Carbon Fiber Reinforced Polymer Strips Research Articles

Prediction of shear strength of CFRP-strengthened reinforced recycled aggregate concrete beams using various strengthening methods

Fibre reinforced polymer (FRP) strengthening is a possible option when the load carrying capacity of a structure needs to be increased for various reasons. On the other hand, the focus nowadays aims to save the environment by reducing the waste material. A suggestion was made to use waste concrete as an aggregate. If this new material was used more, it would be possible to use recycled concrete aggregate (RCA) and carbon fibre reinforced polymer (CFRP) to strengthen reinforced concrete (RC) structures and make them more environmentally friendly. An experimental investigation study on the shear behaviour of RC beams strengthened with CFRP strips was carried out. Tests were conducted on six reinforced concrete beams, with variations in the replacement ratio of RCA and strengthened by different configurations of CFRP under four-point loading. The results indicated that the load carrying capacity was increased, on average, by 18.09 and 35.04% for beams strengthened with CFRP with an inclined strip (IS) and continuous strip (CS) configurations respectively. The results also indicated that the increases in the stiffness were 21.08 and 37.31 for beams strengthened with CFRP in the IS and CS configurations, respectively. In addition the ductility of the beams increased after strengthening.

Shear strengthening performance of GFRP reinforced lightweight SCC beams: Experimental and analytical study

Light weight construction using Glass Fibre-Reinforced Polymer (GFRP) bars and structural light weight concrete (LWC) have increased recently and offers a wide spectrum of advantages over traditional normal weight concrete (NWC) structures. However, the shear strengthening and rehabilitation performance of LWC beams reinforced with GFRP bars is very limited and currently there are no guidelines related to it. Therefore, this study presents the results of an experimental investigation on the shear strengthening behaviour of lightweight self-consolidating concrete (LWSCC) beams reinforced with GFRP bars. The test parameters studied in the experimental program were the longitudinal reinforcement ratio and strip configuration or orientation. A total of twelve shear deficient GFRP reinforced beams were prepared with a shear span to depth ratio of 3.12 and subjected to static four-point bending. Five beams in each series were externally strengthened with different configurations of Carbon Fibre-Reinforced Polymer (CFRP) strips and one beam served as a control specimen to compare the performance of the strengthened specimens. Crack patterns, load–displacement response curves, and strain in the external CFRP strips were recorded until the failure ultimate load. The results of the experimental study indicated that the external CFRP strips improved the nominal shear capacity of GFRP reinforced LWSCC beams, and the contribution of external CFRP strips was sensitive to the reinforcement ratio. The nominal shear capacity of the strengthened specimens increased from 33.3 to 168% compared to the control specimen. U-wraps with horizontal strips in the compression and tension zone were the most effective configuration, showing the highest increase in shear strength compared to other strengthened specimens. Moreover, the shear capacity was theoretically predicted using different Fiber-Reinforced Polymer (FRP) design standards and guidelines which were compared with the experimental results. All the FRP design standards have overestimated the shear capacity of LWSCC beams, and a modified equation with a set of recommendations was proposed based on the experimental study. In addition, a reduction factor of 0.75 is recommended for conservative design.

Impact behavior of low strength concrete slab strengthened with fan type anchored carbon fiber‐reinforced polymer strips

AbstractThis study investigated the behavior of slabs produced with low compressive strength concrete without reinforcements under the effect of sudden dynamic impact loading. In addition, an experimental study was conducted by proposing a strengthening method with anchored carbon fiber‐reinforced polymer (CFRP) strips to strengthen the nonreinforced slabs with low‐strength concrete against sudden dynamic impact loads to improve their performance. The variables examined in the experimental study were the placement of the CFRP strips adhered to the concrete slabs for strengthening purposes and anchors in the strips. A constant energy level of impact loading was applied to the concrete slab test specimens with the authors' free weight drop test setup. The acceleration‐time, displacement‐time, strain‐time, and applied impact loading‐time measurements on the concrete slabs were examined, and comments were made about the strengthening method applied to the slab test specimens. In addition, numerical analysis of the tested concrete slabs with ABAQUS finite element software was performed, and the results were compared with the experimental results. In the comparison, it was investigated to what extent numerical analysis and this type of impact analysis can be done realistically and compatible with the experimental results. Within the scope of the study, the strengthening method applied with fan‐type anchored CFRP strips significantly improved and increased the impact performance of concrete slabs produced with low‐strength concrete.

