NEW METHODS FOR BONDING FRP STRIPS ONTO MASONRY STRUCTURES: EXPERIMENTAL RESULTS AND ANALYTICAL EVALUATIONS

The paper presents and analyzes the results of an experimental research on masonry walls tested first in unreinforced condition and then in FRP reinforced condition. The specimens were three real-scale perforated brick walls. The experimentation consisted in collapse testings under increasing lateral load and constant vertical load. The reinforced condition consisted in strengthening the masonry walls with Carbon Fiber-Reinforced-Polymeric strips bonded onto the masonry surface. The CFRP reinforcement was applied by using three different techniques. The first technique involved epoxy bonding of strips (common application). The second technique involved the bonding of strips with epoxy resin and strengthening the bond with studs (FRP studs embedded into the masonry and connected with the strips). The third technique consisted in the epoxy bonding of strips under vacuum (i.e., using a special vacuum-packed system to push the resin into the masonry as deep as possible). This research aimed at investigating the differences in the structural behaviors of tested perforated masonry walls due to these three different CFRP application techniques. Actually, the experimental results prove that the application technique influences both the load-carrying capacity and the ultimate horizontal displacement of the perforated tested masonry walls. The comparison between the experimental results and code provisions showed that, as regards the debonding of CFRP strips, the latter underestimate the former excessively.