Analytical and experimental investigation on slip-in gusset plate connection for double c-channel sections of cold-formed steel

Abstract

Background: Beam-column connections are one of the most important parts of each building, which influence local/global behaviour of structures under vertical and lateral loads. From a practical point of view, a desirable connection is one that can be implemented conveniently in the construction site. For this reason, the connection with the gusset plate and bolts is one of the most commonly used connections to join structural members together. The application of this type of connection with cold-formed steels has not gotten enough attention in the literature and needs more investigation. Objective: The objective of this study is to evaluate the behaviour of the gusset plate connection with cold-formed steel sections based on its moment-rotation relation obtained experimentally when the beam depth is varied. Methods: Three specimens were built with three different depth of beams (i.e. 200, 250, and 300 mm) and constant depth of column (i.e. 300 mm). A same size gusset plate with a thickness of 10 mm was used for all the connections. A Full-Scale Isolated Joint test (FSIJ) was conducted as a testing method in this study to investigate the behaviour of the connection. Results: Three distinct modes of failure were distinguished based on observations in the experiments. Moreover, the obtained results implied that there is a meaningful difference between experimental and analytical results for moment capacity and rotational stiffness of the tested connections. Likewise, the results showed that the beam depth in this joint should be limited to have a ductile connection when the column depth is constant. Conclusion: The moment capacity of the tested connections was analytically underestimated by Eurocode 3 relative to the experimental results with an average amount of 75%, while the connection rotational stiffness overestimated by the analytical results with an average of 74%.