Numerical Estimation of Crack Openings in Concrete Structures Under Multi-physic Loadings

Cement based material structures are designed to work in pair with steel reinforcement. The cracking of reinforced concrete is a normal phenomenon given the working principle of this material. But, for aesthetic or durability reasons, the openings of these cracks must be controlled. In the modelling, there is often an ambiguity between damage (micro-cracking at the scale of a REV) and crack opening at the scale of the material. The goal of this study is to estimate the crack opening in concrete structures under various multi-physic loadings. To do so, a method based on continuum mechanics is developed. This method post-processes the mechanical damage induced by the diverse loadings. To illustrate the procedure, a numerical application is run on an experimental reinforced shear wall made of ordinary concrete submitted to drying prior to loading. A hygro-mechanical model previously developed by the authors is firstly calibrated on experimental data and secondly used to compute the shear wall's damage induced by drying shrinkage. The resulting computed crack openings are compared to the experimental results. Interestingly, the post-processing technique managed to locate the areas where cracks are of major importance. However, the assumption of perfect adhesion between concrete and steel leads to a slight underestimation of the amplitude of the crack opening. In a first attempt to capture cracks, the proposed method based on continuum mechanics seems to be a good alternative to sophisticated methods.