This grant is to help support costs for the ?EFRI-RESIN Workshop on Infrastructure Sustainability, Resilience, and Robustness? to be held in Tucson, Arizona January 13-14, 2011. The 8 RESIN project teams, as well as additional selected experts in RESIN-related topics, will participate. The principal objective is to develop cross-disciplinary, workable definitions for sustainability, resilience, and robustness in the context of RESIN research. Secondary objectives are to strategize on means to overcome computational roadblocks that are common across RESIN projects and that are necessary to apply the concepts identified in the main objective, and to develop coordination of RESIN outreach activities.
Bruce Hamilton 9/29/10
Discussion of the need for infrastructure sustainability, robustness, and resilience is pervasive. Nevertheless, clarity of meaning and agreement on methods for translating security objectives into design criteriaare lacking. For example, Lansey (2012) discussed the range of definitions of the use of these terms in water infrastructure. A key product of cooperation motivated by EFRI RESIN projects was a set of definitions that are generally agreed upon across teams (and infrastructures). The RESIN sustainability definition is consistent with many others: Sustainable infrastructure provides adequate resource supplies of desired quality – now and for future generations – in a manner that integrates economic well-being, environmental protection and social needs (triple bottom line). This definition is consistent with sustainability concepts for a range of systems. Robustness and resilience measure the reaction of infrastructure to stress or periodic failure in these systems. The robustness of a system to a given class of disturbances is defined as the ability of this system to maintain its function when it is subject to a set of disturbances of this class. Robustness objectives can be approached through planning and design. Planning robustness is the ability to adapt a system design over time to a range of futures that minimize TBL objectives while providing adequate service. Design robustness, on the other hand, is range of conditions under which the current system will perform acceptably as planned. Infrastructure resilience is a measure of infrastructure response to inevitable failures. That is, infrastructure resilience is the ability to gracefully degrade and subsequently recover from a potentially catastrophic disturbance that is internal or external in origin. Most infrastructure will inevitably fail due to the cost of creating a failure proof system. Scholz et al. (2012) further distinguished "generalized" resilience (the ability to withstand and recover from extreme events of low or unknown probability) and "specified" resilience (response to adverse events of known probability). Generally, infrastructures fail under both types of events. Specified resilience failures result from relatively common component failures such as a pipe or powerline in water and electric grid, respectively. These events are relatively common and predictable in a statistical sense. Larger or multiple component failures occur much less frequently (i.e., a power plant or earthquake causing multiple pipe breaks). The likelihood and frequency of those events are not known and classified as general resilience events. Bruneau et al (2007) discuss the components of resilience. The magnitude of failure from a significant disturbance is mitigated by the infrastructures robustness and component redundancy. Infrastructure robustness is intended to avoid failures thus will also reduce a failure's severity. Thus, robustness and resilience are not independent. Similarly, when a component fails backup options can ameliorate the impact. Failure impact is also related to its duration. Failure duration is reduced by a rapid response with sufficient resources to correct the problem. The properties of resourcefulness and rapidity are introduced through planning for the unexpected event. These definitions will provide a guide for researchers to more clearer address infrastructure issues and assure a common language between infrastructure managers, planners, researchers, and the general public. Understanding terminology across disciplines is critical for advancing this highly interdisciplinary field. Given the potential consequences of interdependent infrastructure failures, improving communication on these concepts can have significant benefit to the general pubic.
