Pre-damaging test of a full-scale masonry cross vault subjected to in-plane cyclic shear loading: main results and design of the FRCM-based strengthening intervention

An extensive experimental campaign has been started within the frame of the project REVHEAL (Structural Rehabilitation of Vaults in Heritage Asset Learning), funded by the Italian PRIN 2022 PNRR research program, to investigate the behavior of masonry cross vaults subjected to in-plane shear resulting from seismic actions. A full-scale cross vault was constructed in the laboratory “P. Pisa” of the University of Brescia, where a test rig was built to replicate seismic effects through quasi-static reverse cyclic displacements applied at two moving abutments. The vault, representative of heritage constructions, features arches on three sides and a perimeter wall on the fourth. The experiment investigates structural behavior before and after retrofitting with a Fiber Reinforced Cementitious Matrix (FRCM) system, consisting of a basalt fiber mesh applied exclusively to the vault’s extrados. The study emphasizes the integration of Geomatics and Structural Engineering to create reality-based models that account for typically neglected aspects in historic masonry analysis, such as deformed geometry and block arrangement. This paper reports on the first research phase, focusing on loading cycles designed to simulate severe pre-damage conditions typical of a structure approaching ultimate capacity. Results from the cyclic test are discussed in terms of strength, damage progression, and displacement capacity. An extensive 3D metric survey campaign supported the structural tests, producing dense point clouds with RGB data from LiDAR and photogrammetry. Additional topographic measurements ensured model accuracy and provided high-quality reference data for future comparisons.