Glass Fiber Reinforced Polymer Sheets Research Articles

Influence on the Flexural Behaviour of High-Volume Fly-Ash-Based Concrete Slab Reinforced with Sustainable Glass-Fibre-Reinforced Polymer Sheets

Concrete structures provided with steel bars may undergo deterioration due to fatigue and corrosion, which leads to an increase in repair and maintenance costs. An innovative approach to eliminating these drawbacks lies in the utilisation of glass-fibre-reinforced polymer (GFRP) sheets as reinforcement in concrete structures instead of steel bars. This article relates to the investigation of the flexural behaviour of ordinary portland cement (OPC) concrete slabs and high-volume fly ash (HVFA) concrete slabs reinforced with bi-directional GFRP sheets. Slab specimens were cast with 60% fly ash as a replacement for cement and provided with a 1 mm-thick GFRP sheet in 2, 3 and 4 layers. The flexural behaviour of slabs reinforced with GFRP sheets was compared with that of the slabs reinforced with steel bars. Experiment results such as cracking behaviour, failure modes and load–deflection, load–strain and moment–curvature relationships of the slab specimens are presented. Subsequently, the nonlinear finite-element method (NLFEM) using ANSYS Workbench 2022-R1 was carried out and compared with the experimental results. The results obtained from the numerical investigation correlated with the experimental results. The experimental investigation showed that the HVFA concrete slabs reinforced with GFRP sheet provided a better alternative compared to the steel reinforcement, which led to sustainable construction.

Finite element analyses of FRP-strengthened concrete beams with corroded reinforcement

Existing deteriorated reinforced concrete (RC) structures need strengthening to extend service life. Fibre reinforced polymer (FRP) has been widely used to strengthen sound structures, but its application on damaged concrete structures still needs to be investigated. This paper presents non-linear finite element analyses conducted to assess the flexural behaviour of corrosion-damaged RC beams strengthened with externally bonded FRP. Beams in four different categories were analysed: a reference beam, a corroded but non-strengthened beam, and corroded beams strengthened with glass FRP (GFRP) and carbon FRP (CFRP) respectively. Furthermore, the strengthened beams were modelled with different modelling choices to investigate the effectiveness of FRP applied to the beam soffit and as U-jackets. Pre-loading and corrosion-induced cracks were incorporated by reducing the tensile strength of concrete elements at crack locations. Average and pitting corrosion were incorporated by reducing the cross-sectional area of the reinforcement corresponding to the measured corrosion levels. Interface elements were used to simulate the bond between FRP and concrete. The modelling methods were validated against experimental results. It was found that modelling of pitting corrosion, especially the location of pits, lengths and number of pits considered, were influential in predicting the load and deformation capacity of beams. A CFRP plate at the beam soffit, combined with inclined U-jackets at its ends of the CFRP plate provided sufficient flexural strengthening. Thus, intermediate U-jackets did not further increase the load-bearing capacity for the studied beam geometry and corrosion damages. However, with a GFRP sheet at the beam soffit, both inclined and intermediate U-jackets were needed to provide full utilisation of the GFRP sheet for the studied beam geometry. In further studies of the effectiveness of the strengthening methods, it is recommended to investigate beams of varying dimensions, corrosion patterns and levels, and FRP spacing and dimensions.

Ductility and Stiffness of Laminated Veneer Lumber Beams Strengthened with Fibrous Composites

The paper presents the results of experimental research on unstrengthened and strengthened laminated veneer beams subjected to 4-point bending. Aramid, glass and carbon sheets with high tensile strength (HS) and ultra-high modulus of elasticity (UHM) glued to external surfaces with an epoxy resin adhesive were used as reinforcement. Two reinforcement layouts were used: (1) sheets glued along the bottom surface and (2) sheets glued to the bottom and side surfaces. Based on the test results, the flexural strength, flexural ductility and stiffness were estimated. Compared to the reference beams, the maximum bending moment was higher by 15%, 20%, 30% and by 16%, 22% and 35% for the Aramid Fiber Reinforced Polymers (AFRP), Glass Fiber Reinforced Polymers (GFRP) and Carbon Fiber Reinforced Polymers (CFRP) HS sheets, respectively. There was no significant increase in the flexural bending capacity for beams reinforced with UHM CFRP sheets. Similar values of bending ductility indices based on deflection and energy absorption were obtained. Higher increases in ductility were observed for AFRP, GFRP and CFRP HS sheets in “U” reinforcement layout. The average increase in bending stiffness coefficient ranged from 8% for AFRP sheets to 33% for UHM CFRP sheets compared to the reference beams.

