A Study on the Mechanical Properties of Beam-Column Flat Joints in Light Steel Structures

This study investigates the mechanical properties of beam-column joints without fixed flanges, which are subject to bending. Light gauge steel structures have been utilized in numerous low-rise buildings. However, their thin plate thickness renders them susceptible to local buckling. In general, beam-column joints are designed as pin joints because the design method for rigid joints has not yet been established. In addition, while individual approvals have been obtained when joints are designed as rigid, many are complicated to make, and productivity is an issue. The flat joint method proposed in this study requires only a limited number of high-strength bolt friction joints between a web of beam and a connecting plate. The small brackets facilitate efficient transportation, and the absence of protrusions on the flanges simplifies the process of latter construction. The objective of this study is to determine the mechanical properties of the beam-column joints under bending by cyclic loading tests, and to propose an evaluation equation for the initial stiffness and yield strength by FEA and mechanical theory. The experimental results demonstrated that flat beam-column joints exhibit high stiffness and possess superior energy absorption capabilities without early buckling, which is frequently observed in light gauge steel structures. The initial stiffness is evaluated by a model that accumulates the deformation of deforming elements, and the elastic limit strength is evaluated by regression analysis of the concentration coefficient of shear stress in the FEA, and their validity is confirmed by the experimental results.