Effects of the dilatancy of joints and of the size of the building blocks on the mechanical behavior of masonry structures

The effect of the dilatancy of masonry interfaces and of the size of the building blocks on the strength of masonry structures is quantified herein. The study focuses mainly on out-of-plane loadings, which can appear due to various factors such as wind, earthquakes or explosions. The analysis is performed using the Discrete Element Method (DEM), which allows to access directly various micro-mechanical parameters, such as the joints dilatancy angle and the size of the building blocks. Detailed DEM numerical models of existing experimental configurations are presented. The numerical results are first compared and validated towards the experimental observations and then they are used to derive qualitative and quantitative conclusions regarding the effects of joints dilatancy and blocks size. It is shown that dilatancy plays an important role on the overall strength of masonry even under low confinement. The size of the blocks is also an important parameter that needs to be considered in the modeling of masonry structures.