Experiments on stainless steel hybrid K-joints with square braces and circular chord

This paper presents an experimental investigation on the load-bearing capacities of stainless steel hybrid tubular K-joints with square braces and circular chord. All test specimens were made from austenitic stainless steel of grade AISI 304. For gapped K-joints, as the gap (g) increased, initial stiffness and load-bearing capacities of joints decreased continuously. For overlapped K-joints, the overlap ratio (O_v) did not have a significant effect on the initial stiffness and load-bearing capacities of joints. For the same series of joints with the identical cross-sectional dimensions, the load-bearing capacities of overlapped K-joints were higher than those of gapped K-joints. Test results were also compared against the design predictions in accordance with the current design guidelines of CIDECT (2008), Eurocode 3 (EC3) (2005), Australian/New Zealand Standard (AS/NZS) (2001) and Chinese Code (GB 50017) (2017). Upon comparison, it was found that the GB 50017 (2017) can predict the load-bearing capacities of stainless steel hybrid tubular gapped K-joints accurately, being around 5% conservative to the test results. However, CIDECT (2008) predictions were found to be conservative by 23% on average. In comparison, the nominal strengths calculated from the EC3 (2005) and AS/NZS (2001) are conservative by 28% and 15%, respectively, when compared to the test results for stainless steel hybrid tubular overlapped K-joints.