Experimental and numerical study on a novel self-locking inter-module connection with spring-loaded plunger latches: Under axial tension

Modular construction is gaining popularity over traditional construction methods due to several advantages such as faster construction, better safety control, and improved sustainability. This paper proposes a novel self-locking inter-module connection with spring-loaded plunger latches that can further improve construction speed while providing reliable connectivity. Conceptually, the connection can work with beams and columns made of either open or closed steel sections or even concrete-filled steel tubular (CFST) sections. An experimental program was conducted on six full-scale specimens to investigate their structural performance under axial tension load. Information regarding load-displacement relation and strain distribution were collected. Three distinct failure modes were observed, including shear damage of the latch, tensile fracture of the sleeve, and latch pull-out. The stiffness, strength, and ductility of each failure mode were analysed and discussed. Moreover, the workability of the self-locking mechanism was confirmed through the tests. A detailed finite element model was created and its accuracy was validated against the experimental results. The validated model was then used to uncover complex internal interactions and numerically study the effect of weld effectiveness. Upon experimental and numerical results, design recommendations were provided, and a simplified analytical method was proposed to predict the design capacity of the novel self-locking connection for corresponding failure modes.