Numerical and experimental evaluation of the anisotropic behavior and boundary condition of a structural concrete

Abstract

In this study, an evaluation of the effect of casting and loading direction as well as the boundary condition at the interface of loading platen and specimen of a structural concrete, is presented. This work allows to measure experimentally, the influence of the boundary conditions created by the loading platen and the concrete specimen. The experimental tests shows that the ratio between the unconfined and confined compressive strength, measured in cube samples, is on average 0.35. Therefore, it is possible to observe that the increase of axial compressive strength due to confinement is high. By utilizing the Lattice Discrete Element Method (LDEM) implemented on Abaqus/Explicit software, a detailed study and analysis is carried out on the influence of the boundary condition on the concrete strength, the influence of the loading direction relative to the casting direction as well as the interaction of these two parameters. To conduct this study, an implementation of LDEM is proposed. With the LDEM simulations it is possible to find the same behavior observed experimentally, both in changing boundary conditions and in the direction of casting and loading. The fracture mechanism found with LDEM predicts that for a Fixed boundary condition, the loading direction is not so significant. However, the effect of the loading direction is maximized when the boundary condition is frictionless. Through the use of LDEM, it is possible to capture the magnitude and the failure mechanism that occurs in this case. The degree of confidence of the results was validated through analysis of variance (ANOVA multiple factors) and a correlation was found.