Session B.9: Asset Risk and Reliability

Looking forward, how do you propose these methods could be applied to inventory of structures and prioritised repair programmes for USACE assets?

The reliability estimates featured in the paper use first order second moment (FOSM) approximation to evaluate distance (in number of std dev’s) to the limit state (when FS = 1). These are approximate methods, well-suited for evaluating reliability of discrete performance modes described by empirical equation. FOSM is a good approach to evaluate reliability for project features like rock armour stability in response to wave action, dike overtopping, I-wall resistance to overturning, wave transmission though breakwaters, slope stability, beach fill stability, etc. The FOSM method should not be used to evaluate reliability for complex structures or core components of critical infrastructure where target reliability is > 0.99. Considering the above, the methods in the paper provide an excellent way to screen applicable project features for reliability deficiency. Many projects and project features could be screened relatively quickly to assess potential risk within a portfolio of assets. Projects and project features that fall below an expected reliability target would then considered for a more detailed project-risk evaluation. The authors have been working with USACE asset managers to further apply the above approach.