Integration and Quantification of Resilience and Sustainability in Engineering Projects

Integrating resilience and sustainability into engineering projects from their inception is more crucial now than ever. Our world is grappling with environmental challenges and socio-economic uncertainties, heightened by risks such as climate change impacts, population growth, resource depletion, urban sprawl, and social injustice, among others. A unified framework capable of quantifying and integrating these aspects into engineering projects is essential to address these challenges effectively. Despite the importance, there is a scarcity of frameworks tailored for this purpose, while existing industry rating tools are often subjective and have limitations in integrating these concepts effectively. A general integrated sustainability and resilience assessment framework (named Tiered Quantitative Assessment of Life Cycle Sustainability and Resilience (TQUALICSR)) was developed at the University of Illinois Chicago to bridge this gap. However, the potential of such a framework has not been fully realized in past studies as they are confined to specific techniques, methods, and tools, limiting the applicability of the proposed framework for diverse engineering projects. The primary aim of the current study is to provide a comprehensive understanding of the proposed framework and offer alternative tool options for each stage of the assessment process. We begin with a thorough review of definitions of resilience and sustainability concepts, establishing functional definitions for broader use. The proposed general framework classifies the variables related to resilience and sustainability into quantitative (Tier 3), semi-quantitative (Tier 2), or qualitative (Tier 1) variables, providing flexibility based on data availability. The integrated assessment starts with a robust resilience assessment, incorporating elements such as functionality curves for technical resilience quantification and cascading environmental, social, and economic impacts as other necessary dimensions of resilience. Subsequently, resilient design alternatives resulting from the resilience assessment undergo a comprehensive sustainability assessment that considers all three triple bottom-line aspects of sustainability, using various tiers of variables and tools as available/suitable. The quantified variables then face the challenge of integration and decision-making as these variables often differ in units of measurement and magnitudes. To address this, we discuss various normalization techniques, weighing methodologies, and multi-criteria decision analysis (MCDA) tools, outlining their principles, procedures, advantages, and drawbacks. By delineating the phases of the proposed framework and presenting diverse tool options, engineers can select the most suitable techniques for their projects and perform an integrated quantification of resilience and sustainability.