Longitudinal Fiber-reinforced Polymer Research Articles

Compressive Performance of Longitudinal Steel-FRP Composite Bars in Concrete Cylinders Confined by Different Type of FRP Composites.

This paper presents an experimental study on the compressive performance of longitudinal steel-fiber-reinforced polymer composite bars (SFCBs) in concrete cylinders confined by different type of fiber-reinforced polymer (FRP) composites. Three types of concrete cylinders reinforced with (or without) longitudinal SFCBs and different transverse FRP confinements were tested under monotonic compression. The results showed that the post-yield stiffness of SFCBs is higher when confined with high elastic modulus carbon fiber-reinforced polymer (CFRP) composite than with low elastic modulus basalt fiber-reinforced polymer (BFRP) composite. Decreasing confinement spacing did not significantly improve the compressive strength of SFCBs in concrete cylinders. The compressive failure strain of SFCBs could possibly reach 88% of its tensile peak strain in concrete cylinders confined by CFRP sheets, which is significantly higher than the value (around 50%) in previous studies. Existing design equations, which applied a strength reduction factor or a maximum compressive strain of concrete to consider the compressive contributions of SFCBs in concrete members, underestimate the load-carrying capacity of SFCB-reinforced concrete cylinders. The design equation that considers the actual compressive stress of SFCBs gives the most accurate prediction; however, its applicability and accuracy need to be verified with more experimental data.

Torsional behavior of FRP-strengthened reinforced concrete members considering various wrapping configurations: Theoretical analysis and modeling

Reinforced concrete (RC) structural members such as spandrel, flanged and curved beams, slab beams, and bridge girders may be subjected to significant torsional loading. Despite extensive research on the strengthening of RC members, very little is known about the torsional behavior of RC members strengthened with fiber-reinforced polymer (FRP) sheets. Therefore, very limited guidelines apply to the design of externally bonded FRP systems for torsional strengthening, and no design provisions exist for the U-wrapped and 2-sided strengthening systems in torsion. This study aims to contribute to this growing area of research by developing a new analytical model to predict the full torsional response of strengthened RC members with many conventional configurations such as spiral, transverse and longitudinal FRP, continuous and intermittent strips along the beam length, side bonded, and full-wrapped systems. Moreover, this study provided an analytical model accurately predicting the contribution, efficiency, and failure mode of side-bonded strengthening systems. Additionally, the influence of various parameters such as FRP stiffness and transverse steel reinforcement ratio is taken into account in the constitutive law of concrete and internal reinforcement for the first time. The good agreement between the test results of 32 collected FRP-strengthened RC beams from the literature and the theoretical ones, which were predicted through programming proves the validity and accuracy of the presented theory.

Study on the bond performance of glass fiber-reinforced polymer bars considering the relative position between longitudinal bars and stirrups

Fiber-reinforced polymer (FRP) reinforcements are increasingly recognized as an effective solution to the corrosion problems faced by reinforced concrete structures, and the bond between FRP bars and concrete is an essential basis for the application. Previous research has shown that stirrup restraints on the concrete can significantly enhance the bond performance of middle-arranged longitudinal FRP bars. However, in practical applications, longitudinal bars are typically placed at the corners or sides of stirrups to form reinforcement cages, and there has been limited research on the effects of stirrups on the bond performance of FRP bars under these conditions. To address this gap, this study attempts to further reveal the stirrup effects by varying the relative positions between the longitudinal bars and stirrups. Based on forty-four axial pull-out tests on glass fiber-reinforced polymer (GFRP) bars equipped with Distributed Optical Fiber Sensors (DOFS), the overall and local bond performances of three GFRP bars (sand-coated, helical wound, single helical wrapped) considering four relative positions between the GFRP bars and stirrups (no stirrups, side, middle, corner) were investigated. The test results indicated that the bond strength of FRP bars increased significantly, up to 71.5%, for the relative position of the middle case, but could be reduced by up to 17.5% for the side and corner positions compared with the no-stirrup situation. DOFS proved to be an effective method to obtain the continuous strain distribution and reveal the interfacial bond mechanism. Based on DOFS results, a bond stress-slip model considering the effect of relative positions was developed. Using this model, the development lengths of GFRP bars were proposed and compared with the ACI, CSA, and JSCE codes.

