Seismic assessment and retrofit of historical masonry barrel vaults

Recent earthquakes in Italy highlighted the extreme vulnerability of historical buildings. Masonry vaults, which represent artistic valuable elements, have been recognised as the most vulnerable elements of such buildings. Therefore, the knowledge of their seismic performances, as well as potential retrofit techniques, meets the need to protect cultural heritage buildings which are prone to natural hazards. Vault dynamic behaviour is generally studied according to simplified methods or, as an alternative, to complex Finite Element (FE) analyses. However, a deep knowledge of their dynamic behaviour is still lacking from an experimental point of view. In order to investigate the seismic behaviour of masonry vaults, shaking table tests have been performed of a full scale masonry barrel vault. After the tests, the vault has been retrofitted by means of mortar joint repointing, grout injections and Inorganic Matrix FRP Grid (IMG). Then shaking table tests have been performed on the retrofitted vault. By means of the experimental tests outcomes, reliable numerical models able to predict the dynamic behaviour of the masonry vault (before and after the retrofit) have been developed. This aspect is relevant for studying characteristics which cannot be investigated by means of the experimental test monitoring. In this thesis a comprehensive overview of the main results of the experimental tests is reported. The unreinforced vault exhibits a good seismic behaviour, showing very slight damage up to a horizontal acceleration of about 4.8 m/s2 (measured at the keystone location). The retrofit resulted in a significant increase of both stiffness and capacity. Indeed, very slight damages only after the last test (performed with an achieved PGA of 11.70 m/s2) were detected on the retrofitted vault. However the retrofit did not drastically change the global dynamic behaviour of the vault.