Experimental Study on Strengthening of Concrete Cylinders Using GFRP Sheets with Boron Carbide-Epoxy Composite

Usage of composite materials as a concrete strengthening agent had increased evidently in recent years. One of those materials is the Glass Fibre Reinforced Polymer (GFRP) which is used in various fields for strengthening and retrofitting of concrete structures. Various studies have shown that, the wrapping of concrete specimens with Glass Fibre Reinforced Polymer (GFRP) resulted in increase in the Compressive Strength as well as the ductility of the concrete members. The main Objective of this project is to enhance the axial compressive strength of concrete block wrapped by Glass Fibre Reinforced Polymer sheets tested with various compositions of Boron Carbide (B4C) mixed with epoxy resin to find out the increase in the compressive strength. Cylindrical Concrete specimen of standard size 150mm diameter and 300mm height were casted of M30 Grade Concrete. Totally 6 batches were casted which consists of 18 specimens composing of different compositions of Boron Carbide varying 1.5%, 3.0%, 4.5% and 6.0% of boron carbide (B4C) were added and mixed with epoxy resin. Finally, Glass fibre Reinforced Polymer is wrapped around the Concrete specimen with a single wrap and the results obtained from Compressive strength of the specimens were studied.

Behavior of Reinforced Concrete Beams Strengthened By GFRP Composites Subjected to Combined Bending and Torsion – Experimental Study

This paper presents an experimental investigation on the behavior of reinforced concrete beams subjected to combined bending and torsion, strengthened by using externally bonded glass fiber reinforced polymer (GFRP). The experimental work includes an investigation of three RC beams tested under combined bending and torsion. One beam is kept without strengthening as a control specimen, while the other two beams are strengthened using GFRP wrapping with different configurations. All RC beams have the same concrete grade and steel reinforcement. The strengthened beams in the experimental study include full wrapping with continuous GFRP sheets and discrete GFRP strips with the same GFRP reinforcement ratio. The load-mid span deflection curves and the torsional moment-twist angle curves were recorded to failure. The crack patterns and failure modes of the RC beams were also indicated. The Experimental results reveal that strengthening by using GFRP wrapping helped effectively in improving the overall performance of the strengthened beams.

Pengaruh Ikatan Diagonal GFRP Pada Hubungan Balok Kolom Pracetak Terhadap Kekuatan Sambungan

Precast system is one of the reinforced concrete construction methods that can be used for development. GFRP-S (Glass Fiber Reinforced Polymer Sheet) is one of material that can be used as materials in precast concrete connections. The research aimed at analysing the strenght and behaviour of the concrete beams on beam-column joint precast with GFRP-S.The research was conducted at the Laboratory of Civil Engineering Structures and Materials Hasanuddin University. Beams dimensions was 15cm x 20cm x 120cm and the column was 45cm x 20cm x 100cm. The testing materials were the precast beams with GFRP-S. The imposition given is monotonic static load in one direction.The results showed that an increase in stiffness of the precast beams with GFRP-S. LSI amounted to 16.64% of the LS. LIS amounted to 31.70% of the LS. The average deflection of LS are 55.05 mm. The average deflection of LSI are 45.89 mm. The average deflection of LIS are 37.60 mm. The models of failure in the precast beams with GFRP-S are rupture failure of GFRP-S.

Experimental and numerical investigation of short GFRP- reinforced steel tubular short columns

Abstract This study presents the experimental and analytical modelling of externally bonded glass fibre-reinforced polymer (GFRP) sheets for strengthening circular steel tubular short columns. The GFRP sheets are easy to handle due to the lightweight property and the high-strength can provide a degree of restraint to delay buckling of the thin steel wall. Four short columns of cold-formed steel circular hollow section (CHS) were experimentally tested. One column is conventional (without GFRP wrap) and other 3 columns are externally bonded unidirectional (hoop) GFRP sheets which are varying with numbers of layers (1, 2 and 3 layers). In addition to the experimental studies, finite element analysis was also carried out using ABAQUS software. The experimental result shows that the steel tube is strengthened by GFRP sheets and enhances the axial section capacity. The load carrying capacity of externally bonded GFRP column increases about 17%−49% on comparison with the column without confinement. The study also concluded that the column externally warped with 3 layers of GFRP sheet is found to be optimum and it attains maximum load caring capacity. The prediction of analytical results has been found to be in good correlation with the experimented results.

