New interlocking inter-module connection for modular steel buildings: Simplified structural behaviours

•Structural behaviours of the interlocking inter-module connection are investigated.•Experimental shear behaviour calibrates numerical models.•Connection responses are illustrated under a range of combined loading conditions.•Design models are informed by analytical derivations including yield line analyses.•Shear, axial and bending behaviours are predicted by the proposed design models. Inter-module connections (IMCs) are the key component which transforms individual building modules into complete modular buildings. Structural design of these connections is, however, reported to be a major challenge, due to a lack of knowledge of the structural performance. Therefore, in this study, the structural behaviours of the newly proposed interlocking (IL) IMC, which incorporates interlocking components to improve the constructability and shear force–displacement (V-x) behaviour, are investigated. The simplified model previously proposed for the shear behaviour of the experimental IL connection specimens is reviewed, and numerical simulations are undertaken using ABAQUS to investigate the effect of the loading and boundary conditions on the V-x behaviour. Then, extended numerical models are developed based on a more realistic geometry which has two bolts per column to improve the resistance to in-plane rotation. A simplified empirical model is established, in which the V-x behaviour of the more realistic connections is represented by exponential functions, allowing for the effect of the axial load. Next, the numerical model is extended, and the axial force–displacement and bending moment-rotation behaviours are evaluated, after which semi-empirical models are derived. In this way, simplified models are developed which can predict the structural behaviours of the interlocking IMC.