Toward resilient communities: A performance-based engineering framework for design and evaluation of the built environment

A community is a dynamic system of people, organizations, and patterned relationships and interactions. Most of these relationships and interactions are physically supported by a community's built environment, a complex and interdependent network of engineered subsystems and components, including buildings, bridges, pipelines, transmission towers, and other structures. As a result, the built environment plays a crucial role in enabling a community to function successfully, providing the foundations for much of the economic and social activities that characterize a modern society. Natural hazards such as earthquakes, hurricanes, and floods can damage a community's built environment, which in turn can disrupt the security, economy, safety, health, and welfare of the public. In response, many communities have developed and implemented regulatory frameworks in order to ensure that individual parts of the built environment attain minimum levels of performance.This thesis proposes a performance-based engineering framework for design and evaluation of the built environment in order to improve the overall resilience of communities to natural hazards. It begins by examining the regulatory framework currently used in the United States to design and evaluate a community's built environment to withstand the effects of earthquakes and other natural hazards. Specifically, it analyzes building codes and other engineering standards that establish performance expectations for buildings and lifelines. To this end, the thesis first identifies and describes attributes or characteristics of an ideal regulatory framework. Then, using these attributes as a guide, it discusses both the strengths and shortcomings of the current regulatory framework. The most significant shortcoming of the current framework is its lack of an integrated, coordinated, and comprehensive approach to establishing performance expectations for individual components of the built environment. Consequently, performance objectives for the individual components are not tied to broader performance targets for the community, primarily because these community-level performance objectives typically do not exist.The growing interest in resilient and sustainable communities necessitates an updated regulatory framework, one that employs an integrated, coordinated, and comprehensive approach to account for the built environment's numerous subsystems, components, and interactions. The regulatory framework currently used in the United States to design, analyze, and regulate commercial nuclear power plants to assure their safety offers a promising template for communities to follow. Despite obvious differences in function and configuration, both communities and nuclear power plants are multi- faceted, dynamic systems comprising many interacting subsystems and components that cut across a diverse range of disciplines and professions. The current nuclear regulatory framework handles these numerous subsystems, components, and interactions in a consistent and logical manner, informed partly by an explicit set of system-level performance expectations for the nuclear power plant. Furthermore, the tools and procedures employed by the current nuclear regulatory framework have been implemented successfully and refined extensively over the past several decades, resulting in significant improvements in both the understanding of how these complex, dynamic systems behave and the efficacy of the regulatory framework itself.This thesis studies the current regulatory framework for nuclear power plants and, using recent developments from the rapidly evolving fields of community resilience and lifeline interdependency, adapts it for use in a community setting. To this end, the thesis proposes and describes an integrated engineering framework for design and evaluation of a community's built environment. This new framework provides a transparent, performance-based, risk-informed methodology for establishing a consistent set of performance targets for the built environment and its various subsystems and components in order to enhance the overall resilience of the community. This thesis also presents several conceptual examples that illustrate implementation of the proposed framework, including a demonstration of how to develop seismic performance targets for a new residential building from a community-level performance goal.Ultimately, the work presented herein has the potential to change the way engineers, planners, and other stakeholders design and evaluate a community's built environment. The engineering framework proposed in this thesis provides a comprehensive, integrated, and coordinated methodology for planners and policymakers to set community-level performance targets and, subsequently, for engineers to calibrate the designs of individual components to meet these community-level performance targets. Though additional work is required, the findings presented in this thesis establish the foundations for a much-needed transformation from engineering individual components of the built environment on a component-by-component basis to engineering community resilience using an integrated and coordinated approach that begins at the community level. Future iterations of the framework should aim to expand its scope beyond disaster resilience to address and incorporate broader sustainability considerations like carbon footprint, energy efficiency, resource consumption, and environmental impact of a community and its built environment.