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.

Flexural behaviour of concrete beams internally reinforced with GFRP rods and steel rebars

2003 ◽  
Vol 21 (4) ◽  
pp. 146-157 ◽  
Author(s):  
H.Y. Leung ◽  
R.V. Balendran
Keyword(s):  
Construction Industry ◽  
Concrete Beams ◽  
Concrete Members ◽  
Frp Composite ◽  
Reinforced Polymer ◽  
Beam Design ◽  
Glass Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Glass Fibre Reinforced ◽  
Steel Rebars

Use of fibre‐reinforced polymer (FRP) composite rods, in lieu of steel rebars, as the main flexural reinforcements in reinforced concrete (RC) beams have recently been suggested by many researchers. However, the development of FRP RC beam design is still stagnant in the construction industry and this may be attributed to a number of reasons such as the high cost of FRP rods compared to steel rebars and the reduced member ductility due to the brittleness of FRP rods. To resolve these problems, one of the possible methods is to adopt both FRP rods and steel rebars to internally reinforce the concrete members. The effectiveness of this new reinforcing system remains problematic and continued research in this area is needed. An experimental study on the load‐deflection behaviour of concrete beams internally reinforced with glass fibre‐reinforced polymer (GFRP) rods and steel rebars was therefore conducted and some important findings are summarized in this paper.

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.

Flexural behaviour of concrete beams strengthened with near surface mounted fibre reinforced polymer bars

2010 ◽  
Vol 37 (10) ◽  
pp. 1371-1382 ◽  
Author(s):  
Shehab M. Soliman ◽  
Ehab El-Salakawy ◽  
Brahim Benmokrane
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Near Surface ◽  
Modes Of Failure ◽  
Reinforced Polymer ◽  
External Reinforcement ◽  
Fibre Reinforced Polymer ◽  
Near Surface Mounted ◽  
Frp Bars

Fibre reinforced polymer (FRP) composite materials have been used as internal and external reinforcement for concrete structures. Flexural strengthening of concrete elements using near surface mounted (NSM)–FRP materials are a promising technology. This research is designed to investigate the behaviour of reinforced concrete beams strengthened in flexure with NSM–FRP bars. A total of 20 reinforced concrete beams were tested. Different parameters including internal steel reinforcement ratio, type of NSM–FRP bars, FRP bar diameter, bonded length, and groove size were investigated in this research. Test results showed that the use of NSM–FRP bars is effective in increasing the flexural capacity of concrete beams. In addition, a nonlinear 3D finite element (FE) analysis was used to numerically simulate the behaviour of the test beams. Comparisons between the FE predictions and experimental results showed very good agreement in terms of the load−deflection and load−strain relationships, ultimate capacities, and modes of failure for the tested beams.

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>

Behaviour of reinforced GFRP bars concrete beams having strengthened splices using CFRP sheets

2021 ◽  
pp. 136943322110015
Author(s):  
Akram S. Mahmoud ◽  
Ziadoon M. Ali
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
New Method ◽  
Gfrp Bars ◽  
Reinforced Polymer ◽  
Strength Capacity ◽  
Cfrp Sheet ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer

When glass fibre-reinforced polymer (GFRP) bar splices are used in reinforced concrete sections, they affect the structural performance in two different ways: through the stress concentration in the section, and through the configuration of the GFRP–concrete bond. This study experimentally investigated a new method for increasing the bond strength of a GFRP lap (two GFRP bars connected together) using a carbon fibre-reinforced polymer (CFRP) sheet coated in epoxy resin. A new splicing method was investigated to quantify the effect of the bar surface bond on the development length, with reinforced concrete beams cast with laps in the concrete reinforcing bars at a known bending span length. Specimens were tested in four-point flexure tests to assess the strength capacity and failure mode. The results were summarised and compared within a standard lap made according to the ACI 318 specifications. The new method for splicing was more efficient for GFRP splice laps than the standard lap method. It could also be used for head-to-head reinforcement bar splices with the appropriate CFRP lapping sheets.

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.

scholarly journals Efficacy of Thermally Conditioned Sisal FRP Composite on the Shear Characteristics of Reinforced Concrete Beams

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Tara Sen ◽  
H. N. Jagannatha Reddy
Keyword(s):  
Reinforced Concrete ◽  
Polymer Composite ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Shear Strengthening ◽  
Sisal Fibre ◽  
Reinforced Polymer ◽  
Wide Range ◽  
Fibre Reinforced Polymer ◽  
Fracture Study

The development of commercially viable composites based on natural resources for a wide range of applications is on the rise. Efforts include new methods of production and the utilization of natural reinforcements to make biodegradable composites with lignocellulosic fibers, for various engineering applications. In this work, thermal conditioning of woven sisal fibre was carried out, followed by the development of woven sisal fibre reinforced polymer composite system, and its tensile and flexural behaviour was characterized. It was observed that thermal conditioning improved the tensile strength and the flexural strength of the woven sisal fibre composites, which were observed to bear superior values than those in the untreated ones. Then, the efficacy of woven sisal fibre reinforced polymer composite for shear strengthening of reinforced concrete beams was evaluated using two types of techniques: full and strip wrapping techniques. Detailed analysis of the load deflection behaviour and fracture study of reinforced concrete beams strengthened with woven sisal under shearing load were carried out, and it was concluded that woven sisal FRP strengthened beams, underwent very ductile nature of failure, without any delamination or debonding of sisal FRP, and also increased the shear strength and the first crack load of the reinforced concrete beams.

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