Evaluation of structures affected by Alkali-Silica reaction (ASR) using homogenized modelling of reinforced concrete

Abstract

The computation of large reinforced concrete structures such as nuclear power plants, dams and bridges requires realistic behaviour laws to be considered for concrete and reinforcements. Regarding the problem of cracking in RC structure, meshing separately concrete and rebars is the classical way to perform a nonlinear finite element analysis. However, when the structures have to be studied at full scale, the explicit meshing of rebars becomes so heavy that the computing time reaches values incompatible with engineering applications. The method proposed in this paper consists of using large finite elements considering reinforcement and concrete as a homogenized material. In comparison to the mesh reinforcement approach, this one limits the number of finite elements and returns to a computation compatible with engineering. The particularity of the proposed model resides in its ability to treat interaction between rebars and concrete affected by the Alkali-Silica Reaction (ASR). The model is able to predict the anisotropic swelling induced by the combination of homogenized rebars and external loadings. An application to a well-documented laboratory test for reinforced concrete beams shows the ability of the model to assess residual strength capacity of the beam after a long period of ageing in a natural environment. A parametric study of the size of the finite elements confirms the possibility of using a coarse mesh without loss of the model’s predictive capability.