Comparative Study on Deflection Calculation for Concrete Flexural Members with Fiber Reinforced Polymer Reinforcement

2011 ◽  
Vol 183-185 ◽  
pp. 1979-1983
Author(s):  
Jiang Yong Cai ◽  
Xi Bo Zhou ◽  
Xiong Jia ◽  
Yan Tao He
Keyword(s):  
Concrete Beams ◽  
Reinforce Concrete ◽  
Fiber Reinforced Polymer ◽  
New Method ◽  
Flexural Members ◽  
Modified Method ◽  
Reinforced Polymer ◽  
Steel Bars ◽  
Frp Bars ◽  
Good Agreement

The application and development of FRP bars for reinforce concrete structures necessitates the need for either adopt the current code method or exploiting a new design one to account for the properties of FRP materials. The method for predicting deflection of concrete beams with FRP bars in ACI440 is based on the method for that with steel bars in ACI318. Similarly, a modified method based on GB50010 is proposed in this paper to estimate deflection of concrete beams with FRP bars. Furthermore, the new method, together with ACI318, ACI440 and GB50010 ones, are verified by nine test beams in three existing experiment and show a good agreement with the experimental data. Simultaneously, the new method is also proved to be of the most precise and accurate one and indicates the potential of the method to estimate deflection in Chinese code system.

Comparative Study on Crack Width Prediction for Concrete Flexural Members with GFRP Reinforcement

2011 ◽  
Vol 194-196 ◽  
pp. 989-992 ◽  
Author(s):  
Jiang Yong Cai ◽  
Ying Ying Liu ◽  
Xue Liang Wang ◽  
Jing Liang Xiong ◽  
Hong Xia Wan ◽  
...  
Keyword(s):  
Crack Width ◽  
Concrete Beams ◽  
New Method ◽  
Flexural Members ◽  
Modified Method ◽  
Reinforced Polymer ◽  
Steel Bars ◽  
Corrosion Problem ◽  
Frp Bars ◽  
Crack Widths

Fiber reinforced polymer (FRP) bars are being used as an alternative to steel bars to overcome the corrosion problem. Design criteria and methods have to be reinterpreted for its different properties, and several countries have already established corresponding design codes. The method for predicting crack widths of concrete beams with FRP bars provided in ACI440 is based on the method for that with steel bars. Similarly, a modified method based on GB50010 is proposed in this paper to estimate crack widths of concrete beams with FRP bars. Furthermore, the new method together with ACI440 and GB50010 ones are verified by nine test beams in three existing experiments and most of them show a good agreement with the experimental data. Simultaneously, the new method also proves precise and accurate with the same level as the ACI440 one and indicates its potential to estimate crack width in Chinese concrete code system.

NUMERICAL ANALYSIS OF CONCRETE BEAM REINFORCED WITH GLASS FIBER REINFORCED POLYMER BARS

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Osama A. Mohamed ◽  
Rania Khattab
Keyword(s):  
Finite Element ◽  
Numerical Analysis ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Reinforcing Bars ◽  
Gfrp Bars ◽  
Reinforced Polymer ◽  
Steel Bars ◽  
Frp Bars

The use of fiber reinforced polymer (FRP) bars to reinforce concrete beams has received significant attention in the past decade due to their corrosion resistance, high tensile strength, and excellent non-magnetic properties. Glass FRP (GFRP) reinforcing bars have gained popularity due to the relatively lower cost compared to carbon FRP (CFRP) bars. In this study, sixteen concrete beam finite element models were created using the finite element computer program ANSYS to perform linear and non-linear analyses. Twelve beams were longitudinally reinforced with GFRP bars, while the remaining four beams were reinforced with conventional steel bars as control specimens. In terms of mechanical properties, FRP reinforcing bars have lower modulus of elasticity compared to conventional reinforcing steel and remain linear elastic up to failure. This leads to lack of plasticity and a brittle failure of beams reinforced with FRP bars. The objective of this study is to investigate flexural behavior of concrete beams reinforced with GFRP reinforcing bars. Some of the parameters incorporated in the numerical analysis include longitudinal reinforcement ratio and compressive strength of concrete, both of which affect the flexural capacity of beams. It is shown in this study that replacement of traditional reinforcing steel reinforced bars by GFRP bars significantly decreases mid-span deflection and increases ultimate load. The strain distribution along GFRP longitudinal reinforcing bars is totally different from that of traditional steel bars.

Deflection and Crack-Width Prediction of Partially Boned CFRP Concrete Beams

2010 ◽  
Vol 168-170 ◽  
pp. 2182-2185
Author(s):  
Yu Deng ◽  
Jiong Feng Liang
Keyword(s):  
Crack Width ◽  
Concrete Beams ◽  
Experimental Results ◽  
Fiber Reinforced Polymer ◽  
Reinforced Polymer ◽  
Low Modulus ◽  
Monotonic Loads ◽  
Frp Bars ◽  
Unbonded Length ◽  
Good Agreement

Concrete beams reinforced with fiber reinforced polymer(FRP)bars exhibit large deflections and crack widths as compared to concrete beams reinforced with steel due to the low modulus of elasticity of FRP. Consequently,in many cases,serviceability requirements may govern the design of such members. This paper describes six partial bonded concrete beams prestressed with CFRP tendons are tested under monotonic loads. deformation and crack width of this kind of beams with varying unbonded length are systematically investigated. The predictions of the 《Code for Design of Concrete Structures》（GB50010－2002）equations are compared with the experimental results obtained by testing six partial bonded concrete beams prestressed with CFRP tendons. Good agreement was shown between the theoretical and the experimental results.

