Experimental study on the performance of tensile lap-spliced GFRP rebars in concrete beam

Concrete reinforcement using a combination of steel and glass-fibre-reinforced polymer (GFRP) bars promises higher strength, serviceability and durability. To verify this potential and promote the design of concrete structures with this type of hybrid reinforcement, the load–deflection behaviour of GFRP-reinforced flexural concrete beams is experimentally and theoretically investigated. Twelve beam specimens are tested to examine the effects of the lap splice length, clear spacing of the GFRP reinforcements and cover thickness on the flexural behaviour. All the test specimens have a span of 4000 mm and contain steel and GFRP rebars with a nominal diameter of 12·7 mm. The specimens are tested under two-point loads to subject their spliced region to a constant moment. Comparison of the experimental results with the predictions of the simplified equations proposed by the American Concrete Institute (ACI) 440 Committee reveal that the ACI 440.1R-06 equations do not guarantee the safety of GFRP-reinforced lap-spliced beams.