Iri

Kser where F is the SLS load on the connection, and Kser is the slip modulus of the fastener per shear plane at the service condition.

When a structure is subjected to a characteristic permanent action Gk, a dominant characteristic variable action Qk1 and accompanying unrelated characteristic variable actions Qk,i, the design load on a connection at the SLS, Fd, will be obtained by analysing the structure under the characteristic loading combination referred to in 2.2.25.2, i.e.:

4 U4444 l siig,e shear plane shear plane n fasteners per shear plane

Two shear planes n fasteners per shear plane

(a) Single shear onne ion

(b) Double shear onne ion

Kser dc = 2xnxKser n fasteners per shear plane

(a) Single shear onne ion

(b) Double shear onne ion

Kser dc = 2xnxKser n fasteners per shear plane

n fasteners per shear plane

(c) oin with two single shear onne ions

(c) oin with two single shear onne ions

n fasteners per shear plane

Kser,dc1 2xnxKser Kser,dc2 2xnxKse

(d) oin with two double shear onne ions

Fig. 10.24. Stiffness of single and double shear connections and joints.

n fasteners per shear plane

n fasteners per shear plane

n fasteners per shear plane

Kser,dc1 2xnxKser Kser,dc2 2xnxKse

(d) oin with two double shear onne ions

n fasteners per shear plane

where f is the combination value factor for the variable action Qk>;, obtained from the UKNA to EN 1990:2002 [12].

To obtain the final deformation of a connection, the method of analysis will depend on whether or not the connections have the same time-dependent properties as the members or components in the structure, and the appropriate methodology for each condition is given in 2.3.2.

For structures that comprise members, components and connections with the same creep behaviour, the final deformation is obtained by applying the combined characteristic and quasi-permanent combination of actions to the structure. In this situation, the design load on the connection due to the characteristic combination, Fcd, will be obtained by analysing the structure under the combined characteristic and quasipermanent loading combinations referred to in 2.2.25.2, i.e.:

Gk(1 + kdef) + Qk,1(1 + f2,1 kdef) + Qk,i (fo,i + f 2,ikdef) ^ Fcd (10.76)

where the symbols are as previously defined and f is the quasi-permanent value factor for the quasi-permanent combination of actions obtained from the UKNA to EN 1990:2002, and kdef is the deformation factor for timber and wood-based materials for quasi-permanent actions. Values for kdef for timber and some wood-related products are given in Table 2.10.

The final deformation, ufin, at the SLS of a connection with a single shear plane in a structure comprising members, components and connections having the same creep behaviour will be:

K ser

The above will also apply in the case of statically determinate structures (e.g., pin jointed trusses) where the connections do not have the same creep behaviour as the members.

For structures that comprise members, components and connections having different creep behaviour and where the creep effect will influence the stiffness distribution, the above approach cannot be applied. In these situations, the final deformation will be determined from an analysis of the structure subjected to the characteristic combination of actions, and the stiffness properties of the members, components and connections are reduced in value. The reduced stiffness properties, referred to in EC5 as final mean values, are given in equations (2.34), (2.35) and (2.36), and are as follows:

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