Carbon Fiber Reinforced Polymer Bars Research Articles

Bond strength of FRP bars in recycled-aggregate concrete

This study presents an experimental program conducted to investigate the bond strength of FRP bars in recycled-aggregate concrete compared to the one in normal-aggregate concrete for better evaluation of the results. The experimental program contains thirty six specimens that are tested using the direct pull-out test. In this study, glass, carbon and basalt FRP bars are used with 12 mm diameter and bar bond length of 5d, where d is the bar diameter. The FRP bars are casted in different recycled-aggregate concrete strengths of 30, 45 and 60 MPa. The behaviour of bars in natural-aggregate concrete strength of 30 MPa is used as a benchmark and its behaviour is compared with the ones in recycled-aggregate concrete. The impact of the concrete strengths considered is identified based on the gain in the bond behaviour. The experimental results demonstrate the promise of the recycled aggregates as an alternative to natural aggregates in FRP reinforced concrete. In addition, the use of recycled aggregate enlarges the bearing friction behaviour between the FRP bars and concrete. Analytical models proposed in the literature for the bond behaviour of FRP reinforced concrete are compared with the experimental results obtained here. Organgun et al. equation, and the CMR and the BPE models can accurately predict the bond strength, and bond stress–slip behaviour, respectively, of FRP bars in recycled-aggregate concrete.

Experimental and Numerical Analysis of a Reinforced Wood Lap Joint.

During the restoration of ancient wood structures, the original material of the structures should be kept as much as possible, so a spliced method by using lap joints is commonly used to repair ancient wood structures. This study studies the mechanical behavior of a lap joint which was reinforced with fiber composite materials or steels. An experimental and numerical analysis were performed to study the strength, stiffness and failure modes of the lap joints. The test results showed that the strengthening effect of sticking carbon fiber-reinforced polymer (CFRP) sheets is better than that of sticking CFRP bars or steel bars due to the better bonding conditions; therefore, the lap joint reinforced with CFRP sheets was further analyzed using a numerical approach. The strength and stiffness were enhanced by increasing the reinforcement ratio of CFRP sheets. The use of a 0.34% reinforcement ratio made the bearing capacity of the lap joint reach that of the intact beam. The numerical model agreed well with the experiments in terms of stiffness. By analyzing the numerical analysis results, the structural behavior of the lap joint was revealed. A numerical model can be used to predict the stiffness and behavior of spliced beams with lap joints of different sizes.

Potential advantages of basalt FRP bars compared to carbon FRP bars & conventional steel

ABSTRACT In this study an attempt is taken to evaluate the performance of basalt FRP bars compared with carbon FRP bars and conventional steel bars. Specimens of reinforced concrete will be casted to fulfil this comparison. These beams will comprise a common top reinforcement, stirrups spacing, and concrete properties. The difference is in the bottom reinforcement where it was once steel, Carbon FRP, Basalt FRP, and a hybrid of Basalt FRP and steel. These beams were tested for their behaviour under a flexural load through a four-point bending test. The remaining specimens were casted as columns with common stirrups spacing, and concrete properties. The behaviour of Basalt FRP, Carbon FRP, and steel reinforcement will be tested upon the application of an axial compressive load. The bonding strength between concrete and the different candidate bars is tested through the bond pull-out test. Furthermore, tests will be conducted on the thermal, chemical, and mechanical properties of the individual bars. This study is expected to yield an evaluation of the main characteristics of the newly developed Basalt FRP bars and an identification of the key differences and limitations of using BFRP in concrete structures in relation to CRFP and traditional steel reinforcement of concrete structure.

Structural Behavior of Large-Scale I-Beams with Combined Textile and CFRP Reinforcement

With the innovative composite material carbon-reinforced concrete, thin-walled, high-performance components can be realized. A combination of carbon fiber reinforced polymer (CFRP) bars and non-metallic textile grids is advantageous as it exploits the full potential of the high-performance materials to reduce dead loads, increases durability, and extends lifespan. For new components with such mixed reinforcement, applicable design concepts and engineering rules are necessary to accurately determine the structural and deformation behavior. To validate models and detailing rules previously developed, three large carbon reinforced concrete I-beams were designed and tested to failure with a realistic line load. CFRP bars served as principal bending reinforcement, whereas shear and flange reinforcement consisted of textile grids. Results showed that existing models for bending using variation of strain distribution as well as non-linear finite-element analysis predicted the flexural behavior of structural components with mixed reinforcement in ultimate limit state (ULS) appropriately. Yet, calculation of shear capacity requires further studies to determine textile reinforcement contribution and estimate reduction for concrete strength in reinforced compression struts. For serviceability limit state (SLS), three methods for determination of deflection delivered good results. In future, a rethinking is required with regard to the ductility and robustness of CFRP-reinforced concrete components. In this respect, pronounced cracking as well as the large ultimate strain and deflection compensate for the lacking yield capacity of the reinforcement.