Experimental Investigation on the Ecofriendly External Wrapping of Glass Fiber Reinforced Polymer in Concrete Columns

An ecofriendly fiber reinforced polymer (FRP) had been used in the last decade to enhance the short concrete column’s strength and deformation capacity. This study involves the wrapping of FRP sheets with a thickness of 3 mm and 5 mm on a short column, and then the compressive strength is determined. The rectangular columns of size 150 mm × 300 mm are used for this study, and cast under the grades of M20 and M40 are wrapped with GFRP sheets at the thickness of 3 mm and 5 mm. These results are clarified at a specific thickness of the FRP‐wrapped columns. It provides a maximum axial compressive strength, and Young’s modulus gets enhanced rigorously when it is to be compared to the normal concrete. This thesis deals with experimental studies of different parameters associated with wrapped glass fiber reinforced polymer (GFRP). In M20 grade, when the 3 mm wrapped specimen and the 5 mm wrapped specimen are compared, the specimen wrapped with 5 mm increases 5.182% more than the specimen wrapped with 3 mm. In M40 grade, when the 0 mm, 3 mm, and 5 mm wrapped specimens are compared, the specimen wrapped with 5 mm increases 2.47% more than the specimen wrapped with 0 mm. The 5 mm wrapping attains the maximum strength.

Strength Capacity Cracks Propagations Deflection and Tensile Enhancement of Reinforced Concrete Beams Warped by Glass Fiber Reinforced Polymer Strips

Different approaches were adapted to strength the structural elements to increase the load capacity and reduce the deformation such as deflection. The easiest and light external strengthening of reinforced concrete members are Fiber Reinforced Polymer (FRP) family such as Armed, Carbon, Glass and Basalt, respectively. This paper presents the theoretical approach to check out the experimental tests of reinforced concrete beams strengthened by glass fiber reinforced polymer (GFRP) using finite elements method by ANSYS software in which all models are simulate the tested beams. All models have the same geometry and mechanical properties but differ in GFRP layers and width. The main objectives of present work are evaluating the strength capacity, cracks propagations, deflection and tensile enhancement of reinforced concrete beams warped by GFRP strips subject to four points static load. Analysisof results indicate that the presences of GFRP sheets enhance the capacity and ductility of reinforced concrete beams in additional to delay the post crack concrete. The delay in the formation of first crack, increase in the number of cracks and ultimate loads of the models compared with the control model. There are improvements in flexural strength based on the modulus of rupture. Also, the cracks propogation become less in case of presence of GFRP and there is improvements in tensile resistance due to flexural. Analysis results inicated that the presence of GFRP at the bottom face of reinforced concrete beam in case of two layers gave increase in ultimate load 104.3% as compared with the control model. The reduction of the deflection for same models is 10.84%. Factor of the modulus of rupture range between (0.76-1.36) that is more than with ACI code suggested as 0.6. All model results were close to the experimental tests.

Behavior of Square Reinforced Concrete Columns Strengthened by Different Layers of Glass Frp Sheets

The behavior of reinforced square concrete columns strengthened by specific layers of glass fiber reinforced polymer (FRP) sheets were investigated through an experiment by testing of thirteen variety of concrete columns that were axially loaded at their ends. The most variable thought of during this study were the quantity or number of layers of glass fiber reinforcement polymer sheets and also the effect of confinement techniques (fully wrapped, strip ties and spiral sheets). The test values were compared with the proposed equation of ACI 440.2R-02, for samples strengthened by one layer of GFRP sheet can upgrade the load carrying capacity of columns in numerous ways of strengthening (fully wrapped, strip ties and spirally) by 25.5%, 6.7% and 29.5% respectively compared to the control (unstrengthen) column. Be that as a result of it would, for columns strengthen by 2 layers of GFRP sheets (fully wrapped, strip ties and spirally) the load carrying capacity increases by 36.5%, 19.6% and 29.8% respectively. While, for 3 layers of strengthen sample the percent of enhancement in the load carrying capacity increases by 38.2%, 20.1% and 30.7% respectively. Finally, the load carrying capacity increases by 43.2%, 29.2% and 33.2% for different confinement techniques (fully wrapped, strip ties and spiral sheets) respectively if they are strengthened by 4 layers of GFRP sheets.

