TRM reinforcement of masonry specimens for seismic areas

Abstract

This document analyses the resistant behaviour to diagonal compression and direct compression of brick masonry specimens, reinforced with textile reinforced mortars (TRM) and without them. The numerical models have been calibrated with experimental results in order to have a suitable technique to reinforce masonry historic constructions where extraordinary tension stresses could occur in seismic situations. For the numerical modelling, FEM models have been developed using non-linear layered bi-dimensional shell elements. Moreover, a comparative analysis has been developed between the numerical models and the experimental ones. There are two different types of reinforced specimens: two layers to reinforce both surfaces (i), and one layer for only one surface (ii). The point of this (ii) is to respect the Italian legislation indications for the protection of historic constructions. Keywords: reinforced masonry TRM walls FEM INTRODUCTIONMany residential areas in the historical centres of European Seismic areas have a very high vulnerability due to of their structural system based in masonry or brick masonry walls. These structures have a very low capacity to resist tension or shear stresses. The use of textile reinforced mortar (TRM) as a reinforcing element can provide an additional capacity to solve these structural problems. Mortar cementitious materials as matrix of these reinforcement systems are more compatible with masonry than other polymeric matrices where its use in historical constructions is not permitted by the authorities in charge of protecting these constructions.Brick masonry walls are building systems made up of brick elements joined by mortar with a specific disposition. Due to its configuration, with elements of different properties, their simulation by finite element method becomes a complicated task. Brick and mortar have different strength capacities, and the very different strength behaviour in tension and in compression generates an anisotropic behaviour. Another important factor is the influence of the elastic modulus of both materials. By having different elastic modulus, their strain, for a given stress, will be different and the compatibility equations should solve this interaction. For these reasons, the ultimate load behaviour of brick masonry specimens are very dependent on the direction of the applied load and the plane on which the loads act.Some studies, such as those carried out at the Polytechnic University of Catalonia [1], analyse the out-of-plane behaviour, although the present paper will only focus on the loads acting on the plane of the wall. Masonry structures are especially weak against lateral cyclic loads such as those caused by earthquakes and this work analyses them. The difference of elastic modulus and the differences between the maximum stresses in tension and compression for brick and mortar are the cause of the specimen fault in the weakest areas of the wall. It is necessary to understand that the weakest areas will be the joints between the bricks: the m...

In-plane shear behaviour by diagonal compression testing of brick masonry walls strengthened with basalt and steel textile reinforced mortars

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