Modeling the behaviour of statically indeterminate reinforced concrete structures under load

Abstract

One of the main differences of reinforced concrete is the possibility of cracking in concrete, which leads to a significant change in stiffness along the length of the element with cracks. The current state of the issue of the analysis of reinforced concrete elements is characterized by the widespread use of complex mathematical models and computational tools based largely on empirical and semi-empirical approaches to the analysis of the operation of reinforced concrete with cracks (deformation design model of the cross section based on concrete and reinforcement deformation diagrams, block model based on the dependences of the adhesion of reinforcement to concrete and the finite element method for calculating internal forces). So, the deformation design model of a flat section is used to calculate the moment of cracking and the strength of the element; block model of reinforced concrete between cracks – to calculate the opening width and crack pitch; structural mechanics methods (including the finite element method) for calculating internal forces and deflections. Using these approaches in the calculations of the stress-strain state of reinforced concrete elements (successively, moving from one method to another), the accumulation of calculation errors invariably occurs, since the parameters of the reinforced concrete structure calculated using different approaches have a mutual influence on each other. The purpose of this work is to attempt to combine these approaches for calculating the stress-strain state of reinforced concrete elements at all stages of work within the framework of a single calculation model, avoiding, if possible, the use of empirical relationships between them. On the example of a continuous two-span reinforced concrete beam, the authors analyzed the proposed calculation model and obtained satisfactory results of convergence with experimental data