Loaded parallel to the grain

The design strength of a laterally loaded single connector, Fv Rd, is obtained from the characteristic load-carrying capacity of the laterally loaded connector as follows:

where:

• kmod is the modification factor referred to in 2.2.20, and where the connection comprises two timber elements, kmod,1 and kmod,2, the value used in the equation will be kmod = k mod, 1 kmod ,2, as required by EC5, equation (2.6).

• km is the partial factor for connections given in Table 2.6. Except when determining the plate strength of punched metal plate fasteners, the factor value will be 1.3.

• Fv,Rk is the characteristic load-carrying capacity of the connector per shear plane when loaded laterally, i.e. the lowest value determined from the relevant strength equations in 11.3 for toothed-plate connectors or in 11.4 for ring or shear-plate connectors.

For a connection in single or double shear containing rpi rows of connectors laterally loaded parallel to the grain, with each row containing n equally spaced connectors of the same type and size, each with a design strength, Fv>Rd, the effective lateral load design capacity of the connection per shear plane parallel to the grain, Fv ef Rd, will be:

where nef is the effective number of connectors in the connection in each row parallel to the grain, nsp is the number of shear planes in the connection, and:

(a) Effective number of toothed-plate connectors.

The effective number of toothed-plate connectors in a row shall equal the number of connector bolts in the row. For the strength contribution from the bolts in the connection, the effective number of bolts shall be derived as described in 10.4.1.3.

(b) Effective number of ring or shear-plate connectors.

The effective number of ring or shear-plate connectors in a row is obtained from equation (11.25).

11.8.2 Loaded perpendicular to the grain

Where loads are imposed on the timber by connectors loaded perpendicular to the grain, there are two possible forms of failure:

(a) By the timber splitting in tension and this condition is covered in 11.6 and 10.3.6.1.

(b) By ductile yielding of the connector and for this condition, where there are rpr lines of connectors with each line containing n connectors all of the same size,

where:

• Fv,ef,Rd is the effective design strength of the connector per shear plane when loaded laterally and perpendicular to the grain.

• nsp is the number of shear planes in the connection.

• ncb is the number of connector bolts per line perpendicular to the grain.

• Fv,Rd is the design load-carrying capacity of a laterally loaded single connector per shear plane when loaded perpendicular to the grain, i.e. the lowest value determined from the relevant strength equations in 11.3 for toothed-plate connectors or in 11.4 for ring and shear-plate connectors.

From the above, the design load-carrying capacity of a connection loaded perpendicular to the grain will be:

Design capacity of connection = min(F90jRd, Fv>efjRd) (11.29)

where F90 Rd is the design splitting capacity of the timber, which, for softwood, is obtained from equation (10.41c).

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