Tensile lap splicing of fiber-reinforced polymer reinforcing bars in concrete

There are very limited studies on bond of spliced fiber-reinforced polymer (FRP) bars as a reinforcement of flexural concrete members. The current standards for steel reinforcement cannot be used for the FRP bars due to the inherent differences in their mechanical properties and surface configurations. The results of 12 concrete beams of dimensions 250 mm (9.85 in.) in width and 400 nm (15.76 in.) in thickness and spanned at 4200 mm (165.48 in.) are presented. The beams were reinforced with spliced carbon or glass FRP bars. The effects of the bar diameter and splice length on the bond strength are investigated. Furthermore, an evaluation of the existing recommendations for the spliced FRP bars (ACI 440.1R-03, CAN/CSA-S806-02, ISIS-M03-01, and CAN/CSA-S6-00) is presented. Tests indicated that the FRP stress limit is directly proportional to the splice length. Moreover, the ultimate strength analysis method can be used to predict the maximum stress in the spliced FRP bars. In addition, the average bond strengths and the critical splice lengths for the FRP bars with different diameters are outlined.