Role of recovery profile dependency in time‐dependent resilience

Abstract

Resilience assessment of civil structures and infrastructure systems plays a vital role in quantitatively measuring the object's ability to withstand and recover from disruptive events (e.g., natural hazards). The performance of the object (structure or system) may degrade with time, and the external loads often display nonstationary characteristics with time‐varying occurrence rate and/or magnitude. In this context, the resilience would be dependent on the duration of the reference period of interest, known as time‐dependent resilience. This article investigates the effect of recovery profile dependency on the time‐dependent resilience of structures and systems. The term “recovery profile dependency” refers to the association of the post‐hazard recovery processes in the aftermath of different load events within the object's service life, and is reflected through the following three aspects: (1) the temporal correlation between the remaining functionalities associated with different load events; (2) the load–recovery interaction (i.e., the scenario that a load event occurs before the full recovery of the degraded functionality due to the previous load event), and (3) the resource allocation strategy in the presence of limited resources, which affects the expeditiousness of each recovery process. In particular, for (2), the concept of average ratio of interaction is proposed to measure the frequency of load‐recovery interaction. The evaluation of time‐dependent resilience is demonstrated through two examples. It is shown that, the time‐dependent resilience is sensitive to the impact of load–recovery interaction and the selection of resource allocation strategy, but is insensitive to the temporal correlation of the remaining functionalities.