Years back, the discussion of resilience started with somewhat vague notions of building to better resist and recover from extreme events. As the concept has advanced, there have been attempts to provide more concrete definitions by multiple organizations, such as the National Infrastructure Advisory Council, the National Security Council, the Office of the Press Secretary, the Industry Statement on Resilience, and others. All of these definitions included wording that resilience involved reducing the magnitude and/or duration of the effects of an event on the building, infrastructure, community, etc. While this is a clear step forward in defining what resilience means in a general sense, none of the definitions provided ways to measure resilience and, maybe more importantly, to objectively determine if a design is more resilient than the alternatives.
The objective resilience committee of the American Society of Civil Engineers’ Engineering Mechanics Institute has addressed this issue with a series of manuals of practice (MOPs) addressing various aspects of evaluating resilience in an objective manner. The intent is to provide a resource for engineers, architects, government officials, contractors, owners, etc., who want to incorporate resilience into their projects and are looking for ways to either evaluate its impact or best practices. Multiple authors worked on the various chapters, and the entire series was evaluated by a Blue Ribbon Panel. The MOP is split into four volumes, each of which looks at a different aspect of resilience.
Volume 1 of the series investigates policies and strategies relating to resilience. Starting with a look at the definition of resilience, and the evolution of design objectives over the past few decades, the MOP then explores various aspects of incorporating these concepts in projects. The use of codes, inclusion of resilience in project management, and the use of asset and system modeling to assess infrastructure resilience are also discussed. An interesting aspect that is explored is defining metrics that can be used in a multi-hazard, multidiscipline analysis.
Objective Processes, Volume 2 of the MOPs, takes a more mathematical look at the problem of objective resilience. The topics include quantifying uncertainty, reliability modeling, interdependence of systems, simulation of complex systems, and system modeling. Each chapter provides a set of best practices and the technical basis for those practices. The discussion of quantifying and evaluating the interdependencies amongst systems provides some guidance toward taking a very subjective and intuitive realm and moving it toward being able to objectively determine how to evaluate different options for dealing with the interdependencies.
The use of various technologies in addressing enhanced resilience is covered in Volume 3 of the MOPs. The discussion starts with a look at the two main resilient materials: concrete and steel. The use of advanced technologies is also examined with consideration of the role of seismic isolation and other protective devices in increasing resilience. Monitoring of structures and other systems to evaluate their resilience over time is also addressed. This is important because what matters is the condition of the infrastructure at the time of the event, not the condition when it was first built. Monitoring can provide a way to prioritize repairs when attempting to enhance the resilience of a complex system.
Finally, Volume 4 of the MOPs presents multiple applications and case studies of projects attempting to objectively evaluate their resilience. The chapters look at assessing the resilience of entire communities as well as specific examples related to blast loading and extreme climatic events. Case studies are presented for health care systems, transportation infrastructure, and rapid transit systems. The volume and MOPs conclude with a chapter discussing how climate change and global warming impact civil infrastructure and looks at ways to help mitigate the impact.
The field of resilience has, to this point, been largely dependent on subjective measures, particularly when it came to recovery from an extreme event. The ASCE MOPs have gathered much of the current knowledge on the subject of objectively analyzing resilience, including numerous best practices and case studies. While the topic of resilience and how to evaluate it is continuously evolving, the MOPs provide an important resource for those looking to determine if their designs are meeting their resilience objectives.