Minimum thickness of concrete members reinforced with fibre reinforced polymer bars

2001 ◽  
Vol 28 (4) ◽  
pp. 583-592 ◽  
Author(s):  
Amin Ghali ◽  
Tara Hall ◽  
William Bobey
Keyword(s):  
Reinforced Concrete ◽  
Minimum Thickness ◽  
Reinforced Polymers ◽  
Flexural Members ◽  
Steel Reinforced Concrete ◽  
Concrete Members ◽  
Reinforced Polymer ◽  
Steel Bars ◽  
Fibre Reinforced Polymer ◽  
Frp Bars

To avoid excessive deflection most design codes specify the ratio (l/h)s, the span to minimum thickness of concrete members without prestressing. Use of the values of (l/h)s specified by the codes, in selecting the thickness of members, usually yields satisfactory results when the members are reinforced with steel bars. Fibre reinforced polymer (FRP) bars have an elastic modulus lower than that of steel. As a result, the values of (l/h)s specified in codes for steel-reinforced concrete would lead to excessive deflection if adopted for FRP-reinforced concrete. In this paper, an equation is developed giving the ratio (l/h)f for use with FRP bars in terms of (l/h)s and (εs/εf), where εs and εf are the maximum strain allowed at service in steel and FRP bars, respectively. To control the width of cracks, ACI 318-99 specifies εs = 1200 × 10–6 for steel bars having a modulus of elasticity, Es, of 200 GPa and a yield strength, fy, of 400 MPa. At present, there is no value specified for εf; a value is recommended in this paper.Key words: concrete, cracking, deflection, fibre reinforced polymers, flexural members, minimum thickness.

Deflection Prediction of FRP-Strengthened Reinforced Concrete Beams

2011 ◽  
Vol 243-249 ◽  
pp. 621-624
Author(s):  
Gui Bing Li ◽  
Yu Gang Guo
Keyword(s):  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Rc Beams ◽  
Test Results ◽  
Structural Members ◽  
Modified Model ◽  
Reinforced Polymer ◽  
Service Load ◽  
Good Agreement

Bonding fiber reinforced polymer (FRP) laminates to the tension face of RC members has been proven to be an effective method to improve the flexural strength. However, structural members are not only needed to have adequate strength, but also to have adequate performance of deformation at service load levels. To evaluate the deflection of externally FRP-strengthened RC beams, a total of 18 RC beams, including 16 beams strengthened with CFRP laminate under different preload levels and 2 control beams, were tested. Based on the assumption that the section of the beam behaves a tri-linear moment-curvature response characterized by pre-crack stage, post-crack stage and failure stage and the test results, this paper presents a modified model to evaluate the deflection of CFRP-strengthened RC beams. The present modified model was verified by the similar test results, and shows a good agreement with the test results.

Concrete flexural members reinforced with fiber reinforced polymer: design for cracking and deformability

2002 ◽  
Vol 29 (1) ◽  
pp. 125-134 ◽  
Author(s):  
John Newhook ◽  
Amin Ghali ◽  
Gamil Tadros
Keyword(s):  
Cross Sectional Area ◽  
Fiber Reinforced Polymer ◽  
Sectional Area ◽  
Fiber Reinforced ◽  
Cross Sectional ◽  
Flexural Members ◽  
Crack Control ◽  
Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Frp Bars

Fiber reinforced polymer (FRP) bars have lower modulus of elasticity than steel bars. For this reason when FRP bars are used as flexural nonprestressed reinforcement in concrete sections, the stress in the FRP is limited to a relatively small fraction of its tensile strength. This limit, necessary to control width of cracks at service, governs design of the required cross-sectional area of the FRP. Parametric studies on rectangular and T-sections are presented to show that the design based on allowable strain in the FRP results in sections that exhibit large deformation before failure. The concept of deformability, given in the Canadian Highway Bridge Design Code, as a requirement in the design of sections is discussed and modifications suggested. Using the new definition, it is shown that when, in addition to the crack control requirement, an upper limit is imposed on the cross-sectional area of the FRP, no calculations will be necessary to check the deformability.Key words: fibre reinforced polymer, reinforcement, concrete, design, deformability.

scholarly journals Behavior of Cross Arms Inserted in Concrete-Filled Circular GFRP Tubular Columns

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2280 ◽  
Author(s):  
Fang Xie ◽  
Ju Chen ◽  
Qian-Qian Yu ◽  
Xinlong Dong
Keyword(s):  
Fiber Reinforced Polymer ◽  
Stress And Strain ◽  
Tubular Columns ◽  
Reinforced Polymer ◽  
Steel Bars ◽  
Structural Responses ◽  
The Cross ◽  
Experimental Findings ◽  
Glass Frp ◽  
Good Agreement