Acoustic emission characteristics of concrete cylinders reinforced with steel-fiber-reinforced composite bars under uniaxial compression

An experimental study of the acoustic emission characteristics of concrete cylinders reinforced with steel fiber-reinforced composite bars (SFCB) under uniaxial compression was performed. SFCB-reinforced concrete cylinders, plain concrete cylinders, and fiber-reinforced polymer (FRP) bar-reinforced concrete cylinders were tested under uniaxial compression. The entire failure process of different concrete cylinders was monitored in real time using acoustic emissions (AE). Damage characteristics of the cylinders were analyzed using the AE hit number distribution, Ib value analysis method, and AE event location and energy. The Ib value characteristics were closely correlated with the microcracks and their extension inside the concrete cylinders. For the reinforced concrete cylinders, the damages were predominantly microcracks of the concrete observed before the first turning point of the load-displacement curve. Subsequently, damage to the longitudinal SFCBs and FRP bars occurred. The AE characteristic of FRP reinforcement damage was similar to that of the macroscopic crack damage in concrete, that is, with a small Ib value. According to the AE event location analysis, the plain concrete cylinder demonstrated obvious shear failure, which was primarily suppressed in the reinforced concrete cylinders owing to the confinement effect of the spiral. The AE energy released by the compression damage of the longitudinal FRP bar was higher than that released by the tensile damage of the FRP spiral. This could trigger a distinguishable high AE location source amplitude for detecting the compression damage to the FRP bar. The analysis of the AE event distribution characteristics proves that the SFCB has a stable post-yield stage, and the compressive damage process of the SFCB is relatively stable and mild compared with the FRP bars in concrete cylinders.

Experimental investigation on axial compressive behavior of fiber reinforced polymer-reinforced concrete columns confined with external fiber reinforced polymer jackets

An innovative glass fiber reinforced polymer (GFRP) closed-type winding (GFRP-CW) tie was developed to eliminate the bond slip failure and make full use of the tensile strength of ties compared with conventional pultruded fiber reinforced polymer (FRP) rod ties. Although better confinement effect of GFRP-CW ties, however after spalling of concrete cover, the compressive longitudinal FRP bars in the plastic hinge regions of columns are most likely to crush or buckle. External FRP jackets can effectively restraint damage to concrete cover. Against this background, a novel FRP-reinforced concrete column confined with external FRP jackets and the internal GFRP-CW ties were proposed to prevent the FRP bars from premature buckling or crushing. In this article, twelve square new columns were constructed and tested to characterize the axial compressive behavior. The test parameters included FRP wrapping type (GFRP or carbon fiber reinforced polymer (CFRP)), FRP wrapping layers, and spacing of ties. Test results confirmed that FRP-reinforced concrete columns with external FRP jackets had significantly larger ductile behavior and exhibited higher load-carrying capacity than their counterparts FRP-reinforced concrete columns due to the contribution of longitudinal GFRP bars and the concrete cover. The test results also suggested reasonable spacing of ties and layers of GFRP jackets for an expected moderate confinement behavior.

Slender RC Columns Strengthened with a Novel Hybrid Strengthening System of External Longitudinal and Transverse FRPs

In this study, the performance of slender circular concrete columns strengthened with a novel hybrid system of longitudinally bonded prefabricated fiber-reinforced polymer (FRP) laminates and transverse FRP wrapping is investigated. The novelty of the hybrid system is to improve the load-carrying capacity of slender steel-reinforced concrete (RC) columns under eccentric axial compression by providing high modulus longitudinal carbon FRP (CFRP) laminates through enhancing the flexural stiffness of the slender column and to laterally support the longitudinal laminates by FRP wraps to prevent debonding and local buckling. A total of 6 large-scale circular slender RC columns with a diameter of 260 mm and a length of 3,048 mm were tested under combined axial and flexural loads. The results showed that, for the strengthening of the slender columns, the hybrid system is a more effective strengthening system than wrapping controlling second-order deformations due to the slenderness effect and enhancing the load-bearing capacity. Also, the performance of the system was further investigated using an analytical-numerical model considering the second-order deformations of the slender columns. The model considered nonlinearity in material and confinement effects plus the geometrical nonlinearity via an iterative second-order analysis. The model was verified against experimental data from the current study (hybrid system) and an independent study (wrapping system) and showed a good agreement with the test results. Then, a comprehensive parametric study was conducted to study the effect of various parameters including slenderness ratio, load eccentricity, longitudinal and transverse FRP reinforcement ratios, concrete strength, and column diameter on the performance of slender RC columns strengthened with the hybrid system. It was found that the hybrid strengthening system was more effective for RC columns with high slenderness ratios, high load eccentricities, and low concrete strength.