Behavior of GFRP strengthening masonry walls using glass fiber composite anchors

This paper presents experimental and theoretical investigations on the short-term behavior of stone masonry walls constructed with lime mortar. The walls were strengthened using unidirectional GFRP (Glass fiber reinforced polymers) sheets to resist out-of-plane loads. Two methods of anchorage were used to enhance the behavior of strengthened stone masonry walls by preventing premature peeling-off of the GFRP sheets caused by GFRP debonding. Nine GFRP strengthened limestone masonry wall specimens including two control specimens were tested under combined constant low axial load levels and out-of-plane bending caused by two point monotonic loading. All the specimens have height-to-thickness (h/t) ratio of 7.1. The main variables investigated were GFRP reinforcement ratio, arrangement of GFRP, axial load level, and anchorage method. The strengthened walls showed an improvement in the out-of-plane performance which was significantly enhanced by anchorage. The increase in wall ultimate load carrying capacity reached 100%.

Experimental and numerical studies on the flexural behaviour of GFRP laminated hybrid-fibre-reinforced concrete (HFRC) beams

The main objective of this paper is to study the structural behaviour of hybrid fibre-reinforced concrete beams strengthened with glass fibre-reinforced polymer (GFRP) laminates. For the above purpose, three distinct groups of beam elements were cast, namely: (1) group A consisting of reinforced concrete (RC) and laminated RC beams, (2) group B consisting of fibre-reinforced concrete (FRC) and laminated FRC beams and (3) group C consisting of hybrid fibre-reinforced concrete (HFRC) and laminated HFRC beams. In beams of group B, basalt fibres were incorporated with a total volume fraction of 1%, whereas in group C beams, polyolefin and basalt fibres in the ratio of 30:70 were used with the total volume fraction of 1%. For lamination, 5-mm-thick GFRP sheet was used at the soffit of the all laminated beams. All the beams were tested under the four-point bending, until failure. The study parameters included evaluation of initial crack load, yield load and ultimate load and their corresponding deflections, ductility and failure modes. From the results, it was observed that the laminated HFRC beams exhibited higher load carrying capacity and larger deformation than the other beams. The ultimate load of laminated RC beam was about 33.44% higher than that of the control beams. The ultimate load of laminated HFRC improved by about 83.04% and 37.16% than the control and laminated RC beam, respectively. The load at FRP debonding initiation for ‘laminated HFRC beam’ is 43.06% higher than the laminated RC beam and 10.34% higher than the ‘laminated FRC beam’. Moreover, a 3-D finite element (FE) technique was adopted to simulate the performance of the beam elements. A fairly similar agreement was reached between the findings of the experimental and FE model results.

Experimental investigation on strengthening of reinforced concrete beams using GFRP laminates

The objective of this paper is to study the strengthening and stiffness of concrete while using FRP laminates. Glass Fibre Reinforced Polymer (GFRP) which are taken in form of sheets and are wrapped by three methods and find out its strengthening properties. The grade of concrete of beam which is going to be used is M25. The beam is going to be undergoing flexural strength test. Again, the same ruptured beam is going to be laminated with GFRP sheets by intermittent spacing, cross over and inclined way. Then the beam is again subjected to test. Then the test results are compared between various types.

Strengthening and Rehabilitation of Concrete Prisms Using GFRP Sheets

The use of external strengthening by fiber reinforced polymer (FRP) technology has significantly increased in recent decades. This is because (FRP) has the properties that make it the most suitable option for strengthening and rehabilitation of damaged concrete structures instead of using traditional materials such as steel plates. In this paper, the behaviour of non-reinforced concrete beams externally wrapped with Glass Fiber Reinforced Polymer (GFRP) sheets has been examined. Fourteen unreinforced concrete prisms were cast with a rectangular section of (150 × 125 mm) and a length of (760mm), these specimens were divided into five group. First group was not externally wrapped with GFRP sheets (control specimens), and the remaining groups were GFRP wrapped with a variable number of GFRP layers (thickness of wrapping). In the first stage of study, the prisms have been tested and the effect of external wrapping and increasing the wrapping thickness on the behaviour of prisms was observed. In the second stage, the unwrapped concrete prisms that were tested and failed (control specimens) were rehabilitated by externally wrapping them with one layer of GFRP sheets. The results have shown that wrapping with GFRP sheets increased the capacity of the prisms and failure load had reached to (342.5%) for prisms wrapped with three layers when compared to the control specimens. It was also noticed that there was an increase in the toughness of the prisms by increasing the number of GFRP layers. The results have shown that there was a decrease in the failure load of the four layer wrapped prisms, and this was due to the early failure of the prisms due to the debonding of the GFRP sheets from the prism surface. The damaged specimens which were later rehabilitated have shown an increase in load carrying capacity compared to the control specimen.

