An experimental analysis about the effects of mortar joints on the efficiency of anchored CFRP-to-masonry reinforcements

Fiber reinforced composite materials are widely used for structural rehabilitation and retrofitting of existing buildings; recent studies, devoted to Carbon Fiber Reinforced Polymers (CFRP) reinforcements of concrete structural elements [1-5], demonstrated that spike anchors are able to effectively increase the load carrying capacity and the ductility of CFRP bonded joints. However, application to masonry structures is disregarded by research since few experimental results are available. One of these, described in Refs. [6,7], compares the efficiency of a CFRP strengthening system provided with one or more CFRP spike anchors, also in dependence of some geometrical parameters; reinforcement sheets and spike anchors were applied only on the brick surface in order to evaluate the effects due to anchors only. In this paper the authors investigate the influence of mortar joints on the efficiency of anchored CFRP reinforcements on brick masonry. For this reason, an experimental campaign was planned on masonry pillars built with the same materials employed in Refs. [6,7], subjected to Near End Supported Single Shear Tests. Masonry pillars were built according to two different patterns, in order to detect the influence of both bed and perpend joints. The results are compared with results obtained from previous experimental campaign.