Discussion of 'Practical Approach to Using Uncertainties in Structural Condition Assessment' by Jamshid Mohammadi and Mehdi Modares

摘要

Having read this paper several times but not having verified any of the numbers included in the example problems, my opinion is that this is a potentially useful paper. It lays out how one should quantify uncertainties in loads and material and geometric properties. It presents the formulation of failure probability in terms of a factor of safety and illustrates the procedure for computing the probability of failure using two relatively simple but practical example problems. The example problems are fairly easy to follow. The interesting aspect that is not implied in the title of this paper is the factor of safety. For each of the examples, the authors present the factor of safety associated with the probability of failure and also provide other factors of safety and their corresponding probabilities of failure. One generally thinks of the factor of safety as a number that, if reached in a design, will guarantee a probability of failure very close to zero. Clearly, this is not the concept used in this paper. The factor of safety in this paper is a random variable, and the associated probability of failure may be useful to know in design.