A Study of the fracture process at the FRP-masonry interface: the role of the periodic pattern of bricks and mortar joints

This paper sheds light into the effect of the periodic pattern of bricks and mortar joints on the load-carrying capacity of the interface between fiber-reinforced polymer (FRP) composites and masonry. Two simplified cohesive material laws are proposed for the FRP-mortar and FRP-brick interfaces, which allow for the computation in closed form of a finite effective bond length Leff of the interfaces. The aforementioned simplified interfacial laws are employed to compute the load response of the FRP-masonry interface, and to obtain the interfacial shear stress, the FRP axial strain, and the slip profiles along the bonded length. The results indicate that length of the stresstransfer zone (LSTZ) of the FRP-masonry interface varies periodically as its location shifts with respect to the position of the mortar joints. Furthermore LSTZ can be different from the effective length Lbeff of the FRP-brick interface and is influenced by the size of the bricks and mortar joints.