This paper presents the experimental studies of two partially overlapped CHS K-joints specimens (Specimens S1 and S2) with through brace subjected to basic and combined loads. The stress analysis of the joints revealed the maximum stress concentration factor (SCF) to be located on the brace side. Then, the maximum SCF was compared with existing Efthymiou's formulae. It is observed that the Efthymiou's formulae are over-conservative in in-plane bending load case (IPB), but in axial load case (AX) are not conservative. In addition, the fatigue life was also compared with existing S-N curves. The S-N curve was found to be marginally conservative for first specimen, but it was not conservative for other one.