ABOUT STRESS STATE HETEROGENEITY OF WELDED JOINTS OF OFFSHORE PLATFORM SUBSTRUCTURES This article discusses the welded joints of offshore platforms, their mechanical properties and the way these properties change in the course of experiments. <...> The paper explains the reasons for altering the stress state of the weld metal and the base metal, the appropriate calculations are given. <...> The areas of welded connection, which are subjected to the maximum stress, are identified experimentally. <...> Currently strength calculation of the welded joints stress state of fixed offshore platforms’ substructures is carried out by formulas: [1, 2, 3]. τ – stresses in welded joints when vectors of force and torque acting perpendicular In case of collinear vectors: N zf k L f 6 zf k L M N f Where МN – torque on the total load of action, N- resultant of forces, L- seam length, kfz – weld leg, βzf- coefficient depending on the type of welding [4] Thus, initially it is assumed that stress in the tubular welded joint of fixed offshore platform’s substructure is distributed evenly over the seam. <...> During the experiments of studying the fatigue life of the welded joints it was noticed that the primary degradation always starts in a certain area, at a point in the plane formed by the casing and branch. <...> This suggested that while the bending under load areas of stress in welded joints occur unevenly. <...> Research of the stress state in the area showed that the maximum stress has effect at the points №1 and №5 (see. <...> Schematic diagram of load on the welded joint There is a different view of the stress state of welded joints in foreign regulatory documentary (schematic on Figure 1and Figure 2) and the rated voltage are determined by the conditions [5, 6]: (1) Where: α- coefficient depending on the class of compounds in the range from 0.72 to 0.9 depending on the connection type. <...> In this case, the maximum shear stress at the site is situated at an angle 450, and the value of maximum shear stress determined by the formula: (3) Fig. 3a and 3b. <...> The schematic diagram of stress state and position of a crack 205 Актуальные проблемы современной науки, № 2, 2017 Calculations (compound pipe diameter 114x114mm) for the bending action in the plane <...>