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.

Analytical models to predict structural behaviour of reinforced concrete beams bonded with prestressed fibre-reinforced polymer laminates

2017 ◽  
Vol 21 (4) ◽  
pp. 532-544
Author(s):  
MS Mohamed Ali
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Analytical Models ◽  
Experimental Investigations ◽  
Poor Correlation ◽  
Reinforced Polymer ◽  
Wide Range ◽  
Fibre Reinforced Polymer ◽  
Polymer Laminates

The strengthening of reinforced concrete members with prestressed fibre-reinforced polymer laminates has been investigated by researchers due to major improvements in member serviceability characteristics. Currently, analytical models generally employ mostly empirical procedures in predicting member behaviour, and as a result, the analytical results exhibit poor correlation to experimental investigations. In this article, an analytical model is developed using new and existing theoretical techniques to critically analyse strengthened reinforced concrete beams for a range of loading scenarios to generate moment–rotation and load–deflection relationships. The prestress level and the intermediate crack debonding strain of the prestressed fibre-reinforced polymer laminate with the inclusion of mechanical end anchorage were highlighted as key parameters within the model. The proposed model adopts closed-form solutions to allow for a wide range of beams with varying steel and fibre-reinforced polymer reinforcement ratios and dimensions. The model incorporates calibrated crack spacing theory to predict the crack width and spacing as well as the length of the cracked region in the beam. The models have good correlation with collected experimental data and thus can be used for the analysis of reinforced concrete beams strengthened with prestressed fibre-reinforced polymer, throughout all stages of loading from serviceability to failure.

scholarly journals Flexural behaviour of reinforced concrete beams strengthened with pre-stressed and near surface mounted steel–basalt-fibre composite bars

2019 ◽  
Vol 23 (6) ◽  
pp. 1154-1167
Author(s):  
Yajun Zhao ◽  
Yimiao Huang ◽  
Haiyang Du ◽  
Guowei Ma
Keyword(s):  
Reinforced Concrete ◽  
Polymer Composite ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Basalt Fibre ◽  
Near Surface ◽  
Reinforced Polymer ◽  
Load Carrying ◽  
Fibre Reinforced Polymer ◽  
Near Surface Mounted

Fibre-reinforced polymer bars have been widely used for strengthening concrete members due to their high strength, light weight and strong corrosion resistance. A near-surface mounted strengthening system has been adopted to protect the fibre-reinforced polymer bars from external hazards. To make up the lower stiffness and ductility of fibre-reinforced polymer bar compared to steel rebar, this study proposed to use a pre-stressed near-surface mounted steel–basalt-fibre-reinforced polymer composite bar. The steel–basalt-fibre-reinforced polymer composite bar is manufactured through wrapping a steel rod by a basalt-fibre-reinforced polymer cover. A total of nine reinforced concrete beams, including one control or calibration and eight others strengthened by pre-stressed near-surface mounted steel–basalt-fibre-reinforced polymer composite bars, are fabricated and tested. Results show that the proposed steel–basalt-fibre-reinforced polymer composite bar strengthening method can improve both the strength and ductility of the reinforced concrete beams. Pre-stressing of the steel–basalt-fibre-reinforced polymer composite bars further increases substantially the beams’ load-carrying capacity by restraining crack propagation in concrete. Standard-based load analysis correctly predicts the cracking load, however, underestimates the ultimate strength of the beams. Finite element method modelling is conducted to provide a more effective load-carrying capacity prediction and a case study is carried out with regard to the amount of the strengthening steel–basalt-fibre-reinforced polymer composite bars.

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.

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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