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1
Deniaud, Christophe, and JJ Roger Cheng. "Review of shear design methods for reinforced concrete beams strengthened with fibre reinforced polymer sheets." Canadian Journal of Civil Engineering 28, no. 2 (April 1, 2001): 271–81. http://dx.doi.org/10.1139/l00-113.
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This paper reviews the different shear design methods found in the literature for reinforced concrete beams strengthened externally with fibre reinforced polymer (FRP) sheets and compares the adequacy of each method by using the test results from the University of Alberta. The FRP shear design methods presented include the effective FRP strain and the bond mechanism criteria, the strut-and-tie model, the modified compression field theory, and a mechanical model based on the strip method with shear friction approach. Sixteen full-scale T-beam test results were used in the evaluation. Two web heights of 250 and 450 mm and two ready mix concrete batches of 29 and 44 MPa were used in the test specimens. Closed stirrups were used with three spacings: 200 mm, 400 mm, and no stirrups. Three types of FRP were used to strengthen externally the web of the T-beams: (i) uniaxial glass fibre, (ii) triaxial (0/60/60) glass fibre, and (iii) uniaxial carbon fibre. The results showed that the mechanical model using the strip method with shear friction approach evaluates better the FRP shear contribution. The predicted capacities from this mechanical model are also found conservative and in excellent agreement with the test results.Key words: beams, carbon fibres, composite materials, fibre reinforced polymers, glass fibres, rehabilitation, reinforced concrete, shear strength, sheets, tests.
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Bakhtiyari, Saeed, Leila Taghi Akbari, and Masoud Jamali Ashtiani. "An investigation on fire hazard and smoke toxicity of epoxy FRP composites." International Journal of Disaster Resilience in the Built Environment 8, no. 3 (June 12, 2017): 230–37. http://dx.doi.org/10.1108/ijdrbe-07-2016-0030.
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PurposeThe purpose of this study is assessment of fire and smoke hazards of some fiber reinforced polymers (FRP). The use of FRP strengthening strips has been found rapid growth in construction industry of Iran and many other countries. However, the fire and smoke hazards of these materials in both construction and use phases need to be determined and the appropriated measures against fire should be taken. Design/methodology/approachThe fire hazards of two types of fibre-reinforced epoxy composites (graphite fibre-reinforced polymer and carbon fibre-reinforced polymer) were investigated in bench-scale using cone calorimeter test method. Time to ignition, heat release rate, total heat release, smoke release and carbon monoxide production were measured and analysed. Time to flashover of an assumed room lined with the tested FRP was analysed with Conetools software. Smoke production and toxicity of the considered composites were also analysed and discussed, using the fractional effective dose parameter. FindingsThe results showed that the tested FRP products had a high fire hazard and a potential high contribution to fire growth. The tests also proved that the used epoxy resin had a low glass transition temperature, around 50°C; therefore, the mechanical strength of the product could be drastically reduced at first stages of a probable fire incident. This also showed that a regular thermal barrier, typically used for protection of plastic foams against fire, could not be sufficient for the protection of strengthening FRP composites. Originality/valueThis research was carried out for the first time for the materials used in construction industry of Iran. The results and achievements were very useful for safe use and development of proper details of application of the system.
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Shehata, Emile, Ryan Morphy, and Sami Rizkalla. "Fibre reinforced polymer shear reinforcement for concrete members: behaviour and design guidelines." Canadian Journal of Civil Engineering 27, no. 5 (October 1, 2000): 859–72. http://dx.doi.org/10.1139/l00-004.
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This paper describes an experimental program conducted to examine the structural performance of fibre reinforced polymer (FRP) stirrups as shear reinforcement for concrete structures. A total of ten large-scale reinforced concrete beams were tested to investigate the contribution of the FRP stirrups in a beam mechanism. The ten beams included four beams reinforced with carbon fibre reinforced polymer (CFRP) stirrups, four beams reinforced with glass fibre reinforced polymer (GFRP) stirrups, one beam reinforced with steel stirrups, and one control beam without shear reinforcement. The variables were the material type of stirrups, the material type of the flexural reinforcement, and the stirrup spacing. Due to the unidirectional characteristics of FRP, significant reduction in the strength of the stirrup relative to the tensile strength parallel to the fibres is introduced by bending FRP bars into a stirrup configuration and by the kinking action due to inclination of the diagonal shear crack with respect to the direction of the stirrups. A total of 52 specially designed panel specimens were tested to investigate the bend and kinking effect on the capacity of FRP stirrups, along with two control specimens reinforced with steel stirrups. The variables considered in the panel specimens are the material type of the stirrups, the bar diameter, the bend radius, the configuration of the stirrup anchorage, the tail length beyond the bend portion, and the angle of the stirrups. Based on the findings of this investigation, shear design equations for concrete beams reinforced with FRP, appropriate for the Canadian Standards Association (CSA) code, are proposed. The reliability of the proposed equations is evaluated using test results of 118 beams tested by others.Key words: shear, fibre-reinforced polymers, CFRP, cracks, GFRP, kink, stirrups, bend capacity.
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Šlaitas, Justas. "Flexural Reinforced Concrete Elements, Strengthened with Fibre Reinforced Polymer, Bearing Capacity Evaluation According to Limit Crack Depth." Mokslas - Lietuvos ateitis 9, no. 5 (December 27, 2017): 507–19. http://dx.doi.org/10.3846/mla.2017.1079.
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The research was made on condition assessment of flexed reinforced concrete structures, strengthened with fibre reinforced polymers, in fracture stage. Universal bearing capacity calculation method based on limit normal section crack depth was proposed. This paper confirms the hypothesis of triangular concrete’s compressive zone chart usage for flexural strength calculation, without tensile concrete above crack evaluation. There is established connection between crack depth and FRP stressstrain, which allows to decide about structures bearing capacity reserve. The calculation results are confirmed with experimental studies of 73 reinforced concrete beams, strengthened with carbon fibre reinforced polymer (CFRP) and glass fibre reinforced polymer (GFRP) sheets, plates, strips and rods, taken from different researches. Furthermore, recommended limits of strengthening with FRP were proposed.
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Bisby, L. A., V. KR Kodur, and M. F. Green. "Numerical parametric studies on the fire endurance of fibre-reinforced-polymer-confined concrete columns." Canadian Journal of Civil Engineering 31, no. 6 (December 1, 2004): 1090–100. http://dx.doi.org/10.1139/l04-071.
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Confinement of reinforced concrete columns by circumferential fibre reinforced polymer (FRP) wraps is a promising application of FRP materials for structural strengthening and seismic upgrading of deteriorated or under-strength members. However, if this technique is to be used in buildings, parking garages, and industrial structures, then the ability of FRP materials and FRP-wrapped columns to withstand the effects of fire must be demonstrated and evaluated. This paper presents the results of parametric studies conducted using a previously presented and partially validated numerical fire simulation model to investigate the effects of a number of parameters on the fire behaviour of FRP-wrapped reinforced concrete columns. It is demonstrated that appropriately designed and adequately protected FRP-wrapped reinforced concrete columns are capable of achieving fire endurances equivalent to conventionally reinforced concrete columns. Furthermore, this study also suggests that a holistic approach to the fire design of FRP-wrapped members is required, rather than an approach based on the specific performance of the FRP materials. Design recommendations for the fire-safe design of FRP-wrapped concrete columns are presented and discussed.Key words: reinforced concrete, rehabilitation, strengthening, fibre reinforced polymer, fire endurance, fire insulation, numerical modelling.
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Ostrowski, Krzysztof Adam, Carlos Chastre, Kazimierz Furtak, and Seweryn Malazdrewicz. "Consideration of Critical Parameters for Improving the Efficiency of Concrete Structures Reinforced with FRP." Materials 15, no. 8 (April 9, 2022): 2774. http://dx.doi.org/10.3390/ma15082774.
