7 · fub · As / γM7
(Formula 3.1)
Fp,Cd
=
155.91
kN
for preloaded bolts per §3.1.2(1)
Only bolt assemblies of classes 8.8 and 10.9
5 Torque Reference Values — EN 1090-2 §8.5.2
Friction Coefficient (k-factor)
k-class value declared by manufacturer
Typical: 0.20 (steel/zinc-plated), 0.18 (lubricated), 0.16 (cadmium-plated)
Slip-Resistant Torque (100% Fp,Cd)
Mr
= km · d · Fp,Cd
Mr
=
623.64
N·m
Non-Slip Torque (reduced preload)
%
of Fp,Cd
Fp,red
= 50% · Fp,Cd
=
77.95
kN
Mr,red
= km · d · Fp,red
=
311.82
N·m
Per EN 1993-1-8 §3.4.2 — when preload is not used for slip resistance but required for execution/durability.
Bolt Tensile Stress Areas (reference)
Bolt Class Properties
| Class | fyb (N/mm²) | fub (N/mm²) |
|---|
| 8.8 | 640 | 800 |
| 10.9 | 900 | 1000 |
Design Preload Force
155.91 kN
Slip-Resistant Torque
623.64 N·m
Tension Resistance Ft,Rd
176.40 kN
EN 1090-2:2008 — Execution of steel structures and aluminium structures — Part 2: Technical requirements for steel structures
EN 1993-1-8:2005 — Eurocode 3: Design of steel structures — Part 1-8: Design of joints