Stress concentration factor in concrete-filled steel tubular K-joints under balanced axial load

Steel tubular K-joints are widely used in railway and highway bridges. In this study, stress concentration factor (SCF) has been investigated in uniplanar K-joints made of steel circular hollow section (CHS) braces welded to concrete-filled circular hollow section (CFCHS) chord (CHS-to-CFCHS) under balanced axial loading. Experimental SCF measurements at 45° interval on the chord and two braces are performed in one CHS-to-CFCHS K-joint specimen under balanced axial loading. A finite element (FE) model has been developed using ABAQUS. The FE model was verified with experiments by the author and other experiments reported in the literature. Parametric study on the SCF in the brace and chord has been conducted. Parametric equations for predicting the SCF in the brace and chord have been derived. The predicted SCF by the derived equations are comparable with the experimental stress concentration factors