A Method for Calculating Cracking Moment of FRP Reinforced Concrete Beam

This paper presents an analytical method for calculating the cracking moment of concrete beams reinforced with fiber reinforced polymer (FRP) bars, which considers the non-linear behavior of concrete in the tension zone and the contribution of FRP reinforcement. Theoretical cracking moments obtained by the proposed method were verified with the experimental results and the theoretical results calculated according to ACI 440.1R-15. The comparison results show good agreement between theoretical and experimental data. A parametric study on the effect of longitudinal FRP reinforcement ratio and elastic modulus of FRP on the cracking moment of FRP reinforced concrete beams also were done by using the proposed method. The parametric study results show that both longitudinal reinforcement and modulus of elasticity of FRP significantly affect the cracking moment of FRP reinforced concrete beams. Moreover, parametric study results also clarify the weakness of ACI 440.1R-15 in determining the cracking moment of concrete beams reinforced with a large amount of FRP reinforcement ratio and with high modulus of elasticity of FRP.

Evaluation of code provisions predicting the concrete shear strength of FRP-reinforced members without shear reinforcement

Concrete shear strength for elements without shear reinforcement and longitudinally reinforced with Fiber-Reinforced Polymer (FRP) bars is considered one of the critical issues that has been enormously estimated by many researchers as well as different code provisions. The implementation of various design codes for the estimation using similar input parameters observes the broad predictive spectrum of shear strength for FRP-reinforced members without stirrups. The element cross-section width and effective depth, the ratio of shear span to effective depth, concrete compressive strength, FRP-reinforcement ratio, and FRP-modulus of elasticity are mostly used as input parameters in various standards to predict the shear strength. This paper focuses on evaluating the efficiency of predicting equations used in different code provisions to estimate the shear strength compared to the nominal shear test-results of 501 tested samples collected from different literatures. An analytical study was conducted to determine the influence of each input parameter on the shear capacity as a pre-step to improve the efficiency of different code provisions when used at specific range of input parameters to predict the shear strength of members reinforced with longitudinal FRP bars. An optimized model was proposed based on refining of the Canadian Standard Association (CSAS806-12) formula and numerical analysis. The study concluded that the CSAS806-12 formula has high efficiency for predicting shear strength of FRP-reinforced members without stirrups. While both the American Concrete Institute (ACI440.1R-15) and the American Association of State and Highway Transportation Officials’ (AASHTOLRFD-17) are significantly conservative in predicting shear capacity for these members. The proposed model's performance was found to be considerably higher as compared to the CSAS806-12 formula and other studied code provisions.

Experimental investigation on shear behavior of FRP post-tensioned concrete beams without stirrups

To investigate the shear behavior of post-tensioned concrete beams with longitudinal fiber-reinforced polymer (FRP) reinforcements and without stirrups, seven large-scale beams, with a shear span-to-effective depth ratio of approximately 3.0, were tested. The test variables included the prestressing level, type of flexural reinforcement, and tendon profile. The shear crack width and slip were tracked using digital image correlation technique. It was found that the post-tensioned concrete beams failed in shear-compression or shear-tension, while the nonprestressed concrete beam failed in diagonal tension. The post-tensioned beams designed to have approximately the same longitudinal reinforcement stiffness, exhibited similar shear strength. Draping FRP tendons resulted in an increase of 8.8% in shear cracking strength, while it had slight effect on the maximum shear strength. In this study, it was demonstrated that arching action played a major role in the shear resistance of FRP post-tensioned beams, while the contribution of aggregate interlock was negligible.

Sensitivity of lateral impact response of RC columns reinforced with GFRP bars and stirrups to concrete strength and reinforcement ratio

This is the first study in the literature which experimentally and numerically investigates the impact behavior of concrete columns reinforced with fiber-reinforced polymer (FRP) reinforcements. The effect of concrete strength (50 MPa vs 100 MPa) and longitudinal FRP ratio on the lateral impact response of the columns was investigated. The experimental results showed that the longitudinal reinforcement ratio strongly affected the failure modes and impact-resistant capacity while the use of high strength concrete (HSC) did not effectively improve the performance of the columns, which on the contrary, might have caused spalling failure due to its brittleness. The peak impact force and displacement of the columns increased linearly with the impact velocity up to their maximum capacity. The longitudinal reinforcement ratio slightly affected the peak impact forces while the concrete strength showed marginal variation. The use of HSC did not effectively reduce the maximum displacement of the columns. The energy absorption of the columns and the impact velocity exhibited an approximately linear relationship regardless of the reinforcement ratio and concrete strength. Different from the static case, the numerical results show three critical sections, i.e. at the impact location and column ends, which need to be carefully designed.

