As stated in 4.3, in order to verify the ultimate and serviceability limit states, each design effect has to be checked and for each effect the largest value caused by the relevant combination of actions must be used.
However, to ensure attention is primarily focussed on the EC5 design rules for the timber or wood product being used, only the design load case producing the largest design effect has generally been given or evaluated in the following examples.
Example 7.5.1 The floor in a domestic building comprises glued thin-webbed beams spaced at 450 mm centres with an effective span of 4.0 m. The beams are supported laterally along their full length, and solid timber blocking is also fitted at the ends to ensure lateral torsional rigidity. Allowing for the self-weight of the structure the beams support a characteristic permanent loading of 0.9 kN/m2 and a characteristic variable medium-term loading of 2.0 kN/m2. The timber used for the flanges is service class C18 in accordance with BS EN 338:2003 and the web is 12.5 mm thick 5 ply Canadian softwood plywood, with the face ply aligned perpendicular to the direction of span. The web is continuously bonded and no splice plates are required. The cross-section of the beam is shown in Figure E7.5.1. The structure functions in service class 2 conditions.
Excluding the requirement to check vibration behaviour of the floor, show that the beams will comply with the rules in EC5.
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