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Fibre-reinforced polymer materials (FRP) are increasingly used to reinforce structural elements. Due to this, it is possible to increase the load-bearing capacity of polymer, wooden, concrete, and metal structures. In this article, the authors collected all the crucial aspects that influence the behaviour of concrete elements reinforced with FRP. The main types of FRP, their characterization, and their impact on the load-carrying capacity of a composite structure are discussed. The most significant aspects, such as type, number of FRP layers including fibre orientation, type of matrix, reinforcement of concrete columns, preparation of a concrete surface, fire-resistance aspects, recommended conditions for the lamination process, FRP laying methods, and design aspects were considered. Attention and special emphasis were focused on the description of the current research results related to various types of concrete reinforced with FRP composites. To understand which aspects should be taken into account when designing concrete reinforcement with composite materials, the main guidelines are presented in tabular form.
7
Qureshi, Jawed. "A Review of Fibre Reinforced Polymer Structures." Fibers 10, no. 3 (March 8, 2022): 27. http://dx.doi.org/10.3390/fib10030027.
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This paper reviews Fibre Reinforced Polymer (FRP) composites in Civil Engineering applications. Three FRP types are used in Structural Engineering: FRP profiles for new construction, FRP rebars and FRP strengthening systems. Basic materials (fibres and resins), manufacturing processes and material properties are discussed. The focus of the paper is on all-FRP new-build structures and their joints. All-FRP structures use pultruded FRP profiles. Their connections and joints use bolting, bonding or a combination of both. For plate-to-pate connections, effects of geometry, fibre direction, type and rate of loading, bolt torque and bolt hole clearance, and washers on failure modes and strength are reviewed. FRP beam-columns joints are also reviewed. The joints are divided into five categories: web cleated, web and flange cleated, high strength, plate bolted and box profile joints. The effect of both static and cyclic loading on joints is studied. The joints’ failure modes are also discussed.
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Wang, Wenjie, Zonglai Mo, Yunpeng Zhang, and Nawawi Chouw. "Dynamic Splitting Tensile Behaviour of Concrete Confined by Natural Flax and Glass FRP." Polymers 14, no. 20 (October 19, 2022): 4424. http://dx.doi.org/10.3390/polym14204424.
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Flax fibre has been used to reinforce concrete composite, but its dynamic properties have not been thoroughly studied. This study investigates the dynamic splitting tensile properties of plain concrete (PC) confined by flax-fibre-reinforced polymer (FFRP) and glass-fibre-reinforced polymer (GFRP). The dynamic splitting tensile tests were carried out on PC, FFRP-PC, and GFRP-PC cylinder specimens by the high-speed servo-hydraulic machine, with the impact-induced strain rates ranging from 0.1 to 58 s⁻1. The effect of the FRP confinement, FRP thickness and strain rate on the dynamic splitting tensile behaviour were assessed. The results indicated that similar confinement effectiveness of FFRP and GFRP is observed. The dynamic tensile strength of 1- and 2-layer FFRP-PC increased by 29% and 67%, and the one- and two-layer GFRP-PC increased by 32% and 84%, respectively. FFRP-PC and GFRP-PC cylinders showed less sensitivity to the strain rate compared with PC. The empirical relationship between the tensile DIF and strain rate for PC, FFRP-PC and GFRP-PC was proposed based on experimental data. The proposed model was developed to predict the dynamic splitting tensile strength. The results suggested the potential of FFRP composites applied into concrete structures under extreme dynamic loadings.
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Koenig, Ch R., D. H. Mueller, J. Mueller, and Mircea Calomfirescu. "Fibre-Reinforced Polymers under Impact Load." Key Engineering Materials 326-328 (December 2006): 1563–68. http://dx.doi.org/10.4028/www.scientific.net/kem.326-328.1563.
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Structural failure of fibre-reinforced polymers (FRP) caused by impact is an important factor in product development for the aircraft industry. Therefore it is necessary to obtain knowledge of the mechanisms and of the material loading during and shortly after an impact load. On account of this a Finite-Element-Model was developed with the goal to deduce design rules for impact tolerant composite materials. To verify and validate the Finite-Element-Model it is essential to have information of the state of stress on the surface of the FRP shortly after the impact. An impact test device was developed at the University of Bremen. The time variable, stress and strain conditions in composite plates are measured using photoelastic technique, strain gauges and holographic interferometry.
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Lathamaheswari, R., R. BalaKeerthana, K. Nandhini, B. Parkavi, and A. Nivedha. "Study on GFRP Reinforced Beams under Flexure." International Journal of Emerging Research in Management and Technology 6, no. 7 (June 29, 2018): 156. http://dx.doi.org/10.23956/ijermt.v6i7.205.
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Acute shortage of raw materials and deterioration of reinforced concrete structural elements lead to implementation of new substitute materials and innovative technologies. Reinforced Cement Concrete structures are usually reinforced with steel bars which are subjected to corrosion at critical temperature and atmospheric conditions. The structures can also be reinforced with other materials like Fibre Reinforced Polymers (FRP). In this line Fibre Reinforced Polymer based reinforcement replacing conventional steel rod for a precast element of a prefabricated structure is considered. The precast member cast out of M25 grade concrete reinforced exclusively with locally produced Glass Fibre Reinforced Polymer (GFRP) bars including GFRP stirrups is designed, cast. Flexural behaviour of rectangular concrete beams reinforced with FRP bars and stirrups is examined with two specimens one with conventional sand as fine aggregate and another with quarry dust as fine aggregate. The load at cracking and ultimate, type of failure and crack patterns are observed and compared with those of conventional cement concrete.
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Ghali, Amin, Tara Hall, and William Bobey. "Minimum thickness of concrete members reinforced with fibre reinforced polymer bars." Canadian Journal of Civil Engineering 28, no. 4 (August 1, 2001): 583–92. http://dx.doi.org/10.1139/l01-021.
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To avoid excessive deflection most design codes specify the ratio (l/h)s, the span to minimum thickness of concrete members without prestressing. Use of the values of (l/h)s specified by the codes, in selecting the thickness of members, usually yields satisfactory results when the members are reinforced with steel bars. Fibre reinforced polymer (FRP) bars have an elastic modulus lower than that of steel. As a result, the values of (l/h)s specified in codes for steel-reinforced concrete would lead to excessive deflection if adopted for FRP-reinforced concrete. In this paper, an equation is developed giving the ratio (l/h)f for use with FRP bars in terms of (l/h)s and (εs/εf), where εs and εf are the maximum strain allowed at service in steel and FRP bars, respectively. To control the width of cracks, ACI 318-99 specifies εs = 1200 × 106 for steel bars having a modulus of elasticity, Es, of 200 GPa and a yield strength, fy, of 400 MPa. At present, there is no value specified for εf; a value is recommended in this paper.Key words: concrete, cracking, deflection, fibre reinforced polymers, flexural members, minimum thickness.
12
Bazli, Milad, and Milad Abolfazli. "Mechanical Properties of Fibre Reinforced Polymers under Elevated Temperatures: An Overview." Polymers 12, no. 11 (November 5, 2020): 2600. http://dx.doi.org/10.3390/polym12112600.
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Fibre-reinforced polymer (FRP) composite is one of the most applicable materials used in civil infrastructures, as it has been proven advantageous in terms of high strength and stiffness to weight ratio and anti-corrosion. The performance of FRP under elevated temperatures has gained significant attention among academia and industry. A comprehensive review on experimental and numerical studies investigating the mechanical performance of FRP composites subjected to elevated temperatures, ranging from ambient to fire condition, is presented in this paper. Over 100 research papers on the mechanical properties of FRP materials including tensile, compressive, flexural and shear strengths and moduli are reviewed. Although they report dispersed data, several interesting conclusions can be drawn from these studies. In general, exposure to elevated temperatures near and above the resin glass transition temperature, Tg, has detrimental effects on the mechanical characteristics of FRP materials. On the other hand, elevated temperatures below Tg can cause low levels of degradation. Discussions are made on degradation mechanisms of different FRP members. This review outlines recommendations for future works. The behaviour of FRP composites under elevated temperatures provides a comprehensive understanding based on the database presented. In addition, a foundation for determining predictive models for FRP materials exposed to elevated temperatures could be laid using the finding that this review presents.
