Hemp-FRP for Seismic Retrofitting of Existing Masonry Buildings

Nowadays, renewable technologies and reduced environmental impacts are important concepts of the modern construction systems, especially in relation to the production of building materials. In this framework, the seismic performance of H-FRPs (Hemp - Fibre Reinforced Polymers) for retrofitting masonry structures are studied in the current paper, where both analytical and experimental researches on laminated composite green materials are reported and discussed. With respect to analytical studies, proper equations ruling the percentages of fibres and matrixes to be used in green composites are examined. Moreover, full scale experimental tests in order to evaluate the hemp fibres mechanical behaviour and the seismic behaviour of masonry panels are taken into account. The numerical calibration of the above experimental tests are conducted with the ABAQUS non linear numerical software in order to know the behaviour of hemp fibres and masonry walls under the combined effect of vertical and horizontal actions. This activity is used to apply hemp fibres under form of a grid of strips (with variable pitch) as seismic retrofitting system applied on one or both sides of an existing masonry panel. The behaviour of hemp strips in terms of resistance and ductility is compared to that of C-FRP (Carbon - Fibre Reinforced Polymer) ones aiming at both evaluating the effectiveness of using green fibres and finding the best retrofitting system of the analyzed masonry panel. The analysis results have shown the convenience of using hemp fibres, which allow to perform low cost and minimally invasive seismic interventions without the building disruption of use, offering at the same time strength and ductility comparable to those of the most famous C-FRP materials.