Rotational stiffness of inter-module connection in mid-rise modular steel buildings

Abstract The inter-module connection used for the assembly of prefinished modules is a unique key issue for modular steel buildings (MSBs). Previous types of inter-module connection require additional operation spaces and have conflicts with architecture decoration. To overcome these limitations, this study proposed an innovative rotary inter-module connection applied at the end of modular columns with corner fitting. The working mechanism of the rotary connection was introduced through a bending resistance test. Then, finite element analysis (FEA) and theoretical derivation were conducted to investigate the initial rotational stiffness obtained through the preceding test. In terms of the feature of double beams in MSBs and the results obtained, the influence of the stiffness ratio of double beams on the internal force distribution was investigated via FEA and theoretical calculation. Some recommendations for the design were also presented. Finally, the manner in which stiffness characteristics of the inter-module connection is considered accurately in the structural design was discussed and the conceptual design procedure of the inter-module connection was given accordingly. The results obtained could serve as a reference for the design of mid-rise MSBs.