525 research outputs found

    Comparative study of Steel-FRP, FRP and steel reinforced coral concrete beams in their flexural performance

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    In this paper, a comparative study of Carbon Fiber Reinforced Polymer (CFRP) Bar and Steel-Carbon Fiber Composite Bar (SCFCB) reinforced coral concrete beams are made through a series experimental tests and theoretical analysis. The flexural capacity, crack development and failure modes of CFRP and SCFCB reinforced coral concrete were investigated in detail. They are also compared to ordinary steel reinforced coral concrete beams. The results show that under the same condition of reinforcement ratio, the SCFCB reinforced beam exhibits better performance than those of the CFRP reinforced beams, and its stiffness is slightly lower than that of the steel reinforced beam. Under the same load condition, the crack width of the SCFCB beam is between the steel reinforced beam and the CFRP bar reinforced beam. Before the steel core yields, the crack growth rate of SCFCB beam is similar to the steel reinforced beam. SCFCB has a higher strength utilization rate, about 70% -85% of its ultimate strength. The current design guidance was also examined based on the test results. It was found that the existing design specifications for FRP reinforced normal concrete is not suitable for SCFCB reinforced coral concrete structures

    Comportement à l'effort tranchant et à la flexion de poutres en béton autoplaçant léger armé d'armature en PRF de fibres de verre et de basalte

