Approximation Models of the Method of Design Resistance of Reinforced Concrete for Bending Elements with Double and Multirow Reinforcement

Abstract

Approximation models of the method of design resistance of reinforced concrete were considered for the calculation of normal sections of reinforced concrete bending elements with double and multirow reinforcement. It is proposed to use approximation dependences of two types—polynomial and linear. Approximation models were developed based on the method of design resistance of the reinforced concrete, which is based on generally accepted theoretically proved assumptions and hypotheses. This method is based on the use of nonlinear diagrams of concrete deformation, acception of the Bernoulli hypothesis, and the usage of the extreme criterion for determining the bearing capacity based on the nonlinear deformation model of calculation. The proposed approximation formulas can greatly simplify the calculation of reinforced concrete bending elements with double and multi-row reinforcement. They eliminate the need for the usage of tables and the performance of complex calculations with iterative methods, as is the case with most existing deformation models. The results of calculations indicate sufficient accuracy for practical calculations of the proposed methods. The authors considered the examples of determining the bearing capacity and area of working reinforcement of normal cross-sections of bending elements from reinforced concrete in double and multi-row reinforcement. The proposed methods of calculation of bending elements, made of reinforced concrete, can be widely used in design practice.