BFRP GRID CONFINED CLAY BRICK MASONRY CYLINDERS UNDER AXIAL COMPRESSION: EXPERIMENTAL RESULTS

Abstract

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.