Experimental and Analytical Investigation of FRP Reinforced Concrete Beams in Flexure (original) (raw)
Related papers
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.
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.
Flexural Behavior of Fiber-Reinforced-Concrete Beams Reinforced with FRP Rebars
Synopsis: Synopsis: Synopsis: Synopsis: Synopsis: The main objective of this study was to develop a nonferrous hybrid reinforcement system for concrete bridge decks by using continuous fiber-reinforced- polymer (FRP) rebars and discrete randomly distributed polypropylene fibers. This hybrid system has the potential to eliminate problems related to corrosion of steel reinforcement while providing requisite strength, stiffness, and desired ductility, which are shortcomings of the FRP reinforcement system in reinforced concrete structures. The overall study plan includes (1) development of design procedures for an FRP/FRC hybrid reinforced bridge deck system; (2) laboratory studies of static and fatigue bond performances and ductility characteristics of the system; (3) accelerated durability tests of the hybrid system; and (4) static and fatigue tests on full-scale hybrid reinforced composite bridge decks. This paper presents the results relating to the flexural behavior of the polypro...
Construction and Building Materials, Vol. (84), PP 354-366, 2015
This paper presents an experimental, numerical and analytical study of the flexural behavior of concretebeams reinforced with locally produced glass fiber reinforced polymers (GFRP) bars. Glass fiber rein-forced polymers (GFRP) reinforcement bars has a lower stiffness than steel reinforcement, which shouldbe accounted for the ultimate and serviceability conditions, including the impact on member deflectionand crack widths. The bars are locally produced by double parts die mold using local resources raw mate-rials. A total of ten beams, measuring 120 mm wide 300 mm deep 2800 mm long, were cast andtested up to failure under four-point bending. The main parameters were reinforcement material type(GFRP and steel), concrete compressive strength and reinforcement ratio ( l b , 1.7 l b and 2.7 l b ; where l b is the reinforcement ratio at balanced condition). The mid-span deflection, crack width and GFRPreinforcement strains of the tested beams were recorded and compared. The test results revealed thatthe crack widths and mid-span deflection were significantly decreased by increasing the reinforcementratio. The ultimate load increased by 47% and 97% as the reinforcement ratio increased from l b to2.7 l b . Specimens reinforced by 2.7 l b can produce some amount of ductility provided by the concrete.The recorded strain of GFRP reinforcement reached to 90% of the ultimate strains. A non-linear finite ele-ment analysis (NLFEA) was constructed to simulate the flexural behavior of tested beams, in terms of crack pattern and load deflection behavior. It can be considered a good agreement between the experi-mental and numerical results was achieved. Modifications to ACI 440.1R-06 equation for estimatingthe effective moment of inertia ( I e ) of FRP-reinforced concrete beams, using regression analysis of experi-mental results, is proposed by introducing empirical factors that effectively decrease the I e at high loadlevel. The proposed equation is compared with different code provisions and previous models for predict-ing the deflection. It can proved that the proposed factors gives good estimation for the effective momentof inertia ( I e ) works well for FRP-reinforced concrete beams at high load level
Flexural behaviour of BFRP rebar reinforced concrete beams
2017
Deterioration of concrete structures caused by corrosion of the steel reinforced bar (rebar) inside the structures has led to a significant focus on developing more efficient and sustainable alternatives. Several studies have investigated the ability of Basalt Fibre Reinforced Polymer (BFRP) to be used for structural application in concrete beams. However, the findings have been variable suggesting a more refined experimental model to produce more robust results is needed. Therefore, the overall aim of this study was to improve the current understanding of BFRP rebar reinforced concrete beams’ flexural behaviour. Four class C28/35 concrete beams, reinforced with 8 mm diameter reinforcement elements, made of BFRP and traditional steel, were tested under flexure. The main actions carried out in the experiment were firstly, the recording of failure load and mid-span vertical displacements of the beams. Secondly, observation and investigation of failure modes by removing the concrete fr...
