Historic masonry, a FEM analysis to evaluate the thermal proprieties

Abstract

The crisis related to COVID-19 pandemic and to the Ukrainian conflict led to increase the energetic poverty and social inequalities. The European building energetic sector has a relevant weight in the primary energy demand. Among the European strategies, the Renovation Wave plan aims to encourage the process of restoring the built heritage, in a sustainable way for all EU member countries. Considering the economic difficulties and the European strategic direction for the energetic requalification of buildings, the risk of operate on the historical building heritage with interventions incompatible with the conservation of needs is not negligible. This work has focused attention, in particular, on the recovery of historical buildings and on masonry, in conformity with the energetic aspects. Four different geometric masonry layouts were modeled, which represent the most recurring ones, with the aim of evaluating their thermo-physical performance. The geometric differences are found in single-layer, two-layers or sack masonry, in which there are “diatoni” or “semi-diatoni” ashlars. The evaluation of the energetic performance of masonry was carried out through 3D finite elements models (FEM Finite-elements-modeling) implemented within the software Comsol Multiphysics v. 5.6. In addition, the typical effect of thermal bridges that can be generated in the presence of passing construction elements, such as “diatono” or “semi-diatono” ashlars, was studied. The presence of these constructive elements is fundamental for the structural aspects, like the best distribution of the structural loads. However, according to an approach that also takes into account the energetic performances, it was showed that these constructive elements determine a favorable condition for heat transfer. Consequently, it’s necessary to plan a series of recovery interventions that are compatible with the needs of the construction, then carrying out interventions suitable for each condition, and, finally, considering the energetic contribution of the masonry.