OUT-OF-PLANE EXPERIMENTAL TESTS ON MASONRY PANELS

Out-of-plane mechanisms induced by earthquakes are typical of many masonry structures such as standing out elements (parapets, battlement of fortresses, soaring portion of church façades) or portions of masonry facades badly connected to the building. The displacement-based assessment procedures proposed in codes are mainly based on the hypothesis of rigid block, which sometimes does not properly represent the actual behaviour of these structures. In this context, in order to verify the reliability of the rigid block hypothesis and to analyse the equivalent damping of stone masonry panels under rocking, an experimental campaign on three mock-ups subjected to out-of-plane actions has been performed in the Laboratory of Structural Engineering of the University of Genoa (Italy). Panels are made of a two-leaves irregular stone masonry, characterized by a quite poor quality, like that one usually present in the Italian historical centres. Two types of test have been performed: a) static out-of-plane test under controlled displacements conditions, in order to evaluate the pushover curve; b) free vibration test, in order to measure rocking in the nonlinear range and evaluate the equivalent viscous damping, due to impacts and other sources of dissipation. The above-mentioned tests have been repeated for different levels of displacement. In general, experimental results have shown that rigid block model is able to properly describe the seismic out-of-plane response, by introducing proper modelling strategies in order to take into account the real behaviour of this kind of structures.