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.
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.
Flexural design of concrete beams reinforced with FRP rebars
Revista IBRACON de Estruturas e Materiais, 2023
The corrosion of steel rebars is the main cause of reinforced concrete degradation, which results in increasing costs with structural rehabilitation and repairs. As a solution, corrosion resistant rebars, such as those of FRP-Fiberreinforced polymer-, have been used to replace conventional steel. This paper describes the development of a design program that calculates the flexural FRP reinforcement of T-shape beams. The possibilities as regards the neutral axis position, failure mode and concrete linear or non-linear behavior define the design scenarios for which their respective equations were deduced. The flexural strengths computed using the deduced equations showed agreement with experimental results for 125 beams, validating the proposed methodology. Since FRP rebars are vulnerable to creep rupture, the sustained stresses must be lower than the maximum allowed by ACI 440.1R-15, which may require increases in areas, modifying the flexural strength. Therefore, the equations to compute the new neutral axis depth and flexural strength based on the adjusted area were deduced and implemented in the computational program. Subsequently, this paper presents design examples considering all scenarios for which the equations were deduced. The design of one Tsection considering different FRP rebars combined to normal and high-performance concretes is also reported. The results showed that beams reinforced with aramid and glass FRP required large areas to avoid creep rupture, whereas the areas of those reinforced by carbon FRP rebars were considerably small; however, they exhibited small curvatures and fragile failure when under-reinforced.
DEVELPOMENT AND APPLICATIONS OF GLASS FIBER BARS AS A REINFORCED IN CONCRETE STRUCTURES
Glass Fiber Reinforced Polymer (GFRP) has become more and more popular as construction material in civil engineering due to its advantages of corrosion-resistance, high strength, nonmagnetic, fatigue-resistance and so on. Glass Fiber-reinforced polymers (GFRP) are being increasingly used in the construction industry. One application is to use GFRP rebar as internal reinforcement in concrete. It is thought that GFRP rebar do not exhibit the type of expansive corrosion exhibited by steel reinforcing bars; GFRP bar reinforcement embedded in concrete will result in longer service-life expectancies. The study of GFRP rebar as internal reinforcement for concrete structures has been developed over recent years, however the rebar does not consider that such internal reinforcement can work in compression. This paper presents the development of the research to be able to get a new kind GFRP rebar for work as internal reinforcement of concrete structures, both in tension and compression, and their mechanical properties: strength, bond,… Analysis and design examples were developed and GFRP-reinforced concrete members were constructed to obtain experimental results that compare with theoretical. Methods discussed are: structural analysis; determination of design values; examination of flexural and shear capacity; precautions to ensure ductility or deformability; and calculations of deformation. A first version program was written for flexural and serviceability analysis and design of concrete sections reinforced with GFRP bars, which is in continuous revision.
Strength and serviceability performance of beams reinforced with GFRP bars in flexure
Construction and Building Materials, 2007
Glass fiber reinforced polymer (GFRP) rebars have been identified as an alternate construction material for reinforcing concrete during the last decade primarily due to its strength and durability related characteristics. These materials have strength higher than steel, but exhibit linear stress-strain response up to failure. Furthermore, the modulus of elasticity of GFRP is significantly lower than that of steel. This reduced stiffness often controls the design of the GFRP reinforced concrete elements. In the present investigation, GFRP reinforced beams designed based on limit state principles have been examined to understand their strength and serviceability performance. A block type rotation failure was observed for GFRP reinforced beams, while flexural failure was observed in geometrically similar control beams reinforced with steel rebars. An analytical model has been proposed for strength assessment accounting for the failure pattern observed for GFRP reinforced beams. The serviceability criteria for design of GFRP reinforced beams appear to be governed by maximum crack width. An empirical model has been proposed for predicting the maximum width of the cracks. Deflection of these GFRP rebar reinforced beams has been predicted using an earlier model available in the literature. The results predicted by the analytical model compare well with the experimental data.