A simplified homogenization-discrete element model for the non-linear static analysis of masonry walls out-of-plane loaded

The paper is focused on the macro-scale non-linear modeling of regular running bond masonry panels subjected to out-of-plane pushover analysis. The work is the point of convergence of two research lines: (i) one is focused on the development of an original meso-scale technique based on a heuristic homogenization approach for masonry panels; (ii) the other is devoted to the macro-scale modeling of heterogeneous materials by means of a specific rigid body and spring approach, RBSM. The meso-scale technique is based on a simplified kinematics in which each block is supposed to interact with its six neighbors by means of plane interfaces. In this way, the flexural and torsional moment–curvature constitutive relations in the non-linear field are obtained at the sectional level. Finally, the response of the masonry panel is computed at the macro-scale level by means of a mechanistic model, that is made by rigid elements jointed by spherical hinges and non-linear springs in which all the plastic dissipation and the mechanical damages occur. This combined approach entails a drastic reduction of the computational effort because the standard non-linear FE discretization is completely avoided both at a cell and structural level. The paper presents a validation through comparisons of the step-by-step pressure–displacement curves for masonry panels subjected to various geometry, constraints and flexion conditions. The good agreement found between present numerical results and literature data, suggests that the model may be a valuable tool for practitioners involved in the pushover analysis of masonry walls out-of-plane loaded.