Evaluation of deflection in concrete members reinforced with fibre reinforced polymer (FRP) bars

2002 ◽  
Vol 56 (1) ◽  
pp. 63-71 ◽  
Author(s):  
H.A. Abdalla
Keyword(s):  
Concrete Members ◽  
Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Frp Bars

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.

scholarly journals FLEXURAL CAPACITY OF CONCRETE BEAMS REINFORCED WITH STEEL AND FIBRE‐REINFORCED POLYMER (FRP) BARS

2004 ◽  
Vol 10 (3) ◽  
pp. 209-215
Author(s):  
Hau Yan Leung
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Concrete Members ◽  
Reinforced Polymer ◽  
Beam Design ◽  
Reinforced Concrete Member ◽  
Current Design ◽  
Fibre Reinforced Polymer ◽  
Steel Rebars ◽  
Frp Bars

Although much research on concrete beams reinforced with fibre‐reinforced polymer (FRP) rods has been conducted in recent years, their use still does not receive the attention it deserves from practicising engineers. This is attributed to the fact that FRP is brittle in nature and the collapse of FRP‐reinforced concrete member may be catastrophic. A rational beam design can incorporate a hybrid use of FRP rods and steel rods. Current design codes only deal with steel‐reinforced or FRP‐reinforced concrete members. Therefore in this study some design charts and equations for concrete beam sections reinforced with FRP rods and steel rebars were generated. Results from the theoretical derivations agreed well with experimental data.

A review on experimental flexural cracking in FRP reinforced concrete members

2019 ◽  
Author(s):  
Cristina Barris ◽  
Paula Zubillaga ◽  
Lluis Torres
Keyword(s):  
Reinforced Concrete ◽  
Crack Width ◽  
Design Guidelines ◽  
Flexural Members ◽  
Concrete Members ◽  
Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Maximum Crack ◽  
The Relationship ◽  
Frp Bars

<p>This paper aims to assess the relationship among crack width and several influencing parameters of Fibre Reinforced Polymer (FRP) Reinforced Concrete (RC) flexural members. A database with the results of 133 concrete specimens reinforced with different types of FRP bars available in the literature has been collected and analysed. A bond coefficient <i>k</i>b has been adjusted for the maximum crack width of all specimens by using ACI-440 and ISIS Canada design guidelines in the service range, obtaining a mean bond coefficient of 1.11 and 0.72, respectively. The effect of the surface treatment and modulus of elasticity of the FRP rebar, and the <i>n·</i> ratio on the bond coefficient have been studied, obtaining no significant influence of the studied parameters due to the high scatter of results.</p>

scholarly journals A New Proposal for the Shear Strength Prediction of Beams Longitudinally Reinforced with Fiber-Reinforced Polymer Bars

Buildings ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 86 ◽  
Author(s):  
Czesław Bywalski ◽  
Michał Drzazga ◽  
Mieczysław Kamiński ◽  
Maciej Kaźmierowski
Keyword(s):  
Shear Strength ◽  
Shear Capacity ◽  
Destructive Testing ◽  
Concrete Members ◽  
Reinforced Polymer ◽  
Proposed Model ◽  
Fibre Reinforced Polymer ◽  
Frp Reinforcement ◽  
Non Destructive ◽  
Frp Bars

This paper investigates composite reinforcement with regard to its use as longitudinal reinforcement. The methods used to calculate the shear strength of concrete members reinforced with fibre-reinforced polymer (FRP) bars are analysed. The main parameters having a bearing on the shear strength of beams reinforced with composite bars are defined. A comparative analysis of the shear strength calculating algorithms provided in the available design recommendations concerning FRP reinforcement and formulas derived by others researchers is carried out. A synthesis of the research to date on sheared concrete members reinforced longitudinally with FRP bars is made. The results of the studies relating to shear strength are compared with the theoretical results yielded by the considered algorithms. A new approach for estimating the shear capacity of support zones reinforced longitudinally with FRP bars without shear reinforcement was proposed and verified. A satisfactory level of model fit was obtained—the best among the available proposals. Taking into account the extended base of destructive testing results, the estimation of the shear strength in accordance with the proposed model can be used as an accompanying (non-destructive) method for the empirical determination of shear resistance of longitudinally reinforced FRP bars.

Investigation of bond between fibre-reinforced polymer bars and concrete under sustained loads

2006 ◽  
Vol 33 (11) ◽  
pp. 1426-1437 ◽  
Author(s):  
F Shahidi ◽  
L D Wegner ◽  
B F Sparling
Keyword(s):  
Reinforced Concrete ◽  
Sustained Load ◽  
Reinforcing Bars ◽  
Bond Slip ◽  
Reinforced Polymer ◽  
Sustained Loads ◽  
Fibre Reinforced Polymer ◽  
Term Performance ◽  
Frp Bars

Although the use of fibre-reinforced polymer (FRP) bars to replace steel in reinforced concrete is becoming more common, uncertainty remains concerning the long-term performance of FRP, including the effect of a sustained load on the bond between the FRP bars and the concrete. An experimental study was therefore undertaken to investigate the long-term durability of the bond for various types of bars embedded in concrete: one type of glass FRP, two types of carbon FRP, and conventional steel reinforcing bars. Pullout specimens were tested both statically to failure and under sustained loads for periods of up to 1 year while free-end slip was monitored. Results revealed lower short-term bond strengths for FRP bars relative to steel and significant variability in long-term bond-slip performance among FRP bars of different types. Post-testing investigations revealed damage to bar surfaces at the macroscopic level, as well as broken longitudinal fibres and damage to the surface coatings at the microscopic level.Key words: reinforced concrete, fibre-reinforced polymer (FRP), bond, creep, pullout, sustained loads.

