The development of a methodology for calculating the designed strength of an unconventional kingpin-type load-carrying system for the articulated tractor container carrier on pneumatic wheels is an important and relevant task due to the unique layout of a given specialized vehicle. The purpose of this work is to devise a procedure for calculating the designed strength of a clip load-carrying system for the articulated tractor container carrier on pneumatic wheels, aimed at building an improved structure with rational metal consumption. The results of the theoretical and experimental studies have determined the most common estimation cases. They include the movement over the technological roads' irregularities along the horizontal section of the road ‒ an estimation case of the semi-trailer frame girders. climbing a high curb at an angle was also considered as an estimation case for the semi-trailer frame girders and cross member. Starting a tractor container carrier forward with an insurmountable obstacle in front of the semi-trailer's wheels was analyzed as an estimation case for the cross member of the frame and the suspension attachment units in the semi-trailer of a tractor container carrier. The result of the reported theoretical and experimental research is the determined load that acts on one cradle structure of the load-carrying system; it forms the torsional rigidity of the frame structure. Underlying the derived mathematical model for each case are the torsional moments and inertia moments that act on the structural elements of the girder in different planes. The mathematical models have been built on the basis of strength conditions for each estimation case and thus form a mathematical formula for determining the wall thickness of the frame girder. The mathematical notation demonstrates the degree of advantage of climbing a high curb at an angle over other estimation cases for the semitrailer frame member and girders. The estimation parameters underlying the mathematical model are meant to prevent the breaking and torsion of the semi-trailer frame in a tractor container carrier