EXPERIMENTAL AND NUMERICAL APPROACH TO THE ASSESSMENT OF THE DISSIPATIVE BEHAVIOUR OF A TUFF MASONRY ARCH SUBJECTED TO CYCLIC LOAD TESTS

Masonry structures are the most widespread in southern European city centers, making seismic vulnerability reduction dependent on accurate prediction of their dynamic response. A major challenge in seismic analysis is understanding their structural capacity and dissipative behavior under cyclic loads, especially for curved elements like arches, vaults, and domes, which are common in historic buildings and frequently damaged by lateral forces during earthquakes. We propose an experimental study of a tuff masonry arch subjected to cyclic loading tests in order to evaluate the dissipative effects that occur during loading-unloading cycles. In particular, when the curved masonry structure begins the plasticization process, which involves the repeated opening and closing of cracks during cyclic loading, it does not collapse precisely because of its ability to dissipate energy. This dissipative behavior cannot be evaluated by commonly adopted static tests. Therefore, ad hoc cyclic tests have been performed to estimate dissipative effects of a curved masonry structure. We choose a cyclic test with vertical load which is effective for observing the dissipative effects produced by a horizontal dynamic load (such as an earthquake), which requires more complex and expensive experimental setup. The detailed and accurate nonlinear numerical model has been developed to describe the experimental behavior of the masonry arch and to model the reduction of the overall stiffness of the structure due to the activation of plasticization in arch joints.