In plane loaded masonry walls: DEM & FEM/DEM models. A critical review

This work is dedicated to the assessment of the nonlinear behaviour of masonry panels with regular texture and subject to in-plane loads, by means of numerical pushover analysis and an analytical homogenized model. Two numerical models are considered and adopted for performing a set of numerical tests: a Discrete Model (DEM) developed by authors and a Discrete/Finite Element Model (FEM/DEM) frequently adopted in rock mechanics field and effectively extended to masonry structures. In both models the hypotheses of rigid blocks and elastic-plastic joints following a Mohr-Coulomb yield criterion are adopted. The aim of this work is twofold: i) a comparison and a calibration of the numerical models, evaluating their effectiveness in determining ultimate loads and collapse mechanisms of masonry panels, by assuming a nonlinear homogenized model for regular masonry as reference solution; ii) the evaluation of sensitivity of masonry behaviour and numerical models to panel dimension ratio and to varying masonry texture. Sliding collapse mechanisms changing to overturning collapse mechanisms for increasing panel and block height-to-width ratio are obtained and the results obtained with the numerical models turn out to be in good agreement.