Load factor in case of separating aleatory uncertainty and epistemic uncertainty

The uncertainty exists in loads acting on a structure. In general, this uncertainty contains both aleatory uncertainty and epistemic uncertainty. The former is virtually unavoidable, the latter is caused by the limited ability and/or the imperfect information and knowledge. Thus, the load factor derived from aleatory uncertainty is invariable, while that derived from epistemic uncertainty can be decreased when more reliable model or method is applied. This paper shows two examples of calculating the load factor when aleatory uncertainty and epistemic uncertainty are separated.