Experimental Research On Shear Performance Of Rc Beam Reinforced With SFCB Bars

A Steel-FRP Composite Bar(SFCB)is a novel reinforcing rebar made of inner steel and outer FRP integrated in a pultrusion process.There have been several studies for SFCBs RC structures considering flexural performance of SFCBs,but no one conducted any research work on the behavior of the shear performance of RC beams longitudinally reinforced with SFCB bars.For the purpose to promote the application of this new reinforcing rebar,this paper explores the experimental research on shear performance of RC beam reinforced with SFCB bars.This study presents the experimental results of shear behavior of reinforced concrete beams,longitudinally reinforced with Glass Steel-FRP Composite Bars(GSFCBs).Totally 16 concrete beams were tested under static load.Half of the tested beams were longitudinally reinforced with GSFCB reinforcement,while,the other half were reinforced with conventional GFRP and steel reinforcement.All beams were provided with steel stirrups as shear reinforcement within shear region with deferent spacing.The beams were prepared with varying test variables,such as shear span-to-effective depth ratios(a/d),amount and types of longitudinal reinforcement bars,length of beam and stirrup spacing.The effect of longitudinal reinforcement ratio,?f and effect of reinforcement type are discussed and compared with conventional beams reinforced with GFRP and steel reinforcement.The test results were compared with predictions recommended by ACI 440.1R-06 design guidelines and modified proposed equation.Other performance in terms of compressive strain in concrete and tensile strain in longitudinal and stirrups reinforcement was analyzed.Based on the test results,it is shown that the shear resistance of GSFCBs RC beam is influenced by elasticity modulus of GSFCB bars that resulted in low shear strength compared to conventional steel reinforced beams and high shear strength compared to GFRP reinforced beams.Moreover,due to specific properties of GSFCB materials,shear behavior of beams with GSFCB bars is different to beams with steel and GFRP reinforcement.While the current modified equation was found to be very conservative compared with experimental results.The experimental results show that the ratios of a/d and stirrup spacing significantly influence the ultimate shear capacities of the beams.Moreover,more closely spaced diagonal shear cracks were resulted in GSFCB reinforced concrete beams compared to GFRP and steel RC beams.