Some aspects of modeling nonlinear behaviour of reinforced concrete

Abstract

The paper deals with some aspects of modelling the structures’ behaviour: the ‘engineering nonlinearity’ method; determining stresses on the basis of nonlinear dependences ‘stress-strain’. The ‘engineering nonlinearity’ method enables you to indirectly consider physical nonlinearity while computing by the standard method. The ‘engineering nonlinearity’ method enables you to consider physically nonlinear behavior of reinforced concrete section by iteration and step-type method. The method makes it possible to determine the stiffness parameters of the section. These parameters may be reduced because of the crack propagation, plastic strain in concrete and reinforcement. Concept of the method is described. Suggested method ‘engineering nonlinearity’ enables the user to consider stiffness distribution more accurately. This method is almost similar to standard methods of linear analysis, that is, it is possible to carry out analysis on all types of loads, compose DCF and DCL, analyse reinforcement. Comparison study for peculiar features of ‘Engineering nonlinearity’ method is performed. Analysis results for the test problem (based on engineering nonlinearity) are provided. Analysis results for the test problem shows some redistribution of forces and convergence of results obtained in ‘engineering nonlinearity’ method and in analysis with account of physical nonlinearity. This approach makes it possible to use the ‘engineering nonlinearity’ method for computing and modelling the erection process, analysis of panel buildings (platform joints), etc. The ‘Cross-section Design Toolkit’ module supports nonlinear analysis for a certain set of forces. The proposed methods for modelling and analysis of structures with account of their life cycle enable us to find out dangerous tendencies at the design, erection and further maintenance stage of the structure and to prevent the possible destruction both for separate structural elements and the object as a whole.