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Green, Mark F., Aaron J. S. Dent, and Luke A. Bisby. "Effect of freeze–thaw cycling on the behaviour of reinforced concrete beams strengthened in flexure with fibre reinforced polymer sheets." Canadian Journal of Civil Engineering 30, no. 6 (December 1, 2003): 1081–88. http://dx.doi.org/10.1139/l03-059.
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Externally bonded fibre reinforced polymer (FRP) plates and sheets for strengthening and rehabilitating existing reinforced concrete structures have recently received a great deal of attention within the civil engineering community. Many tests have shown the benefits of FRP, but more information is required on their behaviour in cold regions. Twenty-seven small-scale concrete beams (100 mm × 150 mm × 1220 mm) were strengthened with FRP in flexure (and in some cases also in shear), subjected to up to 200 freeze–thaw cycles, and tested to failure in four-point bending. Test results were compared with those predicted by theoretical models and reasonable agreement between the tests and the models was obtained. Current design guidelines for FRP-strengthened beams were compared against the test data and were found to be adequate for the artificially aged beams. The test data also indicated that no significant damage to the glass or carbon FRP-strengthened concrete beams had occurred because of freeze–thaw cycling.Key words: concrete, rehabilitation, fibre reinforced polymers, FRP, beams, freeze–thaw, cold region engineering, flexure, external strengthening.
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Won, Jong-Pil, Chan-Gi Park, Hwang-Hee Kim, Sang-Woo Lee, and Cheol Won. "Bond Behaviour of Frp Reinforcing Bars in High-Strength Steel Fibre-Reinforced Concrete." Polymers and Polymer Composites 15, no. 7 (October 2007): 569–78. http://dx.doi.org/10.1177/096739110701500707.
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Current design trends for structures require the increased use of high-strength concrete, which has a compressive strength of over 80 MPa. Its enhanced strength, however, leads to brittle failure problems, which have been resolved by adding steel fibres. Fibre-reinforced polymer (FRP) is actively being studied to resolve the corrosion problems encountered with steel reinforcing bars in concrete structures exposed to adverse environmental conditions. In this study, we experimentally evaluated the bond behaviour of FRP reinforcing bars in high-strength steel fibre-reinforced concrete. A high-strength concrete mix was created with a target strength of over 80 MPa, and steel fibre was added. The FRP reinforcing bars had an increased pullout load with a slow gradient, and the slope of the pullout load reduction curve remained small after the maximum pullout load was reached. In addition, the bond strength increased as steel fibre was added to the FRP reinforcing bar.
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Leung, H. Y., and R. V. Balendran. "Flexural behaviour of concrete beams internally reinforced with GFRP rods and steel rebars." Structural Survey 21, no. 4 (October 1, 2003): 146–57. http://dx.doi.org/10.1108/02630800310507159.
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Use of fibre‐reinforced polymer (FRP) composite rods, in lieu of steel rebars, as the main flexural reinforcements in reinforced concrete (RC) beams have recently been suggested by many researchers. However, the development of FRP RC beam design is still stagnant in the construction industry and this may be attributed to a number of reasons such as the high cost of FRP rods compared to steel rebars and the reduced member ductility due to the brittleness of FRP rods. To resolve these problems, one of the possible methods is to adopt both FRP rods and steel rebars to internally reinforce the concrete members. The effectiveness of this new reinforcing system remains problematic and continued research in this area is needed. An experimental study on the load‐deflection behaviour of concrete beams internally reinforced with glass fibre‐reinforced polymer (GFRP) rods and steel rebars was therefore conducted and some important findings are summarized in this paper.
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Shahidi, F., L. D. Wegner, and B. F. Sparling. "Investigation of bond between fibre-reinforced polymer bars and concrete under sustained loads." Canadian Journal of Civil Engineering 33, no. 11 (November 1, 2006): 1426–37. http://dx.doi.org/10.1139/l06-070.
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Although the use of fibre-reinforced polymer (FRP) bars to replace steel in reinforced concrete is becoming more common, uncertainty remains concerning the long-term performance of FRP, including the effect of a sustained load on the bond between the FRP bars and the concrete. An experimental study was therefore undertaken to investigate the long-term durability of the bond for various types of bars embedded in concrete: one type of glass FRP, two types of carbon FRP, and conventional steel reinforcing bars. Pullout specimens were tested both statically to failure and under sustained loads for periods of up to 1 year while free-end slip was monitored. Results revealed lower short-term bond strengths for FRP bars relative to steel and significant variability in long-term bond-slip performance among FRP bars of different types. Post-testing investigations revealed damage to bar surfaces at the macroscopic level, as well as broken longitudinal fibres and damage to the surface coatings at the microscopic level.Key words: reinforced concrete, fibre-reinforced polymer (FRP), bond, creep, pullout, sustained loads.
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Fu, Chao Jiang. "Numerical Simulation Procedure of RC Beam Reinforcement with FRP." Advanced Materials Research 243-249 (May 2011): 5567–70. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.5567.
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The use of fiber reinforced polymers (FRP) to reinforce reinforced concrete(RC) structure has become one of the main applications of composites in civil engineering. FRP composite is analyzed using the serial/parallel mixing theory, which deduces the composite behavior from the constitutive equations of its components. Numerical procedure of RC beam reinforceed with FRP is studied based on the finite element method. The numerical results accord with the test results. The validity of the proposed procedure is proved comparing numerical and experimental results.
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Bakay, Ryan, Ezzeldin Yazeed Sayed-Ahmed, and Nigel Graham Shrive. "Interfacial debonding failure for reinforced concrete beams strengthened with carbon-fibre-reinforced polymer strips." Canadian Journal of Civil Engineering 36, no. 1 (January 2009): 103–21. http://dx.doi.org/10.1139/l08-096.
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Rehabilitation of structures using fibre-reinforced polymers (FRPs) has become a preferred strengthening technique. Crack-induced debonding failure has been repeatedly recorded when using fibre-reinforced polymer (FRP) laminates to strengthen reinforced concrete (RC) beams and (or) slabs in flexure. A testing programme has been performed to determine the effect of the concrete compressive strength and the amount of shear reinforcement on the interfacial debonding. The ultimate strain at failure in the bonded laminates (usage efficiency) and the strain compatibility between the laminates and the concrete sections have been investigated. The current design methods for reinforced concrete members strengthened with FRP do not explicitly consider the interfacial debonding failure; using the results of the experimental programme, the applicability and limitations of these design methods are identified. New design procedures are proposed and compared with the experimental programme results and the currently adopted procedures.
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Mudhukrishnan, M., P. Hariharan, and S. K. Malhotra. "Characterization of Glass Fibre/Carbon Fibre Hybrid Thermoplastics Composite Laminates Fabricated by Film Stacking Method." Applied Mechanics and Materials 787 (August 2015): 518–22. http://dx.doi.org/10.4028/www.scientific.net/amm.787.518.
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The Fibre Reinforced Plastic (FRP) composites are extensively used for a wide variety of applications in automobile, aerospace, chemical, biomedical and civil engineering fields due to their excellent properties. Composite materials offer significant advantages in strength-to-weight ratio and corrosion resistance over metallic materials. Initially FRP composites were based mainly on thermoset polymers because of the ease of manufacturing. But, recently FRP composites using thermoplastics matrices are gaining importance because of their advantages over thermoset composites. In the present work, FRP laminates were fabricated using glass fabric and carbon fabric as reinforcements and thermoplastic polymer (polypropylene) as matrix. Fiber Reinforced Thermoplastics (FRTP) laminates of glass fibre /polypropylene (GF/PP), carbon fibre/ polypropylene (CF/PP) and glass-carbon fibre /polypropylene (GF/CF/PP) hybrid composite laminates were fabricated by film stacking method using hot compression molding press under optimum process parameters (pressure, temperature and dwell time). The fabricated FRTP laminates were tested for various mechanical and physical properties viz., tensile strength/modulus, flexural strength/modulus, izod impact strength, moisture absorption, barcol hardness and density as per relevant ASTM standards. The results of the tests carried out on three materials were compared. It was observed that hybrid laminate (GF/CF/PP) is superior in flexural strength/modulus as compared to GF/PP but the little lower mechanical properties compared to CF/PP laminates. But use of hybrid laminates has great cost advantage compared to CF/PP.
