SEISMIC EVALUATION AND FRP STRENGTHENING OF UNREINFORCED FLANGED MASONRY WALLS

Currently walls in the masonry structures are usually connected to the walls perpendicular to them, hence, they are as flanges for the main walls. The existence of these walls as flanges causes increasing the structural stiffness and finally improving the lateral bearing capacity of the structure. It is obvious that this improvement are obtained when the proper connection between the walls and their compounds can be assured. One of the most weaknesses of the flanged unreinforced masonry wall is the less bond between the compounds and the low tension capacity of the materials that result in the decreased capacity and ductility of the whole. In the recent years, FRP strengthening of unreinforced masonry wall has been identified as an effective technique to increase the resistance and ductility of the system. So, considering the nonlinear behavior of the materials and by means of finite element analysis, this study evaluated the seismic behavior of the FRP strengthened flanged unreinforced masonry walls. In strengthening scheme, two polymer fibers of glass and carbon with different configurations were used. To validate the considered modeling hypothesis and the FE meshing, the results of the nonlinear analysis were compared along with the experimental results. The results of the parametric analysis showed that stiffness and strength of the FRP is effective in increasing the capacity and ductility of the flanged unreinforced masonry walls; so that it caused 185% increase of the capacity and 60% increase of ductility in flanged masonry wall compared with the rectangular one. This increase was 22% in comparison with the ordinary unreinforced masonry walls. Although using FRP sheets as X or L form increases the stiffness and strength of the wall, it has no more effect on the ductility.