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In the last decade, several studies have investigated the application of Fibre Reinforced Polymer (FRP) wraps to masonry piers in order to provide a confinement effect and enhance compressive strength and ductility. Although this technique has proved to be quite effective, various drawbacks arise when organic resins are used to bind fibres. To solve these problems, different techniques have been developed to be used as alternative methods for enhancing the structural performances of weak masonry columns. Among these, the use of Basalt Fibre Reinforced Cementitious Matrix (BFRCM) wrapping, or the application of steel wires at mortar joints. This paper presents the results of an experimental study on the compressive behaviour of clay brick masonry columns reinforced with FRP wraps, Basalt Fibre Reinforced Cementitious Matrix (BFRCM) or with steel wires. Uniaxial compressive tests were performed on twelve retrofitted columns and four control specimens up to failure. Two masonry grades were considered varying the mix used for the mortar. The results are presented and discussed in terms of axial stress-strain curves, failure modes and crack patterns of tested specimens. Comparisons with unreinforced columns show the capabilities of these techniques in increasing the structural efficiency with reduced aesthetical impact.

The application of steel fiber reinforced polymer (SRP) as a means of increasing the capacity of masonry columns is investigated in this study. The behavior of 23 solid-brick specimens that are externally wrapped by SRP sheets in low volumetric ratios is presented. The specimens are subjected to axial monotonic load until failure occurs. Two widely used types of masonry columns of differing square cross-sections were tested in compression (square and octagonal cross-sections). It is concluded that SRP-confined masonry behaves very much like fiber reinforced polymers (FRP)-confined masonry. Confinement increases both the load-carrying capacity and the deformability of masonry almost linearly with average confining stress. A comparative analysis between experimental and theoretical values computed in compliance with the Italian Council of Research (CNR) was also developed.

The use of composite materials for retrofitting of masonry structures has received great attention during the last two decades. For masonry buildings there are several advantages in using composite materials. Traditional techniques that were largely used and investigated in the past, may be inadequate in seismic areas where the added mass could increase seismic actions. Moreover, for historical and architectural heritage structures, the compatibility, sustainability and reversibility of the intervention is a key factor for the selection of the most appropriate strengthening system. Many investigations have shown that fibre reinforced polymers (FRP) can be effectively used to induce a passive confinement action on masonry columns and improve the axial capacity and ductility of the structural members. This paper presents the results of an experimental study on the compressive behaviour of clay brick masonry cylinders reinforced with basalt fibre reinforced polymer (BFRP) grids. The main aim of this study is to assess the effectiveness of the BFRP wraps on the strength and ductility of masonry columns. Twelve clay brick masonry cylinders, cored from masonry walls and columns, were reinforced using either one or two layers of BFRP grids. Two different arrangements were used for producing the cylinders in order to investigate the effect of vertical joints on the response of masonry cylinders. The basalt grid had a cell size of 6x6 mm. After a preliminary experimental study aimed at characterizing the mechanical properties of bricks, mortar and basalt grid, the cylinders were tested under uniaxial compression loading. The test results showed a strength increase between 30% and 38% for cylinders wrapped with one layer and between 69% and 71% for those wrapped with two layers of BFRP grids.