Experimental Study on the Flexural Behaviour of a Novel Concrete Filled Hybrid Beams Reinforced with GFRP and Steel Bars

This study presents the flexural performances of hybrid beams where glass fibre reinforced plastic (GFRP) box profile, concrete, steel or GFRP bars were used together. By conducting flexural tests on beams of varying properties produced for this purpose, the minimum reinforcement effects in GFRP profile-concrete beams were experimentally presented. Beam series of two sizes, as 74-74-500 mm small beams and 100-100-1,500 mm large beams, and varying combinations were produced. In addition, some properties of GFRP box profiles were improved. Following the tests conducted on small beams, the number of large beam samples was reduced and while steel bars were used in some beams, GFRP bars were used in others. The hybrid beams were compared with reinforced concrete beams have the same dimensions in large beams. On the basis of the results obtained from the tests it was determined that the flexural performances of steel reinforced hybrid beams increased at a higher level. Flexural strength of the improved hybrid beams increased by about two times compared to the classical reinforced concrete beams. Fracture toughness of the hybrid beams improved 53%.