Bond between near-surface mounted CFRP laminates and the concrete in structural strengthening

Near Surface Mounted (NSM) Laminate Strips of Carbon Fiber Reinforced Polymer (LSCFRP) is a promising technique for increasing the flexural and shear strength of deficient reinforced concrete members. When compared to externally bonded reinforcing (EBR) technique, NSM LS-CFRP technique shows several advantages, namely: higher prevention to the peeling phenomenon; extra protection against fire, mechanical and environmental damaging effects; easier and faster installation. To evaluate the concrete/ LS-CFRP bond behavior, an experimental campaign of pullout-bending tests was carried out, where the influence of the concrete strength and the LS-CFRP bond length was considered. Taking the experimental results and using a numerical method developed for this purpose, an analytical bond stress-slip relationship was evaluated. The present paper describes the numerical strategy developed, its applicability to the tests carried out and its usefulness for predicting the anchorage length