Computer-Aided Dimensioning of Reinforced Concrete Wall and Flat Slab Structures

A new computer-aided procedure for the ultimate load dimensioning of reinforced concrete wall and flat slab structures is presented. The stress distributions for all required load cases are first determined by means of standard finite element linear elastic analysis. Based on these results, the minimum amount of steel for any number of user-defined reinforcement fields is found by applying well-known linearised dimensioning conditions. In order to "rationalise" the distribution of the reinforcement bars and to reduce the amount of steel, self-equilibrating stress states due to arbitrary plastic strains are then introduced. In contrast to standard nonlinear elasto-plastic analysis, these plastic strains are not determined by a step-by-step incremental procedure, but chosen at will, i.e. either manually by the program user or by means of linear programming optimisation techniques. This approach is justified by the classical theory of plasticity which states that self-equilibrating stress distribution does not alter the ultimate load-carrying capacity of a sufficiently ductile, slightly deformed elasto-plastic structure.