Damage models for the seismic response of brick masonry shear walls. Part I: the mortar joint model and its applications

The response of brick masonry walls to in-plane horizontal cyclic loads analogous to those induced during seismic events is analysed by applying constitutive models which take into account the mechanical behaviour of each component and its interfaces, i.e. decohesion and slipping in the mortar joints and failure in bricks. To this end, a damage model for mortar joints is proposed and then applied in two di¤erent approaches to the analysis of brick masonry walls which are described both in the present paper and in the companion paper.1 The response of the mortar joint model to varying stress and strain is here analysed and applied to the simulation of experimental results from shear tests on mortarÐbrick assemblages. From the description of the mortar joints and assuming brittle constitutive equations for the brick units, a composite model based on a Þnite element approach is here developed and applied to the lateral analysis of rectangular shear walls. Even if this model turns out to be computationally burdensome, it may give information on the inelastic mechanisms and related strains by means of a local description of the element motion. Some simulations of the lateral response of experimented walls under cyclic horizontal actions superimposed on vertical loads are carried out and an interpretation of the inßuence of the wall geometry on the lateral sti¤ness degradation and on the hysteretic energy dissipation is given.