Investigation on stress concentration factor in concrete-filled steel tubular T-joints under out-of-plane bending moment

Experimental investigation of stress concentration factor (SCF) in circular cross section concrete-filled steel tubular (CFST) T-joints under out-of-plane bending has been conducted. The distribution of SCF around the welded brace-to-chord intersection on both the brace and chord has been investigated in three CFST T-joint specimens. The dimensions of three CFST T-joints were chosen considering variation in non-dimensional parameter β only. The experimental SCF results have been compared with the predicted SCF in CFST and empty T-joints. The results have shown that the concrete has a significant effect in reducing the SCF and that the trend in variation of the maximum SCF with parameter β is similar in both CFST and empty T-joints yet it is steeper in empty T-joints.