EXPERIMENTAL INVESTIGATION ON STRENGTHENING OF REINFORCED CONCRETE COLUMNS WITH CARBON CONCRETE COMPOSITE

The application of textile reinforced concrete is well-approved technique for strengthening of reinforced concrete members. When using carbon fiber meshes and carbon fiber reinforced polymer bars as reinforcement, this material is called carbon concrete composite. Based on the outstanding properties of carbon fibers, carbon concrete composite is characterized by high bending and tensile strength, and good durability. Therefore, carbon concrete composite is increasingly applied as replacement for ordinary steel bar or steel mesh reinforced concrete. It is favorable building material for production of new buildings and for strengthening of existing reinforced concrete members. In the context of strengthening of existing reinforced concrete columns, it is a usual procedure to cover the member’s surface with a thin layer of carbon concrete composite aiming on reduction of lateral strains of the core concrete when load is increasing. The result is an increased load-bearing capacity of the strengthened column. However, there is insufficient knowledge about the influence of curvature of the carbon meshes in circular cross-sections and in the corners of rectangular cross-sections on their load-bearing capacity. For this reason, an experimental program started to study the influence of curvature, number and type of mesh layers and specimen dimensions on structural behavior of strengthened columns under axial loading. As main outcome it can be stated that besides the curvature other parameters like yarn properties are of essential importance.

Bond-slip behavior between ultra-high-performance concrete and carbon fiber reinforced polymer bars using a pull-out test and numerical modelling

In the present study, the impact of carbon nanotube (CNT) on the bonding behavior of carbon fiber reinforced polymer (CFRP) and steel rebars in carbon nanotube reinforced ultra-high-performance concrete was studied numerically and experimentally. The finite element (FE) analyses, was used to numerical modelling of the pull-out tests. Mechanical properties of the samples, were extracted from the experimental tests performed on standard samples with different quantities of CNT. In order to consider more realistic assumptions, the interaction and bond between concrete and rebar was simulated using cohesive zone modelling method, whose parameters were obtained by model-updating between the FE models and the experimental pull-out test results. The three-dimensional FE model was validated with the experimental pull-out tests. Then, the effect of the diameter and material of rebar as well as the contents of CNT on the pull-out behavior of bar and UHPC were considered. The results show that for 0.02 wt% CNT the maximum pull-out stress of CFRP rebar with a diameter of 12 mm and 16 mm increased by 176% and 407% compared to the control sample (UHPC without CNT), respectively; also, this increase for steel rebars was 5.7 times and 1.7 times, respectively.

Enhancing flexural capacity of RC columns through near surface mounted SMA and CFRP bars

This study explores the flexural behavior of reinforced concrete (RC) columns strengthened with near surface mounted (NSM) shape memory alloy (SMA) bars or carbon fiber reinforced polymer (CFRP) bars. Seven RC column specimens were designed and fabricated to study the influence of different variables on the flexural response of the strengthened columns. These parameters include type of NSM reinforcement (SMA bars or CFRP bars), ratio of NSM reinforcement, and effect of CFRP jacketing. The columns were tested under cyclic lateral loading with constant axial force. The flexural behavior of each specimen was examined in terms of peak load, failure load, drift ratios, displacement ductility, stiffness degradation, energy dissipation, and seismic damage index. The experimental results indicate that strengthening of RC columns with NSM SMA or CFRP bars improves the flexural behavior of the columns through increasing the lateral load capacity, reducing the stiffness degradation and increasing the cumulative energy absorption up to failure. Further enhancement in the lateral response of RC columns was obtained by combining NSM bars and CFRP jacketing as the later provides an additional confinement to the critical sections of the test specimens.