Fibre-reinforced polymer composite bars for the concrete deck slab of Wotton Bridge

2003 ◽  
Vol 30 (5) ◽  
pp. 861-870 ◽  
Author(s):  
Ehab El-Salakawy ◽  
Brahim Benmokrane ◽  
Gérard Desgagné
Keyword(s):  
Field Test ◽  
Remote Monitoring ◽  
Concrete Bridges ◽  
Fibre Optic ◽  
Reinforced Polymer ◽  
Deck Slabs ◽  
Fibre Reinforced Polymer ◽  
Concrete Deck ◽  
Frp Bars ◽  
Deck Slab

A new concrete bridge in the Municipality of Wotton, Quebec, Canada, was constructed using fibre-reinforced polymer (FRP) bars as reinforcement for the deck slab. The new bridge is a girder type with four main girders simply supported over a span of 30.60 m. One half of the concrete deck slab was reinforced with carbon and glass FRP bars, and the other half with conventional steel bars. The design of the reinforced concrete deck slab was made according to sections 8 and 16 of the new Canadian Highway Bridge Design Code. The bridge was well instrumented at critical locations for long-term internal temperature and strain data collection using fibre optic sensors. The construction of the bridge was completed and the bridge opened for traffic in October 2001. The bridge was then tested for service performance using standard truckloads. Design, construction details, and the results of the field test and 1 year of remote monitoring are discussed. Under the same real service and environmental conditions, very similar behaviour was obtained from the FRP (glass and carbon) and steel bars.Key words: concrete bridges, deck slabs, FRP bars, field test, fibre optic sensors, remote monitoring, serviceability.

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.

Long-term deflection prediction of concrete members reinforced with glass fibre reinforced polymer bars

2000 ◽  
Vol 27 (5) ◽  
pp. 890-898 ◽  
Author(s):  
Tara Hall ◽  
Amin Ghali
Keyword(s):  
Glass Fibre ◽  
Steel Reinforced Concrete ◽  
Model Code ◽  
Concrete Members ◽  
Reinforced Polymer ◽  
Reinforced Beams ◽  
Glass Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Glass Fibre Reinforced

This paper presents the results of an experimental investigation of the long-term deflection behaviour of concrete shallow beams reinforced with glass fibre reinforced polymer (GFRP) bars. The long-term deflections of the GFRP-reinforced beams are compared to deflections of identical beams reinforced with steel bars. All beams were under sustained loading for approximately 8 months. The variables were the level of sustained loading and the reinforcement materials: steel or GFRP. The experimental immediate and long-term deflections of both the steel- and the GFRP-reinforced beams were compared to calculated deflections using the CEB-FIP Model Code 1990, and the ACI 318-95 code using the recommendations of ACI Committee 209; these references are for steel reinforced concrete members. The test results indicate that under similar loading conditions and the same reinforcement ratio, the GFRP-reinforced beams had long-term deflections, due to creep and shrinkage, 1.7 times greater than those of the steel-reinforced beams. A comparison of the theoretical and experimental immediate and long-term deflections indicates that the CEB-FIP Model Code 1990 gives reasonable predictions for all beams, and that the ACI 318-95 code, using the ACI Committee 209 recommendations, overestimates the deflections due to the combined effects of creep and shrinkage.Key words: glass fibre reinforced polymer (GFRP), steel, reinforced concrete, long-term, deflections, flexure, elastic modulus.

scholarly journals OPTIMISATION OF THICKNESS OF FIBRE REINFORCED POLYMER SHEETS FOR STRENGTHENING REINFORCED CONCRETE BEAMS WITH FLEXURAL DEFICIENCY

2016 ◽  
Vol 36 (1) ◽  
pp. 45-49
Author(s):  
JM Kaura
Keyword(s):  
Reinforced Concrete ◽  
High Capacity ◽  
Cost Effective ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Beams ◽  
Concrete Members ◽  
Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Reduced Gradient ◽  
Generalized Reduced Gradient

The use of Fiber Reinforced Polymer (FRP) is becoming a widely accepted solution for repairing and strengthening of deteriorated reinforced concrete members, to restore their load carrying capacities. One of the major concerns in the use of FRP is its cost. This therefore calls for the use of efficient and cost effective design approach. Design efficiency in terms of cost can be achieved through optimisation. In the present paper, Generalized Reduced Gradient (GRG) optimisation technique was employed to optimize the strengthening cost of a simply supported reinforced concrete beam strengthened with Fibre Reinforced Polymer (FRP). Optimum design charts for the considered problem were presented. The results showed that considerable savings in thickness can be achieved using FRP of high modulus of elasticity. For example at very high capacity reduction say 70% (kc = 0.3), the required FRP thicknesses for FRP with elastic moduli of 25GPa, 50GPa, 75GPa, 100GPa, 125GPa and 150GPa are respectively equal to 2.5mm, 1.75mm, 0.75mm, 0.6mm, 0.5mm and 0.4mm.  http://dx.doi.org/10.4314/njt.v36i1.7

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