Strength prediction of connections with Concrete Filled Steel Tubes and axially loaded passing plates

Recent investigations within the LASTEICON and LASTTS projects demonstrated the benefits of introducing 3D laser cutting into steel construction practice, particularly for the fabrication of connections between hollow section columns and IPE beams. These joints can be realised either by passing I‐beams or plates. This design improves the strength and stiffness of the connections, making them more suitable for Moment Resisting Frames than traditional directly welded I‐beam‐to‐HSS columns. Design for fire may necessitate filling the tube with concrete, which also enhances the mechanical properties of the joint at ambient temperature. Within this context, the present study investigates the strength of connections with Concrete Filled Steel Tubes (CFSTs) and passing‐through axially loaded plates, representing the main component of the CFST‐to‐IPE beam‐to‐column connection. Experimental tests on such component have been conducted, and a Finite Element model of the specimens has been developed and compared against experimental results. The numerical model has then been used to perform a parametric analysis over a broader range of geometries. Finally, a theoretical model is proposed to evaluate the strength of CFST‐to‐plate connection and compared favourably against tests and numerical simulations.