In this paper, numerical investigations are performed to investigate the potential of
the discrete macro-element coupled with the mesoscale approach for the seismic assessment
of unreinforced masonry structures. At first, parametric analyses are performed on a U-shape
masonry prototype made with stone. Nonlinear static analyses are performed to investigate
parameters that affect the results when a mesoscale masonry pattern representation is adopted.
Results demonstrate how mesoscale representation is a powerful alternative to model
unreinforced masonry structures within a discrete macro-element approach and highlight how
irregularity of units can affect the structural response leading to a reduction in terms of
strength and ductility if compared to the regular and periodic distribution of masonry units.