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    Abstract : Lightweight self-consolidating concrete (LWSCC) is being more and more widely used in different types of reinforced concrete (RC) structures due to its better structural and durability performance. No research, however, seems to have investigated LWSCC beams reinforced with fiber-reinforced polymer (FRP) bars under shear and flexural loads. In addition, present guidelines for FRP structures in North-America (ACI 440.1R-15, CSA S806-12, and CSA S6-19) do not provide guidance for LWSCC beams reinforced with FRP bars. This research takes charge of providing experimental database as well as extensive analyses and design recommendations of LWSCC beams reinforced with different FRP bars. The experimental tests were completed through two phases. The first phase was conducted to investigate the behavior and concrete shear strength of FRP-reinforced LWSCC beams. 14 full-scale RC beams were tested up to failure. The second phase included testing of 20 full-scale RC beams to investigate the flexural behavior and serviceability performance of FRP bars in LWSCC beams. The experimental results are discussed in terms of cracking behavior, deflection, flexural capacity, concrete shear strength, and mode of failure. The findings of this study indicated that the adoption of LWSCC allowed for decreasing the self-weight of the RC beams (density of 1,800 kg/m3) compared to normal weight concrete (NWC). By comparing the concrete shear strengths of the LWSCC beams with their predicted strengths based on a concrete density reduction factor (λ) of 0.75 and 0.8 in the CSA S806-12 and ACI 440.1R-15 design equations, respectively, revealed that these equations yielded good predictions of LWSCC beams reinforced with FRP bars compared to the NWC beams. In the second phase, the test results indicated that the experimental moment capacities of the LWSCC beams were in good agreement with the predictions based on design standards with an average accuracy of ≥ 90%. In addition, the predicted crack width values for LWSCC beams reinforced with FRP, using the bond-dependent coefficient (kb) values recommended by the standards, were overestimated in most cases. Thus, new values for kb have been suggested for FRP bars when used in LWSCC members. The measured deflections and the experimental values of the effective moment of inertia (Ie) were analyzed and compared with those predicted using the available models.Le béton autoplaçant (BAP) léger est de plus en plus utilisé dans différents types de structures en béton armé en raison de ses meilleures performances structurelles et de durabilité. L'utilisation de barres d’armature en polymère renforcé de fibres (PRF) non corrosives en remplacement des barres d'acier traditionnelles dans les éléments en béton a gagné la confiance et l'acceptation dans le domaine de la construction. Aucune recherche, cependant, ne semble avoir étudié les poutres en BAP léger renforcées avec des barres de PRF sous des charges de cisaillement et de flexion. De plus, les normes de conception actuelles pour les structures en béton armé de barres d’armature en PRF en Amérique du Nord (ACI 440.1R-15, CSA S806-12 et CSA S6-19) ne fournissent pas de directives pour les poutres en BAP léger armé avec des barres en PRF. Cette recherche se charge de fournir une base de données expérimentale ainsi que des analyses approfondies et des recommandations de conception des poutres en BAP léger armé avec différentes barres en PRF. Les tests expérimentaux se sont déroulés en deux phases. La première phase a été menée pour étudier les effets de différents paramètres sur le comportement et la résistance à l’effort tranchant des poutres en BAP léger armé de barres en PRF. Quatorze (14) poutres en béton armé grandeur nature ont été testées à l’effort tranchant. La deuxième phase a été conçue et préparée pour étudier le comportement en flexion et les performances de service des barres en PRF dans des poutres BAP léger. Vingt (20) poutres en béton armé grandeur nature ont été fabriquées et testées sous des charges de flexion. Les résultats expérimentaux sont discutés en termes de comportement à la fissuration, de flèche, de résistance à la flexion, de résistance à l’effort tranchant et du mode de rupture. Les résultats de cette étude ont indiqué que l'adoption du BAP léger a permis de diminuer le poids propre des poutres en béton (densité de 1 800 kg/m3) par rapport au béton normal (BN). Dans la première phase de cette thèse de doctorat, une étude théorique a été menée pour évaluer la précision des équations de calcul à l’effort tranchant poutres en BAP léger armé de PRF. Cette étude a démontré que les poutres en BAP léger armé de PRF peuvent être conçues à condition qu'un facteur de réduction de densité du béton approprié (λ) soit appliqué. L'utilisation d'un facteur de réduction de 0,75 et 0,8 dans les équations du CSA S806-12 et de l’ACI 440.1R-15, respectivement, pour considérer l'influence de la densité du béton a donné une bonne prédiction similaire à celle obtenue pour des poutres en BN armé de PRF. Dans la deuxième phase, les résultats des essais sur poutres en BAP léger armé de PRF a montré que les résistances en flexion des poutres en BAP léger en BN étaient en bon accord avec les prédictions basées sur les équations des normes de conception avec une précision moyenne ≥ 90 %. De plus, les valeurs de largeur de fissure prédites pour les poutres en BAP léger armé de PRF, en utilisant les valeurs de coefficient d’adhérence (kb) recommandées par les normes, ont été surestimées dans la plupart des cas comparativement aux valeurs expérimentales obtenues. Par conséquent, de nouvelles valeurs pour kb ont été suggérées pour les barres en PRFV et PRFB lorsque utilisées dans des structures en BAP léger. Enfin, les flèches mesurées et les valeurs expérimentales du moment d'inertie effectif (Ie) ont été analysées et comparées à celles prédites à l'aide des modèles disponibles

