Mohammad Ali Lotfollahi-Yaghin - Associate Professor , University of Tabriz
Hamid Ahmadi - PhD Candidate , University of Tabriz

The present paper investigates the effect of additional co-planar brace members, as the source of difference between KT- and DKT-joints, on the distribution of stress concentration factors(SCFs) along the weld toe. To do so, the effect of non-dimensional geometrical parameters including τ, γ and β as well as the brace-to-chord inclination angle (θ) on the distribution of SRs along the weld toe of the joint is studied under the balanced axial loads. SR is the ratio of theSCF value at a certain location in a DKT-joint to the corresponding value in a KT-joint having the same geometrical properties. Detailed remarks of geometrical effect on the SR distribution are fully discussed. For specific values of normalized parameters, considerable difference wasobserved between the SCF values in DKT- and KT-joints with the same geometrical properties. This fact highlights the necessity of using parametric equations especially designed for DKTjoints. Such equations are not currently available in the literature. SCFs of tubular joints are necessary parameters for fatigue and fracture mechanics calculations of offshore structures.

Offshore Platforms, Fatigue, Fracture Mechanics, Tubular KT- and DKT-joint, Stress Concentration Factor (SCF), Balanced Axial Loading