Finite Element Analysis of RC Beams Strengthened in Shear with NSM FRP Rods

Abstract

This study presents three-dimensional FE models on RC T-beams strengthened in shear with near surface mounted (NSM) fiber reinforced polymer (FRP) rods, with various rod spacing, strengthening pattern and internal shear reinforcement ratios. The FE models utilized different constitutive material relations for concrete, steel and FRP and implemented a mixed-mode bond-slip law at the NSM FRP rod-concrete interface. Comparisons, such as ultimate loads and load-deflection history, validated the accuracy of the developed models. More importantly, the FE models were able to predict the brittle shear failure of the beams and debonding of the NSM rods. For an accurate simulation of shear failure, the shear retention factor (β) should be less than 0.2. The correlated models will be used in further research to examine the effects of various parameters expected to influence the behavior of strengthened beams, in an effort to strengthen the knowledge on this topic.