Experimental Behavior of Continuous Hybrid Reinforced Concrete Spliced Girders

This paper conducts an experimental study on the behavior of two-spans continuous reinforced concrete spliced girders strengthened using steel fiber concrete of volume fraction of 1% at splice regions and side near surface mounted carbon fiber reinforced polymer bars of 6 and 10 mm sizes. Five beams with 150 × 250 mm rectangular cross section and 2200 mm total length were cast. The first beam was cast as one unit without joints as a reference while the rest were made from assemblage of three precast segments spliced together using cast in place concrete joints of 170 mm length located at the inflection points. All girders were tested using a single concentrated force at each midspan. The studied parameters were: existence of splices, using of steel fiber concrete at splice region, and strengthening of spliced girders using side near surface mounted carbon fiber reinforced polymer bars. The results showed that existence of splices led to a decrease in the ultimate capacity of the spliced girder of about 33.1% with larger midspan deflections in comparison with the non-spliced girder. But, strengthening of spliced girders using CFRP bars could provide additional load capacity from 69.1% to 98.1% compared with the non-strengthened spliced girder with lower midspan deflections while steel fiber concrete at joints raised the ultimate load of spliced girders by 12.3%. However, the failure mode of the spliced beams were brittle if compared with the ductile failure of the control girder.

Investigation on the electrochemical and mechanical performance of CFRP and steel-fiber composite bar used for impressed current cathodic protection anode

Impressed current cathodic protection (ICCP) has been proved to be an effective method to inhibite steel corrosion. Combined with ICCP technique, a new system has been proposed in this paper with carbon fiber reinforced polymer (CFRP) as dual-functional material: auxiliary anode and partial reinforcement simultaneously. The electrochemical and mechanical performances of CFRP in the new ICCP system were investigated experimentally with two kinds of reinforcement bar: CFRP bar and steel-fiber composite bar (SFCB). First, the accelerated anodic polarization test and electrochemical impedance spectroscopy (EIS) measurement were carried out for CFRP bar and SFCB to verify the electrochemical performances. Then, the mechanical performance and underlying degradation mechanism were identified for CFRP bar and SFCB based on the uniaxial tensile test and scanning electron microscopy (SEM). Finally, the service life of CFRP bar and SFCB has been evaluated to confirm the fesibility of the proposed system in practical engineering. Results showed that CFRP bar and SFCB possess excellent electrical conductivity and low electrical resistance as the anode in ICCP system. Compared with SFCB, CFRP bar is more promising as an anode material with a stronger polarization resistance capability, an acceptable degradation of the mechanical property and a longer service life. With a current density of 20 mA/m2, the service life was evaluated as 62 years for CFRP bar while 7 years for SFCB. To improve the application of SFCB in ICCP system effectively, some modifications are necessary, such as replacing the inner steel bar with stainless steel bar or adding a protective layer between the steel bar and fiber layer. Furthermore, the proposed system shows great potential for marine RC structures and the comprehensive study of this system will be carried out in future work.

Effect of Different Constituent Fiber, Resin, and Sizing Combinations on Alkaline Resistance of Basalt, Carbon, and Glass FRP Bars

Abstract When used as an internal reinforcement, fiber-reinforced-polymer (FRP) composite bars are exposed to a highly alkaline (pH > 12.5) concrete environment. This study evaluated the durability...

FE modeling of concrete beams and columns reinforced with FRP composites

Compression and flexure members such as columns and beams are critical in a structure as its failure could lead to the collapse of the structure. In the present work, numerical analysis of square and circle short columns, and reinforced concrete (RC) beams reinforced with fiber reinforced polymer composites are carried out. This work is divided into two parts. In the first part, numerical study of axial behavior of square and circular concrete columns reinforced with Glass Fiber Reinforced Polymer (GFRP) and Basalt Fiber Reinforced Polymer (BFRP)bars and spiral, and Carbon Fiber Reinforced Polymer (CFRP) wraps is conducted. The results of the first part showed that the axial capacity of the circular RC columns reinforced with GFRP increases with the increase of the longitudinal reinforcement ratio. In addition, the results of the numerical analysis showed good correlation with the experimental ones. An interaction diagram for BFRP RC columns is also developed with considering various eccentricities. The results of numerical modeling of RC columns strengthened with CFRP wraps revealed that the number and the spacing between the CFRP wraps provide different levels of ductility enhancement to the column. For the cases considered in this study, column with two middle closely spaced CFRP wraps demonstrated the best performance. In the second part of this research, flexural behavior of RC beams reinforced with BFRP, GFRP and CFRP bars is investigated along with validation of the numerical model with the experimental tests. The results resembled the experimental observations that indicate significant effect of the FRP bar diameter and type ont he flexural capacity of the RC beams. It was also shown that Increasing the number of bars while keeping the same reinforcement ratio enhanced the stiffness of the RC beam.