Investigation of ANN architecture for predicting shear strength of fiber reinforcement bars concrete beams.

In this paper, an extensive simulation program is conducted to find out the optimal ANN model to predict the shear strength of fiber-reinforced polymer (FRP) concrete beams containing both flexural and shear reinforcements. For acquiring this purpose, an experimental database containing 125 samples is collected from the literature and used to find the best architecture of ANN. In this database, the input variables consist of 9 inputs, such as the ratio of the beam width, the effective depth, the shear span to the effective depth, the compressive strength of concrete, the longitudinal FRP reinforcement ratio, the modulus of elasticity of longitudinal FRP reinforcement, the FRP shear reinforcement ratio, the tensile strength of FRP shear reinforcement, the modulus of elasticity of FRP shear reinforcement. Thereafter, the selection of the appropriate architecture of ANN model is performed and evaluated by common statistical measurements. The results show that the optimal ANN model is a highly efficient predictor of the shear strength of FRP concrete beams with a maximum R2 value of 0.9634 on the training part and an R2 of 0.9577 on the testing part, using the best architecture. In addition, a sensitivity analysis using the optimal ANN model over 500 Monte Carlo simulations is performed to interpret the influence of reinforcement type on the stability and accuracy of ANN model in predicting shear strength. The results of this investigation could facilitate and enhance the use of ANN model in different real-world problems in the field of civil engineering.

Behavior of Square Slender RC Columns Strengthened with Longitudinal FRP Sheets Subjected to Eccentric Loading

Abstract In this study, the grooving method was employed to strengthen reinforced concrete (RC) columns with longitudinal fiber-reinforced polymer (FRP) sheets, and the performance of columns was i...

Effect of FRP Spike Anchor Installation Quality and Concrete Repair on the Seismic Behavior of FRP-Strengthened RC Columns

The use of fiber-reinforced polymer (FRP) to repair and seismically strengthen existing deficient or damaged structural elements is now widespread. FRP anchors have become an important component of such FRP strengthening. However, while reasonable quality control and field quality assurance measures exist for FRP fabrics and plates, such attention has not yet been given to FRP anchors. It seems logical to expect that poor FRP anchor installation will adversely impact the performance of the repaired element. This experimental program was envisaged to assess the level of such an adverse impact. It consists of six RC columns subjected to axial load and quasi-static cyclic load. Of the six columns cast for the experimental work, three columns had good concrete placement, while the remaining three showed poor consolidation, with substantial honeycombing and segregation at the base. It was decided that the latter columns could be used as examples of damaged concrete and so they were repaired by a local contractor by removing the poor concrete and replacing it with a commercially available bagged concrete repair material. One column of each set of three was designated as a control column without any FRP strengthening, while the four remaining columns were strengthened using longitudinal FRP sheets for flexural strengthening, anchors to develop the FRP into the foundation, and transverse FRP sheets for confinement. It was observed that the concrete repair did not adversely affect the behavior of the columns or the interaction between the concrete and the FRP. The FRP anchors were installed to replicate poor installation in the field. Those with improperly placed fans, or splays, did not perform at all as intended and it is recommended that such anchors be removed and replaced without exception. Inadequately saturated anchors were able to achieve their design rupture capacity but failed in a more brittle manner than adequately saturated anchors. Based on the observations from the experimental program, several ideas and options are proposed to enhance the quality of FRP anchors. Accompanied with onsite testing and mockups, these suggestions will substantially contribute to the mitigation of the associated variability in the performance of the rehabilitation.

