Probabilistic Risk Management Framework for Tolerance-Related Issues in Modularized Projects: Local and Global Perspectives

Abstract

Modular components and assemblies involve complex geometric relationships whereby excessive geometric variability in a critical component can affect the overall geometry of the aggregated and assembled structure onsite. These unique geometric relationships can expose modular projects to a number of related risks that propagate from one to another by means of escalation phenomena. Improper assessment and reactive management of these related risks typically results in extensive site-fit rework, cost overruns, schedule delays, and quality issues. Current modularization practices and previously developed risk management frameworks/toolkits lack a practical methodology for quantitatively evaluating the unique relationships among tolerance-related risks and for proactively managing their impact. These considerations motivated the research introduced in this paper: the development of a framework for the holistic assessment and efficient management of excessive geometric variability risks in modular construction projects. In the framework presented here, a classical risk assessment technique, in which a probability-impact risk model is employed for evaluating risks individually from a local perspective, is linked with an innovative technique for considering interactions among risks from a global perspective, which employs the concepts of a design structure matrix and pairwise comparisons using the analytical hierarchy process. The results of a case study conducted for validation purposes demonstrate that the developed framework can provide industry practitioners (owners, designers, fabricators, and contractors) with a better understanding of the risk profile for a project as well as new insights into the development of proactive mitigation strategies from both a local and a global perspective.