In plane loaded masonry walls: DEM and 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 developed by authors and a discrete/
finite element model 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: (1) 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;
(2) the evaluation of sensitivity of masonry behaviour and numerical models to panel dimension
ratio and to varying masonry texture. In a first case study, sliding collapse mechanisms changing to
overturning collapse mechanisms for increasing panel and block height-to-width ratio are obtained and the
results given by the numerical models turn out to be in good agreement. Furthermore, a second case study,
dedicated to square panels supported at base ends and vertically loaded, shows different ‘arch mechanisms’
depending on block height-to-width ratio.