Finite element analysis of intermediate crack debonding in fibre reinforced polymer strengthened reinforced concrete beams

2018 ◽  
Vol 45 (10) ◽  
pp. 840-851 ◽  
Author(s):  
Michael Cohen ◽  
Agostino Monteleone ◽  
Stanislav Potapenko
Keyword(s):  
Reinforced Concrete ◽  
Crack Propagation ◽  
Damage Mechanics ◽  
Rate Of Change ◽  
Reinforced Concrete Beams ◽  
Element Analysis ◽  
Reinforced Polymer ◽  
Discrete Crack ◽  
External Reinforcement ◽  
Fibre Reinforced Polymer

The performance of the fibre reinforced polymer (FRP) to reinforced concrete (RC) interface is vital to ensure desired design capacity. Without proper understanding of the interfacial behaviour it is impossible to develop an effective, efficient, and rational bonding technique. This paper presents the results of a comprehensive numerical investigation aimed to assess and better understand the debonding behaviour caused by different types of intermediate flexural crack distributions in FRP–RC strengthened beams. The model is based on damage mechanics modelling of concrete, a bilinear bond–slip relationship with softening to represent the interface, and a discrete crack approach to simulate crack propagation. The model also highlights how crack propagation and debonding is affected by the rate of change of moment. It is shown that the variation of crack spacing and rate of change of moment can significantly affect debonding crack propagation and strain development in the internal and external reinforcement, which directly influences debonding load.

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.

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.

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.

Behaviour of reinforced concrete beams strengthened with carbon fibre reinforced polymer laminates subjected to corrosion damage

2000 ◽  
Vol 27 (5) ◽  
pp. 1005-1010 ◽  
Author(s):  
Khaled A Soudki ◽  
Ted G Sherwood
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fibre ◽  
Concrete Beams ◽  
Corrosion Damage ◽  
Corrosion Process ◽  
Reinforced Concrete Beams ◽  
Cfrp Laminates ◽  
Reinforced Polymer ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer

The viability of carbon fibre reinforced polymer (CFRP) laminates for the strengthening of corrosion damaged reinforced concrete bridge girders is addressed in this paper. Ten reinforced concrete beams (100 × 150 × 1200 mm) with variable chloride levels (0-3%) were constructed. Six beams were strengthened by externally epoxy bonding CFRP laminates to the concrete surface. The tensile reinforcements of three unstrengthened and four strengthened specimens were subjected to accelerated corrosion by means of impressed current to 5, 10, and 15% mass loss. Strain gauges were placed on the CFRP laminates to monitor and quantify tensile strains induced by the corrosion process. Following the corrosion phase, the specimens were tested in flexure in a four-point bending regime. Test results revealed that CFRP laminates successfully confined the corrosion cracking, and the total expansion of the laminate exhibited an exponential increase throughout the corrosion process. All the strengthened beams exhibited increased stiffness over the unstrengthened specimens and marked increases in the yield and ultimate strength. The CFRP strengthening scheme was able to restore the capacity of corrosion damaged concrete beams up to 15% mass loss.Key words: CFRP laminates, corrosion, confinement, expansion, load tests, strengthening, bond strength, reinforced concrete.

Structural behaviour of pre-damaged reinforced concrete beams strengthened with natural fibre reinforced polymer composites

2020 ◽  
Vol 244 ◽  
pp. 112309 ◽  
Author(s):  
Tidarut Jirawattanasomkul ◽  
Suched Likitlersuang ◽  
Nattamet Wuttiwannasak ◽  
Tamon Ueda ◽  
Dawei Zhang ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Polymer Composites ◽  
Concrete Beams ◽  
Natural Fibre ◽  
Reinforced Concrete Beams ◽  
Structural Behaviour ◽  
Reinforced Polymer ◽  
Fibre Reinforced Polymer
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