A Review on the Flexural Behaviour of RC Beams Reinforced with Steel and GFRP Bars (original) (raw)
Related papers
2020
As a solution of steel corrosion, glass fiber reinforced polymer (GFRP) rebars have been recommended to be used as internal reinforcement instead of steel reinforcement during last two decades. Lightweight, no-corrosion, thermal conductivity, electrically and magnetically resistance, and higher tensile strength are main advantageous properties of GFRP rebars over steel reinforcement. However, it has been noted that the recommended design codes in this field still require modifications. Some studies were conducted on concrete structures reinforced with this new reinforcing material worldwide. In this paper, test data of fifty-three concrete beams reinforced with GFRP rebars were collected from eight different works to investigate cracking moment, nominal moment, deflection and neutral axis depth. The selected beams were reinforced with steel stirrups and GFRP rebars in traverse and longitudinal directions, respectively. The beams were tested under four-points loading test to fail in flexure. A comprehensive approach to calculate both experimental and predicted results is given in terms of deflection and flexural capacity. The experimental results are compared with calculated design results according to ACI 440.1R-15. Statistical data analysis is performed for both theoretical and experimental results. In conclusion, the multiplier factors for theoretical cracking moment, nominal moment, ultimate deflection and neutral axis depth have been proposed to be 0.94, 1.25, 1.4 and 0.806, respectively.
Comparative Study of Steel and Glass Fibre Reinforced Polymer (GFRP) Bars in RC Members
2019
Corrosion of steel reinforcements is one of the main problems in reinforced concrete structures that shortens their serviceability and reduces their strength. The RC structures in coastal environments are usually exposed to early deterioration and damage due to the existing extreme conditions that initiates corrosion. Glass fibre reinforced polymer (GFRP) bar is regarded as a next generation substitute material to conventional steel bars. This paper focuses on the behavior of GFRP reinforcement bars and steel reinforcement bars in RC members in terms of bonding and flexure. The flexural behaviours were compared experimentally and using finite element analysis (ABAQUS). 6 beam specimens were used having dimensions 750x150x150mm and were subjected to four-point bending test until failure. Reinforcement ratios of 1%, 1.4% and 2.1% were adopted using each type of the reinforcement bar. The ultimate load capacity and flexural strength of the steel RC beams was higher than GFRP RC beams, ...
Engineering Research Journal, 2024
Due to problem of steel corrosion and high cost, the use of glass fiber reinforced polymers (GFRP) has become more convenient to be used widely nowadays. This study implicated experimental, numerical, and analytical comparison between GFRP and steel RC beams. Twelve beams were tested under four-point flexural load till failure, The beams had a clear span of 2000 mm and a cross sectional area width and height of 120 mm and 300 mm, respectively. The beams were categorized into two groups (A and B) from these twelve beams according to reinforcement type (steel or GFRP). Group A consists of four beams while group B includes eight beams. Two reinforcement types were used: high tensile steel (10 mm dia.) and GFRP rebars (8 mm and 10 mm dia.) with reinforcement ratios 0.5% and 1%. Numerical study using ABAQUS 6.14 was performed with the following parameters: concrete strength, diameter of the reinforcing GFRP bars, reinforcement ratio, and type of reinforcement. According to test results, utilizing GFRP bars in beams of 25 MPa concrete strength increased the failure load by an average of 18% and 7% while beams of 35 MPa concrete strength increased by an average of 22% and 11% for beams of 0.5% and 1.0% reinforcement ratio, respectively. The mid-span deflection was dramatically increased when utilizing GFRP bars as opposed to steel bars. A comparison between experimental, analytical, and numerical results was done and showed good consistency.
Flexural Behaviour of Concrete Beams Reinforced With GFRP Rebars
This study reports test results of 12 concrete beams measuring 150mm wide × 180mm deep× 1200mm long reinforced with glass fiber-reinforced polymer (GFRP) bars subjected to a four-point loading system. The test specimens were classified into three groups according to the concrete compressive strength. The main variation done for each beam in all the three groups was a percentage of reinforcement (0.5%, 1%, 1.5% and 2%). Since all the beams were over reinforced failure occurred due to rupture of concrete at compression zone. The failure is initiated by a vertical crack at the midspan which extended up to compression zone of the beam and propagated horizontally which leads to bond failure between top concrete and compression reinforcement. The test results revealed that the crack widths and mid-span deflection significantly reduced by increasing the reinforcement ratio. The ultimate load increased by 7.5%, 16.8%, 27.7% as the reinforcement percentage increased from 0.5% to 1%, 1.55 and 2% respectively. The flexural provisions of structural design guidelines namely ACI 440.1R-06, ECP 208-2005, and CSA S806-12 were evaluated against the test data. ACI 440.1R-06 overestimates the moment resistance of GFRP bars as compared to other codes and experimental results. Whereas all the design guidelines predict nearly the same values for deflection. And for crack width approximation Toutanji's equation is more accurate compared to ACI equation.
