In-Plane Seismic Response of Masonry Walls through a Hybrid Continuum-Discrete Multiscale Model

Nonlinear static and dynamic analyses of walls through a multiscale numerical model for the in-plane mechanical behavior of masonry are presented. At the microscale, masonry is modelled by rigid blocks interacting through plane nonlinear deformable interfaces. These may represent actual mortar joints or virtual preferential fracture surfaces of the blocks (e.g., vertical surfaces crossing a block and connecting vertical joints in the brick rows above and below the considered one). Damage parameters control the interface transitions from a cohesive linear-elastic phase to an elastic-plastic one (modelling frictional sliding and contact) and then to a completely damaged one. At the panel scale, the material is treated as a finite-element discretized Cauchy continuum, homogenizing the periodic microstructure. The model allows reproducing the main anisotropic nonlinear behaviors of masonry by standard finite element simulations at a reasonable computational cost. With respect to more traditional phenomenological nonlinear models, a more direct use of experimental data for the quantification of the model parameters is possible. Moreover, these parameters are fewer in number, since part of the complexity of the material is represented in the explicitly modelled microstructural geometry. Some examples on masonry walls and triumph-arches are used to show the feature of the model.