Experimental investigation of the behaviour of concrete beams reinforced with GFRP bars under static and impact loading

Abstract

Composite materials, including Fibre Reinforced Polymer (FRP) bars, have been gaining momentum as alternatives to traditional steel reinforcements in civil and structural engineering sectors. FRP materials are non-corrosive, non-conductive, and lightweight and possess high longitudinal tensile strength, which are advantageous for their use in civil infrastructure. This paper presents the results of an experimental investigation into the effects of the use of glass FRP (GFRP) bars as internal reinforcement on the behaviour of concrete beams. Both static and dynamic (impact) behaviours of the beam have been investigated. Twelve GFRP reinforced concrete (RC) beams were designed, cast and tested. Six GFRP RC beams were tested under static loading to examine the failure modes and associated energy absorption capacities. The remaining six GFRP RC beams were tested under impact loading using a drop hammer machine at the University of Wollongong. GFRP RC beams with higher reinforcement ratio showed higher post cracking bending stiffness and experienced flexural-critical failure under static loading. However, GFRP RC beams under impact loading, regardless of their shear capacity, experienced a "shear plug" type of failure around the impact zone. Energy absorption capacities of beams were determined. The average dynamic amplification factor was calculated as 1.15, indicating higher dynamic moment capacities compared to static moment capacities (15-20% increase). Reinforcement ratio and the strength of concrete influenced the behaviour of GFRP RC beams. -------------------------------------------------------- * Corresponding authors Research Highlights Flexural behaviour of GFRP RC beams has been investigated. Twelve GFRP reinforced concrete (RC) beams were designed, cast and tested. Six GFRP RC beams were tested under static loading to examine the failure modes and associated energy absorption capacities. The remaining six GFRP RC beams were tested under impact loading using a drop hammer machine at the University of Wollongong. GFRP RC beams with higher reinforcement ratio showed higher post cracking bending stiffness and experienced flexuralcritical failure under static loading. However, GFRP RC beams under impact loading, regardless of their shear capacity, experienced a "shear plug" type of failure around the impact zone. Energy absorption capacities of beams were determined. The average dynamic amplification factor was calculated as 1.15, indicating higher dynamic moment capacities compared to static moment capacities (15-20% increase). Reinforcement ratio and the strength of concrete influenced the behaviour of GFRP RC beams.

Effect of the plastic hinge and boundary conditions on the impact behavior of reinforced concrete beams

“…The dynamic analysis of the impact process is not required in the current design codes. In reality, the shear force and bending moment of RC beams under impact are significantly different from those under static loads [3][4][5][6][7][8][9]. Upon impact, a stress wave is generated and propagates in the structure.…”

Analytical Study of Reinforced Concrete Beams Strengthened by FRP Bars Subjected to Impact Loading Conditions

“…by GFRP sheets, while the second verification was generated from Goldston et al (2016) experimental test.…”

“…As an example, the difference between displacement and base shear for software output and laboratory for BI-2000 is 2.75 and 0.3%, respectively, while these differences are about 1.8 and 3.2% for BI-500. Goldston et al (2016) conducted experimental programs which were divided into two different groups, the first group consisted of 6 beams subjected to static loading and second group was under impact loading.…”

Behavior of BFRP bars subjected to dynamic impact loads

“…Despite the advancements in the field of the fiber-reinforced polymers, there is insufficient research on the dynamic properties of FRP bars. Goldston, Remennikov, and Sheikh [18] studied the response of GFRP reinforced concrete beams to static and impact loading. The authors implemented the drop hammer test procedure to conduct dynamic tests.…”