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• Very few experiments have investigated the orthotropic shear strength of masonry. • Laboratory tests are presented about three shear collapse mechanisms. • A detailed 3D FEM has been implemented to approximate the non linear responses. In this paper the problem of evaluation of the structural response of 1.20 m × 1.20 m blockwork masonry panels under monotonic shear and diagonal-compression tests is investigated. The digital image correlation technique was used to detect the initiation and propagation of damage. The experimental findings were analyzed and simulated also by means of accurate finite element non-linear analyses. The results revealed the non-isotropic shear response of the masonry panels, which is related to the meso-scale structure. The shear response along the two principal directions, when investigated by a test configuration which recall the Iosipescu method, proved to be quite different, being the shear strength parallel to the bed joints mainly dependent on the mortar properties, while the shear strength perpendicular to the bed joints is affected by the bond pattern. The standard diagonal compression tests, on the other hand, showed an intermediate response, even if the orthotropy of shear response could not be explicitly manifest. [ABSTRACT FROM AUTHOR]

Abstract: 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. [Copyright &y& Elsevier]

Abstract: The seismic analysis of a large monument subjected to strong earthquakes is the object of the present paper. As a case study, the response of the “Maniace Castle” of Syracuse has been investigated by a multi-level approach which adopts traditional finite element modelling as well as a specific mechanistic computational model for the final non-linear seismic analyses. At first, the linear behaviour of the monument was studied by means of two 3D FE models in order to understand the global response of the building, its points of weakness, and the kinematics of the corresponding collapse mechanisms. Then, these results were used to calibrate a mechanistic 2D plane rigid body and spring model, RBSM, specifically formulated with the aim of approximating the macroscopic behaviour of masonry walls with reduced degrees of freedom, and taking into account the influence of the masonry texture and energy dissipation capacity of the material. Given the uncertainties and the variability of the material characteristics, an extensive parametric non-linear static analysis and the dynamic analyses, with artificial and natural accelerograms, were made in accord with the EC8 seismic code, and compared together. These results were then used to formulate and verify a simple proposal for the restoration design. [Copyright &y& Elsevier]

The development of artillery in Europe at the end of the Middle Ages brought a necessary change in military architecture. This change was a radical rethinking of the entire geometry and architectural design of city walls which required an increase in thickness to resist repeated artillery strikes. The damage due to the impact loads on Middle Age fortification walls is analyzed herein with explicit dynamic analyses. This study was developed both with finite element models and an innovative rigid body-spring model with diagonal springs (RBSM), showing the different peculiarities of these two different approaches and how their results can be integrated. The numerical models clearly showed that the presence of an inner core of softer material tends to modify the impact effects by reducing the degree of damage at the expense of an extension of the damaged area. [ABSTRACT FROM AUTHOR]