Numerical Investigation About the Orthotropic Shear Strength of a Periodic Masonry Arrangement

The non-symmetric shear response of masonry is a consequence of the orthotropic bonding in typical masonry blocks arrangement, and more specifically because the horizontal mortar layers are continuous while the vertical joints are stepped. Few studies deal with the non-symmetric shear response and include it within computational models dedicated to the calculation of masonry under loading conditions that mainly leads to shear damage [1]. In this paper, we analyze the shear response of a masonry panel with a periodic arrangement through an enriched rigid-body-spring-model (RBSM) approach. The adopted model consists of an assemblage of “Heuristic Molecules” made by four “atoms” (or rigid elements) of quadrilateral shape interacting with each other through elastic-plastic springs. Each rigid element interacts through two eccentric axial and shear springs on each side, while line spring-bonds are added along the diagonal direction to connect the rigid atoms having a contact in the vertex [2]. A set of tests [3] carried out on square masonry panels according to the standard diagonal compression test and the so-called “Iosipescu method” are regarded as benchmarks for the numerical modelling of the orthotropic shear response. The results obtained have shown a good correspondence with the damage patterns of the experiments on real panels, demonstrating that an appropriate strategy in the definition of discrete topology and the constitutive bonds produces an excellent and effective mechanical model even using very few degrees of freedom.