Non-linear physical relations for reinforced concrete elements under long-term loading

Abstract

The paper presents a method for modelling material non-linearity for use in the analysis of load-carrying capacity and deformations of reinforced concrete beams, columns and membrane-bending plates subjected to long-term loads. Physical relationships expressing relations between internal forces and stresses, strains and stiffness are derived on the basis of the fracture and creep theories for concrete and using non-linear stress-strain diagrams modified for time effects. A specific implementation technique of a genetic algorithm is developed to find multiple solutions to non-smooth problems under consideration. The computation technique proposed is found to be effective in numerical examples, and an adequate accuracy of the analysis is verified by comparison with experimental data.