Fiber Reinforced Cementitious Matrix Research Articles

Intrados FRCM-strengthening of a masonry bridge: Experimental and analytical investigations

This paper will present the results of an experimental campaign aimed to study the structural behavior of solid clay brick masonry arch models strengthened at the intrados with Fiber Reinforced Cementitious Matrix (FRCM). The arch models’ peculiarities are: i) the presence of the haunching made of hydraulic lime mortar-based conglomerate, and ii) the geometry that reproduces a 1:2 scaled longitudinal section of a typical Italian railway single span bridge. The arch models are tested, imposing loading-unloading cycles to analyze the effectiveness of the strengthening system. The results are expressed in terms of failure mode, load carrying capacity and ductility, which shows the increase in the strength and displacement capacity of the strengthened model. Finally, limit analysis was performed to validate the experimental results and to assess the maximum fiber strain and the corresponding stress at the peak load.

Acoustic Emission (AE) based health monitoring of RC beams strengthened with mechanically anchored hybrid Fiber Reinforced Cementitious Matrix (FRCM) system

The debonding between fabric and matrix/substrate hampers the strength and durability of fiber-reinforced cementitious matrix (FRCM) strengthened elements. One of the ways to improve the performance is to use mechanical anchorages. However, damage mechanisms associated with such systems are complex, and structural health monitoring of such systems is quite challenging. While earlier studies have concentrated on monitoring the health of FRCM coupons using acoustic emission techniques, they did not account for the effect of impregnation or use of mechanical anchorages. Also, very few studies are available on the health monitoring of full-scale FRCM-strengthened specimens. The current investigation employs AE-based health monitoring to classify the damage characteristics of reinforced concrete (RC) beams strengthened with FRCM. Two strengthening strategies, with and without mechanical anchorages, are employed. The non-anchored system involves conventional strengthening using two layers of pre-impregnated fabric, while the mechanically anchored method utilizes pre-impregnated fabric and a distributed anchorage system. The AE data is then analyzed using several parameters correlated with the digital image correlation (DIC) technique. Trends of sentry function, historical index, and cumulative signal strength (CSS) provide insights into major event occurrences and changes in the underlying damage modes. Three different b-values indicate a transition from micro to macro cracks during different loading stages. On the other hand, frequency content and RA-AF analysis are employed as qualitative tools to identify the source and type of damage. The strengthened RC beams with mechanical anchorages exhibited a 20.9 % increase in flexural capacity compared to those without, as evidenced by the AE parameters and DIC techniques. Overall, the study revealed that acoustic emission health monitoring could effectively evaluate the overall condition of the strengthened system, even with the complexity of a multi-part composite system.

Corrigendum to evaluating shear capacity in reinforced concrete deep beams with web openings strengthened using fiber-reinforced polymer and fiber-reinforced cementitious matrix

Corrigendum to evaluating shear capacity in reinforced concrete deep beams with web openings strengthened using fiber-reinforced polymer and fiber-reinforced cementitious matrix

Evaluating shear capacity in reinforced concrete deep beams with web openings strengthened using fiber-reinforced polymer and fiber-reinforced cementitious matrix

This research systematically compares the effectiveness of Carbon Fiber-Reinforced Polymer (FRP) and Fabric-Reinforced Cementitious Matrix (FRCM) in shear strengthening of reinforced concrete (RC) deep beams featuring web openings. Through a comprehensive experimental program, six RC beams were subjected to shear tests, considering variations in the number of layers for both FRCM and FRP, employing a U-wrapping configuration. Recorded parameters include load-deflection curves, ultimate strength, cracking patterns, failure modes, and strains in steel bars, allowing a comprehensive comparison between strengthened and un-strengthened RC beams. The study compares observed shear strengths from experiments with shear capacities predicted by proposed models for RC beams strengthened with FRCM and FRP, following codes such as ACI 440.2R-17, CSA S806-12, Eurocode 2, and ACI 549.4R-20. Increasing layers enhanced shear strengths and post-elastic stiffness. The presence of substantial openings led to early shear cracks and reduced strength. CFRP improved shear strength by 13.99% (1-layer) and 18.12% (2-layer), while FRCM strengthened layers by 20.2% (1 layer) and 29.3% (2 layers). FRCM outperformed in strength and stiffness, while FRP excelled in ductility and concrete confinement. Experimental and calculated results varied based on ACI, CSA, and Eurocode, with ACI providing consistent and accurate results. CSA’s calculation surpassed experiments, emphasizing its consideration of effective fabric design strain.