    Doctor of Philosophy

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    dissertationThe present research investigates lightweight and normal weight precast concrete panels for highway bridges. The panels are reinforced with Glass Fiber Reinforced Polymer (GFRP) bars. A benefit of precast concrete panels reinforced with GFRP bars for bridge decks is that they are essentially immune to environments where chloride-induced deterioration is an issue. Twenty panels constructed using lightweight and normal weight concrete reinforced with GFRP bars for flexure without any shear reinforcement were tested to failure. The variables investigated were concrete compressive strength, deck span, panel thickness and width, and reinforcement ratio. The experimental performance of lightweight precast GFRP reinforced panels versus normal weight precast GFRP reinforced panels was investigated in terms of shear capacity, deck deflections, and moment of inertia. The experimental results show that lightweight concrete panels performed similar to normal weight concrete panels; however, they experienced larger deflections under the same load and had a lower ultimate shear strength than normal weight concrete panels. An extended database of 97 test results including normal weight and lightweight concrete restricted to members reinforced with GFRP bars for flexure without any shear reinforcement was compiled. The extended database including 77 normal weight concrete members from literature, 8 normal weight concrete panels and 12 lightweight concrete panels tested in the current research; no lightweight concrete members reinforced with GFRP has been found. ACI 440.1R predicted smaller shear strength conservatism of lightweight concrete panels compared with normal weight concrete panels. A reduction factor has been recommended for the ACI 440.1R shear strength prediction equation when lightweight concrete is used. Modified Compression Filed Theory (MCFT) was also used for the prediction of ultimate shear strength of GFRP reinforced concrete panels. The comparison of prediction to the experimental results shows that MCFT can predict accurately the shear strength for both lightweight and normal weight concrete panels reinforced with GFRP bars. All the tested panels both normal weight and lightweight concrete panels designed according to ACI 440.1R satisfy the service load deflection requirements of the AASHTO LRFD Bridge Design Specifications. The experimental results indicate that the moment of inertia for precast panels reinforced with GFRP bars with initial cracks was less than the gross moment of inertia even before the cracking moment is reached. An expression for predicting deflection using a conservative estimate of the moment of inertia for precast concrete panels reinforced with GFRP bars is proposed. Using the proposed equation, a better deflection prediction is obtained for precast concrete panels reinforced with GFRP bars under service load

    Contribution à l’étude du comportement de dalles de ponts en béton autoplaçant léger armé de barres en PRFV soumises à des charges statiques concentriques