Experimental assessment of the thermo-mechanical bond behavior of NSM CFRP with cement-based adhesives

Cement-based materials, which are incombustible and show low thermal diffusivity, show great potential as a valid alternative to polymeric matrices for bonding near surface mounted (NSM) carbon fiber reinforced polymer (CFRP) systems for the strengthening of reinforced concrete (RC) structures. The performance of these materials in different loading conditions, including high temperature exposure, still needs to be better explored. This paper presents a study on the characterization of the bond behavior using cement-based adhesives and CFRP strips with innovative surface treatment. The CFRP strips used in this study were manufactured specifically with sand-treated surfaces to improve the bonding performance between CFRP and cement-based adhesive by taking advantage of the better grip of increased roughness surfaces. The results of the pull-out tests in ambient conditions, as well as exposed to elevated temperatures, are presented and discussed. The effect of using sand particles of different sizes, adhered with two different resins on the CFRP strips surface embedded in different cement-based matrices, was compared. The obtained results showed that by applying a sand treatment on the surface of CFRP strips, the maximum pull-out force was up to 12 times higher than when using smooth surfaced strips. Pull-out tests showed that, by using the NSM sand treated CFRP strips and CFRP bars with cement-based adhesive, an average bond strength up to about 9 MPa and 11 MPa, respectively, could be achieved. Thermo-mechanical pull-out tests showed the proposed strengthening system is able to withstand up to 30 min of heat exposure before bond failure.

Prediction of fatigue crack propagation in center cracked steel plate strengthened with prestressed CFRP strip

Evaluating the fatigue behavior of steel structures strengthened with prestressed carbon fiber reinforced polymer (CFRP) is of great significance for structural repair and rehabilitation. In this paper, an analytical model based on linear elastic fracture mechanics considering the additional elongation of the steel plate caused by the central crack opening was proposed to predict the fatigue behavior of prestressed CFRP strips strengthened steel plates. The finite element model calibrated by experiments was used to verify the proposed model. The results showed that the proposed model can predict the stress state of various components, the stress intensity factor SIF amplitude, the fatigue crack growth life, and the minimum prestress of CFRP strips required for crack arrest under different strengthening conditions with high accuracy. This study will be conducive to a better application of the prestressed CFRP strengthening of thin-walled steel structures under fatigue loading.

Experimental and Numerical Investigations on Seismic Behavior of RC Beam to PVC-CFRP Confined Concrete Column Exterior Joint with Steel Tube Connector

Recently, substantial investigations were developed on a polyvinyl chloride (PVC)-carbon fiber-reinforced polymer (CFRP) confined concrete (PFCC) structure owing to its superior mechanical behavior and durability. However, a convenient and effective joint configuration between the PFCC columns and reinforced concrete (RC) beams still requires in-depth study. In the present work, the seismic performance of an RC beam to PFCC column exterior joint with steel tube connector (STC) is systematically studied. Eleven joint specimens are fabricated and tested, with the steel ratio of STC, reinforcement ratio of the frame beam, axial compression ratio, stirrup ratio of the joint and CFRP strips spacing as the design parameters. The experimental results, that is, 8 the failure modes, hysteretic response, ductility, strength, stiffness and energy dissipation, are analyzed. All specimens exhibit joint shear failure, although the joints with STC exhibit significantly better performance those of ordinary joint. In addition to reducing the axial compression ratio, the reinforcement ratio of the frame beam or increasing the stirrup ratio of the joint can also produce a positive effect. Furthermore, the numerical analysis of the exterior joints is performed; the calculated skeleton curves agree well with the test results, and additional parametric studies (i.e., the diameter, height and concrete strength of the joint) are carried out based on the verified numerical model.

Mechanical analysis and strength assessment of axially-loaded CFRP wrapped circular CFST stub columns with spherical-cap gaps

This paper investigated the strengthening effectiveness of carbon fiber reinforced polymer (CFRP) on the axially-loaded circular concrete-filled steel tubular (CFST) stub columns with spherical-cap gaps. A finite element model was established and validated. The effects of various parameters on the mechanical behavior of the columns were analyzed. Further explorations on the failure mode, stress distribution and contact stress etc. were also discussed. Design equations for predicting their axial compressive strengths were presented. Results declared that the spherical-cap gap weakened the mechanical behavior of the axially-loaded circular CFST stub column, but wrapping CFRP strips could repair or eliminate the adverse effects.