Ductility and Strength Behavior of Reinforced Concrete Columns Confined by Glass and Carbon FRP Sheets

Background: Fiber reinforced composite materials are becoming popular in civil engineering construction practices. One of the most practical applications of these materials is concerned with the strengthening and retrofitting of reinforced concrete compression members by means of external confinement with the GFRP sheets. The role of FRP for strengthening of existing or new reinforced concrete structures is growing at an extremely rapid pace owing mainly to the ease and speed of construction, and the possibility of the application without disturbing the existing functionality of the structure. Objective: The ductility and strength behavior of reinforced concrete columns (Square & Circle) confined by glass and carbon Fiber Reinforced Polymer (FRP) sheets were experimentally investigated Methods: In the library, we tested and cast a total of fourteen column specimens. The tested specimens in this study were square and circle columns, the square specimens tested in this experimental study had dimensions of 135x135 mm cross-section while the circle specimens had 150 mm diameter. The columns were loaded at their supports and made prepared to avoid local failure at supports due to steel plates. Two types of fiber reinforcements sheets were used for strengthening the columns (Carbon and Glass fiber polymer sheets). To prevent the highly stressed slender longitudinal bars from buckling outward, adequate amounts of steel ties were utilized in the height of the columns. During the test of the columns, the central deflection and central fiber strains were measured using dia1 gauges and strain gauges Discussion: The CFRP strains progressed very slowly before the yielding of longitudinal reinforcement bars but quickly, eventually, due to the concrete expansion in the plastic hinge. The wrapped CFRP sheets contribute to both the shear strength and the confinement of concrete in column specimens. The results signify that the percentages of increase in the carrying load capacity due to strengthen, using carbon and glass FRP sheets, were greater in the circular columns compared with the square columns for all the types of confinements used in this study. The ductility factor increased by the strengthen column ranged between 1.35-2.78, while the greatest ductility factor obtained when the circular columns strengthen with glass FRP sheets fully wrapped. Conclusion: -The maximum ratio of increase in the carrying load capacity obtained when the column strengthens fully wrapped. - The columns (circular and square) strengthen with carbon FRP sheets, the greater carrying load capacity obtained when compared the columns strengthen with glass FRP sheets. -The percentages of increase in the carrying load capacity due to strengthen, using carbon and glass FRP sheets were greater in the circular columns compared with the square columns for all the types of confinements. - The stains developed in the confined circular columns are greater than stains in the confined square columns. -The ductility factor increased by the strengthen column, while the greatest ductility factor obtained when the circular columns strengthen with glass FRP sheets fully wrapped.

Experimental Investigation Into Banana Fibre Reinforced Lightweight Concrete Masonry Prism Sandwiched with GFRP Sheet

Abstract This paper presents the stress-strain behaviour of Natural Banana microfibre reinforced Lightweight Concrete (LWC) prisms under axial compression. The compressive strength of masonry is obtained by testing stack bonded prisms under compression normal to its bed joint. LWC blocks of cross-sectional dimensions 200 mm x 150 mm were used to construct the prism with an overall height of 630 mm. Three series of specimens were cast; (a) prism without Banana fibre (control), (b) prism with Banana microfibres, (c) prism with Banana microfibres sandwiched with Glass Fibre Reinforced Polymer (GFRP) sheets. Natural Banana fibres were used as structural fibre reinforcement at different volume fractions (VF). The results indicate that the presence of fibres helps to improve the strength, stiffness, and ductility of LWC stack bonded prisms under compression. The test results also indicate that banana fibre reinforcement provides an improved crack bridging mechanism at both micro and macro levels. The GFRP sandwiched prism specimens exhibited excellent ductility and load-carrying capacity resulting from improved plastic deformation tolerance under compression and bonding between the LWC block and GFRP sheet.

Combined effects of wetting–drying cycles and sustained load on the behaviour of FRP-strengthened RC beams