Experimental shear behaviour of masonry walls reinforced with FRCM

The shear strength of piers and spandrels is a crucial factor in masonry buildings, affecting structural safety. Such a strength can be increased in several ways, particularly by using fiber reinforced cementitious matrix (FRCM) reinforcements. These reinforcements can be applied symmetrically on both sides of the wall or only on one side. As it is well known, the FRCM-to-substrate adhesive properties strongly affect the effectiveness of such reinforcements. Moreover, a complete covering of the reinforced surface with bidirectional mesh evenly distributes the stresses, improving the load-bearing capacity. Appropriate test methods, for example diagonal tests, can be effectively used to evaluate the shear capacity of masonry panels, even with externally bonded composite material reinforcements, and the corresponding failure mechanism. This paper describes the results of an experimental campaign involving masonry panels, made with three different types of mortar, also reinforced with a PBO-FRCM system, subjected to diagonal tests. Through the experimental results, it was possible to determine the shear capacity of the panels, identify the failure mechanisms and evaluate the effectiveness of the FRCM reinforcements. The predictive capability of design formulas proposed in the literature for evaluating the shear capacity of unreinforced and reinforced masonry panels has been analyzed in the paper.

Enhancing shear strength of RC beams through externally bonded reinforcement with stainless-steel strips and FRCM jacket to mitigate the failure risk

This study aims to assess the efficacy of innovative and sustainable methods in improving the shear performance of Reinforced Concrete (RC) beams lacking shear stirrups. Eleven specimens, including two control specimens and nine strengthened ones, underwent monotonic loading through three-point testing. Various strengthening configurations were investigated, involving the application of Stainless-Steel Strips (SSSs) affixed to the beam surface in the defective zone, along with a Fiber-Reinforced Cementitious Matrix (FRCM) jacket. In the first set of beams, SSSs were vertically applied, while the second set featured beams with SSSs inclined at 60°, and the third set had SSSs inclined at 45°. Each set comprised three beams, allowing for the examination of the impact of SSS thicknesses, set at 1 mm, 1.25 mm, and 1.50 mm. After the installation of SSSs, all strengthened beams received an FRCM jacket, including a 5 mm Engineered Cementitious Composites (ECC) layer with embedded Glass Fiber Reinforced Polymer (GFRP) textile. The study concludes that incorporating SSS strips with an FRCM jacket delays the initiation of the first crack in defective beams. Increasing SSSs thickness contributes to a more favorable crack distribution. The 60° inclined SSSs proves to be the most effective, rectifying the deficiency from the absence of shear stirrups and surpassing the original beam's performance. Additionally, finite element analysis was conducted, and the results supported the accurateness of the developed model in simulating responses and crack patterns throughout all loading stages.

Theoretical investigation of the structural performance of multi–span reinforced concrete beams strengthened with FRCM systems

Few studies have reported on the flexural behavior of multi–span reinforced concrete (RC) structures strengthened using externally–bonded (EB) systems such as fiber–reinforced polymer (FRP) and fiber–reinforced cementitious matrix (FRCM) systems. This paper introduces a theoretical model that can accurately predict the flexural behavior of such structures with a focus on their rotational capacity (curvature) and their moment redistribution response between critical sections. Unlike the available models, the proposed model accounts for the variation in the structure’s stiffness during loading including that of the strengthened section. The model can precisely determine the failure mode, the rotational capacity of the formed plastic hinges and estimate the moment redistribution ratio (MRR) between the critical sections at any applied load. The efficiency of the model was validated against the experimental results of eleven FRCM–strengthened two–span RC beams (including two control beams) previously tested by the authors. A good agreement between the experimental and the theoretical results was obtained with average experimental–to–theoretical ratios of 1.0 and 0.99 for the load carrying–capacity and MRR, respectively. To accurately determine the mid–span deflections of continuous EB–strengthened structures, a new reduction parameter was incorporated in the CSA–A23.3–19 (2019) formulations to account for the variation in stiffness of the strengthened section. The new formulations substantially enhanced the prediction of the deflection capacity of the strengthened structures with an average experimental–to–theoretical ratio of 1.02 versus 1.7 when CSA formulations were used.

