Performance of RC beams with novelty GFRP under the bending load: An experimental and FE study

Abstract

A total of eight reinforced concrete (RC) beams were examined in the experiment to investigate the flexural performance of concrete beams reinforced with locally fabricated hybrid bars. The variables include the type of reinforcement bar (hybrid, GFRP, and steel). Two types of hybrid bars, the first was hybrid reinforcement bars (HRB), which have a steel core encased by GFRP. Steel core had the volume fraction 0.25 %, 0.44 %, and 0.70 % from the total volume of HRB. Second, advanced hybrid reinforcement bars (AHRB) were produced by adding metal powders to the matrix of GFRP with weight percentages of 5 %, 10 %, and 15 %. The load-deflection and crack patterns, failure modes, toughness, and ductility were studied of RC beams. An analytical framework has been developed and verified for RC beams based on the non-linear deformation model. The experimental results show that using hybrid bars instead of GFRP bars improves stiffness significantly. Failure loads for RC beam with volume fractions 0.25 %, 0.44 %, and 0.70 of HRB were 51 kN, 55 kN, and 71 kN, respectively, while failure loads with metal powder 5 %, 10 %, and 15 % of AHRB were 62 kN, 64 kN, and 70 kN, respectively. The failure load of the HRB beams increased to 94.16 %, while the AHRB beams increased to 92.25 % of the total failure loads of the beam with steel bars. The failure mode in the beams reinforced with HRB was a ductile flexural failure, while the beams with AHRB failed under compression failure at the range of the loading points. The HRB and AHRB demonstrated significantly improved ductility index up to 91.10 % and 75.60 %, respectively, compared to sample with GFRP bars. ANSYS Software was used to conduct a finite element model (FEM) analysis. It could be seen good agreement compared to the experimental results and those obtained of the predicted values.