Longitudinal reinforced concrete elements stiffness exhaustion, often used in building practice, precedes obtaining bearing capacity, and therefore deflections determination becomes a determining factor in their design. In connection with it precise methods for determining such reinforced concrete elements deflections become especially relevant. The elastic-plastic properties of concrete and cracks in the stretched zone of reinforced concrete elements lead to a significant change in their bending stiffness. That is why the deflections determined by the materials classical resistance formulas differ significantly from the real ones. A large quantity of methods for determining deflections is based on the elastic characteristics correction of reinforced concrete elements consolidated section. Such methods, although providing calculation satisfactory results, are rather approximate and have empirical nature, due to it they have limited application. More precise calculation methods consist of curvature usage to determine deflections. The curvature of reinforced concrete elements cross sections is determined directly from the equilibrium equations, which are written taking into account nonlinear materials deformation diagrams. Calculation examples for bending reinforced concrete elements deflection are given.

The present article is concerned with basic methods of reinforcement of continuous reinforced-concrete beam constructions. The main disadvantages and difficulties in strengthening such load carrying structures have been identified in this academic paper. There has been offered the method of reinforcement of continuous reinforced-concrete beam constructions. Besides, the authors have established the procedure of designing effective continuous reinforced-concrete beams in case of the reinforcement. The basic principle of enforcement of continuous reinforced-concrete beams is proposed in this exploratory development. This principle lies in the fact that it is necessary to find the desired span stiffness of continuous reinforced-concrete beam constructions, which would provide sufficient reinforcement in the reference section of the beams. In this case, there is no need to strengthen reference sections, which is practically impossible to do in most instances without dismantlement of the existing concrete floor slabs. For reinforcement systems designing, it is proposed to use the method of design resistance of reinforced concrete, which uses theoretically, and experimentally confirmed prerequisites and hypotheses. The calculations are made by the iteration method. There has been provided a calculation example of enforcement of continuous reinforced-concrete beam constructions using the proposed method.

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