Nonlinear simulation of masonry vaults under earthquake loading

Masonry vaults are present in a large number of historical structures and often used as flooring and roofing systems in monumental palaces and religious buildings, typically incorporating no backfill. Many of these structures are located in seismic regions and have been shown to be particularly vulnerable during recent earthquakes, with a need for accurate modelling to avoid future losses. Masonry vaults are often analysed using limit analysis procedures under the hypotheses of no-tension material and absence of sliding along the masonry joints. However, this method can be inaccurate for barrel vaults found in buildings, which are typically slender with no backfill. In this case, the masonry tensile strength and the progressive damage propagation play an important role in the nonlinear behaviour and ultimate strength of the vault. In this study, a detailed mesoscale finite element mesoscale approach is used to model slender unreinforced barrel vaults subjected to cyclic quasi-static and dynamic loading. According to this approach, 3D solid elements connected by 2D damage-plasticity interfaces are used to represent the arrangement of bricks and mortar present in the masonry. The proposed numerical description is first validated against the results from physical tests on a barrel vault under quasi-static cyclic loading. Subsequently, the shear response of a prototype vault is analysed by performing nonlinear simulations under prescribed horizontal displacements at the supports, considering also the influence of previous damage induced by earthquakes with different magnitudes.