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Fastener selector

Size and specify the fastener for one bolted joint: strength to EN 1993-1-8, length from the plates, material and finish from the corrosivity of the site, locking against vibration, and the matching nut and washer.

Joint
Type of joint
Head
Loads

Working loads on one bolt, typed on the drawing; they are multiplied by the load factor.

Shear planes
Shear plane passes through
Vibration
Vibration or shock on the joint

Static loads: structures, frames, brackets.

Site
Corrosivity of the site (ISO 9223)

C3 · Medium

Urban and light-industrial areas, coastal areas with little salt, humid interiors such as food plants. Example: Riyadh, inland industrial estates.

The examples are indicative: classify the place where the joint will be.

Fix size, class or factor

1.25 is the EN 1993-1-8 recommended value; the national annex may set another.

Live joint

Shear plane · in the threadL = 40

Recommended fastener

Passes EN 1993-1-8

M12 × 40

8.8Hot-dip galvanized

Hex head screw, fully threaded ISO 4017 (DIN 933)

Tension31%
Shear70%
Tension and shear together92%
Nut
Hex nut ISO 4032 (DIN 934) · M12 · class 8 · hot-dip galvanized
Washer (2 per bolt)
Flat washer ISO 7089 (DIN 125-A) · 12 · 200 HV · hot-dip galvanized

From the Boltra catalogue

Points to check 2

  • Hot-dip galvanized bolts need nuts tapped oversize (ISO 10684): order bolt, nut and washers as one galvanized set.
  • At M10, M12, M14 and M22 the DIN products (931, 933, 934) have another width across flats than ISO: 17, 19, 22 and 32 mm against 16, 18, 21 and 34 mm. Check spanner sizes and do not mix DIN and ISO.

Strength check (EN 1993-1-8)

Design loadResistanceUtilisation
Tension15.0 kN48.5 kN
31%
Shear22.5 kN32.4 kN
70%
Tension and shear together
92%

Shear plane through the thread (stress area As)

Show the calculation

d = 12 mm, P = 1.75 mm, As = 84.3 mm², A = 113.1 mm²
fub = 800 MPa, γM2 = 1.25, k2 = 0.9, αv = 0.6, γF = 1.5
Ft,Ed = 10 × 1.5 = 15.0 kN
Ft,Rd = 0.9 × 800 × 84.3 / 1.25 = 48.5 kN
Fv,Ed = 15 × 1.5 = 22.5 kN
Fv,Rd = 0.6 × 800 × 84.3 / 1.25 × 1 = 32.4 kN
Fv,Ed/Fv,Rd + Ft,Ed/(1.4·Ft,Rd) = 0.70 + 0.22 = 0.92 ≤ 1
M12 × 40 · 8.8Hex head screw, fully threaded · hot-dip galvanized92%

For preliminary selection. The results follow the methods listed under “Method and limits” and do not replace the design check by a qualified engineer under the code that governs your project.