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Ebead, U. A., and K. W. Neale. "Mechanics of fibre-reinforced polymer - concrete interfaces." Canadian Journal of Civil Engineering 34, no. 3 (March 1, 2007): 367–77. http://dx.doi.org/10.1139/l06-107.
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A finite element model is developed for analyzing the interfacial behaviour for fibre-reinforced polymer (FRP) laminates externally bonded to concrete prisms and subjected to direct shear. The element sizes of the FRP, adhesive, and concrete at the interface were chosen to be very small (0.25–0.5 mm) so that the debonding behaviour could be properly captured. The behaviour at the interface between the FRP composite and the concrete is modelled using truss elements connecting the FRP laminate to the concrete block. The truss elements incorporate a nonlinear bond stress-slip relationship controlled by several parameters related to the characteristics of the FRP composite, adhesive, and concrete. Results are given in terms of the load capacity of the joint and the stress and strain distributions in the FRP, at the interface, and in the concrete. In addition, the transfer lengths, as well as the force transfer between the FRP laminate and the concrete block, are investigated. Comparisons between the finite element results and available experimental data are presented.Key words: nonlinear finite element analysis, FRP-to-concrete bonded joints, interface elements, debonding, interfacial behaviour, transfer lengths.
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Ogrodowska, Karolina, Karolina Łuszcz, and Andrzej Garbacz. "The effect of temperature on the mechanical properties of hybrid FRP bars applicable for the reinforcing of concrete structures." MATEC Web of Conferences 322 (2020): 01029. http://dx.doi.org/10.1051/matecconf/202032201029.
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One of the most common causes of the deterioration of concrete structures is the corrosion of steel reinforcement. Reinforcement made from fiber reinforced polymers (FRP) is considered to be an attractive substitution for traditional reinforcement. The most popular FRP reinforcing bars are made of glass fibers. Basalt fiber reinforced polymer (BFRP) is a relatively new material for reinforcing bars. The main drawback of BFRP bars is their low modulus of elasticity. A new type of bar made from hybrid fiber reinforced polymer (HFRP) in which a proportion of the basalt fibers are replaced with carbon fibers can be considered as a solution to this issue; such a bar is presented in this work. The HFRP bars might be treated as a relatively simple modification to previously produced BFRP bars. A different technical characteristic of the fibre reinforced polymer makes the designing of structures with FRP reinforcement differ from conventional reinforced concrete design. Therefore, it is necessary to identify the differences and limitations of their use in concrete structures, taking into account their material and geometric features. Despite the predominance of FRP composites in such aspects as corrosion resistance, high tensile strength, and significant weight reductions of structures – it is necessary to consider the behavior of FRP composites at elevated temperatures. In this paper, the effect of temperature on the mechanical properties of FRP bars was investigated. Three types of FRP bar were tested: BFRP, HFRP in which 25% of basalt fibers were replaced with carbon fibers and nHFRP in which epoxy resin was additionally modified with a nanosilica admixture. The mechanical properties were determined using ASTM standard testing for transverse shear strength. The tests were performed at -20°C, +20°C, +80°C for three diameters of each types of bar.
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Nisar, Sumirah. "Fibre Reinforced Polymer in Retrofitting." International Journal for Research in Applied Science and Engineering Technology 9, no. 12 (December 31, 2021): 83–87. http://dx.doi.org/10.22214/ijraset.2021.39200.
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Abstract: Retrofitting is the modification of existing structures to make them more resistant to seismic activity, ground motion etc. Many of the existing reinforced concrete structures throughout the world are in urgent need of rehabilitation, repair or reconstruction because of deterioration due to various factors like corrosion, lack of detailing, failure of bonding between beamcolumn joints etc. Fibre Reinforced Polymer (FRP) composite has been accepted in the construction industry as a promising substitute for repairing and in incrementing the strength of RCC structures. It stabilizes the current structure of buildings and making them earthquake resistant. This paper presents a representative overview of the current state of using FRP materials as a retrofitting technique for the structures not designed to resist seismic action. It summarizes the scopes and uses of FRP materials in seismic strengthening of RCC structures and masonry retrofitting. Keywords: Retrofitting, Rehabilitation, Seismic damage, fibre
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S. Syed Ibrahim, S. Eswari, and T. Sundararajan. "Experimental Investigation on FRC Beams Strengthened with GFRP Laminates." Electronic Journal of Structural Engineering 15 (June 1, 2015): 55–59. http://dx.doi.org/10.56748/ejse.15202.
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The external bonding of fibre reinforced polymer (FRP) to reinforced concrete (RC) members has become a popular method of retrofitting/strengthening concrete structures in recent years. Extensive research has been conducted pertaining to RC beams strengthened with FRP laminates. However, the experimental studies on fibre reinforced concrete (FRC) beams strengthened using externally bonded FRP system are limited. The purpose of this research is to investigate the behaviour of steel fibre reinforced concrete (SFRC) beams strengthened with glass fibre reinforced polymer (GFRP) laminates. The beam specimens were incorporated with 1.0% volume fraction of short-steel fibres randomly distributed throughout the section. The beam cross-section was 150 mm wide and 250 mm deep and to a length of 3000 mm. All the beams were tested until failure. The study parameters of this investigation included service load, ultimate load, ductility, crack width and failure modes. Beams tested for this investigation consisted of reference (RC) beam, GFRP laminated RC beam, SFRC beam, and GFRP laminated SFRC beam. The test results showed that the SFRC beams strengthened with GFRP laminates exhibited better performance.
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Benmokrane, Brahim, Burong Zhang, Adil Chennouf, and Radhouane Masmoudi. "Evaluation of aramid and carbon fibre reinforced polymer composite tendons for prestressed ground anchors." Canadian Journal of Civil Engineering 27, no. 5 (October 1, 2000): 1031–45. http://dx.doi.org/10.1139/l00-090.
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This paper presents the tension and bond properties of commercially available Aramid fibre reinforced polymer (AFRP) and carbon fibre reinforced polymer (CFRP) rods and their uplift and sustained loading behaviour as ground anchor tendons. Variables for the tests were tendon type and constituent, grout type, and bond or fixed anchor length. Test results indicated that the tension properties of fibre reinforced polymer (FRP) rods were close to the reported data. The surface geometry of FRP rods and the properties of filling grouts influenced the pullout behaviour and bond strength of grouted FRP rods. CFRP Carbon Fiber Composite Cable and Leadline anchors had a higher uplift capacity but lower creep displacement than AFRP Arapree and Technora anchors. The tested CFRP monorod and FRP multirod anchors with a 1000 mm fixed anchor length exhibited an acceptable uplift behaviour according to existing codes. Creep behaviour appeared to control the long-term uplift capacity of prestressed FRP ground anchors. The recommended working load for post-tensioned FRP ground anchors is 0.40 fpu for AFRP rods and 0.50fpu for CFRP rods, where fpu is the ultimate load or strength of the anchor tendon.Key words: FRP, tendon, bond stress, anchorage, grouted anchor, fixed anchor length, free anchor length, slip, creep.
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Cunha, Rafael, Kevin Oliveira, Antônio Brito, Camila Vieira, and David Amorim. "Evaluation of the behaviour of reinforced concrete beams repaired with glass fibre reinforced polymer (GFRP) using a damage variable." Frattura ed Integrità Strutturale 15, no. 57 (June 22, 2021): 82–92. http://dx.doi.org/10.3221/igf-esis.57.08.
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The use of fibre reinforced polymers (FRP) for increasing the strength of RC structures became a usual method. FRP presents easy application and demands low space and provide significant strength increase. Usually, the decision for FRP use is made in terms of applied loads and deflections. However, such quantities can vary significantly depending on the characteristics of the structural element e.g. span, effective depth and concrete resistance. Therefore, this paper aims to present an alternative control variable to analyse the behaviour of RC beams repaired with glass fibre reinforced polymer (GFRP), called damage. Such damage variable accounts for concrete cracking and it was experimentally measured before and after the application of GFRP. Note that the application of GFRP increased the ultimate load for all repaired beams. The damage values of such beams also increased when collapse was reached. Furthermore, it was observed that the collapse mechanism shifted to shear and did not occurred the failure of the GFRP.
