An enriched and phenomenologically sound multilaminate model for masonry: JMM-E

Masonry is a composite material, whose structural response is strongly influenced by its internal structure: the organised or random arrangement of units and mortar joints in a periodic pattern. A distinctive feature of its constitutive behaviour, in case of organised texture, is anisotropy. In the context of multilaminate constitutive formulations, this paper proposes an enriched version of the Jointed Masonry Model (JMM). Holding the same fundamental hypotheses of elastic-perfectly plastic behaviour of its predecessor, the updated model entails a phenomenological approach, which accounts for possible failure mechanisms at the macroscopic scale and, accordingly, defines the yield domains on preferred, fixed orientations. The paper presents the mathematical formulation of the enhanced model (JMM-E), its response in case of specific stress conditions for a representative volume, and its validation against well documented experimental tests. The model is implemented in a finite element software and features a relatively simple calibration, on which a detailed discussion is presented, also providing standard references in case of both existing and new constructions.