EXPERIMENTAL STRESS CONCENTRATION FACTOR IN CONCRETE-FILLED STEEL TUBULAR T-JOINTS

© 2018 Elsevier Ltd An experimental investigation of stress concentration factor (SCF) in Steel circular hollow section brace welded to concrete-filled circular hollow section chord (CHS-to-CFCHS) T-joints has been performed under axial tension, axial compression, in-plane bending and out-of-plane bending. The distribution of SCF around the welded brace-to-chord intersection on both the brace and chord has been investigated using three CHS-to-CFCHS T-joint specimens. The experimental SCF results have been compared with the predicted SCF in empty T-joints. The relationship between the maximum SCF in relation to parameter β, with fixed other geometrical parameters, has been investigated for the basic load conditions. The experimental maximum SCF under axial tension has been compared with the predicted maximum SCF from parametric equations for CHS-to-CFCHS T-joints previously developed by the authors. The results show that the concrete has a significant effect in reducing the SCF, mostly under axial tension and the parametric equations for predicting SCFs in empty T-joints are not suitable for CHS-to-CFCHS T-joints. The effect of parameter β on the maximum SCF in CHS-to-CFCHS T-joints is significant under axial tension and out-of-plane bending moment

Parametric study and equation of the maximum SCF for concrete filled steel tubular T-joints under axial tension

© 2018 Concrete-filled steel tubular joints are increasingly being used for built infrastructure such as bridges and towers. In this study, the variation of the maximum Stress Concentration Factor (SCFmax) with non-dimensional geometric parameters in concrete-filled steel tubular (CFST) T-joints under axial tension has been investigated. A database of the maximum SCFs in CFST T-joints under axial tension is developed based on three-dimensional (3D) finite element (FE) models. The 3D FE models developed using ABAQUS software have been verified using experimental results. Graphs showing variation of the maximum SCF, in CFST T-joints, with non-dimensional geometric parameters have been produced and compared with those for non-filled empty T-joints. A parametric equation for predicting the maximum SCFs in CFST T-joints, a useful parameter for design, has been developed in a multiple nonlinear regression analysis. There is a good agreement between the maximum SCFs predicted by the parametric equation and those determined from the experiments