Performance evaluation of constructed facilities through linguistic judgment

It is often difficult to estimate exact probabilities of occurrence of fault events for the use in the conventional fault tree analysis (FTA) when failure data are insufficient or fault events are vague such as human error. A hybrid approach utilizing fuzzy sets and possibility theory is presented to overcome this problem. In the approach, failure possibilities of imprecise events are characterized by fuzzy sets to translate expert subjective judgments while fuzzy fault rates are derived from fuzzy possibility scores based on a modified possibility transformation function. An example of beam failure is presented to demonstrate the capability of the approach that can assist safety engineers to effectively assess fault possibilities and better analyze building performance.