TS EN 1993-1-8 – Bolt Resistance Calculations

TS EN 1993-1-8 (Eurocode 3-1-8) defines design resistances for façade fasteners (bolts, rivets) under shear, tension and bearing actions. Key clauses and formulas are summarised below.

1 Shear Resistance (F_v,Rd)

F_v,Rd = α_v · f_ub · A / γ_M2

α_v = 0.60 (standard) or 0.50 (high-strength grades)
f_ub = ultimate tensile strength of bolt (MPa)
A = net shear area through plane(s) (mm²)
γ_M2 = partial safety factor for fasteners

2 Bearing Resistance (F_b,Rd)

F_b,Rd = k₁ · α_b · f_u · d · t / γ_M2

α_b depends on end & edge distances:

a_d = e₁ ⁄ 3d₀ for end bolts
k₁ typically 2.5–1.4
d = bolt diameter (mm) • t = plate thickness (mm)

3 Tension Resistance (F_t,Rd)

F_t,Rd = k₂ · f_ub · A_s / γ_M2

k₂ = 0.63 (countersunk) or 0.90 (standard)
A_s = tension area of bolt (mm²)

4 Punching Shear (B_p,Rd)

B_p,Rd = 0.60 · π · d_n · t_p · f_u / γ_M2

d_n = hole diameter • t_p = plate thickness

5 Combined Shear + Tension Check

(F_v,Ed/F_v,Rd) + (F_t,Ed/1.4·F_t,Rd) ≤ 1.0

If the inequality is not satisfied, the bolt is deemed unsafe.

Note – Formulas are condensed from TS EN 1993-1-8 (Table 3.4). Refer to the full standard for detailed design rules and national annex provisions.

TS EN 1993-1-8 – Bolt Resistance Calculations

1 Shear Resistance (Fv,Rd)

2 Bearing Resistance (Fb,Rd)

3 Tension Resistance (Ft,Rd)

4 Punching Shear (Bp,Rd)

5 Combined Shear + Tension Check

1 Shear Resistance (F_v,Rd)

2 Bearing Resistance (F_b,Rd)

3 Tension Resistance (F_t,Rd)

4 Punching Shear (B_p,Rd)