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t Linear interpolation of kef is permitted for spacings between the stated values; spacing a1 is as shown in Figure 10.15.

t Linear interpolation of kef is permitted for spacings between the stated values; spacing a1 is as shown in Figure 10.15.

Three lines of fasteners perpendicular to the grain. In this connection, nef for each line = 3 when loaded perpendicular to the grain

Fig. 10.16. Lines of fasteners perpendicular to the grain.

Fig. 10.16. Lines of fasteners perpendicular to the grain.

Three lines of fasteners perpendicular to the grain. In this connection, nef for each line = 3 when loaded perpendicular to the grain

(b) Loaded perpendicular to the grain. When loading nails perpendicular to the grain in a single or double shear connection, as shown in Figure 10.16, the effective number of nails, nef, in each line of nails shall be taken to equal the actual number of nails, n, when using single nails or the number of overlapping nails (as defined in equation (10.44)) when using overlapping nails. As explained in 10.3.6.1, when loaded this way there is the risk of splitting of the connection material, and the connection capacity will be the lesser of the splitting capacity of the member(s) subjected to the tension force and the connection strength derived from the summation of the strength of the fasteners.

(c) Loaded at an angle to the grain. When the nails in a single or double shear connection are laterally loaded at an angle to the grain, the force components parallel and perpendicular to the grain have to be derived, and:

(i) the component of the design force acting parallel to the grain must not exceed the load-carrying capacity based on the use of the effective number of nails per row in the connection as defined in 10.4.1.1(a));

(ii) the component of the design force acting perpendicular to the grain must not exceed the load-carrying capacity as defined in 10.4.1.1(b)).

10.4.1.2 Staples

With staples, n is equal to 2 times the number of staples in the row parallel to the grain, and where the angle 0 between the crown of the staple and the direction of the grain of the timber, as shown in Figure 10.17, is greater than 30°, equation (10.43) will apply.

If the angle 0 is less than 30°, the above will again apply but the lateral load carrying capacity should be multiplied by a factor of 0.7. For multiple staples in a row, nef is determined as for nails.

10.4.1.3 Bolts and dowels

(a) Loaded parallel to the grain. As bolts/dowels are stiffer than nails or staples, for connections in single or double shear, the reduction in row capacity parallel to the grain

Fig. 10.17. Spacing for staples.

is less than with these fasteners and:

«ef = min jn, n09^-^} (EC5, equation (8.34)) (10.45)

where nef is the effective number of bolts or dowels in a row parallel to the grain, a1 is the bolt/dowel spacing in the grain direction, d is the diameter of the bolt/dowel, and n is the number of bolts/dowels in the row.

(b) Loaded perpendicular to the grain. For loading perpendicular to the grain, in a single or double shear connection there is no reduction and:

(c) Loaded at an angle to the grain. The load-carrying capacity parallel or perpendicular to the grain shall be determined in the same way as for nails, as described in 10.4.1(c). For angles 0° < a < 90°, nef may be determined by linear interpolation between equations (10.45) and (10.46).

10.4.1.4 Screws

Where the diameter of the smooth shank of the screw is 6 mm or less, the rules for nails will apply and where it is greater than 6 mm, the rules for bolts will apply.

10.4.2 Alternating forces in connections

Where a connection is subjected to short-term alternating forces, the characteristic load-carrying capacity of the connection will not be affected.

If, however, the connection is subjected to alternating forces due to long- or medium-term actions, the characteristic load-carrying capacity of the connection will be reduced. In such circumstances, if the design force on the connection alternates between a tensile value, Ft,Ed, and a compressive value, Fc,Ed, the connection must be designed for:

Design compressive force = (Fc>Ed + 0.5FtjEd)

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