Integrated Risk Management Framework for Tolerance-Based Mitigation Strategy Decision Support in Modular Construction Projects

Abstract

Managing excessive geometric variability risks in modular components and assemblies represents a major challenge in construction projects because of incompatibility between process capabilities and desired tolerance levels. The current modular practices usually apply strict tolerances, ad hoc strategies, or trial-and-error solutions for geometric variability management. The consequences of improper assessment and reactive management of such unique risks can result in extensive site-fit rework, cost overruns, schedule delays, and quality issues. To address this persistent challenge in modular construction (MC), this paper presents a systematic risk management framework for the proactive management of unique modularization risks. The developed framework includes identification and evaluation of tolerance-related issues and unique modularization risks in a quantitative manner, identification of the optimum geometric variability (using either a strict or relaxed tolerance approach) by addressing the trade-offs between offsite and onsite costs, evaluation of mitigation strategy effectiveness based on tolerance theory, and representation of the results in two- and three-dimensional graphs to support decision making with respect to the optimum selection of a mitigation strategy. A case study is used to demonstrate the proposed framework, and the results show that it can be used to effectively support industry practitioners to improve modularization performance and maximize its benefits.