Experimental investigation on a full-scale CEB-Masonry cross-vault: Mechanical characterisation, dynamic identification and quasi-static cyclic tests

Cross-vaults are prominent structures in historic architecture worldwide. The performance of these structural components can be significantly compromised under seismic action due to the brittle and anisotropic nature of materials and their complex geometric characteristics. In this regard, accurately characterising their behaviour under cyclic loads - as done in the paper - may contribute to structural safety assessments of these vaults. This research presents the results of a thorough experimental investigation on a full-scale cross vault constructed using an alternative masonry system based on stabilised compressed earth blocks (CEBs). A support system comprising two fixed and two movable edges was implemented to induce an in-plane shear failure mechanism of the CEB-masonry cross-vault. A parametric modelling approach guided the geometric design conditioned by the characteristics of the testing facilities and the construction of the CEB-masonry cross-vault. The experimental investigation involved assessing the material's mechanical properties through uniaxial and diagonal compression tests. Additionally, Operational Modal Analyses based on Stochastic Subspace Identification were applied to determine the dynamic properties of the structure. Finally, quasi-static cyclic tests were carried out by applying incremental displacements to one of the movable supports. The study concluded that the CEB-masonry material did not experience a drastic quasi-brittle behaviour, but a slight reduction on its strength and a reasonable deformation capacity when subjected to tensile loading. In addition, the dynamic identification evidenced that the behaviour of the CEB-masonry cross-vault was governed by a coupled mechanism influenced by an in-plane shear diagonal and flexural responses. Finally, it was demonstrated that the CEB-masonry cross-vault exhibited limited strength, but it showed moderate deformation capacity and energy dissipation under cyclic loading.