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Key:

Connections (a), (b) and (c) are examples of single shear with one shear plane per fastener. (i-^) > 4x nail

Where nails are used they can overlap as shown in (c) provided, diameter (in mm).

Connection (d) is an example of double shear with two shear planes per fastener. Fig. 10.6. Metal dowel type fasteners loaded laterally in single and double shear.

the failure mode will be the mode associated with the minimum value equation, as shown in the relevant table.

For symmetrical connections in double shear, the characteristic load-carrying capacity per shear plane per fastener, Fv Rk, will be the minimum value equation for the relevant double shear cases given in Tables 10.2 and 10.3, and the failure mode will be the mode associated with that equation. However, because there are two shear planes per fastener, the characteristic load-carrying capacity per fastener will be:

Characteristic load-carrying capacity of a fastener in double shear — 2 • Fv,r.

The main functions used in the strength equations are the diameter of the dowel, d, the characteristic fastener yield moment, My,Rk and the characteristic embedment strength, fh,i,k, of the connected member i, and the significance of these functions is discussed in the following sections.

10.3.1 Dowel diameter

The value to be used for the diameter of a dowel-type fastener in the strength equations in Tables 10.2 and 10.3 is dependent on the type of fastener being used in the connection and is given for different types in Table 10.4.

10.3.2 Characteristic fastener yield moment (My Rk)

In Johansen's original equations, the yield moment was taken to be the moment at the elastic limit of the fastener and was derived from the product of the yield strength and

Table 10.4 EC5 requirement for the diameter of a fastener

Fastener

Smooth round nails (EC5, 8.3.1.1(4)) Square and grooved nails (EC5, 8.3.1.1(3))

The nail diameter as defined in EN 14592 The side dimension

Staples

With round legs (EC5, 8.4(1)) With a rectangular cross-section (EC5, 8.4(2))

The leg diameter

The square root of the product of both dimensions

Bolts (EC5, 8.5.1.1(2))

The bolt diameter

Dowels (EC5, 8.6(1))

The dowel diameter

Screws (EC5, 8.7.1)

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