Stress along tensile lap-spliced fibre reinforced polymer reinforcing bars in concrete

A theoretical study was carried out to investigate stress along tensile lap-spliced spaced or bundled fibre reinforced polymer (FRP) bars in concrete. R. Tepfers developed a mathematical model, which could be applied for any type of reinforcing bar, based on the modulus of displacement theory. The mathematical model can predict the bond stress and stresses in the reinforcing bars and the surrounding concrete. In this paper, the model developed by Tepfers was represented by applying the modulus of displacement theory, and theoretical predictions are compared with the experimental results from testing 16 large-scale concrete beams. Good agreement between the theoretical values and experimental results was observed at three stages of loading. Recommendations for investigating the modulus of displacement from pullout tests have been included. Lastly, the maximum average bond stress of spliced FRP bars can be estimated using the ultimate failure pattern analysis, in which the contributions of the splitting resistance were included.