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    Abstract: Accelerated bridge construction (ABC) is an advanced bridge construction technique which reduces the structural loads and expediting transportation and installation of the precast bridge elements. Over the past decades, there have been progressive advancements in the use of ABC. One of the greatest materials helps reaching ABC approaches is the lightweight self-consolidating concrete (LWSCC). The use of LWSCC results in reducing the cross-sections of concrete members and overall transportation cost of precast elements. No research, however, seems to have investigated the structural behavior of the LWSCC bridge deck slabs reinforced with glass fiber-reinforced polymer (GFRP) bars under a concentrated load. In addition, current North American bridge design codes for FRP-reinforced structures (ACI 440.1R-15, AASHTO LRFD 2018, and CAN/CSA S6-19) do not provide guidance for LWSCC bridge deck slabs reinforced with GFRP reinforcement. This research program focuses on providing experimental results as well as analytical comparison between recorded load capacities and shear strength predictions calculated according to equations provided in CAN/CSA S806-12, ACI 440.1R-15, and AASHTO LRFD-2018. The experimental program included eight full-scale LWSCC bridge deck slabs reinforced with GFRP bars measuring 3,000 mm long × 2,500 mm wide × 200 mm thick which were tested up to failure under a concentrated load simulating the footprint of a standard CL-625 truck wheel load (87.5 kN) defined by the Canadian Highway Bridge Design Code (CHBDC), CAN/CSA S6-19. The investigated parameters were: (i) reinforcement ratio, (ii) top reinforcement; (iii) effect of edge-restraining; and (iv) reinforcement type. The experimental results are discussed in terms of cracking behavior, deflection, shear capacity, concrete and reinforcement strain, and mode of failure. The findings of this study revealed that the mode of failure for all specimens was punching-shear and the ultimate loads recorded for all deck slabs exceeded the design factored load. Moreover, the reinforcement ratio of the transverse direction of bottom assembly is the main parameter significantly affects the behavior of the LWCC deck slabs. The CAN/CSA S806-12 provided accurate yet conservative punching-shear predictions while AAHSTO LRFD 2018 provides the highest average of Vexp / Vpred. Finally, the experimental results of this study validate the use of GFRP-reinforced LWSCC in the construction of bridge-deck slabs.La méthode de construction accélérée des ponts dite ABC (pour accelerated bridge construction) est une nouvelle technique de construction qui permet de raccourcir considérablement les délais de construction des ponts avancée et faire accélère le rythme des travaux, en réduisant la durée des activités de construction et la présence des équipements lourds sur le chantier. Au cours des dernières années, il y a eu des progrès importants dans l'utilisation de la méthode ABC. L'un des matériaux de construction qui aide à atteindre les requis de la méthode ABC est l’utilisation du béton autoplaçant léger (BAL). L'utilisation du BAL permet de réduire les sections transversales des éléments en béton et le coût global de transport des éléments préfabriqués. Cependant, aucune recherche ne semble avoir examiné le comportement sous charges des dalles de tabliers de ponts en BAL armé avec des barres d’armature de polymère renforcé de fibres de verre (PRFV) sous charge statique concentrée. De plus, les codes nord-américains de calcul de ponts routiers en béton armé de PRFV (AASHTO LRFD 2018 et CAN/CSA S6-19) ne fournissent pas de directives pour les dalles de tabliers de ponts en BAL armés avec une armature de PRFV. Le programme de recherche de cette thèse de doctorat vise à fournir des résultats expérimentaux ainsi qu'une comparaison entre les capacités de résistance expérimentales et les prévisions de résistance calculées conformément aux équations fournies dans les différentes normes de calcul (CAN/CSA S806-12, CAN/CSA S6-19, ACI 440.1R-15 et AASHTO LRFD-2018. Le programme expérimental comprend huit dalles de tablier de pont en BAL armé de PRFV a pleine échelle mesurant 3 000 mm de longueur × 2 500 mm de large × 200 mm d'épaisseur. Tous les spécimens ont été testées jusqu'à la rupture sous une charge statique concentrée simulant l'empreinte d'une charge de roue de camion CL-625 standard (87,5 kN) défini par le Code canadien sur le calcul des ponts routiers (CHBDC), CAN/CSA S6-19. Les paramètres d’essais comprennent : (i) le taux d’armature, (ii) le lit d’armature supérieur ; (iii) et (iii) le type d’armature. Les résultats expérimentaux sont discutés en termes de comportement à la fissuration, de flèche, de résistance au cisaillement (poinçonnement), de déformation du béton et des armatures ainsi que du mode de rupture. Les résultats de cette étude ont révélé que le mode de rupture de tous les spécimens testés était le poinçonnement-des dalles. Aussi les résultats obtenus ont montré que les charges ultimes enregistrées pour toutes les dalles de pont testées dépassaient la charge pondérée de conception de la norme CAN/CSA S6-19. De plus, le taux d’armature de la direction transversale du lit inférieur est le paramètre principal qui affecte de manière significative le comportement des dalles de ponts en BAL armé de PRFV. La CAN/CSA S806-12 a fourni des prédictions de résistance au poinçonnement précises et conservatrices, tandis que l'AAHSTO LRFD 2018 fournit la moyenne la plus élevée de Vexp / Vpred. Enfin, les résultats expérimentaux de cette étude valident l'utilisation du BAL armé de PRFV dans la construction de dalles de tabliers de ponts

    Structural performance of lightweight aggregate concrete reinforced by glass or basalt fiber reinforced polymer bars

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    Lightweight aggregate concrete (LWC) and fiber reinforced polymer (FRP) reinforcement are potentially more sustainable alternatives to traditional steel-reinforced concrete structures, offering several important benefits. To further the knowledge in this area, the physical–mechanical properties of LWC produced with 0%, 50%, and 100% expanded clay aggregate were assessed. Subsequently, the flexural behavior of LWC beams reinforced with steel reinforcement and glass and basalt FRP bars was tested. The results of the experimental program allowed quantifying of the effect of expanded clay aggregate incorporation on LWC properties. The use of FRP reinforcement was also compared to steel-reinforced concrete beam behavior. The results of this study can provide additional support for the use of innovative materials such as LWA and FRP reinforcement.The authors wish to thank the Czech Science Foundation which supports the research under project No. 21-00800S.Peer ReviewedPostprint (published version

    Performance of lightweight granulated glass concrete beams reinforced with basalt FRP bars

