scholarly journals An experimental study on flexural strengthening of RC beams using CFRP sheets

2018 ◽  
Vol 7 (4) ◽  
pp. 2075 ◽  
Author(s):  
Yasmin Murad
Keyword(s):  
Flexural Strength ◽  
Orientation Angle ◽  
Longitudinal Axis ◽  
Flexural Behavior ◽  
Experimental Program ◽  
Rc Beams ◽  
Rc Structures ◽  
Flexural Strengthening ◽  
Cfrp Sheets ◽  
Reinforced Polymer

 The use of carbon fiber reinforced polymer (CFRP) sheets is becoming a widely accepted solution for strengthening and repairing rein-forced concrete (RC) structures. To date, the behavior of RC beams, strengthened with 60˚ and 45˚ inclined CFRP sheets, has not clearly explained. An experimental program is proposed in this paper to investigate the flexural behavior of RC beams strengthened with CFRP sheets. CFRP sheets were epoxy bonded to the tension face to enhance the flexural strength of beams inducing different orientation angles of 0˚, 45˚, 60˚ and 90˚ with the beam longitudinal axis. The study shows that strengthening RC beams with CFRP sheets is highly influenced by the orientation angle of the sheets. The orientation angle plays a key role in changing the crack pattern and hence the failure mode. The influence of CFRP sheets was adequate on increasing the flexural strength of RC beams but the ductility of the beams was reduced. The best performance was obtained when strengthening RC beam obliquely using 45˚ inclined CFRP sheets where the specimen experienced additional deflection and strength of 56% and 12% respectively and the reduction in its ductility was the least. It is recom-mended to strengthen RC beams, which are weak in flexure, using 45˚ inclined CFRP sheets.  

scholarly journals The Influence of CFRP Orientation Angle on the Shear Strength of RC Beams

2018 ◽  
Vol 12 (1) ◽  
pp. 269-281 ◽  
Author(s):  
Yasmin Murad
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Experimental Studies ◽  
Orientation Angle ◽  
Shear Behaviour ◽  
Experimental Program ◽  
Rc Beams ◽  
Cfrp Sheets ◽  
Reinforced Polymer ◽  
Cfrp Sheet

Background:Carbon Fiber Reinforced Polymer (CFRP) sheets are widely used for strengthening and repairing reinforced concrete structures. Previous experimental studies have shown that strengthening Reinforced Concrete (RC) beams with CFRP sheet can be greatly influenced by the configuration, orientation and properties of the CFRP sheets.Objective:The behaviour of RC beams, strengthened with 60° and 45° inclined CFRP sheets, has not clearly explained.Method:Thus, an experimental program, proposed in this paper, investigates the shear behaviour of RC beams strengthened with CFRP sheets under different orientation angles including 0˚, 45˚, 60˚ and 90˚.Result:The study shows that strengthening RC beams with CFRP is highly influenced by the orientation angle of the sheets. The influence of CFRP sheets is remarkable on increasing the ultimate deflection, ductility and shear strength of RC beams.Conclusion:It is beneficial to strengthen RC beams, which are weak in shear, obliquely using 45˚ or 60˚ inclined CFRP sheets.

scholarly journals Flexural Performance of RC Beams Strengthened with Externally-Side Bonded Reinforcement (E-SBR) Technique Using CFRP Composites

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2809
Author(s):  
Md. Akter Hosen ◽  
Fadi Althoey ◽  
Mohd Zamin Jumaat ◽  
U. Johnson Alengaram ◽  
N. H. Ramli Sulong
Keyword(s):  
Absorption Capacity ◽  
Experimental Program ◽  
Rc Beams ◽  
Rc Structures ◽  
Functional Changes ◽  
Flexural Strengthening ◽  
Cfrp Laminates ◽  
Flexural Performance ◽  
Design Loads ◽  
Predicted Values

Reinforced concrete (RC) structures necessitate strengthening for various reasons. These include ageing, deterioration of materials due to environmental effects, trivial initial design and construction, deficiency of maintenance, the advancement of design loads, and functional changes. RC structures strengthening with the carbon fiber reinforced polymer (CFRP) has been used extensively during the last few decades due to their advantages over steel reinforcement. This paper introduces an experimental approach for flexural strengthening of RC beams with Externally-Side Bonded Reinforcement (E-SBR) using CFRP fabrics. The experimental program comprises eight full-scale RC beams tested under a four-point flexural test up to failure. The parameters investigated include the main tensile steel reinforcing ratio and the width of CFRP fabrics. The experimental outcomes show that an increase in the tensile reinforcement ratio and width of the CFRP laminates enhanced the first cracking and ultimate load-bearing capacities of the strengthened beams up to 141 and 174%, respectively, compared to the control beam. The strengthened RC beams exhibited superior energy absorption capacity, stiffness, and ductile response. The comparison of the experimental and predicted values shows that these two are in good agreement.

