In the building sector, the theme of sustainability in the use of territory cannot disregard actions aimed at limiting the soil consumption, by encouraging the refurbishment and reuse of existing buildings and preserving historical centers. Masonry, composed of brick or stone units jointed through weak lime mortar, represents the par excellence and most widespread construction material for historic buildings in Europe and worldwide. The safe usability and preservation of historic masonry buildings is an urgent issue for society, due to the intrinsic vulnerability of masonry. In fact, these structures proved to be extremely vulnerable to earthquakes, despite wide areas are subjected to high or moderate seismic hazard. Other exceptional actions can compromise the structure’s integrity: induced seismicity, caused by anthropogenic activities, crushing or blasts… Besides, historic masonry buildings demonstrated to suffer of structural deficiencies related to long-term fatigue, cyclic stress, durability of the materials and to modifications.
The “conFiRMa” project fell within the context of the study on innovative intervention strategies for the reduction of vulnerability and preservation of historic masonry structures and, in particular, dealt with the strengthening of existing masonry through Fibre-Reinforced Mortar (FRM). It is a modern, effective and compatible reinforcement strategy, which consists in plastering the walls by means of mortars with fibre-based elements embedded (meshes or textiles).
The project primarily addressed to the definition and calibration of a robust numerical model for predicting the behaviour of historic masonry structures strengthened with FRM systems, so to fill the current gap between the wide set of simplified laboratory experimental results available in the literature for FRM and the professional designers need to evaluate the performances of the complex, actual configurations. A broad numerical study on the structural performances of FRM strengthened masonry was performed, identifying the resisting mechanisms of such strengthened material, investigating on the interaction among the structural components and reproducing the damage evolution process under critical loading conditions. According to a “Multi-Level Approach”, different modelling strategies were calibrated, varying the scale of investigation: starting from a very detailed-level modelling for advanced research at the small scale level, followed by an optimization procedure to get a more computationally efficient multi-layer model, based on layered elements, to reliably simulate the behaviour of entire masonry walls and structures, until attain to very simplified models for the global analysis of structures to be used in the everyday professional practice.
