12 12 Second moment of area of the web, Ief.,

Instantaneous second moment of area of the transformed section, Ief (equation (7.4))

Final - transformed section properties: Transformed web thickness:

The largest stress to strength ratio will be the larger of the permanent action/£mod.perm and the combined permanent and variable action/£mod.med.

Let the ratio of one to the other be r:

i.e. because the factor is less than 1, the variable loading produces the higher stress/strength ratio, so the factor f2 will be associated with variable loading.

Value of the quasi-permanent factor for the variable action, f2 (Table 2.2)

b z.tfd bw

Ep.c.90.mean E0.mean

Second moment of area of the web, Ic. ef. w

0 0

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