Numerical insights on the structural assessment of historical masonry stellar vaults: the case of Santa Maria del Monte in Cagliari

The aim of this paper is to present an in-depth numerical investigation on the statics of historical masonry stellar vaults, a special class of masonry ribbed vaults whose three-dimensional geometry features a star-shaped projection on the horizontal plane. In particular, the mechanical behavior of the masonry stellar vault belonging to the church of Santa Maria del Monte in Cagliari (Italy) is analyzed and illustrated as an especially meaningful case study. This church, which was built during the second half of the sixteenth century, is a beautiful example of Gothic-Catalan style, and its ribbed stellar vault is one of the most representative of this type in the town of Cagliari. The geometric outline of the vault has been obtained through laser scanning techniques and a procedure of reverse engineering. Starting from a three-dimensional representation of its geometry, the ultimate load-bearing capacity of the stellar vault can be accurately estimated through a recently developed, NURBS-based upper-bound limit analysis scheme. A comparison with incremental nonlinear analyses carried out with the commercial finite element code DIANA is presented. Furthermore, the paper also includes a sensitivity study aimed at investigating the role of ribs on the ultimate load-bearing capacity of the structure.