Double shooting method for FRCM reinforced systems in debonding problems

The debonding process in FRCM (Fiber Reinforced Cementitious Matrix) strengthened brittle substrates, such as concrete and masonry, is characterized by complex failure modes that include debonding at both the external and internal interfaces of the composite, as well as damage to the mortar matrix. This study addresses this problem classically as a mode-II fracture process by accounting for the one-dimensional non-linear interfacial shear stress-slip relationship combined with matrix axial non-linearity. The approach employed considers the longitudinal displacements of both the inner and outer layers of mortar, along with that of the fiber textile, as unknowns, and analytically solves the second-order ordinary differential equation (ODE) system that governs the debonding problem. Then, the boundary value problem (BVP) is transformed into an initial value problem (IVP) and a double shooting method is proposed to find displacements and stresses along the bonded length in the presence of non-linearity. The appropriate initial values of matrix layer displacements, satisfying the required boundary conditions, are efficiently determined through a two-dimensional bisection method working on rectangular and triangular patches. The softening behavior of both mortar layers and interfaces between mortar and fiber are taken into account using jagged constitutive relationships to enhance convergence. The numerical calculation speed, robustness, and key simulation parameters are thoroughly discussed. Moreover, the proposed numerical approach is compared with existing experimental data and models, on both concrete and masonry FRCM-reinforced specimens. The influence of mortar failure and interfacial strength is also explored. The model demonstrates its ability to effectively reproduce the global bond behavior observed in experimental studies, while capturing the local behavior and simulating various failure modes observed in the tests.

Simplified Procedure to Determine the Cohesive Material Law of Fiber-Reinforced Cementitious Matrix (FRCM)-Substrate Joints.

Fiber-reinforced cementitious matrix (FRCM) composites have been largely used to strengthen existing concrete and masonry structures in the last decade. To design FRCM-strengthened members, the provisions of the Italian CNR-DT 215 (2018) or the American ACI 549.4R and 6R (2020) guidelines can be adopted. According to the former, the FRCM effective strain, i.e., the composite strain associated with the loss of composite action, can be obtained by combining the results of direct shear tests on FRCM-substrate joints and of tensile tests on the bare reinforcing textile. According to the latter, the effective strain can be obtained by testing FRCM coupons in tension, using the so-called clevis-grip test set-up. However, the complex bond behavior of the FRCM cannot be fully captured by considering only the effective strain. Thus, a cohesive approach has been used to describe the stress transfer between the composite and the substrate and cohesive material laws (CMLs) with different shapes have been proposed. The determination of the CML associated with a specific FRCM-substrate joint is fundamental to capture the behavior of the FRCM-strengthened member and should be determined based on the results of experimental bond tests. In this paper, a procedure previously proposed by the authors to calibrate the CML from the load response obtained by direct shear tests of FRCM-substrate joints is applied to different FRCM composites. Namely, carbon, AR glass, and PBO FRCMs are considered. The results obtained prove that the procedure allows to estimate the CML and to associate the idealized load response of a specific type of FRCM to the corresponding CML. The estimated CML can be used to determine the onset of debonding in FRCM-substrate joints, the crack number and spacing in FRCM coupons, and the locations where debonding occurs in FRCM-strengthened members.

Strengthening non-engineered building using vegetal FRCM retrofitting: A numerical modeling approach for seismic assessment

The concept of developing alternative rehabilitation techniques to enhance the performance of structures with low seismic resistance has come to light in recent years. Substantial research and methods have been devoted to evolving strengthening techniques worldwide for structures with economic value, with the ultimate goal of enhancing seismic resilience in them. Among these, Fiber Reinforced Cementitious Matrix (FRCM) stands out as a reliable alternative to conventional retrofitting approaches due to its high strength-to-density ratio and negligible mass increment. However, the inadequacy of full-scale modeling and the application of FRCM in building components persist in the research domain. Therefore, this paper aims to develop a numerical model for the full-scale application of vegetal FRCM composites in retrofitting a representative non-engineered building. The full-scale application of the four vegetal FRCM materials (hemp, cotton, flax, and sisal) in 1-ply and 2-ply configurations was undertaken to strengthen a non-engineered building. The results of pushover analysis show that buildings retrofitted with 2-ply hemp and 2-ply flax FRCM exhibited the most significant improvement in base shear strength, with increments of about 30% and 28.5% respectively, compared to the peak base shear of the bare frame. Additionally, the retrofitted models demonstrated an increase in their ductility. A subsequent fragility analysis highlighted a reduction in the seismic hazard vulnerability of the building for the relevant earthquake spectrums. Finally, the results from the numerical analysis confirm that the use of vegetal fibers as cementitious matrix can have significant potential to be an effective and sustainable strengthening technique for seismically deficient buildings.