Behaviour of polypropylene fibre-reinforced concrete beam with CFRP reinforcement under elevated temperature

In this paper the behaviour of concrete beam reinforced with carbon fibre-reinforced polymer (CFRP) bars under elevated temperature was numerically studied. The numerical modelling of the concrete beam (N-BECS20-2) reinforced with CFRP rebars was based on the experimental model (BECS20-2) studied earlier. The beams were modelled accounting for thermal gradients and material non-linearity using ABAQUS. To understand the effect of polypropylene fibre-reinforced concrete (PPFRC) under fire loads a new PPFRC beam with CFRP rebar reinforcement (NPP-BECS20-2) was numerically modelled and was compared with the behaviour of beam made of conventional concrete with CFRP reinforcement (N-BECS20-2). From the results the load carrying capacity and ductile behaviour of the PPFRC beam with CFRP bar reinforcement under elevated temperature were comparatively studied. The load carrying capacity and the ductile capacity of PPFRC beam (NPP-BECS20-2) under elevated temperature were found to be higher than the conventional concrete beam (N-BECS20-2). Parametric studies were carried out by varying the diameter of CFRP rebar and concrete cover at elevated temperature. The increase of cover of concrete to few millimeters protected the reinforcement from heat exposure resulting in better performance of PPFRC beam.

Bond Performance of Carbon Fiber-Reinforced Polymer Bar with Dual Functions of Reinforcement and Cathodic Protection for Reinforced Concrete Structures

The dual function of a carbon fiber-reinforced polymer (CFRP) bar working as reinforcement and impressed current cathodic protection (ICCP) anode for reinforced concrete structures has been proposed and researched in this paper. The ICCP tests with different current densities and polarization durations were first conducted for the concrete with high chloride content. After the ICCP application, pull out tests were then performed to investigate the bond behaviors of CFRP bars. Experimental results have shown the effectiveness of the new-type ICCP system with the CFRP bar as the anode on corrosion protection. The ICCP system provided electrons to the steel bar continuously and brought the potential of the steel bar down to the immunity region. Under the anodic polarization with a large current density of 100 mA/m2, the CFRP bar-concrete interface presented acidification and the chemical adhesion on the interface was decreased significantly. However, for cases in the experiment, the ICCP application had an insignificant influence on the ultimate bond strength.

Improvement of bond performance between concrete and CFRP bars with optimized additional aluminum ribs anchorage

The slippage of fiber-reinforced polymer (FRP) bars in concrete occurs frequently because of the insufficient anchorage capacity of FRP bars in concrete, and it considerably affects the reliable application of FRP bars as reinforcing steel bars in civil engineering structures, especially in prestressed structures. In this paper, an optimized additional rib (AR) anchorage system was applied to the carbon-FRP (CFRP) bars to improve this weak anchorage characteristic of CFRP bars. The extrusion technology of the additional ribs was optimized, and only a slight deterioration of approximately 1.85% in the tensile strength of the CFRP bars was noted, compared to that corresponding to our previous extrusion technology (a loss of approximately 7.84%). Subsequently, pull-out tests were performed to investigate the influence of the number of additional ribs and bond length on the bond performance between the CFRP bars and concrete. The experimental results demonstrated that the existence of additional ribs, which produced an end pressure, transformed the bond stress transferring mechanism and reduced the radial force exerted on the surrounding concrete, thereby delaying the occurrence of the concrete splitting failure. In addition, the CFRP bars anchored with the additional ribs exhibited a remarkable enhancement in the pull-out strength, whereas this improvement was influenced by the embedment length of the CFRP bars and the ratio of the additional rib length to the bond length (lar/L). Finally, an empirical expression to calculate the development length of the CFRP bars with and without an AR anchorage was proposed and compared with the expressions provided in the existing design standards. It was concluded that the applied AR anchorage system could effectively reduce the development length of the CFRP bars. Compared to that of the control specimens, there was approximately 16.7% decrease in the development length for the specimens anchored with one additional rib.

Study on the Flexural Performance of Hybrid-Reinforced Concrete Beams with a New Cathodic Protection System Subjected to Corrosion.