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Gribniak, Viktor, Pui-Lam Ng, Vytautas Tamulenas, Ieva Misiūnaitė, Arnoldas Norkus, and Antanas Šapalas. "Strengthening of Fibre Reinforced Concrete Elements: Synergy of the Fibres and External Sheet." Sustainability 11, no. 16 (August 17, 2019): 4456. http://dx.doi.org/10.3390/su11164456.
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In structural rehabilitation and strengthening, the structural members are often required to cope with larger design loading due to the upgrading of building services and design standard, while maintaining the member size to preserve the architectural dimensions and headroom. Moreover, durability enhancement by mitigating or eliminating the reinforcement corrosion problem is often desired. Concrete cracking is a major initiating and accelerating factor of the corrosion of steel reinforcement. The application of fibres is a prominent solution to the cracking problem. Furthermore, the fibres can increase the mechanical resistance of the strengthening systems. This study reveals the synergy effect of the combined application of steel fibres and external carbon fibre-reinforced polymer (CFRP) sheets. The investigation encompasses the use of fibre-reinforced polymer (FRP) reinforcing bars, discrete steel fibres, externally bonded and mechanically fastened FRP sheets in different combinations. It is discovered that the steel fibres can help to control concrete cracking and eventually alter the failure mode and enhance the flexural resistance. The FRP reinforcement system, together with the steel fibres, radically resolves the structural safety problem caused by corrosion of the steel bar reinforcement. Finally, the impact of the external sheet on the fire limit state performance needs to be resolved, such as by adopting fire protection rendering for the finishes layer.
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Sen, Tara, and H. N. Jagannatha Reddy. "Pretreatment of Woven Jute FRP Composite and Its Use in Strengthening of Reinforced Concrete Beams in Flexure." Advances in Materials Science and Engineering 2013 (2013): 1–15. http://dx.doi.org/10.1155/2013/128158.
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Environmental awareness motivates researchers worldwide to perform studies of natural fibre reinforced polymer composites, as they come with many advantages and are primarily sustainable. The present study aims at evaluating the mechanical characteristics of natural woven jute fibre reinforced polymer (FRP) composite subjected to three different pretreatments, alkali, benzyl chloride, and lastly heat treatment. It was concluded that heat treatment is one of the most suitable treatment methods for enhancing mechanical properties of jute FRP. Durability studies on Jute FRP pertaining to some common environmental conditions were also carried out such as effect of normal water and thermal aging on the tensile strength of jute FRP followed by fire flow test. The heat treated woven jute FRP composites were subsequently used for flexural strengthening of reinforced concrete beams in full and strip wrapping configurations. The study includes the effect of flexural strengthening provided by woven jute FRP, study of different failure modes, load deflection behavior, effect on the first crack load, and ultimate flexural strength of concrete beams strengthened using woven jute FRP subjected to bending loads. The study concludes that woven jute FRP is a suitable material which can be used for flexural upgradation of reinforced concrete beams.
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Kaura, JM. "OPTIMISATION OF THICKNESS OF FIBRE REINFORCED POLYMER SHEETS FOR STRENGTHENING REINFORCED CONCRETE BEAMS WITH FLEXURAL DEFICIENCY." Nigerian Journal of Technology 36, no. 1 (December 28, 2016): 45–49. http://dx.doi.org/10.4314/njt.v36i1.7.
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The use of Fiber Reinforced Polymer (FRP) is becoming a widely accepted solution for repairing and strengthening of deteriorated reinforced concrete members, to restore their load carrying capacities. One of the major concerns in the use of FRP is its cost. This therefore calls for the use of efficient and cost effective design approach. Design efficiency in terms of cost can be achieved through optimisation. In the present paper, Generalized Reduced Gradient (GRG) optimisation technique was employed to optimize the strengthening cost of a simply supported reinforced concrete beam strengthened with Fibre Reinforced Polymer (FRP). Optimum design charts for the considered problem were presented. The results showed that considerable savings in thickness can be achieved using FRP of high modulus of elasticity. For example at very high capacity reduction say 70% (kc = 0.3), the required FRP thicknesses for FRP with elastic moduli of 25GPa, 50GPa, 75GPa, 100GPa, 125GPa and 150GPa are respectively equal to 2.5mm, 1.75mm, 0.75mm, 0.6mm, 0.5mm and 0.4mm. http://dx.doi.org/10.4314/njt.v36i1.7
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Sharifianjazi, Fariborz, Parham Zeydi, Milad Bazli, Amirhossein Esmaeilkhanian, Roozbeh Rahmani, Leila Bazli, and Samad Khaksar. "Fibre-Reinforced Polymer Reinforced Concrete Members under Elevated Temperatures: A Review on Structural Performance." Polymers 14, no. 3 (January 25, 2022): 472. http://dx.doi.org/10.3390/polym14030472.
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Several experimental and numerical studies have been conducted to address the structural performance of FRP-reinforced/strengthened concrete structures under and after exposure to elevated temperatures. The present paper reviews over 100 research studies focused on the structural responses of different FRP-reinforced/strengthened concrete structures after exposure to elevated temperatures, ranging from ambient temperatures to flame. Different structural systems were considered, including FRP laminate bonded to concrete, FRP-reinforced concrete, FRP-wrapped concrete, and concrete-filled FRP tubes. According to the reported data, it is generally accepted that, in the case of insignificant resin in the post curing process, as the temperature increases, the ultimate strength, bond strength, and structure stiffness reduce, especially when the glass transition temperature Tg of the resin is approached and exceeded. However, in the case of post curing, resin appears to preserve its mechanical properties at high temperatures, which results in the appropriate structural performance of FRP-reinforced/strengthened members at high temperatures that are below the resin decomposition temperature Td. Given the research gaps, recommendations for future studies have been presented. The discussions, findings, and comparisons presented in this review paper will help designers and researchers to better understand the performance of concrete structures that are reinforced/strengthened with FRPs under elevated temperatures and consider appropriate approaches when designing such structures.
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Zhang, Tai Feng, Xiao Hua Yang, Wen Sheng Sun, and Zeng Jie Cai. "A Two-Parameter Model of FRP Laminates Stiffness Reduction." Advanced Materials Research 236-238 (May 2011): 1187–94. http://dx.doi.org/10.4028/www.scientific.net/amr.236-238.1187.
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Matrix crack and fibre breakage are the main damage models of the fibre reinforced polymer (FRP) laminates under cyclic loading. In this paper, meso-mechanical analysis is used and a two-parameter model is developed to describe the stiffness reduction. Based on the probability distribution function of fiber strength, the evolution of fibre breakage is deduced. Then with the help of the damage evolution, the stiffness reduction of laminates can be predicted. As an example, the stiffness reduction of grass fibre reinforced polymer (GFRP) laminate is made and the simulation results show that the proposed model has good capacity to describe the stiffness reduction of FRP laminates resulted in the combination of matrix crack and fibre breakage.
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Newhook, John, Amin Ghali, and Gamil Tadros. "Concrete flexural members reinforced with fiber reinforced polymer: design for cracking and deformability." Canadian Journal of Civil Engineering 29, no. 1 (February 1, 2002): 125–34. http://dx.doi.org/10.1139/l01-085.
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Fiber reinforced polymer (FRP) bars have lower modulus of elasticity than steel bars. For this reason when FRP bars are used as flexural nonprestressed reinforcement in concrete sections, the stress in the FRP is limited to a relatively small fraction of its tensile strength. This limit, necessary to control width of cracks at service, governs design of the required cross-sectional area of the FRP. Parametric studies on rectangular and T-sections are presented to show that the design based on allowable strain in the FRP results in sections that exhibit large deformation before failure. The concept of deformability, given in the Canadian Highway Bridge Design Code, as a requirement in the design of sections is discussed and modifications suggested. Using the new definition, it is shown that when, in addition to the crack control requirement, an upper limit is imposed on the cross-sectional area of the FRP, no calculations will be necessary to check the deformability.Key words: fibre reinforced polymer, reinforcement, concrete, design, deformability.
