OPTIMUM REINFORCEMENT AND SIZING OF CONCRETE CROSS SECTIONS SUBJECTED TO FLEXURAL AND AXIAL LOADING

Abstract

Although the cross-section optimization problem has been sufficiently studied in the past, a disadvantage persists regarding the programming complexity, with the need to use methods which are not straightforward for the structural engineer in his/her routine work and require excessive computing time. This contribution aims not so much as to obtain the dimensions of the section and the required reinforcement, which have already been solved, but to provide an automated design procedure for calculating the optimum dimensions and reinforcement. A simple optimization method has been programmed in a MATLAB® routine that is attached in the Appendix of this paper. Conventional-strength or high-strength concrete may be chosen, the minimum reinforcement area may be considered selecting the ACI 318 or Eurocode 2 standards, and the neutral axis depth may be constrained in order to guarantee a certain cross-sectional ductility. Therefore, the interest of the proposal is focused on providing an automated procedure for optimizing the dimensions and reinforcement of a concrete cross-section, together with the corresponding calculation routine, in which the structural engineer may include certain design conditions. Three examples are presented and comparisons between the results from different methods and standards are drawn. Keywords: optimization, automated design, reinforced concrete, cross section dimensioning, flexural/axial loading