Time-dependent reliability and resilience of aging structures exposed to multiple hazards in a changing environment

Engineering structures are often subjected to the influences of performance deterioration and multiple hazards during their service lives, and consequently may suffer from damage/failure as a result of external loads. Structural reliability and resilience assessment is a powerful tool for quantifying the structural ability to withstand these environmental or operational attacks. This paper proposes new formulas for structural time-dependent reliability and resilience analyses in the presence of multiple hazards, which are functions of the duration of the reference period of interest. The joint impacts of nonstationarities in multiple hazards due to a changing environment, as well as the deterioration of structural performance, are explicitly incorporated. The correlation between the structural resistances/capacities associated with different hazard types is modeled by employing a copula function. It is observed that, under the context of multiple hazards and aging effects, the time-dependent resilience takes a generalized form of time-dependent reliability. The proposed formulas can be used to guide the adaptive design of structures, where adaptive strategies are identified across a range of possible future service conditions. An example is presented to demonstrate the applicability of the proposed method for structural reliability and resilience analyses.