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Szmigiera, E. D., K. Protchenko, M. Urbański, and A. Garbacz. "Mechanical Properties of Hybrid FRP Bars and Nano-Hybrid FRP Bars." Archives of Civil Engineering 65, no. 1 (March 1, 2019): 97–110. http://dx.doi.org/10.2478/ace-2019-0007.
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AbstractThe paper describes the recent developments of Hybrid Fibre-Reinforced Polymer (HFRP) and nano-Hybrid Fibre-Reinforced Polymer (nHFRP) bars. Hybridization of less expensive basalt fibres with carbon fibres leads to more sustainable alternative to Basalt-FRP (BFRP) bars and more economically-efficient alternative to Carbon-FRP (CFRP) bars. The New-Developed HFRP bars were subjected to tensile axial loading to investigate its structural behaviour. The effect of hybridization on tensile properties of HFRP bars was verified experimentally by comparing the results of tensile test of HFRP bars with non-hybrid BFRP bars. It is worth to mention that the difference in obtained strength characteristics between analytical and numerical considerations was very small, however the obtained results were much higher than results obtained experimentally. Authors suggested that lower results obtained experimentally can be explained by imperfect interphase development and therefore attempted to improve the chemical cohesion between constituents by adding nanosilica particles to matrix consistency.
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Milovancevic, Milos. "Shear strength of fibre reinforced polymers (FRP) used as internal reinforcement for reinforced concrete (RC) beams." Facta universitatis - series: Architecture and Civil Engineering 19, no. 2 (2021): 207–18. http://dx.doi.org/10.2298/fuace210909016m.
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The main aim of the study was to perform selection procedure in order to find the optimal predictors for the shear strength of fibre reinforced polymers (FRP) used as internal reinforcement for reinforced concrete (RC) beams. The procedure was performed by adaptive neuro fuzzy inference system (ANFIS) and all available parameters are included. The ANFIS model could be used as simplification of the shear strength analysis of the FRP-RC beams. MATLAB software was used for the ANFIS application for the shear strength prediction of the FRP-RC beams. The results from the searching procedure indicated that ?beam width? and ?effective depth? form the optimal combination of two input attributes or two predictors for the shear strength prediction of the FRP-RC beams. This selected two predictors could be used effectively to estimate the strength of the FRP-RC beams.
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Azad, Fathima. "Analysis of Columns Strengthened using Fibre Reinforced Cementitious Matrix Jackets." International Journal for Research in Applied Science and Engineering Technology 9, no. 9 (September 30, 2021): 1795–800. http://dx.doi.org/10.22214/ijraset.2021.38272.
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Abstract: Maintenance, repair and strengthening of existing concrete structures, either reinforced or prestressed,are important activities of civil engineers. Nowadays different techniques are available for the strengthening. Various techniques were adopted for strengthening RC structures, namely, steel plates, external post tensioning, externally bonded Fibre-Reinforced Polymer (FRP), and near- surface-mounted FRP systems to increase shear and flexural capacity. During the last few decades, strengthening of concrete structural elements by fibre-reinforced polymer has become a widely used technique. But it has several disadvantages due to the epoxy resin like debonding of FRP from the concrete structure, unstable nature of the epoxy at higher temperatures etc. To overcome this, an upgraded system was introduced as an alternative for FRP known as Fibre Reinforced Cementitious Matrices (FRCM). The objective of this paper is to investigate the feasibility of Fibre-Reinforced Cementitious-Matrix materials as an alternative external strengthening technique for RC members. Columns with circular geometry were wrapped with different fibre materials using cementitious matrix. The analysis was done using ANSYS software. Keywords: RC columns, FRCM, Strengthening, fibre, ANSYS
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Purba, Burt K., and Aftab A. Mufti. "Investigation of the behavior of circular concrete columns reinforced with carbon fiber reinforced polymer (CFRP) jackets." Canadian Journal of Civil Engineering 26, no. 5 (October 1, 1999): 590–96. http://dx.doi.org/10.1139/l99-022.
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Recent advancements in the fields of fiber reinforced polymers (FRPs) have resulted in the development of new materials with great potential for applications in civil engineering structures, and due to extensive research over recent years, FRPs are now being considered for the design of new structures. This study describes how carbon fiber reinforced polymer jackets can be used to reinforce circular concrete columns. Fibers aligned in the circumferential direction provide axial and shear strength to the concrete, while fibers aligned in the longitudinal direction provide flexural reinforcement. Prefabricated FRP jackets or tubes would also provide the formwork for the columns, resulting in a decrease in labor and materials required for construction. Also, the enhanced behavior of FRP jacketed concrete columns could allow the use of smaller sections than would be required for conventionally reinforced concrete columns. Furthermore, FRP jacket reinforced concrete columns would be more durable than conventionally reinforced concrete columns and therefore would require less maintenance and have longer service life.Key words: bridge, carbon, column, concrete, confinement, fiber reinforced polymer, jacket, retrofitting, seismic, strengthening.
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van Loon, R. R. L. (Rick), Ester Pujadas-Gispert, S. P. G. (Faas) Moonen, and Rijk Blok. "Environmental Optimization of Precast Concrete Beams Using Fibre Reinforced Polymers." Sustainability 11, no. 7 (April 11, 2019): 2174. http://dx.doi.org/10.3390/su11072174.
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Increasing importance is being attached to materials in the life-cycle of a building. In the Netherlands, material life-cycle assessments (LCA) are now mandatory for almost all new buildings, on which basis the building is then awarded a building environmental performance or MPG [Milieuprestatie Gebouwen] score. The objective of this study is to reduce the environmental–economic (shadow) costs of precast reinforced concrete (RC) beams in a conventional Dutch office building, thereby improving its MPG score. Two main optimizations are introduced: first, the amount of concrete is reduced, designing a cavity in the cross-section of the beam; second, part of the reinforcement is replaced with a fibre reinforced polymer (FRP) tube. The structural calculations draw from a combination of several codes and FRP recommendations. Hollow FRP-RC beams (with an elongated oval cavity), and flax, glass, and kenaf fibre tubes yielded the lowest shadow costs. In particular, the flax tube obtained shadow costs that were 39% lower than those of the hollow RC beam (with an elongated oval cavity); which also contributed to decreasing the shadow costs of other building components (e.g., facade), thereby reducing the MPG score of the building. However, this study also shows that it is important to select the right type of FRP as hemp fibre tubes resulted in a 98% increase in shadow costs.
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Raja, R. Satheesh, K. Manisekar, and V. Manikandan. "Effect of Carbon Black and Fly Ash Fillers on Tensile Properties of Composites." Key Engineering Materials 471-472 (February 2011): 26–30. http://dx.doi.org/10.4028/www.scientific.net/kem.471-472.26.
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Fibre reinforced polymer composites play an incredible role in almost all spheres of day to day life and the field of carbon composites is one of the prime research area in recent decade. Polymers are mostly reinforced with fibre or fillers to obtain better mechanical properties. The properties of the polymer composites can be improved largely by varying the type of filler/fibre materials and its volume percentage. Composites properties depend on the size, shape and other physical properties of the reinforcements. A relative easy way to improve the mechanical properties of a polymer is the addition of filler materials. In all particulate filled systems, the adhesion between the matrix and filler plays a significant role in determining the key properties such as strength and toughness. The mechanical properties of composites are also influenced by the filler’s nature, size and distribution profile, aspect ratio, volume fraction, the intrinsic adhesion between the surfaces of filler and polymer. In this paper, the effect of filler material on mechanical properties of E-Glass fibre reinforced polymer has been studied out by varying filler materials. For these study three different types of specimens were prepared, viz FRP without filler material, the FRP with 10 volume percentages of carbon black and the FRP with 10 volume percentage of Fly ash as filler material. The polyester composites were fabricated by hand-layup method. Mechanical properties of the specimens are analyzed using computerized Universal Testing Machine as per ASTM D 638 standards. The resulting behavioral patterns of the FRP with filler material are listed and compared to those of the FRP without filler material. Mechanical properties such as ultimate tensile strength, percentage of elongation, yield strength, Poisson’s ratio and percentage reduction in area were found out.
