Economic efficiency of the CBEBS (composite bearing element of building structures) construction is achieved through the multipurpose usage of a strengthening element, which provides reliable adhesion between a steel supporting sheet and concrete, sustains a lateral load along durability of oblique sections, provides inflexibility during concrete mix feeding, sustains stretching and compressing forces along the durability sections to longitudinal axes of the element. At the expense of the strengthening element performance, the authors specified calculation methods for durability of normal (elastoplastic model) and oblique sections to longitudinal axes of the element (deformative model). There were offered dependencies to define bending rigidity with a different location of the wave of the strengthening element. There were validated geometrical sizes of the welded framework of the CBEBS reinforced concrete bending element. Besides, the authors came up with regression dependencies to define geometrical sizes for different fastening schemes. The paper presents a developed method to carry out experimental research on the CBEBS braced bending element. We have obtained data about bearing capacity, nature of the limiting state, the stress – strain state of the examined samples. The data that have been obtained can be used to design similar constructions.