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Robustness and Extensibility in Infrastructure Systems

Description

Resilient infrastructure research has produced a myriad of conflicting definitions and analytic frameworks, highlighting the difficulty of creating a foundational theory that informs disciplines as diverse as business, engineering, ecology,

Resilient infrastructure research has produced a myriad of conflicting definitions and analytic frameworks, highlighting the difficulty of creating a foundational theory that informs disciplines as diverse as business, engineering, ecology, and disaster risk reduction. Nevertheless, there is growing agreement that resilience is a desirable property for infrastructure systems – i.e., that more resilience is always better. Unfortunately, this view ignore that the fact that a single concept of resilience is insufficient to ensure effective performance under diverse and volatile stresses. Scholarship in resilience engineering has identified at least four irreducible resilience concepts, including: rebound, robustness, graceful extensibility, and sustained adaptability.

In this paper, we clarify the meaning of the word resilience and its use, explain the advantages of the pluralistic approach to advancing resilience theory, and clarify two of the four conceptual understandings: robustness and graceful extensibility. Furthermore, we draw upon examples in electric power, transportation, and water systems that illustrate positive and negative cases of resilience in infrastructure management and crisis response. The following conclusions result:

1. Robustness and graceful extensibility are different strategies for resilience that draw upon different system characteristics.
2. Neither robustness nor extensibility can prevent all hazards.
3. While systems can perform both strategies simultaneously, their drawbacks are different.

Robust infrastructure systems fail when policies and procedures become stale, or when faced with overwhelming surprise. Extensible systems fail when a lack of coordination or exhaustion of resources results from decompensation. Consequently, resilience is found neither only in robustness, nor only in extensibility, but in the capacity apply both and switch between them at will.

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Created

Date Created
  • 2017-07-17

Transportation Resilience to Climate Change and Extreme Weather Events - Beyond Risk and Robustness

Description

The long-term reliability and functioning of the transportation system will increasingly need to consider and plan for climate change and extreme weather events. Transportation systems have largely been designed and

The long-term reliability and functioning of the transportation system will increasingly need to consider and plan for climate change and extreme weather events. Transportation systems have largely been designed and operated for historical climate conditions that are now frequently exceeded. Emerging knowledge of how to plan for climate change largely embraces risk-based thinking favoring more robust infrastructure designs. However, there remain questions about whether this approach is sufficient given the uncertainty and non-stationarity of the climate, and many other driving factors affecting transportation systems (e.g., funding, rapid technological change, population and utilization shifts, etc.).

This paper examines existing research and knowledge related to the vulnerability of the transportation system to climate change and extreme weather events and finds that there are both direct and indirect “pathways of disruption.” Direct pathways of disruption consist of both abrupt impacts to physical infrastructure and impacts on non-physical factors such as human health, behavior, and decision making. Similarly, indirect pathways of disruption result from interconnectedness with other critical infrastructure and social systems.

Currently, the direct pathways appear to receive considerably more focus and assessment than the indirect pathways, and the predominant approach for addressing these pathways of disruption emphasizes strengthening and armoring infrastructure (robustness) guided by risk analysis. However, our analysis reveals that indirect pathways of disruption can have impacts that are on par with disruptions via direct pathways, while also being less amenable to risk/robustness-based approaches. As a result, we posit that concepts like flexibility and agility appear to be well suited to complement the status quo of robustness by addressing the indirect and non-physical pathways of disruption that often prove challenging - thereby improving the resilience of transportation systems.

Full Version of Manuscript Available in Transport Policy:
https://www.sciencedirect.com/science/article/pii/S0967070X17305000

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Created

Date Created
  • 2017-07-17