2:00pm - 2:20pm
Hurricane Resilience: An approach for community-informed building-scale assessments
MIT, United States of America
Building-scale resilience assessments are generally carried out through convolving hazard curves with fragility curves. Hazard curves describe the probability of excitation level, wind speed in the case of hurricanes, and fragility curves describe the probability of physical damage for each given excitation level. Our group at the MIT Concrete Sustainability Hub is working on updating hazard and fragility curves to include community characteristics, such as orientation and mitigation of the building stock. Hazard curves are modified to include “texture”, the orientation of buildings relative to each other, which can act to amplify wind risk. Fragility curves are dictated by the design of structural and nonstructural elements. Design iterations are modeled and simulated using molecular dynamics to produce detailed fragility curves representing incremental levels of mitigation. Finally, characterizing the building stock enables aggregation of community-scale loss. The extent of this aggregated loss influences demand surge, the increase in repair time and unit repair costs in larger-scale disaster events due to demand for materials and labor outpacing local supply. Our research goal is to understand the mechanisms of demand surge and couple surge with "texture" effects for an estimation of loss amplifications in different communities. We find that building-scale repair costs are avoided for higher standard buildings especially when located in communities where surrounding buildings are also appropriately mitigated. Our aim is to promote performance-based design while emphasizing the importance of community-scale implementation.
2:20pm - 2:40pm
Metrics of Community Resilience: Estimating the social burden of attaining critical services following major power disruptions
1University at Buffalo; 2Sandia National Laboratories
Electric power is critical to almost every aspect of American life, powering everything from healthcare systems to transportation to telecommunications. These and other infrastructure systems vitally depend on a functional power grid; consequently, the federal government has deemed the energy sector “uniquely important” to the overall resilience of infrastructure systems. If the value of the nation’s infrastructure systems is understood to be derived from its ability to “provide the essential services that underpin American society,” (PPD-21, 2013) then infrastructure resilience—defined as “the ability to prepare for and adapt to changing conditions and withstand and recover rapidly from disruptions” (PPD-21, 2013)—can be understood similarly. From this perspective, the value of infrastructure resilience (notably, grid resilience) can be assessed by the degree to which it serves to bolster community resilience.
Despite the practical connections between grid and community resilience, there is a disconnect between efforts to plan for these two objectives. Efforts to plan for grid resilience often are aligned with a utility perspective of energy, which focuses on the supply of energy, and considers energy resilience in terms of the frequency and duration of a power outage. In contrast, efforts to plan for community resilience often focus on the human outcomes of energy supply, considering energy resilience through health and wellbeing indicators such as access to food, water, sanitation, and healthcare (The Rockefeller Center & Arup, 2015; Cutter, 2016). The disconnect between these two perspectives prevents efforts to plan and regulate for community-focused grid resilience. The lack of resilience metrics leaves utilities with few incentives to invest in grid resilience (Mukhopadhyay & Hastak, 2016), and fewer still to go beyond kilowatts and kilowatt hours to evaluate potential investments in terms of how energy supply contributes to human wellbeing in outage events.
This research seeks to bridge the gap between these two perspectives and facilitate efforts to plan and regulate for community-focused grid resilience. Drawing upon theories of human development, namely the human capabilities approach (Nussbaum, 2003; Sen, 2005), this research explicitly draws the link between infrastructure systems and infrastructure services, and the ultimate human benefits they provide (Clark, Seager, & Chester, 2018). The capabilities framework provides a theoretical basis for the key objective of the project: the development and validation of a social burden metric to quantify the strain placed upon members of a community to attain all their infrastructure service needs after a disaster. The capabilities framework highlights three key concepts integral to the development of the social burden metric: need, or the ways in which different demographics require different types and quantities of particular services; ability, the differing resources certain populations have at their disposal and the ways in which these resources might facilitate resource acquisition; and acquisition effort, the difficulty of satisfying service needs, based on service availability and properties of the service location. Building from this theoretical basis, the social burden metric adapts a variant of the travel cost method (TCM) known as the Random Utility Model, an approach long used by environmental economists seeking to quantify the value of recreational services to communities (Heal, 2000). This adapted RUM explicitly reflects the needs of different populations, their abilities, and the level of effort necessary acquire their service needs in power outages.
The employment of RUM as a means of quantifying the social burden of power outage demonstrates a new application of a long-established method. In addition to such scholarly contribution, this research has the potential to inform planners and policymakers for assessing the human impact of proposed infrastructure investments.
2:40pm - 3:00pm
A resilience engineering approach to integrating human and socio-technical system capacities and processes for national infrastructure resilience
1Resilience Engineering Institute, Tempe, AZ; 2Department of Operations Research, Naval Postgraduate School, Monterey, CA; 3School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ; 4School of The Future of Innovation in Society, Arizona State University, Tempe, AZ
Despite Federal directives calling for an integrated approach to strengthening the resilience of critical infrastructure systems, little is known about the relationship between human behavior and infrastructure resilience. While it is well recognized that human response can either amplify or mitigate catastrophe, the role of human or psychological resilience when infrastructure systems are confronted with surprise remains an oversight in policy documents and resilience research. Existing research treats human resilience and technological resilience as separate capacities that may create stress conditions that act upon one another.
This interdependence between human and technological aspects of resilient infrastructure systems is not yet fully appreciated in infrastructure policy or practice. In particular, guiding Federal policy directives for U.S. infrastructure security and resilience do not explicitly identify human or social behavior as essential components of critical infrastructure system resilience. A prominent example of this is the National Infrastructure Protection Plan of 2013 (NIPP 2013) – a guide to managing national infrastructure risks created by the Department of Homeland Security in response to Presidential Policy Directive 21. Although NIPP 2013 names 16 sectors of critical infrastructure (including “communication” systems), and acknowledges that threat prevention, recovery, and mitigation requires close coordination of partnerships between public and private interests the document fails to consider how human behavior impacts infrastructure resilience. Further, while the NIPP emphasizes that critical infrastructure security and resilience is essential to national well-being, it makes no reference to how infrastructure designers, operators, maintenance workers, or users might contribute to or undermine infrastructure resilience. Thus, a gap remains regarding the study of human attributes that relate to infrastructure and help build resilience to support national goals. Given that human performance is dynamically coupled with infrastructure performance, a comprehensive approach to resilience must consider this coupling.
To address this gap, we review resilience engineering and psychology research to produce four novel outputs that inform an integrated perspective of human and infrastructure resilience not available elsewhere in the literature: (1) a list of resilient system capacities for engineered systems, (2) a list of human psychological resilience capacities for the people embedded in infrastructure systems, (3) a conceptual framework for linking system and human capacities together via four socio-technical processes for resilience: sensing, anticipating, adapting, and learning (SAAL), and (4) a mapping of human and system characteristics using the framework to inform infrastructure resilience policies. Our analysis shows that the human and technical resilience capacities reviewed are interconnected, interrelated, and interdependent when applied to the SAAL framework. While reinforcing the important roles of cognitive and behavioral dimensions, our findings further suggests that the affective dimension of human resilience is effectively ignored in the resilience engineering literature. Together, we present a simple way to link the resilience of technological systems to the cognitive, behavioral, and affective dimensions of humans responsible for the system design, operation, and management.