Post-disaster functional recovery of the built environment: A systematic review and directions for future research

Life safety has been a primary design requirement in codes and standards for the built environment. However, over the past several years, better building performance goals that consider acceptable recovery times and continued functionality following major disasters have been advocated. Functional recovery, a new design philosophy that establishes holistic performance goals, and focuses on the robustness of structures, enhanced safety, and, specifically, fast return to operation post-disaster, has been introduced in earthquake engineering to govern future building designs. This article utilised the systematic review procedures as a tool to provide a state-of-the-art review of functional recovery research within the built environment. A critical review of 78 publications was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol. The evolution of paradigm shifts from seismic resilience to functional recovery in earthquake engineering research has been discussed in detail. Two frameworks, namely the Federal Emergency Management Agency's (FEMA) P-58 and Arup's Resilience-Based Earthquake Design Initiative (REDi), have been recognised as the most commonly utilised frameworks for modelling the functional recovery of buildings post-earthquake due to their effectiveness and widespread adoption. However, it is essential to acknowledge that recently developed frameworks, such as the F-Rec framework, ATC-138, and TREADS, which explicitly formulate functional recovery calculation procedures, have the potential to replace FEMA P-58 and REDi and advance functional recovery research in the future. Moreover, aligned with modular-based characteristics of existing frameworks, indicators required in functional recovery analysis have been extracted and classified into four distinct categories: 1) hazard analysis, 2) structural response analysis, 3) damage analysis, and 4) recovery analysis. This categorisation enables a comprehensive and systematic approach to understanding the multifaceted aspects of functional recovery in a structured manner. Detailed investigation of frameworks and indicators offers insights for future research exploration. These include (a) expanding the fragility library of components to permit more widespread recovery analysis, (b) comparing, validating and optimising existing frameworks and models, (c) enhancing the modelling of interdependencies between the building and its adjacent buildings and services, (d) improving the capability for uncertainty analysis, and (e) acquiring empirical data to enable predictability of the existing frameworks and models for functional recovery.