Development of interaction diagrams of reinforced concrete short columns strengthened by NSM-CFRP strips using finite element method

PurposeThe main aim of this study is to examine the behavior of reinforced concrete short columns strengthened using longitudinal near surface mounted (NSM)-carbon fiber reinforced polymer (CFRP) strips.Design/methodology/approachA full 3D-finite element (FE) model was developed using ABAQUS in order to conduct the analysis. The model is first validated based on experimental data available in the literature, and then the effect of concrete compressive strength, number of CFRP strips that are used and the spacing between them were taken in consideration for both concentric and eccentric loading cases. The parametric study specimens were divided into three groups. The first group consisted of unstrengthened columns and served as control specimens. The second group consisted of columns strengthened by longitudinal CFRP strips at two opposite column faces.FindingsThe results of this study are used to develop interaction diagrams for CFRP-strengthened short columns and to develop best-fit equations to estimate the nominal axial load and moment capacities for these strengthened columns. The results showed that the specimens that were strengthened using more longitudinal CFRP strips showed a significant increase in axial load capacity and a significant improvement in the interaction diagram, especially at large load eccentricity values. This result can be justified by the fact that longitudinal strips effectively resist the bending moment that is generated due to eccentric loading. Generally, the process of strengthening using longitudinal strips only has a reasonable effect and it can be typically considered an excellent choice considering the economic aspect when the budget of strengthening is limited.Originality/valueThis research aims at studying the performance of strengthened rectangular reinforced concrete short columns with CFRP strips using FE method, developing interaction diagrams of strengthened columns in order to investigate the effect of different parameters such as compressive strength (20, 30 and 40 MPa), number of CFRP strips (1, 2, 3 and 4) and the spacing between CFRP strips in terms of the ratio of CFRP center point distance to column outside dimension ratio (0.60, 0.70 and 0.80) on the behavior of strengthened RC columns and improving empirical formulas to predict the nominal axial load and moment capacities of strengthened RC columns. These parameters that directly affect short column load carrying capacity are presented in ACI-318 (2014).

Investigation of CFRP Reinforcement Ratio on the Flexural Capacity and Failure Mode of Plain Concrete Prisms.

The utilization of carbon-fiber-reinforced polymer (CFRP) composites as strengthening materials for structural components has become quite famous over the last couple of decades. The present experimental study was carried out to examine the effect of varied widths of externally bonded CFRP on the debonding strain of CFRP and the failure mode of plain concrete beams. Twelve plain concrete prims measuring 100 mm × 100 mm × 500 mm were cast and tested under identical loading conditions. The twelve specimens include two control prisms, i.e., without CFRP strips, and the remaining ten prisms were reinforced with CFRP strips with widths of 10 mm, 20 mm, 30 mm, 40 mm, and 50 mm, respectively, i.e., two prisms in each group. Four-point loading flexural testing was carried out, and the resulting data are presented in the form of peak load vs. midpoint displacement, load vs. concrete strain, and load vs. CFRP strain. The peak load was directly recorded from the testing machine, while the midpoint deflection was recorded through the linear variable differential transducer (LVDT) installed at the midpoint. To measure the strain, two separate strain gauges were installed at the bottom of each concrete prism, i.e., one on the concrete surface and the other on the surface of the CFRP strip. The results of this study indicate that the debonding strain is a function of CFRP strip width and that the failure patterns of beams are significantly affected by the CFRP reinforcement ratio.

A universal solution of the bond behaviour between CFRP-steel double strap joints considering steel yielding

Steel structures strengthened with CFRP (carbon fiber-reinforced polymer) composite may encounter extreme load such as earthquake or impact which may cause steel yielding and plasticity. But very limited investigations exist on the effect of steel yielding on the bond behaviour between CFRP and steel. This paper presents a comprehensive study on the effect of steel yielding on the bond behaviour of CFRP-steel double strap joints. Firstly, a stress-based analytical model is established for the analysis of the ultimate load and failure initiation position of the double strap joints. This is a universal model which is able to analyse elastic joint as well as plastic joint with steel yielding. Then a series of tensile tests with double strap joints is carried out and the experimental results are used to validate the proposed analytical model. Finally, a parametric analysis is performed using the analytical model and an additional numerical method in which the debonding between steel and CFRP strips is simulated by a cohesive approach. The parametric analysis considers both geometrical and material variables. It can be concluded that the steel yielding has a significant effect on the bond behaviour of CFRP-steel double strap joints, including ultimate load, stress and strain distributions of CFRP, steel and adhesive, and debonding initiation position of the joint. Based on the experimental and analytical results, criteria are proposed for the determination of effective bond length and yielding bond length, debonding initiation position and ultimate load of CFRP-steel joints.