Fiber-reinforced polymer (FRP) materials nowadays have attracted much attention in both retrofitting of aged infrastructure and developing of new structural systems attributed to the outstanding mechanical properties. Extensive studies have been performed on concrete-filled glass FRP (GFRP) tubes for the potential application in piling, poles, highways overhead sign structures and bridge components. The new hybrid member also provides an alternative solution for traditional transmission structures. However, the connection between concrete-filled GFRP tubes and cross arms has not been fully understood. In this paper, an experimental study and theoretical analysis were conducted on the behavior of cross arms inserted in concrete-filled circular GFRP tubular columns. Steel bars with a larger stiffness in comparison with GFRP tubes were selected here for the cross arm to simulate a more severe scenario. The structural responses of the system when the cross arms were subjected to concentrated loads were carefully recorded. Experimental results showed that the concrete-filled GFRP tubes could offer a sufficient restraint to the deformation of the cross arm. No visible cracks were found on the GFRP tube at the corner of the cross arm where the stress and strain concentrated. Theoretical solutions based on available theories and equations were adopted to predict the displacement of the cross arms and a good agreement was achieved between the prediction results and experimental findings.

Research on the Flexural Behaviour of Reinforced Concrete Beams Strengthened with CFRP

2011 ◽  
Vol 194-196 ◽  
pp. 1781-1784
Author(s):  
Hua Wei ◽  
Ji Ye Zhang ◽  
Da Wei Zhu ◽  
Zhi Yuan Peng ◽  
Hai Jun Wang
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Ultimate Load ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Experimental Result ◽  
Reinforced Polymer ◽  
Flexural Member ◽  
Good Agreement

In order to clear the influence of carbon fiber reinforced polymer (CFRP) on the bearing capacity of reinforced concrete beams, tests of three reinforced concrete beams strengthened with CFRP are carried out. Experimental result shows that CFRP can effectively increase bearing capacity of flexural member, and can restrain the development of crack. Cracking load, yield load and ultimate load are significantly increased. At the same time numerical simulation is done; it is good agreement with experimental results.

Experimental Study on Behavior of Flexural Member with Lab-Spliced GFRP Bar

2010 ◽  
Vol 452-453 ◽  
pp. 781-784 ◽  
Author(s):  
Yun Cheul Choi ◽  
Hyun Ki Choi ◽  
Chang Sik Choi
Keyword(s):  
Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Design Procedures ◽  
Gfrp Bars ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Low Elastic Modulus ◽  
Steel Bars ◽  
Flexural Member ◽  
Strain Relationship

The use of glass-fiber-reinforced polymer (GFRP) bars to replace steel reinforcement in concrete structures is a relatively new technique. GFRP bars possess mechanical properties different from steel bars, including high tensile strength combined with low elastic modulus and elastic brittle stress–strain relationship. Therefore, design procedures should account for these properties. This paper presents the experimental moment deflection relations of GFRP reinforced beam which are spliced. Test variables were lab-spliced length of GFRP rebar. A total of 6 concrete beams reinforced with steel and GFRP rebar tested. Three concrete beams reinforced with spliced GFRP rebar and 1 reference beams reinforced with non-spliced GFRP rebar was tested. All the specimens had a span of 4000mm, provided with 12.7mm nominal diameter steel and GFRP rebar. All test specimens were tested under 2-point loads so that the spliced region is subject to constant moment. The experimental results show that the splice length of GFRP increased with the ultimate load increasing and decreased with stiffness.

scholarly journals Behavior of concrete beams reinforced with FRP during bending

2021 ◽  
Vol 263 ◽  
pp. 02052
Author(s):  
Igor Gorbunov ◽  
Vladimir Kakusha
Keyword(s):  
Crack Formation ◽  
Concrete Beams ◽  
Bending Moment ◽  
Bending Stiffness ◽  
Fiber Reinforced Polymer ◽  
Strain Behavior ◽  
Linear Elastic ◽  
Reinforced Polymer ◽  
Glass Frp ◽  
Frp Bars

Article describes methods and results of experimental research for strain behavior, crack formation and fracture of concrete beams reinforced with fiber reinforced polymer (FRP) bars during bending moment action. 18 beams (3+3 series) reinforced with glass FRP (GFRP) and basalt (BFRP) 6, 10 and 14 mm in diameter were tested. Deflection in the middle of the beam, concrete and bars strain and ultrasonic transmission time for 4 routes were measured during tests besides visual inspection. Main crack formation occurred at 8-20% of the ultimate load for all beams. Crack formation was transition border to linear (elastic) straining at low bending stiffness. More than 15 times decrease in bending stiffness was seen for beam reinforced with two types of bars 6 mm in diameter compared to initial values. Existence of main cracks and major deflections is not allowed during design of bending elements. However small bending stiffness at linear elastic straining is a positive factor in case of «hard» loading and impact (pulsed) loading. It is possible to prevent structures collapse and people deaths at impact loading and cyclic «hard» loading by permitting crack formation in load bearing structures.

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