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    This paper presents an investigation into the flexural behaviour of basalt FRP reinforced concrete beams through experimental and analytical methods. To achieve the research objectives, four concrete beams reinforced with steel and four identical concrete beams reinforced with BFRP bars were tested under four-point bending. The main parameters examined under the tests are the type of concrete (lightweight foam glass concrete and normal concrete) and the type of longitudinal reinforcement bars (BFRP and steel). Test results are presented in terms of failure modes; deformation crack pattern and the ultimate moment of resistance are presented. The experimental results are analysed and compared to predictive models proposed by ACI 440.1R, 2006 and BS EN 1992, Eurocode 2, for deformations and ultimate flexural capacities of the steel and BFRP reinforced concrete beams. The experimental results indicated that the flexural capacity decreased for the beams reinforced with BFRP bars compared to that of a corresponding beam reinforced with steel bars. Both types of beams failed in the modes predicted. The prediction models underestimated the flexural capacity of BFRP reinforced concrete beams. The increase in foam glass aggregate content was observed to reduce the cracking load by almost 10-40% and 25-50% for steel and BFRP reinforced concrete beams, respectively. The flexural capacities of BFRP reinforced beams were underestimated by using equations stipulated in ACI 440.1R and Eurocode 2 codes of practice. © 2019 Growing Science Ltd. All rights reserved

    Flexural Behaviour of Lightweight Foamed Concrete Beams Reinforced with GFRP Bars

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    Lightweight foamed concrete is a type of concrete characterized by light in self-weight, self-compaction, self-leveling, thermal isolation, and a high ratio of weight to strength. The advantages of GFRP bars include lightweight, high longitudinal tensile strength, non-conductivity, and resistance to corrosion. This study investigated the behavior of LWFC beams reinforced with GFRP bars under flexural loading. A total of four reinforced concrete beams were cast, where it consisted of two LWFC beams and two normal weight concrete beam which acted as control specimen. One of the lightweight foamed concrete beams and the normal concrete beams is reinforced with two GFRP bars and the other reinforced with two steel bars. All beams were designed with singly reinforced of two bars of diameter 12mm. The LWFC beams were with cement to sand ratio (1:1) and average dried density of 1800± kg/m^3. The main variables considered in this study was type of concrete and type of reinforcement. The flexural parameters investigated are ultimate load, crack width, ductility, deflection and stiffness. The lightweight foamed concrete beam reinforced with GFRP bars showed deflection and crack width greater than in beam reinforced with steel bars due to the low modulus of elasticity of GFRP bars

    Shear contribution of fiber-reinforced lightweight concrete (FRLWC) reinforced with basalt fiber reinforced Polymer (BFRP) bars