Steel-FRP Reinforced Concrete Moment-Resisting Frames under Lateral Loads: Numerical Investigation

This paper suggests using a combination of steel and fiber-reinforced polymer (FRP) reinforcements to introduce sustainable reinforced concrete moment-resisting frames (RC-MRFs) characterized by damage-controlled seismic performance, cost-effectiveness, and postearthquake recoverability. The aim of this study is twofold. First, according to a predefined seismic performance of RC-MRFs, this study introduces the optimum replacement ratio of the longitudinal FRP reinforcement of FRP RC-MRFs with steel bars. Second, this study investigates the application of FRP-steel reinforcement details to alleviate damage in the plastic-hinge zones of the beams. A detailed three-dimensional finite-element model (3D-FEM) of an RC-MRF is developed and validated against the experimental results of a large-scale, two-bay, two and half story MRF entirely reinforced with FRP rebars and stirrups. Results indicate that compared with FRP RC-MRFs, for a replacement ratio of FRP reinforcement ≤42%, the serviceability state of the proposed steel–FRP RC-MRFs is characterized by a controlled deformability, and the ultimate state is characterized by an acceptable residual lateral strength ensuring safe exit of the structure from its functionality. Furthermore, when steel reinforcements are only provided at the ends of the beams, the frame lateral deformability is based on the development of two sequential plastic hinges at each end of the beams, leading to higher deformability and lower damage levels.

Shear strength calculating model of FRP bar reinforced concrete beams without stirrups

The models in ACI 440.1R-15, AASHTO LRFD-17, CSA S806-12, CSA S6-14, ISIS M03-07, JSCE-97, CNR DT203-06 and BISE-99 did not properly reflect the effects of the reinforcement ratio and modulus of elasticity of the longitudinal fiber reinforced polymer (FRP) bars, shear span-to-depth ratio or size effect on the shear strength of FRP bar reinforced concrete beams without stirrups. A database of 389 FRP bar reinforced concrete beams without stirrups failed in shear was collected lately, and a new model was proposed to calculate the shear strength based on the experimental data of 188 beams in the database, whose variables are reinforcement ratio and modulus of elasticity of the longitudinal FRP bars, shear span-to-depth ratio, or the effective depth of the beams. The efficiency of the proposed model has been evaluated by comparing the calculated shear strength with the experimental data of another 201 beams in the database. It indicated the calculated shear strength values using the proposed model are more consistent with the experimental results compared to those using the models in existing design codes.

Axial\u2013Flexural Interaction in FRP-Wrapped RC Columns

The study reported herein aims at investigating the behavior of medium-scale circular reinforced concrete columns wrapped with fiber reinforced polymer (FRP) sheets under concentric and eccentric axial loads. The experimental program was devised to assess the effects of loading conditions, absence/presence of an FRP jacket as well as the FRP wrapping system. To achieve the study objectives, four column groups were tested under axial compression at 0, 25, 50 and 65 mm loading eccentricities corresponding to eccentricity-to-diameter ratios of 0, 0.13, 0.26 and 0.34, respectively. Specimens in a fifth group were tested in pure bending simulating axial compression at infinite loading eccentricities. Three column subcategories were tested under each of the 5 loading eccentricities: unwrapped; wrapped with one ply of hoop FRP sheets; and wrapped with two FRP plies with fibers oriented at 0 and 90° to the longitudinal column axis thereby providing externally-bonded longitudinal reinforcement and hoop confinement, respectively. Tests confirmed that FRP confinement enhances the axial–flexural column resistance even at large eccentricities that exceed the balanced state of unconfined columns. Although axial column resistance decreased with increasing bending moments, relative enhancements (25–35%) in axial resistance provided by FRP confinement were found to be more significant under eccentric loading than in pure compression. Compared to hoop FRP-confined columns, using additional longitudinal sheets resulted in minor (7–9%) but stable enhancements in axial resistance that were unaffected by the increase in loading eccentricity. The FRP hoop wraps had a minor effect on the flexural resistance of specimens tested in pure bending but managed to double their resistance when combined with the externally-bonded longitudinal FRP sheets. Finally, three stress–strain models of FRP-confined concrete were used in conventional section analysis to assess the axial–flexural interaction in the FRP-jacketed columns. Strength predictions made using the stress–strain model proposed in ACI 440.2R-17 design guidelines did not agree with the test results of the eccentrically-loaded columns and underestimated the moment resistance at a given axial force even when considering higher confinement ratios than those permitted by the guidelines. Strength predictions made using eccentricity-dependent stress–strain models showed better results especially when accounting for the increase in ultimate axial strains under eccentric loading.