Steel corrosion is considered as the main factor for the insufficient durability of concrete structures, especially in the marine environment. In this paper, to further inhibit steel corrosion in a high chloride environment and take advantage of the dual-functional carbon fiber reinforced polymer (CFRP), the impressed current cathodic protection (ICCP) technique was applied to the hybrid-reinforced concrete beam with internally embedded CFRP bars and steel fiber reinforced polymer composite bar (SFCB) as the anode material while the steel bar was compelled to the cathode. The effect of the new ICCP system on the flexural performance of the hybrid-reinforced concrete beam subjected to corrosion was verified experimentally. First, the electricity-accelerated precorrosion test was performed for the steel bar in the hybrid-reinforced beams with a target corrosion ratio of 5%. Then, the dry–wet cycles corrosion was conducted and the ICCP system was activated simultaneously for the hybrid-reinforced concrete beam for 180 days. Finally, the three-point bending experiment was carried out for the hybrid-reinforced concrete beams. The steel bars were taken out from the concrete to quantitatively measure the corrosion ratio after flexural tests. Results showed that the further corrosion of steel bars could be inhibited effectively by the ICCP treatment with the CFRP bar and the SFCB as the anode. Additionally, the ICCP system showed an obvious effect on the flexural behavior of the hybrid-reinforced concrete beams: The crack load and ultimate load, as well as the stiffness, were enhanced notably compared with the beam without ICCP treatment. Compared with the SFCB anode, the ICCP system with the CFRP bar as the anode material was more effective for the hybrid-reinforced concrete beam to prevent the steel corrosion.

Comparison of the Flexural Performance and Behaviour of Fly‐Ash‐Based Geopolymer Concrete Beams Reinforced with CFRP and GFRP Bars

A construction system with high sustainability, high durability, and appropriate strength can be supplied by geopolymer concrete (GPC) reinforced with glass fibre‐reinforced polymer (GFRP) bars and carbon fibre‐reinforced polymer (CFRP) bars. Few studies deal with a combination of GPC and FRP bars, especially CFRP bars. The present investigation presents the flexural capacity and behaviour of fly‐ash‐based GPC beam reinforced with two different types of FRP bars: six reinforced geopolymer concrete (RGPC) beams consisting of three specimens reinforced with GFRP bars and the rest with CFRP bars. The beams were tested under four‐point bending with a clear span of 2000 mm. The test parameters included the longitudinal‐reinforcement ratio and the longitudinal‐reinforcement type, including GFRP and CFRP. Ultimate load, first crack load, load‐deflection behaviour, load‐strain curve, crack width, and the modes of failure were studied. The experimental results were compared with the equations recommended by ACI 440.1R‐15 and CSA S806‐12 for flexural strength and midspan deflection of the beams. The results show that the reinforcement ratio had a significant effect on the ultimate load capacity and failure mode. The ultimate load capacity of CFRP‐RGPC beams was higher than that of GFRP‐RGPC, more crack formations were observed in the CFRP‐RGPC beams than in the GFRP‐RGPC beams, and the crack width in the GFRP‐RGPC beams was more extensive than that in the CFRP‐RGPC beams. Beams with lower reinforcement ratios experienced a fewer number of crack and a higher value of crack width, while numerous cracks and less value of crack width were observed in beams with higher reinforcement ratio. Beams with the lower reinforcement ratios were more affected by the type of FRP bars, and the deflection in GFRP‐RGPC beams was higher than that in CFRP‐RGPC beams for the same corresponding load level. ACI 440.1R‐15 and CSA S806‐12 underestimated the flexural strength and midspan deflection of RGPC beams; however, CSA S806‐12 predicted more accurately.

Bond load-slip behaviour of FRP bars in recycled-aggregate concrete

This study presents an experimental program conducted to investigate the bond strength of FRP bars in recycled-aggregate concrete compared to the one in normal-aggregate concrete for the improved evaluation of results. The experimental program contains thirty six specimens tested using direct pull-out test. In this study, glass, carbon and basalt FRP bars are used with 12 mm diameter and bar bond lengths of 5d, where d is the bar diameter. The FRP bars are casted in different recycled-aggregate concrete strengths of 30, 45 and 60 MPa. The behaviour of bars in normal-aggregate concrete strength of 30 MPa is used as a benchmark and its behaviour is compared with the ones in the recycled-aggregate concrete. The impact of the concrete strength considered is identified based on the gain in the bond behaviour. The experimental results demonstrate the prospect of the recycled aggregates applied as an alternative to normal aggregates in the FRP reinforced concrete. In addition, the use of the recycled aggregate increases the bearing friction behaviour between the FRP bars and concrete.

