Damage models for the seismic analysis of masonry structures

The in-plane modeling of shear walls of masonry buildings subjected to earthquake motions is considered. Stiffness degradation, peak load, strain softening, hysteretic dissipation, influence of the compressive stress are taken into account by considering structural models defined at different level of detail. At first, a damage model for the mortar-brick joint is considered, and implemented in a detailed finite element model for simple shape walls. A further approach, characterized by an intermediate level of detail, is based on a continuum model, with constitutive equations obtained by a homogenization procedure of brick and mortar layers undergoing damage and frictional contact. Finally, a coarse model based on macroelements, representative of the piers and of the spandrels, is considered, that allows to model three-dimensional structures by introducing a reduced number of d.o.f.s and elements. Some example are considered in order to show the capabilities of the proposed models.