Timber bolt and dowel group design to Eurocode 5.

Enter the fastener size, spacing and the number in a row, and Volex Anvil computes the effective number of fasteners nef — which is less than the physical number because of the load concentration in a row loaded parallel to grain — the reduction factor nef/n, and the group lateral capacity Fv,Rd.

The nef relationship follows EC5 §8.5.1.1, so the group reduction and capacity match the code for bolted and dowelled connections loaded along the grain.