Discrete element analysis on the Sardinian "Nuraghe"

The "Nuraghe" in Sardinia are very fascinating architectural documents of the ancient pre-roman civilisations of the Mediterranean Sea, that still need to be deeply studied and explained. Some important problems arise regarding the conservation of these architectures from the past, that are so spread over the Sardinian Island. A deeper knowledge of the materials and of the overall structural behaviour is strongly needed to assess the stability and to choose appropriate methods for restoration. Starting from a survey on the Nuraghe "Santu Antine" in Torralba (SS), a numerical analysis was performed on the stability of the dome, considering different hypothesis on the construction process. In order to the take into account the real characteristic of the dry stone masonry, made by big and stiff blocks laying together, a discrete element approach was adopted, able to model the discontinuities, that are the relevant mechanic characteristic of this masonry. A particular approach was needed to simulate in 2D the thickness variation of the dome slice studied, neglecting the stabilising contribution of adjacent slices. The results are encouraging, and demonstrate the possibility of constructing such domes without the aid of centring, if the right shape is controlled.