Research on mechanical performances and deformation mechanism of steel irregular joint

 According to an analysis of the mechanical behaviour of irregular joints between steel box columns and beams such as ductility, ultimate bearing capacity, degradation of strength and stiffness, energy dissipation, the deformation mechanism of the steel irregular joint panel zone is established based on the plastic hinge theory. Experimental study results indicate that irregular joints between steel box columns and beams exhibit good seismic performance and energy dissipation capacity. Ductility is consistent with the requirements of plastic ultimate deformation; bearing capacity degradation of all specimens is not significant when the displacement of the layer exceeds the ultimate displacement. Strength and stiffness degradation of all specimens are not notable when the interstory displacement exceeds ultimate displacement. The experimental results indicate that shear buckling failure in the small core area of the panel zone is the main failure mode