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    Cette étude porte sur le comportement au cisaillement des poutres en béton léger fibré et renforcées par des barres de polymère renforcé de fibres de basalte (PRFB). Dix poutres (150x250x2400 mm) coulées avec du béton fibré ou non-fibré ont été testées en flexion. Deux poutres ont été coulées sans fibres (poutres contrôles) tandis que les huit autres poutres ont été coulées avec du béton contenant des différents types et pourcentages de fibres. Les paramètres étudiés comprenaient le type de fibres ajoutés au béton (fibres de basalte, de polypropylène et d’acier), la fraction volumique des fibres (0, 0,5 et 1,0%) et les taux de renforcement des barres de PRFB (0,95 et 1,37%). Une comparaison entre les résultats expérimentaux et les modèles analytiques actuellement disponibles dans la littérature a été réalisée pour évaluer l'applicabilité de tels modèles pour prévoir la capacité des poutres testées en cisaillement. Les résultats de la présente étude indiquent que la géométrie des fibres joue un rôle important dans l'augmentation du nombre de fissures que celles observées dans les poutres contrôles. L'ajout de fibres a entraîné une défaillance plus ductile et le taux d'ouverture des fissures était retardé. La largeur de la fissure a diminué avec l'augmentation des ratios de renforcement longitudinal et des fractions volumiques des fibres. L'augmentation du taux de renforcement longitudinal a entraîné une rigidité plus élevée et a diminué les flèches à tous les stades du chargement. Les poutres coulées avec 1% de fibres de basalte, de polypropylène et d'acier ont montré une augmentation dans leurs capacités de cisaillement par rapport aux poutres contrôles d'environ 11, 16 et 63%, respectivement. Le type de fibres affectait de manière significative le gain dans les capacités de cisaillement des poutres, ce qui était attribué aux différentes propriétés physiques et mécaniques des fibres utilisées, telles que leurs dimensions, leurs géométries, et leurs mécanismes de liaison avec le béton. Les poutres coulées avec des fibres en acier à 0,5% présentaient des capacités de cisaillement plus élevées que celles coulées avec des fibres de basalte et de polypropylène de 23 et 16% respectivement, alors que les poutres coulées avec des fibres en acier à 1% de volume présentaient un gain de 47 et 41%, respectivement, dans leurs capacités. Les capacités de cisaillement prévues selon les équations de la norme CSA-S806-12 étaient conservatrices avec un rapport moyen Vprév/Vexp de 0,80 (écart type, ÉT = 0,12) pour les poutres sans fibres. Les modèles établis par Shin (1994) et Gopinath (2016) ont fourni de bonnes prévisions quant aux capacités de cisaillement des poutres en béton renforcé de fibres de basalte avec des ratios moyens Vprév/Vexp de 1,34 (ÉT = 0,09) et de 1,35 (ÉT = 0,07), respectivement. De même, le modèle de Shin (1994) a bien prédit les capacités de cisaillement des poutres en béton armé de fibres de polypropylène avec un rapport Vprév/Vexp de 1,34 (ÉT = 0,18). Les modèles de Gopinath (2016), Ashour A (1992) et Shin (1994) ont prédit les capacités de cisaillement des poutres en béton armé de fibres d'acier assez raisonnablement avec des ratio Vprév/Vexp de 1,01 (ÉT = 0,06), 1,07 (ÉT = 0,01) et 1,20 (ÉT = 0,08), respectivement. Un nouveau modèle a été proposé pour prédire les capacités de cisaillement des poutres en béton léger fibré renforcées par des barres longitudinales PRFB. Le modèle proposé prédit bien les capacités de cisaillement des poutres en béton léger (avec des fibres de basalte) avec un rapport Vprév/Vexp de 1,01 (ÉT = 0,05) et celles des poutres en béton léger (avec des fibres de polypropylène) avec un rapport Vprév/Vexp de 0,99 (ÉT = 0,06). Le facteur de liaison et la matrice de liaison d'interface utilisés étaient respectivement 0,75 et 4,18 MPa. En même temps, le modèle proposé prédit bien les capacités de cisaillement des poutres coulées avec des fibres d’acier avec un rapport Vprév/Vexp de 0,9 (ÉT = 0,00) quand le facteur de liaison et la matrice de liaison d'interface utilisés étaient respectivement 1,0 et 6,8 MPa.This study reports on the shear behavior of fiber-reinforced lightweight concrete (FRLWC) beams reinforced with basalt fiber-reinforced polymer (BFRP) bars. Ten beams (150x250x2400 mm) cast with concrete with and without fibers were tested under fourpoint loading configuration until failure occurred. Two beams were cast without fibers and acted as control while the other eight beams were cast with different types and percentages of fiber. The investigated parameters included the fiber type (basalt, polypropylene, and steel fibers), the fibers volume fraction (0, 0.5, and 1.0%), and the beams’ reinforcement ratios (0.95 and 1.37%). Comparison between the experimental results and the analytical models currently available in the literature was performed to assess the applicability of such models for LWC reinforced with BFRP bars. Based on the outcome of the current study, the geometry of fibers played an important role in increasing the number of cracks than those observed in the control beams. The addition of fibers led to a more ductile failure and the rate of crack opening was delayed. Crack width decreased with the increase of the longitudinal reinforcement ratios and the fibers’ volume fractions. Increasing the reinforcement ratio resulted in higher stiffness and decreased its deflection at all stages of loading. Beams cast with 1% of basalt, polypropylene, and steel fibers showed an increase in their shear capacities in compared to control beams about 11, 16, and 63%, respectively. The type of fibers significantly affected the gain in the shear capacities of the beams, which can be attributed to the different physical and mechanical properties of the fibers used such as aspect ratios, lengths, geometries, densities, and their bonding mechanisms. Beams cast with 0.5% steel fibers exhibited higher shear capacities than those cast with basalt and polypropylene fibers by 23 and 16%, respectively, whereas the beams cast with 1% steel fibers showed a gain by 47 and 41%, respectively. The predicted shear capacities according to CSA-S806-12 code provisions were conservative with an average ratio Vpred /Vexp of 0.80 (standard deviation, SD = 0.12) for beams without fibers. Good predictions for the shear capacities of the basalt-fiber reinforced concrete beams (BLWC) were provided by the models derived by Shin (1994) and Gopinath (2016) in which the ratios Vpred /Vexp were 1.34 (SD = 0.09) and 1.35 (SD = 0.07), respectively. Also, the model of Shin (1994) predicted well the shear capacities of the polypropylene-fiber reinforced concrete beams (PLWC) with a Vpred /Vexp ratio of 1.34 and SD of 0.18. The models of Gopinath (2016), Ashour A (1992), and Shin (1994) predicted the shear capacities of steel-fiber reinforced concrete beams (SLWC) fairly reasonable with a Vpred /Vexp ratio of 1.01 (SD = 0.06), 1.07 (SD = 0.01) and 1.20 (SD = 0.08), respectively. A new model was proposed to predict the shear capacities of FRWLC beams reinforced with BFRP longitudinal bars. The proposed model predicted well the shear capacities of BLWC beams with a Vpred /Vexp ratio of 1.01 (SD = 0.05) and those of PLWC beams with a Vpred /Vexp ratio of 0.99 (SD = 0.06). The bond factor and the interface bond matrix used were 0.75 and 4.18 MPa, respectively. The proposed model also predicted well the shear capacities of beams cast with SLWC with a Vpred /Vexp ratio of 0.9 when the bond factor and the interface bond matrix were taken equal to 1.00 and 6.8 MPa, respectively

