SIMULATION OF THE OUT-OF-PLANE BEHAVIOUR OF URM WALLS BY MEANS OF DISCRETE MACRO-ELEMENT METHOD

The seismic response of masonry structures without box-type behaviour is given by
a complex interaction between in-plane and out-of-plane behaviours. Previous earthquakes
demonstrated that out-of-plane failure mechanisms represent the main cause of structural
collapses of UnReinforced Masonry (URM) and historical structures. Previous experimental
and analytical studies, investigating the out-of-plane behaviour of URM structures, mostly
considered the effects of one-way bending moment. In this regard, recent experimental
campaigns and numerical simulations have been conducted in order to investigate the out-ofplane
behaviour of masonry walls subjected to two-way bending. These investigations have
demonstrated the complexity of this mechanism and stressed the need for accurate numerical
tools capable of providing reliable predictions in terms of ultimate strength and failure
mechanisms. This paper focuses on the assessment of the dynamic behaviour of a U-shape URM
prototype, subjected to shaking table tests, by means of a simplified computational strategy
denoted as Discrete Macro-Element Method (DMEM). In this investigation, a comparison
between experimental and numerical results was conducted in order to validate the capabilities
of the proposed modelling approach. Subsequently, a parametric analysis was carried aiming
at determining the influence that masonry mechanical properties, and additional model
parameters, have on the out-of-plane nonlinear dynamic response of URM masonry structures.