An innovative frictional anchorage system for flat CFRP ribbon strips

Unidirectional carbon fibre-reinforced polymer (CFRP) materials represent a promising alternative to steel because of their lightweight, high tensile strength, and excellent corrosion and fatigue resistance. Stress-ribbon structural systems define the potential application object of unidirectional flat CFRP strips. However, anchorage difficulties make this idea problematic—the typical gripping systems are inefficient for anchoring the CFRP ribbons because of the tremendous thrust forces-induced stress concentration. Thus, the innovative frictional spiral anchorage system of the flat CFRP strips is the object of this study, which formulates the design principles for the frictional joins. Furthermore, the proposed theoretical model minimises the gripping system size, satisfying the CFRP strength limitation when the developed modified Archimedean spiral determines the shape of the contact surface. This work experimentally demonstrates the theoretical concept’s adequacy—the mechanical resistance prediction error does not exceed 7% in the loading range covering the service load conditions. In addition, the manuscript presents several examples of frictional gripping systems, including the stress-ribbon pedestrian bridge prototype, and provides further insights into the frictional anchorage systems.

Model for predicting the shear strength and strains of thin concrete panels retrofitted with CFRP

Carbon Fiber Reinforced Polymers (CFRP) can be an alternative material to retrofit thin and low-rise concrete walls. The literature review reports no predictive backbone models that include the deformation associated with the main limit states of concrete panels retrofitted with CFRP fabrics. This paper aims to describe a backbone model to predict the shear strength and strains associated with the peak shear strength (max) and the loss of lateral resistance (llr) limit states of thin concrete panels retrofitted with CFRP strips. A model to correlate the shear strength associated with the max and llr limit states between panels and walls was developed to extrapolate the response from panels to walls. The experimental program includes cyclic diagonal compression tests of 15 panels. The results obtained allowed analyzing the hysteresis curves, the shear strengths and strains, and the energy dissipation associated with the max and llr limit states in the panels. The response of specimens retrofitted with CFRP were compared with those retrofitted with conventional methods, and with specimens that comply the minimum web shear steel ratio. The response measured in the panels showed that the dissipated energy associated with the limit states depends on the volumetric ratio, the inclination, and the number of CFRP strips. Results also demonstrate that performance of panels retrofitted with CFRP strips outperforms that of panels with the minimum web shear steel ratio.

Axial behavior of circular CFST encased seawater sea-sand concrete filled PVC/GFRP tube columns

In order to directly apply seawater and sea sand in construction without desalination, a new type of circular concrete-filled steel tube (CFST) encased prefabricated seawater sea-sand concrete filled Polyvinyl Chloride (PVC)/Glass Fiber Reinforced Polymer (GFRP) tube column was proposed. 24 short columns were tested under uniaxial loads and the test parameters included types of inner tubes, seawater sea-sand concrete replacement ratios, concrete strength, the wrapping area of Carbon Fiber Reinforced Polymer (CFRP) strips and the thickness of inner tube. Moreover, the effects of the parameters on bearing capacity, ductility, stiffness, and strain responses were discussed. The results indicate that the bearing capacity and the strength index of specimens with PVC tube wrapped with CFRP strips and GFRP tube as the inner tube was significantly improved, and the improvement level increased as the wrapping area of CFRP strips or the thickness of GFRP tube increased. The increase in the concrete strength can also improve the bearing capacity and stiffness. In addition, an analytical model was proposed for the composite column with PVC tube wrapped with CFRP strips or GFRP tube as the inner tube.