Punching Strengthening of Concrete Slab-column Connections Using Near Surface Mounted (NSM) Carbon Fiber Reinforced Polymer (CFRP) Bars

This paper investigates experimentally the effect of near surface mounted (NSM) carbon fiber reinforcement polymer (CFRP) bars as externally strengthening on the punching shear behavior of interior slab-column connections. Many researchers used NSM as a novel strengthening technique in various structural elements. However, the strengthening of slab-column connections using NSN is relatively new. Seven Reinforced concrete (RC) square slabs with a concentric column were tested over simply supported four sides. One control specimen was tested without strengthening, four specimens were strengthened using NSM-CFRP bar installed in pre-cut groove surrounded the column at the tension side of the slab, and two specimens were strengthened using externally bonded (EB) CFRP strips which have the same tensile force of the CFRP bars. The arrangement and the location of the strengthened materials were also test variables. The test results showed that using NSM strengthening technique significantly increased the punching shear capacity and ultimate stiffness compared to using EB strengthening technique. Where the increasing in the punching capacity and ultimate stiffness were 18% and 13-18%, respectively. Moreover, the NSM-CFRP bars greatly reduced the cracks in the punching shear zone around the columns. The measured ultimate punching shear capacity for the tested specimens showed very reasonable agreement with the calculated punching loads based on an analytical model for slab-column connections strengthened using FRP that account for its arrangement and location.

Non-linear behaviour of concrete beams reinforced with GFRP and CFRP bars grouted in sleeves

The low-quality bond between fibre reinforced polymer (FRP) bars and surrounding concrete has drawn the attention of many researchers. The use of high-strength materials such as the grout in the intersection of FRP bars and surrounding concrete can effectively prevent any slippage once they are in contact and subsequently increase the bond quality. Therefore, this study was numerically focused on the flexural behaviour of concrete beams reinforced with glass fibre reinforced polymer (GFRP) and carbon fibre reinforced polymer (CFRP) bars, grouted only in the pure bending zone and along the whole beam length. The numerical outputs revealed that the grouted GFRP bars propagated the maximum principal stress in high-strength concrete beams, but not as much as that in normal-strength concrete specimens. In addition, the stress distribution in the grout, created only in the pure bending zone, was nearly constant at the ultimate moment. For the grout, developed along the whole beam length, this stress increased by approaching the mid-span of the concrete beam. Furthermore, at the ultimate moment, the tensile stress of 12-mm diameter CFRP bars was about 3.5 times more than that of the 16-mm diameter CFRP bars, leading to the generation of difference between failure modes of concrete specimens reinforced with various diameters of CFRP bars.

Flexural Behavior of Hybrid-Reinforced Concrete Exterior Beam-Column Joints under Static and Cyclic Loads

This study presents an experimental investigation of the flexure behavior of exterior beam-column joints made from hybrid concrete (normal concrete (NC) and reactive powder concrete (RPC)) or hybrid reinforcement (steel and carbon fiber reinforced polymer (CFRP) bars internally or externally by near surface mounted (NSM) technique). Nine hybrid-reinforced concrete beam-column joint specimens under the effect of static or cyclic loading were studied and tested within three test groups. Several variables that affect the behavior of the beam-column joint region are investigated such as: type of loading (static or cyclic), type of hybridization (concrete hybridization or reinforcement hybridization), and area of concrete hybridization. The results showed that using RPC as a replacement concrete at different areas of beam-column joint under static loading improved the ultimate load capacity and first cracking load to about 8–32% and 20–60%, respectively, compared with the reference NC joint with increase in the ductility of about 6–14%. Moreover, using the same technique under cyclic loading condition showed an increase in the ultimate load of about 39%, with improvement in the cumulative ductility of about 12% compared with the reference NC joint. On the other hand, using CFRP bars as (internal or external) hybridization system (33% of main reinforcement) under static loading caused increments of ultimate and first cracking loads of about 11%, 8% and 0%, 30%, respectively compared with the reference steel reinforced joint; while the ductility ratio increased about 36%, 5%, respectively. Moreover, the internal hybrid reinforcement system exhibited a decrease in the ultimate load of about 15% and reduction in the cumulative ductility of about 40% under cyclic loading.