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Mufti, A. A., B. Bakht, N. Banthia, B. Benmokrane, G. Desgagné, R. Eden, M. A. Erki, et al. "New Canadian Highway Bridge Design Code design provisions for fibre-reinforced structures." Canadian Journal of Civil Engineering 34, no. 3 (March 1, 2007): 267–83. http://dx.doi.org/10.1139/l06-137.
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This paper presents a synthesis of the design provisions of the second edition of the Canadian Highway Bridge Design Code (CHBDC) for fibre-reinforced structures. New design provisions for applications not covered by the first edition of the CHBDC and the rationale for those that remain unchanged from the first edition are given. Among the new design provisions are those for glass-fibre-reinforced polymer as both primary reinforcement and tendons in concrete; and for the rehabilitation of concrete and timber structures with externally bonded fibre-reinforced-polymer (FRP) systems or near-surface-mounted reinforcement. The provisions for fibre-reinforced concrete deck slabs in the first edition have been reorganized in the second edition to explicitly include deck slabs of both cast-in-place and precast construction and are now referred to as externally restrained deck slabs, whereas deck slabs containing internal FRP reinforcement are referred to as internally restrained deck slabs. Resistance factors in the second edition have been recast from those in the first edition and depend on the condition of use, with a further distinction made between factory- and field-produced FRP. In the second edition, the deformability requirements for FRP-reinforced and FRP-prestressed concrete beams and slabs of the first edition have been split into three subclauses covering the design for deformability, minimum flexural resistance, and crack-control reinforcement. The effect of sustained loads on the strength of FRPs is accounted for in the second edition by limits on stresses in FRP at the serviceability limit state.Key words: beams, bridges, concrete, decks, fibre-reinforced-polymer reinforcement, fibre-reinforced-polymer sheets, prestressing, repair, strengthening, wood.
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Protchenko, Kostiantyn, Szmigiera Elżbieta, Marek Urbański, and Andrzej Garbacz. "Mechanical performance of FRP-RC flexural members subjected to fire conditions." Budownictwo i Architektura 19, no. 4 (November 2, 2020): 017–30. http://dx.doi.org/10.35784/bud-arch.2119.
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One of the main concerns that limit the widespread use of Fibre-Reinforced Polymers (FRP) bars as internal reinforcement for reinforced concrete (RC) structures is their relatively unexplored response to elevated temperatures. The behaviour of FRP reinforcement at elevated temperature as well as their post-fire behaviour can be different from conventional reinforcement and depends on the properties of the constituents of the bars. Therefore, the fire resistance of FRP-RC structures is an important issue that needs careful investigation before FRP reinforcement can be implemented in RC structures.
The experimental results for full-scale FRP-RC beams subjected to specific fire action were presented and discussed in this paper. The specimens were exposed to heat in the mid-section from below (tension zone) and from the sides. As one of the main aims was to examine the influence of different reinforcement configurations, the testing was made for concrete beams reinforced with three different types of FRP bars: (i) basalt-FRP (BFRP), (ii) hybrid FRP with carbon and basalt fibres (HFRP) and (iii) nano-hybrid FRP (nHFRP), with modification of the epoxy matrix of the rebars.
The present work describes the behaviour of FRP-RC beams exposed to fire conditions and simultaneous loading (50 % of their ultimate strength capacity at normal temperature) and unloaded beams were tested after the cooling phase in order to evaluate their residual resistance.
Present work shows that the type of FRP bars used has a direct influence on the outcomes and the way of destruction. The maximum ductility, the longest heating time of approximately 100 minutes, was obtained for beams reinforced with BFRP bars and attained deflections were corresponded to the value of 162 mm.
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Blikharskyy, Z., K. Brózda, and J. Selejdak. "Effectivenes of Strengthening Loaded RC Beams with FRCM System." Archives of Civil Engineering 64, no. 3 (September 1, 2018): 3–13. http://dx.doi.org/10.2478/ace-2018-0025.
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AbstractThe composite materials as FRP (Fiber Reinforced Polymers), which are characterized by benefits resulting from the combination of high strength reinforcement (as carbon, glass, steel or aramid fibers) with synthetic matrix are increasingly used to reinforce existing structures. Reinforcing System as FRCM (Fibre Reinforced Cementitious Matrix), which includes, among others, Ruredil X Mesh Gold System, is much less commonly used. However, the uniform and practical methods for calculating composite reinforced structures are not determined. Especially when considering the real conditions of structure exploitation, which requires further research in this field. In the paper the initial loading level influence on the efficiency of reinforced concrete beams strengthen using system Ruredil X Mesh Gold was investigated.
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Martínez, Sonia, Ana de Diego, Viviana J. Castro, Luis Echevarría, Francisco J. Barroso, Gabriel Rentero, Rafael P. Soldado, and José Pedro Gutiérrez. "Strengthening of Low-Strength Concrete Columns with Fibre Reinforced Polymers. Full-Scale Tests." Infrastructures 5, no. 11 (October 31, 2020): 91. http://dx.doi.org/10.3390/infrastructures5110091.
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Confinement of columns with externally bonded fibre reinforced polymers (FRP) sheets is an easy and effective way of enhancing the load carrying and strain capacity of reinforced concrete (RC) columns. Many experimental studies have been conducted on cylindrical small-scale un-reinforced concrete specimens externally confined with FRP. It is widely accepted that confinement of square or rectangular columns is less efficient than the confinement of circular columns. The theoretical models for rectangular sections are mostly based on approaches for circular columns modified by a shape factor, but the different models do not give similar results. This paper presents an experimental program on large-scale square and rectangular RC columns externally strengthened with carbon FRP sheets and subjected to axial load. The main variables were the side-aspect ratio of the cross-section, the radius of curvature of the corners and the amount of FRP reinforcement. The results show that the FRP confinement can increase the strength and strain capacity of rectangular concrete columns with low strength concrete. The FRP hoop ultimate strain was much lower than the material ultimate tensile strain obtained from flat coupon tests and the strain efficiency factor achieved in the tests was less than the value usually recommended by design guides.
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Qureshi, Jawed. "A Review of Recycling Methods for Fibre Reinforced Polymer Composites." Sustainability 14, no. 24 (December 15, 2022): 16855. http://dx.doi.org/10.3390/su142416855.
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This paper presents a review of waste disposal methods for fibre reinforced polymer (FRP) materials. The methods range from waste minimisation, repurposing, reusing, recycling, incineration, and co-processing in a cement plant to dumping in a landfill. Their strength, limitations, and key points of attention are discussed. Both glass and carbon fibre reinforced polymer (GFRP and CFRP) waste management strategies are critically reviewed. The energy demand and cost of FRP waste disposal routes are also discussed. Landfill and co-incineration are the most common and cheapest techniques to discard FRP scrap. Three main recycling pathways, including mechanical, thermal, and chemical recycling, are reviewed. Chemical recycling is the most energy-intensive and costly route. Mechanical recycling is only suitable for GFRP waste, and it has actually been used at an industrial scale by GFRP manufacturers. Chemical and thermal recycling routes are more appropriate for reclaiming carbon fibres from CFRP, where the value of reclaimed fibres is more than the cost of the recycling process. Discarding FRP waste in a sustainable manner presents a major challenge in a circular economy. With strict legislation on landfill and other environmental limits, recycling, reusing, and repurposing FRP composites will be at the forefront of sustainable waste-management strategies in the future.
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Xiao, Yi, Jiaxin Lv, and P.-Y. Ben Jar. "A stress-relaxation approach to determine onset of delamination in angle ply laminates." Journal of Composite Materials 54, no. 19 (January 9, 2020): 2521–27. http://dx.doi.org/10.1177/0021998319899131.
