Classification system for inter- and intra-module joints in non-sway steel MiC structures

The lack of guidelines for determining the rigidity of inter- and intra-module joints in corner-supported steel modular integrated construction (MiC) buildings can lead to unsafe or over-conservative designs. To address this issue, this study proposes a classification system for non-sway steel MiC buildings that covers both inter- and intra-module joints. First, the semi-rigidity of the joint regions in steel MiC buildings was clarified and the necessary degrees of freedom for joint classification were determined. Then a minimum substructure including one joint region was extracted from a steel MiC building, and its carrying capacity was determined as a simplified analytical model that considering the stiffnesses of both the inter- and intra-module joints. The simplified model was adopted to derive explicit formulas for the boundary limits of rigid/non-rigid inter- and intra-module joints, based on the criterion that the carrying capacity of the substructure with finite joint stiffnesses is 95% of that with rigid properties. Finally, the feasibility of the proposed classification system was verified by applying it to prototype MiC structures.