ABSTRACT

Risk and Reliability concepts are not generally understood by bridge engineers

because they are not explicitly used in the everyday practice of bridge

assessment or design. In the last decade or so, however, there seems to have

been a growing appetite to understand both the concepts, and the practical

application of them to make more confident decisions about the maintenance

requirements and priorities of a bridge stock. Very good overviews of the

meaning and application of reliability methods have been produced by Bailey

(1996), Rosowsky (1997) and Melchers (1999) but essentially reliability is

a probabilistic way of defining the limit states performance of a bridge system

or bridge component. This is expressed as the probability of a certain event

(limit state) occurring, the most important of which is that of collapse.