The effect of interactions between failure mechanisms on the reliability of flood defenses

Structural reliability analysis often considers failure mechanisms as correlated but non-interacting processes. Interacting affect each others performance, and thereby the system reliability. We describe such interactions in context of flood defenses, analyze under which conditions have a large impact on using Monte Carlo-based quantification method. provide simple examples an application to levee due landward slope instability backward erosion piping (BEP). The show that largest interaction effects are expected when trigger mechanism is relatively likely occur affected has contribution For studied example, between BEP increased probability up factor 4. Implications for assessment design defenses discussed.