Polynomial approximations to the parabola-rectangle method

Abstract

The article puts forward the formulation of flexure reinforcement in rectangular sections according to the parabola-rectangle model, obtains mass development and discusses the precision obtained by polynomial formulations of varios orders. Said formulation allows the author to ponder the different effects of each variable included in the original formulation. He reaches the conclusion that a first order approximation is sufficiently precise in practical use, an interesting physical interpretation, and notable simplicity, not having any variable difficult to estimate in real cases. The study is extended to the case of compressive reinforcement. Here it is found that the same formulation allows the case to be solved. For T-sections, the author concludes that the simplified expression is too conservative, and suggests corrections in it.