Field assessment of unreinforced masonry walls strengthened with fiber reinforced polymer laminates

Unreinforced masonry (URM) walls strengthened with composites were tested to failure at a decommissioned building in St. Louis, Missouri. The walls were subjected to out-of-plane loading. Previous work on URM as well as reinforced masonry walls strengthened with fiber reinforced polymer (FRP) laminates has shown remarkable increases in capacity and ductility. However, most of this research work has been conducted in the laboratory, where, it is difficult to reproduce real field conditions. In this context, this experimental program offered a unique opportunity for performing field experimentation on URM walls strengthened FRP laminates showing that shear compression led to controlling the failure of either the upper or lower boundary masonry units. An analytical model that provides good agreement with the experimental results is also presented. The model computes the applied concentrated out-of-plane load, midheight deflection, and rotations at the supports. The analytical model can be easily modified to take into account distributed loads acting on the wall.