Vol.22, No.1, 2022, pp. 103–113
UDC:

The glass fibre reinforced polymers (GFRP) can be used to produce reinforcement bars used as suitable alternatives for conventional steel reinforcement due to its reasonable strength/weight ratio and corrosion resistance. The fibre reinforced concrete (FRC) is a kind of concrete that can be fabricated by adding steel fibre to the concrete mix to enhance the mechanical potential and consequent structural performance. This study is presented to inspect shear performance of fibrous concrete beams reinforced by GFRP bars and stirrups. Such a programme includes casting and testing 16 reinforced concrete beams. GFRP stirrups reinforce 15 beams; however, one beam is reinforced by the steel stirrup as a reference beam. The variables of this study comprise the content of steel fibres, shear reinforcement ratio, and concrete compressive strength; the beams are divided into five groups according to test parameters. Experimental results show that increasing the shear reinforcement ratio from 0.222 to 0.443 % increases the failure load by 8, 10, and 11 % for steel fibre content 0, 0.5, and 1 %, in respect. Also, results show that increasing compressive strength of concrete from 30 to 70 MPa increases failure load by 28, 40, and 42 % for steel fibre content 0, 0.5, and 1 %, in respect. Increasing steel fibres content from 0 to 1 % increases the failure load by 8 to 18.9 %. It is found that increase of compressive strength of concrete from 30 to 70 MPa decreases strain in GFRP stirrups between 60-125 %, while increase in shear reinforcement ratio from 0.222 to 0.443 decreases the strain in GFRP stirrups and bars between 5-64 %. Furthermore, the crack width decreases by 32-108 % when steel fibre content is raised from 0 to 1 % for all tested beams. The experimental and calculated ultimate shear load comparison shows that CSA S806-12 and ISIS-07 codes results are very conservative, with a safety factor reaching 66 %. In contrast, the ACI440-1R-15 and Tureyen equation code results show good agreement with experimental results.

Keywords: shear stress, high strength concrete beams, GFRP bars and stirrups, cracks, CSA and ISIS codes and practice