FRP EXTERNALLY BONDED SYSTEMS FOR A SUSTAINABLE STRENGTHENING OF MASONRY STRUCTURES

According to recent design Codes and Recommendations, verification against debonding of FRP-reinforcement is imperative in the design of strengthening interventions. In FRP bonded masonry elements, end debonding must be avoided by checking the maximum force which can be carried out by reinforcement. In this paper, design criteria against debonding in masonry elements externally strengthened by FRP sheets are proposed. For different masonry supports, the results of a statistical analysis of bond tests reported in the literature are collected and used for calibrating prediction formulas. Starting from the experimental database, formulas for fracture energy of interface bond law and bond strength are assessed. In order to provide design formulas according to the Partial Safety Factor Method for Ultimate Limit State verification, mean and characteristic values of the bond strength have been determined by means of statistical methods