This paper presents the results of an experimental study designed to investigate the performance of reinforced concrete (RC) beams strengthened with fibre-reinforced polymer (FRP) sheets subjected to wetting–drying cycles and a sustained load. Twenty-one RC beams were manufactured and externally bonded with carbon-FRP (CFRP) or glass-FRP (GFRP) sheets. Two U-shaped FRP anchorages were also applied on the ends of the beams to prevent end peeling failure. The FRP-strengthened beams were subjected to combined wetting–drying cycles in 5% NaCl solution and sustained loads for 0, 90, 180, and 360 days at load levels of 0%, 30%, and 60% of the ultimate loading capacity of the unstrengthened beam. During this period, the mid-span deflections and cracks of the beams were monitored, following which the beams were monotonically loaded to failure under a four-point bending. The failure patterns, mid-span deflections, and debonding loads were also examined. The test results showed that during sustained loading, the time-dependent and residual deflections of the FRP-strengthened RC beams increased with the increase in their periods of sustained loading and load levels. Intermediate crack-induced (IC) debonding of the CFRP-strengthened RC beams was induced by concrete separation and CFRP–concrete interface debonding, whereas that of the GFRP-strengthened RC beams was mainly caused by GFRP–concrete interface debonding. Combined wetting–drying cycles and a sustained load had an adverse effect on the yielding and debonding load of the FRP-strengthened RC beams, and the ductility of the GFRP-strengthened RC beams was higher than that of the CFRP-strengthened beams. In addition, a model considering the effects of wetting–drying cycles and sustained loads was proposed to predict the debonding load of FRP-strengthened RC beams, and it showed a reliable prediction.

Dynamic performance enhancement of RC slabs by steel fibers vs. externally bonded GFRP sheets under impact loading

Recently, to improve the dynamic behavior of Reinforced Concrete (RC) slabs under impact load, the methods of externally bonding Glass Fiber Reinforced Polymer (GFRP) sheets to slab and internally reinforcing concrete by steel fibers have been proposed. Nevertheless, it is required to investigate the comparison between these two methods on response of RC slabs under impact loads. In this study, the influence of volume fraction of steel fibers, the number of GFRP sheet layers (one or two) and the arrangement of GFRP sheets (covering the whole or parts of surface), are examined.Performance of fourteen 1000 × 1000 × 75 mm concrete slabs including one plain slab, one steel RC slab, three steel RC slabs containing steel fibers with different volume fractions and nine steel RC slabs strengthened with externally bonded GFRP sheets or strips under impact loads induced by drop weight is experimentally examined. In this article, crack development, failure modes and dynamic responses including displacement-time, strain-time, as well as acceleration-time are investigated and compared between slabs with various configuration. In addition, finite element analyses are carried out using LS-DYNA explicit software. The results indicate that increasing the bottom layer GFRP enhances the performance of RC slabs under impact loads. In general, slabs with totally bottom GFRP layers provide better performance than those with steel fibers.

Behaviour of Reinforced Concrete Beams Bonded with Glass Fibre Reinforced Polymer and Carbon Fibre Reinforced Polymer Sheets

Concrete, a mixture of different aggregates bonded with cement, first developed around 150BC in Rome has been bedrock to the modern Infrastructure. It is used to build everything from roads, bridges, dams to sky scrapers. Strengthening concrete is traditionally done by using steels but the developments in technology in recent decades allowed to use fiber reinforced plastics which are externally bonded to concrete . Such composite materials offer high strength, low weight, corrosion resistance, high fatigue resistance, easy and rapid installation and minimal change in structural geometry. This study investigates the behavior of reinforced concrete beams bonded with fiber composites. A numerical study is conducted to study the behavior of RC beam under Static third point loading. Concrete beam specimens with dimensions of 150 mm width, 300 mm height, and 2600 mm length are modelled. These beams are externally bonded with Glass Fiber Reinforced Polymer (GFRP) sheets and Carbon Fibre Reinforced Polymer (CFRP) sheets. In present study, we examine the performance of reinforced concrete beams which are bonded with GFRP and CFRP sheets with various thicknesses (1, 2 & 3 mm) using ABAQUS in terms of failure modes, enhancement of load capacity, load-deflection analysis and flexural behaviour

Internal GFRP Reinforcement of Low-Grade Maritime Pine Duo Timber Beams.

This paper presented an experimental structural-scale test campaign used to analyze the flexural behavior of low-grade maritime pine (Pinus pinaster Ait.) duo timber beams reinforced with an internal glass fiber-reinforced polymer (GFRP) sheet. For this purpose, thirty (30) unreinforced duo beams and thirty (30) duo beams internally reinforced with a unidirectional GFRP sheet with an areal mass of 1200 g/m2 were produced and tested. The addition of a low GFRP reinforcement ratio (1.07%) in the tension zone of the duo beams provided an average improvement of 8.37% in bending stiffness (EI) and an increase of up to 18.45% in ultimate moment capacity. In addition to this improved bending behavior, the internal GFRP reinforcements seemed to decrease the influence of wood singularities and wood heterogeneity on mechanical properties, which allowed for better characteristic values to be reached and for the achievement of results with less variability.