Welded tubular joints are used in a wide range of onshore and offshore structures. However, insufficient information is available for the design of multiplanar connections between them. Stress Concentration Factors (SCF) should be applied to assess fatigue life of tubular connections that is necessary to indicate fatigue life of offshore jacket structures. Most researches have concentrated on uni-planar connections and there is not wholly accepted way to evaluate multiplanar connections. In practice, the latter is designed by considering them in separate planes, and calculating the least fatigue life. Neglecting the effect of out-of-plane bracing members on the overall behavior might provide conservative results. Using a three dimensional finite element modeling, a numerical research has been carried out to increase the insight into the static behavior of multiplanar joints. The paper aims at discussing above mentioned difference in SCF for multi- planar connections should are they designed as uni-planar for two common types of tubular connections; i.e. TT and XX; the validity of the common practice and the affecting factors in office design are also explained.
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