Flexural Behavior of Reinforced-Concrete (RC) Beams Strengthened with Hemp Fiber-Reinforced Polymer (FRP) Composites

2016 ◽  
Vol 860 ◽  
pp. 156-159
Author(s):  
Seyha Yinh ◽  
Qudeer Hussain ◽  
Winyu Rattanapitikon ◽  
Amorn Pimanmas
Keyword(s):  
Reinforced Concrete ◽  
Fiber Reinforced Polymer ◽  
Flexural Behavior ◽  
Rc Beams ◽  
Fiber Reinforced ◽  
Hemp Fiber ◽  
Flexural Strengthening ◽  
Frp Composites ◽  
Reinforced Polymer ◽  
Fiber Thickness

This experimental study has been conducted on the efficiency of epoxy-bonded hemp fiber reinforced polymer (FRP) composites in flexural strengthening of reinforced concrete (RC) beams. A total of five RC beams were cast and tested up to failure. The test parameters included fiber thickness and strengthening configuration. The experimental results show the capability of hemp FRP composites to increase the loading capacity in flexure of RC beams compared with the un-strengthened beam. The enhancement of ultimate load becomes more significant as the fiber thickness is increased. The effectiveness of strengthened beams in U-wrapped scheme is found greater than strengthened beams in bottom-only scheme. Based on results, it indicates that hemp FRP has a potential to considerably increase the strength and stiffness of the original RC beam.

scholarly journals SHEAR CAPACITY PREDICTION FOR STIRRUP-CORRODED RC BEAMS STRENGTHENED WITH FRP

2019 ◽  
Vol 11 (1) ◽  
pp. 32-39 ◽  
Author(s):  
Ahmed K. El-Sayed
Keyword(s):  
Shear Capacity ◽  
Fiber Reinforced Polymer ◽  
Rc Beams ◽  
Accelerated Corrosion ◽  
Rc Structures ◽  
Cfrp Sheets ◽  
Four Point Bending ◽  
Reinforced Polymer ◽  
Shear Reinforcements ◽  
Corrosion Of Steel

Corrosion of steel reinforcement represents one of the main causes of deterioration and degradation of reinforced concrete (RC) structures. Shear reinforcements (stirrups) as an outer reinforcement in RC beams are more susceptible to corrosion problems and damage. This paper describes an analytical procedure for predicting the shear capacity of stirrup-corroded RC beams strengthened in shear using FRP laminates. The procedure shows how to incorporate the effects of the damages due to corrosion of stirrups into the design equations. An experimental investigation has been conducted to provide experimental data on the shear capacity of RC beams with corrosion-damaged stirrups strengthened using carbon fiber reinforced polymer (CFRP) sheets. The experimental study comprised three beams of 200 mm wide, 350 mm deep, and 2800 mm long. The steel stirrups in the beams were corroded using an accelerated corrosion technique. After CFRP strengthening, the beams were tested in four-point bending under a simply supported span of 2400 mm. The shear capacity of the strengthened beams was predicted using the proposed procedure and compared with the experimental ones. Good correlations were found between the predicted and experimental shear strength of the beams.

scholarly journals TEXTILE REINFORCED MORTAR BASED FLEXURAL STRENGTHENING OF REINFORCED CONCRETE BEAMS

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Muhammad Imran Rafiq ◽  
Ameer Baiee
Keyword(s):  
Reinforced Concrete ◽  
Basalt Fiber ◽  
High Strength ◽  
Reinforced Concrete Beams ◽  
Experimental Program ◽  
Rc Beams ◽  
Rc Structures ◽  
Flexural Strengthening ◽  
Strengthening Technique ◽  
Textile Reinforced Mortar

Strengthening of reinforced concrete (RC) structures is often necessary due to the change of using or to enhance the strength of deteriorated existing RC structures attributed to aging and environmental effects. Interfacial bond between the existing RC member and the strengthening layer is known to be the main factor for any successful strengthening technique. This study investigates the efficiency of utilizing high strength cementitious connectors in preventing the debonding of textile reinforced mortar (TRM) strengthening layer from substrate concrete of RC beams. An experimental program is developed to investigate the effect of strength of mortars and the distribution of cementitious connectors on the behavior of the strengthened beams. TRM comprising eight and sixteen textile basalt fiber layers were utilized in these experiments. The results demonstrate the effectiveness of cementitious connectors on the failure mode of strengthened beams by means of controlling the debonding of TRM. The increase in cracking and ultimate loads is demonstrated due to the strengthening of RC beams using TRM.

