The Effect of the Vertical Component of Ground Motion on a Masonry Cross Vault Model

Recent earthquakes have emphasized the high vulnerability of vaulted structures. Their collapse may entail only local damage or can affect the surrounding building because of its heavy mass and the significant horizontal thrust on supporting elements. In this paper, the influence of the vertical component of ground motion on the performance of a numerical model of an unreinforced masonry cross vault is investigated using sets of one-component and two-component ground motions to perform nonlinear dynamic analyses. The set of motions represents the actual seismicity of L’Aquila, Italy, while the investigated vault mimics a reference brickwork specimen. The numerical model falls within the mixed finite–discrete element method and accounts for crack formation, complete separation and new contact formation. The modelling strategy is capable to evaluate the ultimate displacement and load-bearing capacity of the vault under seismic loading and the progressive deformation of the vault up to collapse. The vault is excited by a horizontal component alone or by both horizontal and vertical components. Although without a systematic trend, adding the vertical component worsens the response in about 10% of cases.