In this paper, the bond strength of lap-spliced glass fiber–reinforced polymer (GFRP) bars in concrete beams is experimentally investigated. Thirteen beam specimens were manufactured for laboratory experiments. The parameter of transverse reinforcement along the splice length was selected as the main variable for the beam specimens. Other variables were surface properties of GFRP bars, bar diameter, and concrete compressive strength. Test results show that the effect of transverse reinforcement on bond strength between GFRP bars and concrete depends on the surface properties of reinforcing bars. The experimental results obtained in the present study and the results reported in the literature are compared with the current design equation provided by the American Concrete Institute (ACI) Committee 440 guidelines. The equation of ACI Committee 440 for evaluating the bond strength of GFRP bars underestimates the bond strength of spliced GFRP bars confined with large amounts of transverse reinforcement. For cases of small values of transverse reinforcement and splices without transverse reinforcement, the equation of ACI Committee 440 is unconservative and overestimates the bond strength. In this paper, an equation for predicting the bond strength of GFRP bars is also proposed on the basis of test results and the Monte Carlo simulation method.

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