Hemp-based systems as seismic strenghtening interventions of existing masonry buildings

The work aims to illustrate three research issues dealing with the use of hemp for seismic strengthening of existing masonry buildings. Hemp fibres, thanks to their mechanical properties, represent a valid alternative to artificial ones in the context of environmental sustainability. Two types of reinforced plasters are herein investigated by means of laboratory tests: the first one is a plaster with hemp fibres randomly arranged in the matrix, while the second one is a plaster reinforced with a hemp mesh to obtain a Hemp Fibre-Reinforced Cementitious Matrix (H-FRCM). The last matter is a numerical study on the seismic behaviour of a masonry school building located in Southern Italy reinforced firstly with a Hemp Fibre Reinforced Polymer (H-FRP) and then with the experimented H-FRCM system. Both experimental campaigns display an increase of compressive and flexural strength of the used plasters due to the presence of hemp. Moreover, the hemp mesh allows to obtain a significant improvement of the collapse mode of the masonry. The increase in strength achieved from tests is also confirmed by the numerical analyses, even if with the H-FRCM reinforcement the seismic upgrading of the studied building is not achieved. As a conclusion, the gotten results show interesting perspective in the use of hemp fibres for reinforcement of masonry buildings under seismic viewpoint.