Resilience Capacity of Civil Structures and Infrastructure Systems

Reliability assessment is a powerful tool in evaluating the safety level of civil structures and infrastructure systems. The underlying concept is to probabilistically compare the relative magnitudes of resistance and load effect. During the past decades, engineers and asset owners have been expanding their focus from reliability to resilience, in an attempt to adapt and manage risks in such a manner that the impacts of hazardous events on structures/systems are minimized. With this, one would naturally ask: Can we establish a unified framework for reliability and resilience analyses? This paper addresses this question, and the answer is “yes.” To this end, a new concept of “resilience capacity” is proposed, which is a generalization of the traditional load bearing capacity (resistance). By definition, the resilience capacity is a random variable that represents the structural (or system’s) ability of absorbing, recovering from and adapting to a load effect. Applying the concept of resilience capacity, this paper shows that the reliability of a structure/system is a special case of resilience.