Data-Driven Resilience

The introduction of a new concept, such as resilience, into the design paradigm often leads to confusion about the real meaning of the notion and how to determine when (or if) the project goals are met. We frequently see this problem with regards to sustainability, which became a buzzword some years ago. There are many different definitions of what being sustainable means, multiple measures used to evaluate sustainability, and little agreement on which one should be used in a situation or even how to exactly determine compliance for a given project. The same issue may arise for resilience, as interest in obtaining a more resilient built environment continues to grow. The idea of developing objective measures for use in design is not a new concept, and multiple activities are underway to bring objectivity to resilient design. A recent session of the Global Concrete Summit (access to the recordings are free!) explored some concepts of objective or data-driven resilience. There were many excellent talks presented over multiple sessions, but I would like to highlight three presentations (in Session 4B) that directly addressed this issue.

Dr. Mohammad Ettouney, a renowned expert on blast, structural health monitoring, and disproportionate collapse, and editor of an upcoming American Society of Civil Engineers Manual of Practice on Objective Resilience, discussed the need for objectivity in resilient design. He highlighted ways in which the “four Rs” of resilience — robustness, resourcefulness, recovery, and redundancy — relate to concepts such as preparedness, protection, mitigation, resource allocation, and planning. Ettouney further illustrated subjective versus objective measures of resilience and outlined three possible objective measures: continuity of operation, time to recovery, and monetary losses.

Dr. Henry Burton, associate professor of civil and environmental engineering at UCLA, discussed the use of risk analysis for resilient design of distributed systems. In particular, he addressed the need for end-to-end simulations models, looking at the entire process from hazard to resilience metrics as well as the role of data in developing models and the interdependence of various models. Through examination of the water distribution system of Napa, California, as an example, Burton demonstrated the step-by-step process ranging from determining fragility curves for the components to predicting damage based on the risks over the project lifetime and determining damage and restorative actions. The incorporation of uncertainty into the model and the effect on the predicted outcomes was also described.

Dr. Franz Ulm, professor of civil and environmental engineering at MIT, and technical director of the Concrete Sustainability Hub, described several projects that make use of statistical physics to address both resilience and sustainability issues. This involves looking at the internal aspects of a problem and considering how physics-based knowledge of material behavior can be used to predict response. One facet is the use of city texture, that is, the layout of streets and buildings, to better predict the forces exerted by the wind during hurricanes. Another application considers the flooding risk due to rainfall. Finally, an examination of the socioeconomic impact of natural hazards showcased that even though financial losses due to hurricanes are greater at higher income levels, the ability to absorb those costs is also greater, leading to lower income populations being impacted much more by natural hazards as measured by their ability to withstand the costs.

What can we take away from these talks and other similar activities around the world aimed at bringing objectivity to the concept of resilience? First, that it is possible to define resilience in a way that is both logical and measurable. Second, techniques exist for translating those definitions into predictions of resilient behavior, taking into account uncertainty in both the hazard and response. And, finally, if we are aiming at achieving true resilience in our projects, we have to look beyond the equivalent of “greenwashing” and show how our designs are actually providing value to the client and community. By demonstrating that resilience can be based on rational, measurable goals, the research and development performed by the speakers provide platforms on which further advancement of engineered resilience can be achieved. This is also the goal of my employer, the National Ready Mixed Concrete Association, as my colleagues and I work with many groups, including connecting industry, academia, government, and other professional organizations, to find ways to increase resilience, in all its manifestations, through improved guidelines, codes and standards, and dissemination of the latest advancements. As the concepts and tools developed become available to practicing engineers, it is up to us to put them to use advancing the state of practice to include enhanced resilience.