Initial geometric imperfections of modules in modular integrated construction structures

Modular Integrated Construction (MiC) structures possess unique sources of initial geometric imperfections that differ significantly from those found in traditional steel structures. Conventional design approaches, which often focus on element-level or non-structural deviations, fail to adequately capture these module-level imperfections, potentially leading to substantial errors in structural assessment and design. This study addresses this critical gap by proposing mathematical models that characterize module-level imperfections based on localized manufacturing tolerances. The effectiveness of the models is validated through Monte Carlo simulations, which establish clear relationships among allowable tolerances, module dimensions, and geometric deviations. By enabling the direct consideration of initial imperfections at the modular unit level, the proposed method fully leverages the high-precision nature of MiC and supports efficient structural design using the Direct Analysis Method (DAM) without reliance on the effective length method. Furthermore, the statistical analysis of manufacturing tolerances provides a foundation for setting appropriate precision requirements to ensure desired module quality. This approach offers a practical and reliable solution for the performance-based design of MiC structures.