Semi-analytical approach for curved masonry pillars reinforced with FRCM

The paper presents a semi-analytical approach for the study of the debonding phenomenon of Fiber Reinforced Cementitious Matrix (FRCM) systems externally applied to curved masonry pillars. One of the main features of the approach consists of considering the strengthening system composed by three separated components: external mortar layer, central fiber net and internal mortar layer. These components, assumed subjected to a longitudinal state of stress, interact one each other through tangential stresses developing at the level of zero-thickness interfaces. Regarding the latter, a tri-linear shear stress-slip relationship is assumed to account for a first elastic phase, a second phase exhibiting linear softening and a third phase with a possible non-null residual strength. Since in case of curved substrates, by equilibrium, normal stresses at the interfaces between fiber and matrix arise, which modify the peak tangential resistance and the ductility, a classic Mohr-Coulomb criterion is introduced in the approach. Additionally, the central fiber net progressively transfers along the bond length the force applied at its loaded end by means of an elastic interface interposed between the internal mortar layer and the substrate, the latter assumed rigid and infinitely resistant. The longitudinal equilibrium equations written for the two mortar layers, suitably re-arranged considering the constitutive behavior of the layers, allow to deduce a field problem governed by six first order differential equations into six unknowns. The non-linearity is tackled by means of a recursive elastic numerical algorithm where the elastic modulus of the damaged materials is progressively dropped down, subdividing the bonded length into small portions where the material properties are assumed constant. For each element the solution of the field problem is known in closed form and the only variables to determine are the integration constants coming from the solution of the differential equation system. After a standard assemblage, all constants are derived imposing the boundary conditions at the extremes of the elements, which depend on the state of cracking of the matrix layer. The validation of the proposed approach is carried out with reference to recent experimental tests carried out by the Authors. The obtained results show the reliability of the approach to account for the influence of the curvature of the substrate on the debonding process of FRCM systems.

AE-Based Health Monitoring of Full-scale RC Beams Strengthened with FRCM Composites

Using fiber-reinforced cementitious matrix (FRCM) offers several advantages, making it a potential replacement for conventional fiber-reinforced polymers (FRP). Integrating mechanical anchorage enhances the robustness and cost-effectiveness of the FRCM system. This research study primarily focuses on the comprehensive flexural strengthening of reinforced concrete (RC) beams using FRCM. To achieve this, three RC beams were intentionally partially damaged, and subsequently, two layers of FRCM were applied with three distinct strengthening strategies, including options with and without mechanical anchorage. These beams were then subjected to a monotonic four-point bending loading test. Monitoring of the front face of the beam is carried out using the Digital Image Correlation (DIC) technique, while the bottom and back faces were equipped with three acoustic sensors, each with a frequency range of 20-1000 kHz. It was observed that the FRCM strengthening strategy involving mechanical anchorage proved highly effective in increasing the load capacity of the beam by approximately 20% when compared to other strategies using a similar percentage of fabric reinforcement. The analysis of acoustic emission (AE) data involved the assessment of parameters such as AE cumulative hits, Cumulative signal strength, event rate, RA-AF, and historical index. These metrics helped identify different test phases based on changing trends in event rate and RA-AF over time. The historical index revealed the patterns of significant events.

Mechanical properties of flax fibers as a green alternative for FRCM systems

In recent years, thanks to policies oriented toward the rehabilitation of existing heritage and the introduction of more environmentally sustainable choices, an increased attention has been devoted to the study of new structural strengthening solutions. With reference to masonry buildings, which constitute a significant part of the built heritage, Fiber Reinforced Cementitious Matrix (FRCM) systems are widely adopted to achieve more effective structural capacity, making use of inorganic matrices and composite grids, the latter being formed of carbon, basalt, glass, or aramid fibers. However, the necessity to reduce the carbon emissions, also considering the new European perspectives on sustainability, have prompted the scientific and engineering community to explore eco-friendly alternatives. In this context, the use of natural fibers as potential alternatives for enhancing the structural performance of a building or part of it, rises as a promising area of study. The present study proposes an analysis on the use of flax fibers within FRCM systems, aimed at reinforcing masonry structures. The mechanical and durability properties of the material are investigated through tensile tests on flax yarns, as well as tests on a fabric composed by flax bundles supported by a mesh of glass fibers. The results obtained in this study shaw how the natural type of fiber studied is so interested when it is treated with coating in terms of mechanical properties and durability.