Characterization of combined longitudinal and transverse FRPs for strengthening concrete columns

This paper presents the results of a study on the characterization of combined longitudinal near-surface-mounted (NSM) fiber-reinforced polymer (FRP) bars and transverse FRP wraps for strengthening concrete columns. A total of 21 concrete cylinders were prepared, strengthened, and tested to characterize the performance of the strengthening system. Three arrangements of glass FRP (GFRP) bars were mounted in surface grooves, and unidirectional basalt FRP (BFRP) composite was used to wrap the specimens. It was shown that the wrapping system effectively prevented premature failures of the NSM bars and extended the contribution of the bars from a mean of 17.5% in the NSM specimens to a mean of 27.7% in the specimens strengthened with the combined NSM and transverse FRPs. An analytical model was also presented to predict the load–strain behavior and the effect of combined axial load and bending moment.

Innovative warp and woof strap (WWS) method to anchor the FRP sheets in strengthened concrete beams

U-shaped straps are an effective means to postpone premature debonding failure when fiber-reinforced polymer (FRP) composites are applied in structures. However, the U-wrap anchors are not cost-effective and in many cases cannot completely prevent the debonding phenomenon. In the current study, an innovative technique named “warp and woof strap” (WWS) is introduced for anchoring longitudinal FRP sheets, in which some parts of FRP fibers are manually made bi-directionally. Unlike the conventional U-shaped anchors, the anchorage system in this method is in direct contact with the tension side of the beam. Totally, 20 reinforced concrete (RC) beams, 120 × 160 × 1400 mm in size, were subjected to the four-point loading to evaluate the efficiency of the introduced anchorage system in comparison to the U-shaped anchorage. The effect of different parameters including the method employed for anchoring the longitudinal carbon fiber reinforced polymer (CFRP) sheet, anchorage height and width, location of FRP anchorage application, use of the corner strip and rounding corner method, and configuration of WWS anchorage were investigated. The experimental results indicated that the efficiency of the WWS method in preventing undesired debonding mode of failure is much better than that of conventional U-shaped anchor. It was also observed that using WWS method can improve the load carrying capacity and ductility up to 32% and 80%, respectively, compared to U-shaped anchors.

Performance Improvement of a Fiber-Reinforced Polymer Bar for a Reinforced Sea Sand and Seawater Concrete Beam in the Serviceability Limit State.

Fiber-reinforced polymer (FRP) has supreme resistance to corrosion and can be designed with optic fibers. FRP can be an alternative to steel reinforcement for concrete structures, and can serve as a sensor for smart concrete structures. Due to poor cracking control and bond performance, the limit of flexural capacity in the serviceability limit state has not been determined, which has obstructed the wider application of FRP bars in smart structures. In this study, in order to overcome these shortcomings, a new engineering cementitious composite (ECC) with superior tensile strain capacity was used to replace the cover around the FRP bars in the tensile zone. To investigate the anti-cracking performance of the new composite beam, seven simply supported beams were designed. In the preliminary investigation, the longitudinal FRP bars in these beams were designed without optic fibers to focus on the mechanical behavior. The beams were tested under four-point load and measured using the digital sensor technique, digital image correlation (DIC). The test results showed that introducing a new ECC layer on the tensile side improves the cracking control and flexural behavior (load capacity and deformability) of a FRP-reinforced sea sand and seawater concrete (SSC) beam, especially in the serviceability limit state. We demonstrate the new composite beam can steadily and fully improve the tensile capacity of FRP bars, which is the basis of using FRP bars as sensors.

Composite mechanics-based design approach for FRP-strengthened walls

ABSTRACTThis study deals with development of a composite mechanics-based design approach for flexural strengthening of masonry walls using different layers of fiber-reinforced polymer (FRP) strips externally bonded and/or near surface mounted (NSM) FRP bars. To verify the developed design approach, experimental study was also conducted on three groups of walls. Six burnt clay brick masonry walls of size 780 × 480 × 230 mm were fabricated. Out of six, four masonry walls are strengthened with combination of longitudinal carbon fiber-reinforced polymer strips and horizontal NSM bars. The flexural responses of these masonry walls were predicted using three-point static loading. To evaluate the effect of using horizontal NSM FRP bars in conjunction with the longitudinal FRP strips on the response of the strengthened wall, an analytical approach using classical lamination theory has been presented. The developed analytical approach shows good agreements with the experimental results in terms of load carrying capacity and mid-span deflection. This analytical approach will help in setting up the design procedure to evaluate the response of a wall that is strengthened with FRP bars/strips provided in multiple layers. A design example has also been provided for easy understanding of the design approach.