The effects of in-plane shear displacements at the springings of Gothic cross vaults

Abstract

Extensive damages recorded during recent strong Italian earthquakes highlighted how vulnerable masonry vaults are and what deformations they receive from the rest of the building, which can be simulated as two phenomena: (i) a dynamic response of the vault itself, above the lateral walls and piers, and (ii) a pseudo-static response of the vault to imposed displacements at its springings, triggered by significant movement from the lateral walls and piers. This paper aims at improving knowledge in this field by simulating the first of these phenomena as static shear deformation at the springings. An experimental programme was set on a model of a typical quadripartite square Gothic cross vault (from the aisle of the Holyrood Abbey in Edinburgh). The test on a 1:4 scaled model had the shear displacement applied by moving two abutments in the longitudinal sense until failure, recording the crack pattern evolution and displacements of the ridges, identifying the diagonal cracks normal to the shear displacement that cause the damage and collapse in the vault. The crack pattern was validated with linear and non-linear numerical models, confirming particular observations like the uplift of the ridges and concentration of damage along the notional shear diagonal. Non-linear models are capable of capturing not only the crack pattern evolution, but also the vertical and horizontal displacements of the structure.

Seismic response of a small-scale masonry cross vault: Experimental investigation by performing quasi-static and shake table tests

“…Even though the target failure mechanism was the one related to the shear failure, the vault collapsed at 0.4 g, due to the activation of an out-of-plane mechanism that led to the development of the typical four-hinge mechanism. Carfagnini (2018) and Baraccani (2020) performed also important works on this topic. They tested a 1:4 scaled specimen of a Gothic cross vault, subjected to shear deformation at two of its springings.…”

“…The rst one is to evaluate the three-dimensional damage and collapse mechanism of masonry cross vaults subjected to in-plane shear forces caused by the seismic action. In-plane shear is a common type of failure that occurs during an earthquake as it was widely observed during post-earthquake surveys (Arcidiacono et al 2016;Carfagnini et al 2018;Borri, Corradi, and Vignoli 2002).…”

Historic Barrel Vaults Undergoing Differential Settlements

“…Then, PVA glue and water were added. This mixture was used in previous experiments involving cross vaults [31] and it has been found to be convenient for construction reasons [27].…”

Experimental test on a fibre-reinforced scaled cross vault subjected to in-plane shear displacements at the springings

“…This leads to a strong difference in the lateral stiffness of the supporting structures (walls, piers, columns) that, during an earthquake, may cause significant global shear action on the whole vault. The pseudo-static response of the vault induced by these imposed shear displacements at its springings often represents the predominant cause of damage/failure, overshadowing the dynamic response of the vault itself [8].…”