Lattice discrete modeling of out-of-plane behavior of irregular masonry

Stone masonry buildings are known to be highly vulnerable to seismic actions. In this context, the analysis of the out-of-plane response of unreinforced masonry structures is crucial. For this purpose, the Lattice Discrete Particle Model (LDPM) was employed to simulate the mechanical behavior of stone masonries up to their failure. Unlike commonly used continuum-based methods or simplified analytical models, that are often limited in modeling correctly complex failure mechanisms, LDPM is able to capture accurately crack distributions and failure patterns. LDPM describes the masonry at the scale of stones and takes into account their interactions through tailored constitutive equations for tensile, compressive, shear, and frictional behaviors. First, LDPM was validated against experimental results on masonry panels subjected to out-of-plane loading. Next, the vertical bending mechanism was studied in the cases of one- and two-story walls with and without openings. Finally, more complex mechanisms were considered where the damage evolution and the fracture propagation were analyzed for a set of panels assumed to be placed within the continuity of a facade. The overall results presented in this paper show that LDPM can realistically predict the collapse mechanisms associated with out-of-plane loading for different structural configurations and geometries.