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Bolt Capacity to EC5 §8.2

Project
Ref
Engineer
Date
Service class
Fastener
Members
Member 1
Member 2
Johansen Yield Modes
ModeEC5 refRaw (N)+Rope (N)Fv,Rk (N)
aEC5 Eq. 8.6 (a)9092.2-9092.2
bEC5 Eq. 8.6 (b)9092.2-9092.2
c ◄EC5 Eq. 8.6 (c)3766.1-3766.1
dEC5 Eq. 8.6 (d)7252.81813.29066.0
eEC5 Eq. 8.6 (e)7252.81813.29066.0
fEC5 Eq. 8.6 (f)11092.42773.113865.5
EC5 Minimum Spacings - Table 8.4 (bolts)
Member 1
Spacing between bolts parallel to the grain (a1)60.0 mm
Spacing between bolts perpendicular to the grain (a2)48.0 mm
Loaded end distance (a3,t)84.0 mm
Unloaded end distance (a3,c)48.0 mm
Loaded edge distance (a4,t)36.0 mm
Unloaded edge distance (a4,c)36.0 mm
Angle of load to the grain
Member 2
Spacing between bolts parallel to the grain (a1)60.0 mm
Spacing between bolts perpendicular to the grain (a2)48.0 mm
Loaded end distance (a3,t)84.0 mm
Unloaded end distance (a3,c)48.0 mm
Loaded edge distance (a4,t)36.0 mm
Unloaded edge distance (a4,c)36.0 mm
Angle of load to the grain
Design Capacity
ArrangementTimber-timber, single shear
Governing modec
Fv,Rk per shear plane3766.1 N
Number of shear planes1
Fv,Rk total per bolt3766.1 N
γM,connection1.30
Design capacity Fv,Rd = kmod · Fv,Rk / γM - per EC5 Table 3.1 load-duration class:
Load durationkmodFv,Rd (N)kN
Permanent0.600017381.74
Long-term0.700020282.03
Medium-term0.800023182.32
Short-term0.900026072.61
Instantaneous1.100031873.19
Assumptions & advisory notes
  • Timber penetration assumed = full member thickness (t); no thread/lead-in reduction.
  • Washer/plate bearing diameter dw = min(12·t, 4·d) = 48.0 mm (EC5 §8.5.2(3)).
  • Rope effect (EC5 §8.2.2(2)) applied to plastic-hinge modes only, capped at 25% of the Johansen capacity for bolts.
  • Effective fastener count nef = min(n, n^0.9·(a1/(13·d))^0.25) (EC5 Eq. 8.34) is NOT applied - single fastener (n = 1).

How a single bolt carries lateral load

A laterally loaded bolt is not a shear pin. Load transfers by bearing: the shank presses into the hole wall, the timber crushes locally at its embedment strength fh,k, and the bolt bends. Capacity is set by whichever combination of timber crushing and bolt yielding forms first - the Johansen yield modes of EC5 §8.2.2.

What this calculator does

It evaluates every Johansen mode applicable to the arrangement you enter - two- or three-member, timber-to-timber or steel-to-timber - and takes the governing minimum as Fv,Rk. The rope effect (§8.2.2(2)) is added to plastic-hinge modes only, from the washer-bearing capacity F2,ax,Rk with dw = min(12·t, 4·d) per §8.5.2(3), capped at 25% of the Johansen term for bolts. Design values Fv,Rd follow for each load-duration class via kmod and γM, with minimum spacings and edge/end distances from Table 8.4.

Bolt or dowel?

A bolt sits in a hole up to 1 mm oversize (§10.4.3), so it slips before it bears. Separately, it carries a washer - and that washer is what mobilises the rope effect. A dowel is a tight fit with no head, so it has neither: no initial slip, and no rope effect. See Bolts vs Dowels for the full comparison.

Fv,Rk (char.)3.77 kN
Permanent1.74 kN
Long-term2.03 kN
Medium-term2.32 kN
Short-term2.61 kN
Instantaneous3.19 kN