3D Heterogeneous Finite Element Analysis of a Masonry Cloister Vault in the Former Monastery of Santa Maria della Pace in Piacenza (Italy)

This paper presents a nonlinear finite element analysis of a cloister vault located in the former monastery of Santa Maria della Pace in Piacenza (Italy). The vault, supporting a longitudinal wall and the roofing system at its midspan, is studied through a heterogeneous approach. The structure is modelled in three dimensions and discretised with elastic macroblocks connected by nonlinear mortar joints. The joint material is assigned a Mohr-Coulomb failure criterion and sensitivity analyses are run to find the dependency of the result on the cohesion value. Non-liner static analyses are carried out by increasing the self-weight of the vault and the superimposed structures to test the ultimate capacity of the vault. This procedure is done both including and excluding the backfill to evaluate its effect on the stability and the collapse mechanism. A key aspect of this contribution is the identification of plastic hinges through the quantity of energy dissipated by the nonlinear joints. Results confirm that backfill plays a determining role in enhancing the structural capacity, especially under the no-tension material assumption. The three-dimensional modelling enables to consider the influence of a bond pattern. Compared to a stacked bond, the running bond configuration shows improved ultimate capacity and a realistic distribution of stress.