Page 34 - Dynamic Loading and Design of Structures
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Figure 1.9 Schematic representation of time-varying actions (a) permanent, (b) variable, (c) accidental.
1.5.2 Specification of characteristic values
Permanent actions
The most common action in this category is the self-weight of the structure. With modern
construction methods, the coefficient of variation of self-weight is normally small (typically
does not exceed 0.05). Other permanent actions include the weight of non-structural elements,
which often consists of the sum of many individual elements; hence, it is well represented by
the normal distribution (on account of the central limit theorem). For this type of permanent
action, the coefficient of variation can be larger than 0.05. An important type of action in this
group with high variability is foundation settlement.