    Assessing the applicability of a smeared crack approach for simulating the behaviour of concrete beams flexurally reinforced with GFRP bars and failing in shear

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    Numerical simulation of beams failing in shear is still a challenge. With the scope of verifying the applicability of smeared crack approaches to simulate the behavior of reinforced concrete (RC) beams failing in shear, a set of concrete beams reinforced with longitudinal glass fiber reinforced polymer (GFRP) bars, experimentally tested up to their failure, and comprehensibly monitored, are numerically simulated. The simulations are carried out with a multi-directional fixed smeared crack model available in the FEMIX computer program that has several options for modeling the crack shear stress transfer, which is a critical aspect when simulating RC elements failing in shear. The predictive performance of the numerical simulations is assessed in term of load vs deflection, crack pattern at failure, concrete strains in critical shear regions, and moment–curvature relationship. The influence on the predictive performance of the following modeling aspects is also investigated: finite element mesh refinement; simulation of the crack shear stress transfer by using the classical shear retention factor and a crack shear-softening diagram; bond conditions between flexural reinforcement and surrounding concrete. The simulations carried out demonstrate that small dependence of the results on the finite element mesh refinement and adequate crack patterns can be obtained with refinement levels suitable for design purposes and taking into account the actual computer performances, as long as a crack shear-softening diagram is used. However, the predictive performance of the simulations depends significantly on the values adopted for the parameters that define this diagram, as demonstrated by the performed parametric studies.The first author aims to acknowledge the support provided by FCT through the research project ICoSyTec -Innovative construction system for a new generation of high performance buildings, with reference: POCI-01-0145-FEDER-027990
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