Bernoulli Compatibility Truss Model

The bending theory has been used to analyze the behavior of flexural members since the advent of the theory for reinforced concrete more than a century ago. This theory is called as the Bernoulli compatibility truss model. The bending theory is given in the most general terms for the stress-strain relationships of concrete and reinforcement. This chapter presents the practical applications of this theory with various simplifications of the constitutive laws of materials. Bending theory based on Hooke's law is called the linear bending theory. Bending theory based on the nonlinear stress-strain relationship of concrete is called as the nonlinear bending theory. To study the behavior of reinforced concrete beams at ultimate load stage, a nonlinear stress-strain curve of concrete must be assumed. Three types of problems are frequently encountered in the analysis and design of underreinforced beams: analysis, first type of design, and second type of design.