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A new test method, named multi-relaxation test, is proposed for detecting on-set of delamination in fibre-reinforced polymers. Multi-relaxation test is based on the principle that uses change of stress relaxation behaviour of fibre-reinforced polymer to detect the occurrence of delamination. In this study, angle-ply laminated fibre-reinforced polymer (APL-FRP) is used to demonstrate and evaluate multi-relaxation test for detection of the delamination occurrence. The stress relaxation behaviour is characterized using a standard, three-element viscoelastic model in which the Eyring’s law is used to govern the time-dependent stress response to deformation. Results suggest a high possibility of using the trend line change of viscous stress at the beginning of stress relaxation to determine the critical stroke for the onset of delamination. The results also suggest that value for the corresponding static stress is very close to the value reported in the literature for APL-FRP of the same fibre lay-up. The major advantage of multi-relaxation test over other tests for the same purpose is that multi-relaxation test is able to detect delamination without relying on ancillary information such as acoustic signals. Therefore, multi-relaxation test can be used to characterize critical loading and deformation in fibre-reinforced polymer structures of any size and geometry, even when subjected to a loading mode that mimics the in-service loading.
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Green, Mark F., Luke A. Bisby, Yves Beaudoin, and Pierre Labossière. "Effect of freeze-thaw cycles on the bond durability between fibre reinforced polymer plate reinforcement and concrete." Canadian Journal of Civil Engineering 27, no. 5 (October 1, 2000): 949–59. http://dx.doi.org/10.1139/l00-031.
Full textAbstract:
Deterioration of infrastructure is one of the most pressing concerns facing today's civil engineering community. As a result, new rehabilitation techniques, such as the external bonding of fibre reinforced polymer (FRP) plates and sheets, are being developed. To apply these rehabilitation methods in Canada, the durability of the rehabilitated structures in cold regions must be assessed. This paper examines the effects of freeze-thaw cycling on the bond between FRP and concrete. An experimental investigation was conducted using both single lap pull-off and bond beam specimens. Only uniaxial carbon FRP strips were considered. The specimens were exposed to up to 300 freeze-thaw cycles consisting of 16 h of freezing and 8 h of thawing in a water bath. After exposure, the specimens were tested to failure. The development of strain along the bond length and the failure mode are presented for both types of specimens. Load deflection curves are presented for the beam specimens. The results indicate that the bond between carbon FRP strips and concrete is not significantly damaged by up to 300 freeze-thaw cycles.Key words: reinforced concrete, repair, rehabilitation, strengthening, fibre reinforced polymers, freeze-thaw, bond damage.
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Frigione, Mariaenrica. "Fiber Reinforced Polymers in Civil Engineering: Durability Issues." Advanced Materials Research 1129 (November 2015): 283–89. http://dx.doi.org/10.4028/www.scientific.net/amr.1129.283.
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In the last decades, the use of fiber reinforced polymers (FRP) composites to repair and/or upgrade existing buildings or infrastructure systems proved to be an effective solution, being able to overcome some of the drawbacks experienced with traditional interventions. The knowledge of durability behavior of polymer composite materials in terms of their degradation/aging causes and mechanisms is a critical issue for a safe and advantageous implementation of FRP. The durability of FRP employed in civil infrastructure applications mainly depends on the durability of any single component and on the environment (service conditions) in which the system operates. The components of FRP are: polymeric resins (more frequently thermosetting resins cured in service, i.e. at ambient temperature), fibers and the interface between them. Referring to the resins, heavy concerns arise from the behavior of “Cold-cured” thermosetting resins, often epoxy, used as matrices to manufacture (through wet layup technique) and adhesives to apply, also precured, FRP. The experimental studies present in current literature on the effect of environmental agents on the properties of FRP highlight the crucial role of the adhesive/matrix on the behavior of the whole system. Many other parameters (i.e. direction and disposition of fibers, direction of load application) are involved in the assessment of the durability of FRP. However, in the durability studies of FRP and their components, a lack of specific standards for such materials is recognized. In addition, the results of durability studies do not always agree, possibly due to different curing/conditioning conditions employed. The aim of this work is to critically illustrate the durability studies carried out on FRP for civil engineering applications and appeared in current literature, highlighting the issues that are not yet assessed and addressed.
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CoDyre, Luke, Kenneth Mak, and Amir Fam. "Flexural and axial behaviour of sandwich panels with bio-based flax fibre-reinforced polymer skins and various foam core densities." Journal of Sandwich Structures & Materials 20, no. 5 (December 5, 2016): 595–616. http://dx.doi.org/10.1177/1099636216667658.
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This study investigates the effect of foam core density on the behaviour of sandwich panels with novel bio-composite unidirectional flax fibre-reinforced polymer skins, along with a comparison to panels of conventional glass-FRP skins. Eighteen 1000 mm long flexural specimens and 18 500 mm long stub column specimens were fabricated and tested. All specimens had a foam core of 100 × 50 mm2 cross-section with symmetrical 100 mm wide skins. The study compares the effect of three separate polyisocyanurate foam cores when used in conjunction with either three layers of flax fibre-reinforced polymer or a single glass-FRP layer for each skin. Flexural specimens were tested in four-point bending and stub columns were tested under axial compression with pin–pin end conditions. Doubling the core density from 32 to 64 kg/m3 and tripling the density to 96 kg/m3 led to flexural strength increases of 82 and 213%, respectively, for flax fibre-reinforced polymer skinned panels, and comparable increases in glass-FRP skinned panels. Similarly, flax fibre-reinforced polymer-skinned columns showed similar increases in ultimate axial capacity of 85% and 196%, while glass-FRP- skinned columns experienced lower increases when core density was varied. The three-layered flax fibre-reinforced polymer skin, only 17% thicker than the single layer glass-FRP skin, was shown to provide equivalent flexural and axial strengths at all three core densities, within −5 to +13%.
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Alzate, Albert, Angel Arteaga, Ana de diego, and Ricardo Perera. "Shear strengthening of reinforced concrete beams using fibre reinforced polymers (FRP)." Revue européenne de génie civil 13, no. 9 (November 14, 2009): 1051–60. http://dx.doi.org/10.3166/ejece.13.1051-1060.
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Alzate, Albert, Ángel Arteaga, Ana de Diego, and Ricardo Perera. "Shear strengthening of reinforced concrete beams using fibre reinforced polymers (FRP)." European Journal of Environmental and Civil Engineering 13, no. 9 (October 2009): 1051–60. http://dx.doi.org/10.1080/19648189.2009.9693172.
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Leung, Hau Yan. "FLEXURAL CAPACITY OF CONCRETE BEAMS REINFORCED WITH STEEL AND FIBRE‐REINFORCED POLYMER (FRP) BARS." JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 10, no. 3 (September 30, 2004): 209–15. http://dx.doi.org/10.3846/13923730.2004.9636308.
Full textAbstract:
Although much research on concrete beams reinforced with fibre‐reinforced polymer (FRP) rods has been conducted in recent years, their use still does not receive the attention it deserves from practicising engineers. This is attributed to the fact that FRP is brittle in nature and the collapse of FRP‐reinforced concrete member may be catastrophic. A rational beam design can incorporate a hybrid use of FRP rods and steel rods. Current design codes only deal with steel‐reinforced or FRP‐reinforced concrete members. Therefore in this study some design charts and equations for concrete beam sections reinforced with FRP rods and steel rebars were generated. Results from the theoretical derivations agreed well with experimental data.
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Ahmed, Ehab A., Ehab F. El-Salakawy, and Brahim Benmokrane. "Fibre-reinforced polymer composite shear reinforcement: performance evaluation in concrete beams and code prediction." Canadian Journal of Civil Engineering 37, no. 8 (August 2010): 1057–70. http://dx.doi.org/10.1139/l10-046.
Full textAbstract:
This paper evaluates the performance of carbon and glass fibre-reinforced polymer (FRP) stirrups and the accuracy of the shear design provisions incorporated in the currently available design codes and guidelines. A total of seven large-scale T-beams were constructed and tested: three reinforced with carbon fibre-reinforced polymer (CFRP) stirrups, three reinforced with glass fibre-reinforced polymer (GFRP) stirrups, and one reinforced with a steel stirrup for comparison, when applicable. The test results revealed that the design strength of the tested beams is not affected by the reduced strength of FRP stirrups at bend locations. Also, the recent CAN/CSA-S6 update is capable of adequately predicting the shear strength of the beam specimens reinforced with FRP stirrups. The software, Response-2000, which is based on the modified compression field theory (MCFT), predicted well the shear strength and the average strain in the stirrups of the tested beams; however, it overestimated the shear crack width.