DEM modelling of masonry vaults: influence of brick pattern and infill on stability during supports displacements

The paper proposes a discrete element method to study both the effects of brick pattern and infill on the stability of masonry vaults subjected to settlements of the supports. The open-source multi-physics simulation engine ProjectChrono - ChronoEngine, which is an open source C++ library based on a regularized non-smooth contact dynamics approach, was used to model the vaults. In particular, the voussoirs of the vault were modelled with rigid blocks reproducing the brick pattern, whereas the infill was modelled by means of thousands of rigid spheres. Initially, the parameters of the model were calibrated by means of experimental results on three types of vaults (barrel, cross, pavilion) with different brick patterns. Then, a barrel vault was investigated considering six brick patterns, suggested in ancient treatises, and the presence of the infill. Results show that the brick pattern, thanks to interlocking and friction between blocks, provides an equivalent tensile strength of masonry, which affects the behavior of the vault in terms of failure mode and failure load/settlement. Furthermore, the infill causes additional compression, which affects the thrust net configuration and, consequently, the stability of the vault.