Design Method of Reinforced Concrete Beams Strengthened with Prestressed CFRP Plates Base on Ductility

2011 ◽  
Vol 243-249 ◽  
pp. 5517-5522
Author(s):  
Lang Ni Deng ◽  
Jun Zhang ◽  
Hua Chen ◽  
Peng Zhang
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Design Method ◽  
Rectangular Cross Section ◽  
Engineering Application ◽  
Design Methods ◽  
Reinforced Concrete Beams ◽  
Initial Tension ◽  
Reinforced Polymer ◽  
Plate Area

For reinforced concrete beams strengthened with prestressed carbon fiber reinforced polymer (CFRP) plates, design methods are derived for determining the allowable plate area or initial tension control stress of CFRP plate to achieve a targeted value of ductility. The derivation of equilibrium and compatibility equations for a rectangular cross section is presented. Base on the test of 2 reinforced concrete beams strengthened with prestressed CFRP plates, analytical results are compared with experimental results. Comparisons show that the design methods have good applicability. It can provide a reference for engineering application of strengthening design.

Review of shear design methods for reinforced concrete beams strengthened with fibre reinforced polymer sheets

2001 ◽  
Vol 28 (2) ◽  
pp. 271-281 ◽  
Author(s):  
Christophe Deniaud ◽  
JJ Roger Cheng
Keyword(s):  
Reinforced Concrete ◽  
Glass Fibre ◽  
Mechanical Model ◽  
Concrete Beams ◽  
Design Methods ◽  
Reinforced Concrete Beams ◽  
Test Results ◽  
Shear Design ◽  
Reinforced Polymer ◽  
Fibre Reinforced Polymer

This paper reviews the different shear design methods found in the literature for reinforced concrete beams strengthened externally with fibre reinforced polymer (FRP) sheets and compares the adequacy of each method by using the test results from the University of Alberta. The FRP shear design methods presented include the effective FRP strain and the bond mechanism criteria, the strut-and-tie model, the modified compression field theory, and a mechanical model based on the strip method with shear friction approach. Sixteen full-scale T-beam test results were used in the evaluation. Two web heights of 250 and 450 mm and two ready mix concrete batches of 29 and 44 MPa were used in the test specimens. Closed stirrups were used with three spacings: 200 mm, 400 mm, and no stirrups. Three types of FRP were used to strengthen externally the web of the T-beams: (i) uniaxial glass fibre, (ii) triaxial (0/60/–60) glass fibre, and (iii) uniaxial carbon fibre. The results showed that the mechanical model using the strip method with shear friction approach evaluates better the FRP shear contribution. The predicted capacities from this mechanical model are also found conservative and in excellent agreement with the test results.Key words: beams, carbon fibres, composite materials, fibre reinforced polymers, glass fibres, rehabilitation, reinforced concrete, shear strength, sheets, tests.

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.

Numerical Analysis of Reinforced Concrete Beam Strengthened with CFRP or GFRP Laminates

2016 ◽  
Vol 707 ◽  
pp. 51-59 ◽  
Author(s):  
Osama Ahmed Mohamed ◽  
Rania Khattab
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Ultimate Load ◽  
Concrete Beams ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced

The behaviour of reinforced concrete beam strengthened with Carbon Fiber Reinforced Polymer (CFRP) and Glass fiber reinforced polymer GFRP laminates was investigated using finite element models and the results are presented in this paper. The numerical investigation assessed the effect of the configuration of FRP strengthening laminates on the behaviour of concrete beams. The load-deflection behaviour, and ultimate load of strengthened beam were compared to those of un-strengthened concrete beams. It was shown that using U-shaped FRP sheets increased the ultimate load. The stiffness of the strengthed beam also increased after first yielding of steel reinforcing bars. At was also observed that strengthening beams with FRP laminates to one-fourth of the beam span, modifies the failure of the beam from shear-controlled near the end of the unstrengthened beam, to flexure-controlled near mid-span. CFRP produced better results compared GFRP in terms of the ability to enhance the behavior of strengthenened reinforced concrete beams.

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