Method for calculating strength, crack resistance and stiffness of reinforced concrete beams reinforced with steel fiber concrete based on a nonlinear deformation model

A very promising way of strengthening reinforced concrete beams looks to be the use of a “jacket” made of steel fiber reinforced concrete for these purposes. There are two good reasons for this: first, in terms of the manufacturing laboriousness, the device of such a “jacket” is comparable to the application of ordinary plaster, and, second, the observed increase in the reinforced beams’ bearing capacity is quite comparable with the use of a steel clip. The literature analysis has shown that the methods for calculating the considered reinforcement method, which would take into account the features of steel fiber concrete as a material, as well as the features of the joint work of the “jacket” with the reinforced beam, does not yet exist. To obtain such a technique, the most suitable, in our opinion, is a numerical diagrammatic method based on the so-called nonlinear deformation model. With its use, a detailed algorithm for calculating the strength, crack resistance and stiffness of reinforced beams has been developed in this article. Comparison of the calculation results with their own experimental data and other authors, the difference in the moment of destruction was 16.46%, for the moment of cracking 9.2%, which indicates the proposed method’s efficiency.