Dimensioning of longitudinal reinforcements in concrete beams with a non-rectangular section and variable height

Abstract

Lately, structural typologies of agricultural infrastructures have undergone significant changes. These have been especially important in the case of farm buildings where reinforced concrete structures are the most commonly used. In order to make precast concrete items which are interesting because of their cost, it is necessary to optimize their design and implement accurate calculation procedures. This paper presents a methodology to calculate longitudinal reinforcements in reinforced concrete (RC) beams with non-rectangular sections and a variable height along the main direction of the beam. This method has been developed taking into account the interaction diagrams of the different sections in which the beam has been previously split. Checks included considering the contribution of all the reinforcements in a section, including the support reinforcements. For each section, the different combinations of resistant axial force and bending moment were estimated, i.e. their interaction diagram was drawn. Once the axial force of the studied beam was known, the bending moment of each section was calculated. These values were then integrated for the whole beam and the maximum moment diagram was represented. By repeating the whole process for different reinforcements, the optimal reinforcement could be determined for each loading situation in the beam. A software tool has been developed so this methodology can be easily performed and design of the RC beams optimized.