Experimental data of RC beams shear strength with different shear span and strengthening by FRCM system

The article presents the results of experimental testing of reinforced concrete beams with different shear spans and strengthened by the FRCM (Fiber Reinforced Cementitious Matrix) system. The shear spans were 2, 1.5, and 1. Strengthening was performed for shear span 2 with three vertical strips of composite fabric 70 mm width each. In total, the results of the eight tests (the four experimental samples) are presented. Each beam was tested twice, separately for each support section of the beam A change in the failure type of reinforced concrete beams at shear is shown. It was determined how the bearing capacity and deformability of concrete and transverse reinforcement in all samples changed with the change in test parameters. The use of strengthening strips at the level of 20% of their maximum elongation values was achieved.

Lime-based plasters reinforced with hemp meshes for retrofitting masonry structures

The recent earthquakes in the Mediterranean area provoked serious damages and collapses to the built-up, including masonry buildings that represent the highest percentage of existing structures. The protection of the historical heritage to prevent economic and human losses is always accompanied by the compelling need of preserving the environment due to the increasing attention to the sustainability issue. In this framework, retrofit solutions already widespread and effective in the Seismic Engineering field can also be improved from an environmental point of view. In past years, one of the techniques most applied to masonry structures is the Fiber Reinforced Cementitious Matrix (FRCM), that is usually made of artificial fibres, such as steel, carbon, and glass, immersed into a matrix used to fix the reinforcing system to the structural support. The sustainability of this reinforcement kind can be improved by replacing artificial fibres with natural ones, such as hemp, that claims good mechanical properties and is carbon negative. The research aims at experimenting a retrofitting system, called Hemp-FRCM, that is made of a hemp mesh drowned in a lime matrix. The hemp fibres are preliminary subjected to tensile tests. Then, the Hemp-FRCM system is applied to a brick masonry wall tested under compressive loads. Finally, the adhesion capacity of the system to a Neapolitan yellow tuff support is evaluated by performing delamination tests. The experimental campaign shows promising results on the use of hemp meshes instead of artificial systems for the structural retrofit of existing masonry buildings.

Refined modelling methods of structural reinforcements in the analysis of masonry bridges

Masonry arch bridges constitute a large part of today’s Italian architectural heritage. Italy has the highest percentage in Europe of masonry railway bridges with respect to the total. Due to the processes of degradation and to the increased levels of the loads and of the safety requirements, rehabilitation and retrofitting of these bridges is required. Among the available reinforcement techniques, the use of reinforcements with mortar/cement matrix fiber nets has gained great popularity due to the advantages shown over traditional techniques in terms of strength and durability. The FRCM, acronym of “Fiber Reinforced Cementitious Matrix” is a valid reinforcement alternative to the use of polymeric matrix reinforcements, due to its greater compatibility with the masonry support. The Italian technical standards suggest a simplified method for the design of the reinforcement based on empirical coefficients that increase the mechanical properties of the masonry materials, disregarding the consideration of the complex crisis mechanisms occurring, especially in more complex systems like the multi-arch bridges.The object of this work is the definition of a more refined and efficient method for the numerical modeling of FRCM reinforcement in the structural analysis of multi-span masonry arch bridge. Specifically, an equivalent reduced nets embedded in a mortar continuum determined with the area equivalence principle.The model is calibrated based on experimental characterization tests carried out on PBO-Mesh, and on the constituents. A validation test of the model is performed with reference to arch models reinforced with PBO-Mesh experimentally tested.The effectiveness of the proposed approaches is verified analyzing the seismic behavior of a masonry multi-span bridge, also considering the soil-structure interaction.