Challenge Journal of Concrete Research Letters
Glass Fiber Reinforced Plastic (GFRP) composites as rolled bars can be used as steel rebar to prevent oxidation or rust which is one of the main reasons concrete structures deteriorate when exposed to chlorides and other harmful chemicals. GFRP is successful alternative for reinforcement with high tensile strength- low strain, corrosion resistance and congenital electromagnetic neutrality in terms of longer service life. The main goal of the study is to investigate the mechanical and bonding properties of GFRP bars and equivalent steel reinforcing bars then compare them. GFRP and steel rebar are embedded in concrete block with three different levels. Mechanical properties of GFRP and steel bars in terms of strength and strains are determined. On the other hand; modulus of elasticity of GFRP and steel bars, modulus of toughness and modulus of resilience were calculated using stress-strain curves, as a result of the experiments. Pull-out tests are conducted on each GFRP and rebar samp...
GFRP bars for internal reinforcement of concrete structures
2016
This paper presents the activities developed at Politecnico di Milano that deal with the use of glass fibre reinforced polymers (GFRP) rebars for the internal reinforcement of concrete structural elements. Problems related to experimental characterization of the rebars, to bond of GFRP rebars and concrete, to fatigue of GFRP reinforced slabs and to the effect of elevated temperature on GFRP reinforced beams are discussed after showing the outcomes of the experimental tests conducted. All these studies support the view that GFRP rebars can be used profitably in some structural elements particularly exposed to corrosion.
Glass fibre reinforced plastic (GFRP) rebars for concrete structures
Construction and Building Materials, 1995
The study described is a part of a large-scale experimental-and theoretical programme on the application of fibre reinforced plastic (FRP) reinforcement for concrete structures initiated at the LiniversitB de Sherbrooke (Sherbrooke, Canada). The programme is being carried out to gain an insight into the flexural behaviour of concrete beams reinforced with glass fibre reinforced plastic (GFRP) rebars. Results of experimental study on 3.3 m long beams reinforced with two different types of GFRP rebars are presented and compared to that of conventional steel reinforced concrete beams. Three series of reinforced concrete beams were tested in flexure. The beams were 200 mm wide and respectively 300,450 and 550 mm high. The paper also attempts to present the properties of GFRP and its components and to give an oversight of relevant research activities involving GFRP rebars as reinforcement for concrete units.
Influence of fibers on flexural behavior and ductility of concrete beams reinforced with GFRP rebars
This research studies the influence of fibers on flexural behavior and ductility of concrete beams reinforced with GFRP bars. The experimental program included seven beams. The tested beams were divided into four groups. Each of the first three groups consisted of two beams one of normal strength and the other of high strength while the fourth group consisted of one normal strength beam. The first group is the reference group which had no internal fibers. The second group studied the effect of using internal polypropylene fibers in the concrete mix. The third group studied the effect of using internal glass fibers in the concrete mix while the fourth group studied the effect of using internal steel fibers in the concrete mix. The experimental results of tests showed that using GFRP as the main reinforcement for the concrete beams achieves reasonable flexural strength. Also the theoretical results calculated using ACI 440 code showed good agreement with the experimental results with an error of about 20%. The results of the current research indicated that all types of the fibers used improved the ductility of FRP-reinforced concrete beams. It was found that the span-to-experimental service load deflection ratio is relatively high when compared to the usually accepted ratio of about span/250.
Comparative Study of GFRP Rebar and Steel Rebar used in Concrete Sections
The main problem encountered in steel reinforced concrete structures is the corrosion of the steel bars which eventually results in the failure and disintegration of the structure. Fiber-reinforced polymer (FRP) rebar has been considered as an alternative for this since corrosion is a material problem. The purpose of this research was to investigate flexural behaviour of GFRP and steel reinforced beams. The beam sections used in this research is of size 150 x 200 mm and of 1600 mm length. Flexural strength was determined and crack pattern studies were carried out.
EXPERIMENTAL INVESTIGATION OF CONCRETE BEAMS REINFORCED WITH GFRP BARS
Glass fiber reinforced polymers (GFRP) reinforcement bars has a lower stiffness than steel reinforcement, which should be accounted for the ultimate and serviceability conditions, including the impact on member deflection and crack widths. This paper presents an experimental study of the flexural behavior of concrete beams reinforced with locally produced glass fiber reinforced polymers (GFRP) bars. The bars are locally produced by double parts die mold using local resources raw materials. A total of seven beams measuring 120 mm wide x 300 mm deep x 2800 mm long were caste and tested up to failure under four-point bending. The main parameters were reinforcement material type (GFRP and steel), concrete compressive strength and reinforcement ratio (μb, 1.7μb and 2.7μb). The mid-span deflection, crack width and GFRP reinforcement strains of the tested beams were recorded and compared. The test results revealed that the crack widths and mid-span deflection were significantly decreased by increasing the reinforcement ratio. The ultimate load increased by 47% and 97% as the reinforcement ration increased from μb to 2.7μb. Specimens reinforced by 2.7μb demonstrated an amount of ductility provided by the concrete. The recorded strain of GFRP reinforcement reached to 90% of the ultimate strains.