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To estimate the fatigue life of connections in structures which are under cyclic loads, Stress Concentration Factors (SCF) are required. Few researches exist in the literature for multiplanar connections made up of rectangular hollow sections (RI-IS). Therefore, in the absence of such reliable results, existing relevant planar
formulations are being used in fatigue life evaluations. which are mostly uneconomicaL In this paper the connection is modeled using finite element method in three dimensional fi'ame and clements: thc selected mesh density and details are verified against existing experiments in planar connections. The effect of out-ofplane braces into the SCF of XX and TT multiplanar RHS is studied using the similar model extended to contain the out of plane members, The effect of various geometrical parameters on SCF of XX & TT type connections are compared with conventional formulas and discussed via figures: the resulting stress contours are also presented for each case study.