Effects of module-to-module connection rotational stiffness on the structural performance of high-rise steel modular buildings

With advantages including high productivity and sustainability, modular construction has attracted increasing interest in building project developments. As modular buildings are stepping higher, the modular systems should be better designed to ensure structural safety. In such systems, different types of connections, such as module-to-module (M2M) connections, play an important role in the loading transfer. However, the investigation into the rotational stiffness of the M2M connection was still insufficient in the literature. This paper aims to examine the effects of M2M connection rotational stiffness on the structural performance of high-rise steel modular buildings. A theoretical analysis was conducted on a hypothetic three-storey three-span steel frame to simplistically demonstrate the significant effect of connection rotational stiffness on the internal force distribution of modular buildings. To assess the applicability of preliminary findings in real-life high-rise steel modular buildings, validated numerical models were employed to determine the rotational stiffness of a newly proposed innovative and practical M2M connection. Subsequently, structural models of a 40-storey steel modular building with different M2M connection rotational stiffness values were established to conduct comprehensive investigations. The analysis results indicated that the rotational stiffness of M2M connections plays a critical role in determining the behaviours of critical structural members. The findings provide important references for the design of M2M connection stiffness and structural performance analysis of high-rise steel modular buildings.