Importance of Concrete Mesoscale Structure on Bond-Slip Behavior of Externally Bonded CFRP Strips

Currently, the effect of the concrete substrate on the load-bearing capacity of externally bonded carbon fiber-reinforced polymer (CFRP) strips is determined in the guidelines solely on the basis of the concrete strength. In addition to strength, surface preparations can improve the bond resistance by exposing the aggregates of the substrate. However, the interlocking also depends on the parameters that derive from the inner concrete structure such as the aggregate grain dimension and shape, as well as the air void distribution. Therefore, the influence of the concrete inner structure on the bond is investigated with double shear tests by comparing specimens with equivalent concrete strength and varying grain shape and dimension. Bond parameters are calculated using a novel procedure based on optical measurements. Furthermore, crack paths are analyzed by means of computed tomography (CT) scans, which prove to be an essential inspecting technique for characterizing the inner concrete structure. The fracture energy is approximately 30% higher for concrete with a maximum grain size of 8 mm compared to an equivalent mortar with 4 mm maximum grain size.

Axial behavior of square and circular concrete columns confined with CFRP sheets under elevated temperatures: Comparison with welded-wire mesh steel confinement

The main goal of this study was to carry out an experimental investigation of the effectiveness and the efficiency of using carbon fiber-reinforced polymer (CFRP) strips and welded wire mesh jackets for retrofitting square and circular columns exposed to highly elevated temperatures. The investigated variables included the geometry of the column, strengthening scheme, and heating temperature. The samples were divided into three groups. The first group contains column samples not exposed to elevated temperatures and had no strengthening applied. The second category contains un-strengthened column samples subjected to elevated temperatures; the third category comprises strengthened column samples exposed to elevated temperatures. The elevated temperature exposure consisted of heating the specimens to 600 °C for 3 h. The column samples were subjected to axial compression testing till failure. The test results showed that both the circular and square columns exhibited reductions in axial capacity and initial stiffness when exposed to elevated temperatures. The use of welded wire mesh confinement around the circular and square columns exposed to elevated temperatures provided a more significant increase in strength as well as stiffness compared to strengthening the columns with unidirectional CFRP strips. In contrast, the CFRP repaired heated columns exhibited a significant increase in ductility and deformation capability without any reduction in strength than the WWM jacketed heated columns. Furthermore, the confinement effectiveness of CFRP jacketing provides considerable confinement to micro-cracked concrete compared to the WWM jacketed RC circular columns. However, in square columns the confining effectiveness for WWM was better compared to CFRP strips. Moreover, the use of CFRP strips were ineffective for recovering the stiffness of columns exposed to elevated temperatures. In addition, the results demonstrated that the use of welded wire mesh confinement and CFRP strips are cost-effective retrofitting techniques that could be used for circular and square RC columns.

Analysis of behavior and failure modes of timber beams prestressed with CFRP strips

The article presents research on timber beams strengthened with pre-tensioned carbon fiber reinforced polymer (CFRP) strips. The prestress level was different in individual series of beams as the result of different prestressing forces introduced into the strips. The reference non-strengthened beams were also prepared. The beams were tested in four-point bending. Special attention is paid to the analysis of their failure modes and the influence of the prestress level on the crack pattern. The longitudinal strains of the strip and adjoining wood grain were also measured and their differences were analyzed. It was proved that the prestress level influences the number and length of cracks depending on the prestress level as well as the beams’ stiffness and consequently their deflection. The analysis revealed that the slip between the strip and timber occurred due to the deformability of the adhesive used for strip gluing.

Experimental Research and Numerical Analysis of CFRP Retrofitted Masonry Triplets under Shear Loading.

This paper presents an experimental and numerical study into the shear response of brick masonry triplet prisms under different levels of precompression, as well as samples reinforced with carbon fiber-reinforced polymer (CFRP) strips. Masonry triplets were constructed with two different mortar mix ratios (1:1:3 and 1:1:5). In this study, finite element models for the analysis of shear triplets are developed using detailed micro-modelling (DMM) approach and validated with the experimental data. The failure mechanisms observed in the masonry triplets were simulated using a coupled XFEM-cohesive behaviour approach in ABAQUS finite element software. The nonlinear behaviour of mortar and brick was simulated using the concrete damaged plasticity (CDP) constitutive laws. The cohesive element with zero thicknesses was employed to simulate the behaviour of the unit–mortar interfaces. The extended finite element method (XFEM) was employed to simulate the crack propagation in the mortar layer without an initial definition of crack location. CFRP strips were simulated by 3D shell elements and connected to masonry elements by an interface model. The changes in failure mechanism and shear strength are calculated for varying types of mortar and fiber orientation of CFRP composite. Based on this study, it was concluded that the ultimate shear strength of masonry triplets is increased due to the external bonding of CFRP strips. The performance of masonry specimens strengthened with CFRP strips is assessed in terms of gain in shear strength and post-peak behaviour for all configurations and types of mortar considered. The comparison of FE and experimental results proved that the models have the potential to be used in practice to accurately predict the shear strength and reflect damage progression in unreinforced and CFRP-reinforced masonry triplets under in-plane loading, including the debonding of the CFRP reinforcement. Additionally, XFEM was found to be a powerful technique to be used for the location of crack initiation and crack propagation in the mortar layer.

