SCFs and fatigue design of multiplanar tubular DT joints

Abstract

This paper concerns the fatigue design of multiplanar welded tubular DT (double T) steel connections. Stress Concentration Factors (SCFs) are used for the calculation of the geometric or hot-spot stress of a DT joint and for the subsequent assessment of joint structural integrity against fatigue. Following extensive finite element analyses, a simple and efficient methodology has been developed to predict stress concentrations and calculate fatigue design capacity in DT joints with equal-size braces subjected to axial loads and bending moments. The proposed design methodology is based on simple SCF parametric equations and graphs and is illustrated in 2 design examples. The results of the present investigation aim towards an improved DT-joint design in tubular structures subjected to repeated loading.