Anchorage length of near-surface mounted fiber-reinforced polymer rods for concrete strengthen - Analytical modeling

Among strengthening techniques based on fiber-reinforced polymer (FRP) composites, near-surface mounted (NSM) FRP rods are one of the most recent and promising acquisitions. As the bond performance is a critical aspect of the technology, experimental and theoretical investigations on this issue have been performed and the latter are the focus of this paper Analytical modeling is conducted in two phases. First, the experimental local bond stress-slip curves are modeled analytically and the numerical solution of the differential equation of bond allows computing the bond failure load as a function of the bonded length and the anchorage length of NSM FRP rods required in design. In the second phase, an approximate bi-dimensional analysis in the elastic range and a limit analysis assuming plastic behavior of concrete are conducted to compute upper and lower bounds to the local bond strength. In both phases, analytical predictions are compared with experimental results, showing satisfactory agreement.