Use of FRP fabrics and stainless steel grids for strengthening brick masonry columns

This work presents the results of an experimental investigation on 42 solid clay brick columns internally strengthened by FRP fabrics or stainless steel grids placed in the horizontal joints of mortar. Monotonic compressive loading tests were carried out under concentric and eccentric load. Eccentric tests were carried out loading the specimens on a reduced area with respect to the entire crosssection producing a D-region. The reinforcing of every course and of alternate courses are studied. The effectiveness of the proposed strengthening techniques is discussed, in terms of increase in strength and energy required to the collapse of brick columns. An analytical expression is proposed that gives the strength value of confined brick columns by considering that the biaxial strength domain of the bricks is modified due to the tensile contribution offered by the presence of reinforcement. Moreover, a strut and tie model is utilized to calculate the load carrying capacity of D-regions.