Improving Ductility for Composite Beams Reinforced with GFRP Tubes by Using Rebars/Steel Angles

The ductile behaviour of composite beams reinforced with glass fibre-reinforced polymer (GFRP) pultruded rectangular tubes was investigated in this paper. The composite beams were reinforced with GFRP tubes and different steel products, aiming to improve their ductility by using steel products. The main parameters were the types of the steel reinforcement, namely rebars and steel angles. The flexural behaviour of four beam specimens was tested by using a four-point bending test. The experimental results show that the yield load of the specimens was determined by the steel products and the ultimate load was controlled by the GFRP tubes. Two ductility methods (displacement ductility and energy ductility) were used to evaluate the change of the ductility. Both the methods confirmed that the ductility of the composite beam was improved in varying degrees by using rebars and steel angles. Moreover, the analysis shows that improving the yield load or decreasing the ultimate load of the composite beams contributed to the improvement of the ductility.