Design method of irregular-shaped concrete-filled steel tube column joints with inner semi-diaphragm

This paper studies the mechanical behavior and design method of the irregular-shaped concrete-filled steel tube column to H-shaped steel beam joints with inner semi-diaphragm (ICFSTC-Joint) by numerical and theoretical investigation. ICFSTC-Joint was proposed and tested in the authors' previous paper, which can be adopted in steel-concrete composite structures. Firstly, the tensile and compressive bearing capacity of ICFSTC-Joint under the tension or compression of a single beam flange is investigated. Secondly, based on the tensile and compressive bearing capacity, the bending capacity of the ICFSTC-Joint under the bending exerted by a complete H-shaped beam is investigated. Finally, the interaction between multiple ICFSTC-Joints is considered. The FE model verified by the hysteretic experiment of ICFSTC-Joint is adopted in the parameter analysis. The parameter analysis involves the height of beam, width and thickness of beam flange, height and thickness of diaphragm, thickness of column wall, length of column limb and axial compressive ratio. Based on the parameter analysis results, the mechanical models of ICFSTC-Joint under various conditions are established. The complete set of design method as well as some constructional requirements are finally established through the theoretical derivation of mechanical models and fitting the FE investigation results and exhibit good precision.