Damage Classification Using CNN-Based Model for Multi-Part Strengthening System

Strengthening and retrofitting systems, including FRCM (Fiber-Reinforced Cementitious Matrix), play a vital role in improving the durability and safety of structures facing challenges such as aging, increased loads, or seismic risks. To ensure the long-term integrity and performance of these structures, it’s crucial to monitor the health of repaired structural components. Acoustic emission (AE) is a non-destructive and passive technique that involves the detection and analysis of stress waves emitted by various material components undergoing damage. In this particular research, the study focuses on the classification of damage in different material components of RC (Reinforced Concrete) beams strengthened with FRCM. This classification is achieved using a convolutional neural network (CNN) model that utilizes image-based waveform data from the AE testing. The study collected waveforms from four distinct failure modes: fabric-matrix debonding, fabric rupture, tensile cracking in the cementitious matrix, and yielding of steel. These waveforms were used to train the CNN model. Each waveform was converted into a Discrete Wavelet Transform (DWT) scalogram as an input into the model. The model demonstrated prediction accuracy of approximately 95% during training. The pre-trained model was further employed to classify failure mechanisms with a separate test dataset with an accuracy of approximately 87%, which is considered satisfactory considering added noise to the test dataset.

Experimental and numerical investigation of two–span RC beams strengthened with fiber–reinforced cementitious matrix (FRCM)

This paper investigated both experimentally and numerically the flexural performance of two–span beams after being strengthened with polyparaphenylene benzobisoxazole (PBO) fiber–reinforced cementitious matrix (FRCM) systems at different hogging–to–sagging (H/S) strengthening ratios. The test results revealed that the enhancement in the flexural response of the strengthened beams was highly dependent on the strengthening configuration and the number of layers used in both the hogging and sagging sections. The H/S ratio had a notable effect on the failure modes of the hogging sections only whereas the sagging sections showed similar failure modes regardless of the H/S used. Strengthening the sagging sections governed the ductility of the tested beams with a slight effect of the H/S ratio on their ductility. Despite strengthening, the hogging sections were capable to redistribute up to 37% of their moments to the sagging sections, which represented 93% of the redistribution capacity of the unstrengthened sections. This finding suggests the revision of the CSA and ACI formulations that prohibit any moment redistribution in the design of externally–bonded strengthened elements. The developed finite element model accurately predicted the experimental results in terms of the failure modes, the load–carrying capacity, the ductility, and the moment redistribution ratios between the critical sections.

Experimental investigation on a FRCM bio-composite for sustainable retrofitting of masonry buildings

Strengthening masonry structures by using green and natural materials has received increasing attention. Natural fibers can be obtained from vegetables, animals or mineral sources and can be used to meet modern buildings safety standards and to reduce carbon dioxide emissions. This paper presents a novel method to strengthen masonry buildings through the application of a mortar coating reinforced with natural fibers made of a jute or a basalt grid. This class of materials is known as Fiber Reinforced Cementitious Matrix (FRCM). FRCM composites can produce an increment in the mechanical properties of masonry members and contribute to the thermal-acoustic insultation of the building envelope. The mortar coating is made of a hydraulic lime: to increase thermal properties this was admixed with short spelt fibers. Both matrix (lime mortar) and fibrous material were initially mechanically and thermally characterized. Laboratory tests have been carried out to study the bond characteristics between the FRCM composite and brickwork masonry. It was found the low mechanical properties of jute fibers are aggravated by a low FRCM-to-masonry bonding, making difficult to use this material for structural retrofit. On opposite, basalt fibers exhibit high mechanical properties and their use in conservation is surely promising and interesting.

Analysis of the seismic vulnerability and innovative retrofit solutions of cavity brickwork walls

This paper offers the results of an experimental investigation aimed at assessing the seismic vulnerability of a type of cavity wall, with a brief discussion of the advantages of this form of construction. Cavity walls were mainly designed to carry vertical loads and to improve the thermal behaviour of the building envelope: these are made of two single-wythe walls (typically using low-perforated bricks) with a cavity filled with a polystyrene panel. Cavity walls often exhibit poor seismic performance. A total of 12 full-size cavity-wall panels were tested in this experimental programme at the laboratory, by conducting shear and bending tests aimed at studying the in-plane and out-of-plane structural responses under simulated seismic actions. In addition, different retrofit solutions were studied and used to reinforce the cavity-wall panels: this included the traditional method to tie the wall leaves with steel connectors, an innovative method made of GFRP (Glass Fiber Reinforced Polymers) rods, and a mortar coating reinforced with a composite grid, known as FRCM (Fiber Reinforced Cementitious Matrix). It was found that the lateral bending-capacity of the panels reinforced with the GFRP rods and a FRCM coating greatly increased over that of the control unreinforced specimens. The proposed reinforced method was able to provide some seismic resisting capacity to the cavity walls, especially against bending and out-of-plane loading, in a more effective way than the traditional method of steel ties.