Hybrid modular construction system “INNO3DJOINTS”: Experimental behaviour and numerical modelling of isolated sub-frames

With the growing demand for sustainable, cost-effective and overall-efficient building solutions, the need for dependable modular construction systems is steadily on the rise. In the present paper a novel hybrid modular construction system named INNO3DJOINTS is introduced, employing cold-formed welded steel tubular columns, fabricated according to EN 10219, and cold-formed steel thin-wall section based truss-girders, joined by the innovative plug-and-play (P&P) connector, designed to provide ease-of-assembly and -disassembly. The experimental investigation conducted on isolated sub-frame configurations of the novel system is presented, where 6 full-scale specimens were subjected to horizontal and vertical loading. The test configurations differed in the P&P joint socket thickness and the absence/presence of the light steel framing (LSF) wall, encased with oriented strand board (OSB). In addition, a numerical model for predicting the system's global behaviour is proposed, developed in SAP2000. Initially, the behaviour of the employed P&P joint configurations, categorized as partial-strength, is characterized using experimental and validated ABAQUS finite element model (FEM) data, resulting in a spring model implemented into the global FEM. Finally, the numerical and experimental results are compared and discussed, leading to conclusions regarding the system's 2D structural performance, identified behaviour governing phenomena, P&P joint influence, LSF wall and OSB contribution, as well as the capabilities of the developed FEM. • Full-scale tests of a novel hybrid ease-to-assemble modular construction system. • Innovative “plug-and-play” joint globally characterized, leading to a spring model (0D). • FEM developed, accurately predicting the frame initial stiffness and deformed shape. • Joint, LSF wall and OSB contribution to the horizontal stiffness assessed. • Open-frame specimen failure governed by the stress concentration in the CFS truss nodes.