Flexural Strengthening of RC Slabs with SRP/SRG: An Experimental-Numerical Comparison

2016 ◽  
Vol 847 ◽  
pp. 381-390 ◽  
Author(s):  
Annalisa Napoli ◽  
Roberto Realfonzo ◽  
Massimo Petracca ◽  
Francesca Candeloro ◽  
Guido Camata ◽  
...  
Keyword(s):  
Nonlinear Behavior ◽  
Cost Effective ◽  
Flexural Behavior ◽  
Numerical Comparison ◽  
Cross Sectional ◽  
Rc Structures ◽  
Flexural Strengthening ◽  
Numerical Predictions ◽  
Reinforced Polymer ◽  
Rc Slabs

Steel reinforced polymer (SRP) and steel reinforced grout (SRG) systems have emerged as promising and cost-effective technologies for the external strengthening of RC structures. An experimental campaign was recently performed to investigate the effectiveness of SRG/SRP systems in increasing the flexural strength of RC slabs. Test results are herein used to validate a Fiber based finite element code developed with the aim of simulating the flexural behavior of SRP/SRG strengthened RC beams/slabs. The model provides an accurate prediction of the cross-sectional response by explicitly modeling each constituent, their position inside the discretized cross-section, and their nonlinear behavior. The satisfactory comparison between numerical predictions and experimental results assessed the accuracy of the developed code.

scholarly journals Flexural strengthening of Reinforced Concrete (RC) Beams Retrofitted with Corrugated Glass Fiber Reinforced Polymer (GFRP) Laminates

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
N. Aravind ◽  
Amiya K. Samanta ◽  
Dilip Kr. Singha Roy ◽  
Joseph V. Thanikal
Keyword(s):  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Fiber Reinforced Polymer ◽  
Load Carrying Capacity ◽  
Rc Beams ◽  
Glass Fiber Reinforced Polymer ◽  
Flexural Strengthening ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Load Carrying

AbstractStrengthening the structural members of old buildings using advanced materials is a contemporary research in the field of repairs and rehabilitation. Many researchers used plain Glass Fiber Reinforced Polymer (GFRP) sheets for strengthening Reinforced Concrete (RC) beams. In this research work, rectangular corrugated GFRP laminates were used for strengthening RC beams to achieve higher flexural strength and load carrying capacity. Type and dimensions of corrugated profile were selected based on preliminary study using ANSYS software. A total of twenty one beams were tested to study the load carrying capacity of control specimens and beams strengthened with plain sheets and corrugated laminates using epoxy resin. This paper presents the experimental and theoretical study on flexural strengthening of Reinforced Concrete (RC) beams using corrugated GFRP laminates and the results are compared. Mathematical models were developed based on the experimental data and then the models were validated.

Fatigue Performance of Corroded RC Beams Strengthened with CFRP Sheets

2011 ◽  
Vol 243-249 ◽  
pp. 5589-5594
Author(s):  
Li Song ◽  
Zhi Wu Yu
Keyword(s):  
Fatigue Behavior ◽  
Effective Cross Section ◽  
Fatigue Performance ◽  
Fiber Reinforced Polymer ◽  
Rc Beams ◽  
Cfrp Sheets ◽  
Reinforced Polymer ◽  
Cross Section Area ◽  
Section Area ◽  
Steel Bars

The paper presents the results of an experimental study on fatigue performance of corroded reinforced concrete (RC) beams repaired with carbon fiber reinforced polymer (CFRP) sheets. Five beams were constructed. One specimen was strengthened and not corroded; another four specimens were corroded and was strengthened with CFRP sheets. Five specimens were tested in fatigue. The results showed that steel bars corrosion reduced the fatigue life significantly while the CFRP strengthening enhanced the fatigue performance significantly. The effects of reinforcement corrosion on fatigue behavior of the strengthening beam can be attributed to a combination of four factors, including deteriorated bond behavior between reinforcement bras and surrounding concrete, loss of effective cross-section area of reinforcement, the stress concentration on steel bars, and degradation of mechanical properties of steel bars.

Experimental Study on Flexural Behavior of Damaged Concrete Beams Strengthened with NSM-CFRP Strips

2012 ◽  
Vol 256-259 ◽  
pp. 1012-1016
Author(s):  
Gu Sheng Tong ◽  
Yong Xiang Wang ◽  
Qiu Lan Wu ◽  
Yong Sheng Liu
Keyword(s):  
Failure Modes ◽  
Fiber Reinforced Polymer ◽  
Flexural Behavior ◽  
Rc Beams ◽  
Near Surface ◽  
Damage Level ◽  
Reinforced Polymer ◽  
Near Surface Mounted ◽  
Strengthen Effect ◽  
Capacity Loading

In order to investigate the strengthen effect of different embedment lengths of the NSM strip on different damage levels. A series of tests were conducted on damaged reinforced concrete (RC) beams in flexure strengthened with near surface mounted (NSM) carbon- fiber-reinforced polymer (CFRP) strips, and initial cracking load, ultimate capacity, loading-deflection curves, and failure modes are examined and analyzed in the paper. The results showed that not only the initial cracking loads and ultimate capacities of the beams are significantly increased，but also the flexural stiffness of the beams in the yield and ultimate behavior stages are improved by using NSM-CFRP strips. The strengthen effect on lower damage level RC beams has no obvious difference with that on non-damaged RC beams. Anchoring of the strip end can increase the ultimate load capacities and decrease the ductility of RC beams. Debonding was found to be the primary failure mode in all cases.

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