Tensile behavior of a novel self-locking inter-module connection in modular steel buildings

Abstract

Modular steel buildings (MSBs) consist of complete steel modules and inter-module connections; the latter plays a crucial role in assembly efficacy on-site and in resisting the tension load at the base of a high-rise modular building subjected to lateral loads. This paper investigates the tensile performance of the proposed self-locking inter-module connection. Two full-scale experiments were conducted to evaluate the axial tensile behavior of this innovative connection. The mechanical properties of the self-locking inter-module connection were obtained and analyzed, including the failure modes, ultimate bearing capacity, and strain distribution. Under axial tension load, the self-locking inter-module connection exhibited adequate load-carrying capacity and ductility, as evidenced by the results. The refined finite element (FE) model of the self-locking inter-module connection was developed and validated against experimental data. Then, FE modeling was used to further investigate the working mechanism of the self-locking inter-module connection under axial tensile force. Two essential parameters were considered, including the bottom plate thickness of the upper corner fitting and the top plate thickness of the lower tenon. The numerical results demonstrated that the failure mode of such a self-locking inter-module connection was dependent on the relative relationship of the aforementioned two key parameters, which is reflected by the ratio (Kt) of the vertical shear area of the bottom plate of the upper corner fitting and the top plate of the lower tenon. Considering tensile resistances and material strength utilization, a range of values for the parameter Kt and design recommendations were provided.