Flexural behavior of high strength concrete deep beams reinforced with GFRP bars

Abstract

This paper presents an experimental and numerical study of the flexural behavior of high concrete deep beams reinforced with locally produced glass fiber reinforced polymers (GFRP) bars using high strength concrete (HSC). Both studies were carried out to study the effect of using (GFRP) bars with different ratios of reinforcement and concrete compressive strengths on the behavior of these beams.A total of eight beams, measuring 150 mm wide 500 mm depth and 1800 mm length, were cast, and tested up to failure under two-point loading. The main parameters were the types of reinforcement used, whether steel or GFRP bars. Also, concrete compressive strengths of 50 MPa and 60 MPa were used. In addition, different reinforcement ratios of 0.0033 for steel reinforcement and ratios (0.8, 1.0 and 1.2) of the balanced condition were used. The mid-span deflections, failure loads and GFRP reinforcement strains of the examined deep beams were recorded and compared with each other.The test results revealed that the crack widths and mid-span deflections significantly decreased when using 1.2μb of GFRP reinforcement ratio compared with beams reinforced with steel bars where μb is balanced reinforcement ratio of beam. The decrease in deflection varied between 20%–39.0% for specimens having 50 and 60 MPa respectively, with a significant decrease in the concrete cracks’ widths. Also, the ultimate load slightly increased by 2.5 % and 4.0 % as the concrete strengths increased.A Non-Linear finite element analysis (NLFEA) using ANSYS 2019-R1 was constructed to simulate the flexural behavior of the tested deep beams, in terms of failure load, crack pattern and load deflection behavior. Comparison between the experimental and numerical methods showed good agreement between both results.