Experimental Investigation of Behavior of Reinforced Concrete Columns Strengthening with Carbon Fiber Reinforced Polymer Under Axial and Uniaxial Bending Loadings

Betonarme kolonlar, yapının yaşlanması, çevresel etkiler, deprem vb. gibi durumlardan dolayı güçlendirilmesi ya da onarılması gereken en önemli yapısal elemanlardır. Bir yapı elemanı güçlendirilirken hangi etkilere maruz kaldıklarını tespit etmek oldukça önem arz etmektedir. Betonarme kolonlar da çoğu kez eş merkezli yüklemelere maruz kalsalar da özellikle kenar kolonlar dış merkezli olarak da yüklemelere maruz kalarak eğilme momentleri tesiri altında eksenel yük taşımaya çalışmaktadır. Bu çalışma kapsamında eş merkezli ve dış merkezli olarak yüklenen betonarme kolonların karbon fiber takviyeli elyaf kumaş (KFTEK) şeritler ile güçlendirilmesinin deneysel olarak incelenmesi amaçlanmıştır. Bu amaçla 6 adet büyük ölçekli deney elemanı üretilmiştir. Bu deney elemanlarından 2 adeti referans olarak seçilmiştir. Geriye kalan 4 adet deney elemanı is KFTEK şeritler ile güçlendirilmiştir. Yükleme tipi (eş ve dış merkezli) ve ankraj kullanımı değişkenler olarak belirlenmiştir. Şerit genişliği ve aralığı ise sabit tutulmuştur. Gerçekleştirilen deneysel çalışma sonucunda deney elemanlarının maksimum yük taşıma kapasitesi, başlangıç rijitliği, sünekliği ve enerji tüketim kapasitesi hesaplanarak sonuçlar karşılaştırılmıştır.

Experimental investigation of the shear behaviour of concrete beams with CFRP strip stirrups under static and fatigue loading

Existing reinforced concrete (RC) structures often decrease in safety and service life owing to reinforcement corrosion or fatigue. Therefore, there are urgent requirements to propose new structures for engineering applications. This study investigates the static and fatigue shear behaviours of concrete beams using carbon fibre reinforced polymer (CFRP) strips instead of steel stirrups. The study mainly conducted the shear tests on nine statically loaded beams and six cyclically loaded beams with varied shear span ratios (a /d = 1.0, 2.5 and 3.5) and configurations of CFRP strip stirrups. The results reveal that concrete beams with CFRP strip stirrups have similar static shear behaviour to RC beams. Nevertheless, the CFRP strip stirrup beams exhibit superior fatigue life compared to that of RC beams, which significantly restrain the development of deflection, concrete cracks, and stirrup strain. Using CFRP strip stirrups instead of steel stirrups can effectively improve the shear resistance of the concrete beams under static and fatigue loading.

The Behavior of RC Beams Retrofitted with Carbon Fiber Reinforced Polymers (CFRP)

The need for the introduction of economical and quicker retrofitting techniques is increasing due to the ever-aging infrastructure and damages produced by major catastrophic events around the world. The application of Carbon Fiber Reinforced Polymers (CFRP) for strengthening and retrofitting of reinforced concrete structures is gaining popularity due to its higher strength, lightweight, durability, corrosion resistance, and aesthetic value. This study presents the results of two strengthened and two retrofitted beams in comparison to control specimens. Two specimens were strengthened and two were retrofitted by attaching CFRP (Sika Carbo-Dur S812 or Sika-Wrap 230C) to the tension side of the beams using high strength epoxy. The results show that one CFRP strip/wrap simply attached at the tension side can help the damaged beam regain/pass the original strength. All specimens fail due to debonding of CFRP from the concrete surface emphasizing the need for efficient anchorage systems. Among the four patterns adopted, CFRP strips along with u-shaped anchorages at the ends provided the highest strength enhancement of 17.36%.