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Yu, Jianru. "Stress transfer between FRP reinforcement and concrete." Thesis, University of Bristol, 2007. http://hdl.handle.net/1983/e1707871-89d2-48be-8633-4468d3e82bc1.
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This thesis investigates gaps in the current understanding of some key aspects of Fibre Reinforced Polymer (FRP) strengthened reinforced concrete (RC) members. There are four important issues have been investigated. Firstly, a novel pullout test was developed to investigate the stress transfer mechanics and failure modes of near surface mounted (NSM) FRP strengthened RC blocks at a fundamental level. Secondly, the (FEA) was used to gain a detailed understanding of stress distribution both along the bond line and through the thickness of the adhesive layer for the RC members strengthened either by NSM or externally bonded plate (EBP) FRP technique.
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Stratford, Timothy John. "The shear of concrete with elastic FRP reinforcement." Thesis, University of Cambridge, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.621730.
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Baena, Muñoz Marta. "Study of bond behaviour between FRP reinforcement and concrete." Doctoral thesis, Universitat de Girona, 2011. http://hdl.handle.net/10803/7771.
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El uso de barras de materiales compuestos (FRP) se propone como una alternativa efectiva para las tradicionales estructuras de hormigón armadas con acero que sufren corrosión en ambientes agresivos. La aceptación de estos materiales en el mundo de la construcción está condicionada a la compresión de su comportamiento estructural. Este trabajo estudia el comportamiento adherente entre barras de FRP y hormigón mediante dos programas experimentales. El primero incluye la caracterización de la adherencia entre barras de FRP y hormigón mediante ensayos de pull-out y el segundo estudia el proceso de fisuración de tirantes de hormigón reforzados con barras de GFRP mediante ensayo a tracción directa. El trabajo se concluye con el desarrollo de un modelo numérico para la simulación del comportamiento de elementos de hormigón reforzado bajo cargas de tracción. La flexibilidad del modelo lo convierte en una herramienta flexible para la realización de un estudio paramétrico sobre las variables que influyen en el proceso de fisuración.<br>The use of Fibre Reinforced Polymers (FRP) as reinforcement in concrete structures is considered to be a possible alternative to steel in those situations where corrosion is present. The full acceptance of FRP reinforcement in concrete construction is contingent on a complete study and comprehension of all aspects of their structural performance. This thesis investigates the bond behaviour between Fibre Reinforced Polymer (FRP) reinforcement and concrete. Two experimental programs were conducted. In the first program the role of the variables which affect the bond behaviour was studied through pull-out test. In the second program, GFRP RC members were tested in tension to study their cracking response. To conclude the thesis, a numerical model was developed to simulate the cracking behaviour of RC tensile members. Since the model was flexible enough to include any "user-defined" bond-slip law and variable materials' properties, a parametric study was conducted to analyze which are the variables that influence the cracking behaviour.
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Kesse, Gyamera. "Concrete beams with external prestressed carbon FRP shear reinforcement." Thesis, University of Cambridge, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.615688.
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DeFreese, James Michael. "Glass Fiber Reinforced Polymer Bars as the Top Mat Reinforcement for Bridge Decks." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/36289.
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The primary objective of this research was to experimentally investigate material and bond properties of three different types of fiber reinforced polymer (FRP) bars, and determine their effect on the design of a bridge deck using FRP bars as the top mat of reinforcement. The properties evaluated include the tensile strength, modulus of elasticity, bond behavior, and maximum bond stress. The experimental program included 47 tensile tests and 42 beam end bond tests performed with FRP bars. Tensile strength of the bars from the tensile testing ranged from 529 MPa to 859 MPa. The average modulus, taken from all the testing, for each type of bar was found to range from 40 GPa to 43.7 GPa. The maximum bond stress from the beam end bond tests ranged from 9.17 MPa to 25 MPa. From the tests, design values were found in areas where the properties investigated were related. These design values include design tensile strength, design modulus of elasticity, bond coefficient for deflection calculations, bond coefficient for crack width calculations, and development length. The results and conclusions address design concerns of the different types of FRP bars as applied in the top mat of reinforcement of a bridge deck.
A secondary objective was to evaluate the disparity in results between direct pullout tests, and beam end bond tests. Results from the experimentally performed beam end bond test were compared to previous literature involving the direct pullout tests. Results from the performed beam end bond tests were higher than all of the literature using direct pullout results. No recommendations were given on the disparity between the two test methods.<br>Master of Science
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Ewen, Kristian A. J. "Ductility in FRP rods for concrete reinforcement by interfacial shearing." Thesis, University of Ottawa (Canada), 2005. http://hdl.handle.net/10393/10798.
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Non-corrosive reinforcement of concrete provides great potential for reducing life cycle costs (LCC) of highway infrastructure (bridge decks and columns, light-standards, dividers) and concrete structures near water (piers, retaining walls, platforms). This is especially important in areas where salts are common (cold weather road salting, coastal regions) and is achieved by extending the life of structures and the period between major repairs. Costs of infrastructure rehabilitation due to corrosion of reinforcement are estimated to be $1.2 billion dollars in Ontario in the next few years, and up to 40% of all annual infrastructure costs in the province of Quebec. Efforts to reduce the frequency of repair and replacement of ageing structures include using epoxy coating of the reinforcing bar (rebar), cathodic protection, alternate types of steel and fibre reinforced polymer (FRP) rebar. Of these, FRP rebar appears to be the most promising. The limitation of FRP rebar is the low maximum strain and linear behaviour up to failure. Prior attempts at increasing the ductility and producing non-linear behaviour have had limited success. Maximum strain remains limited to that of the highest strain fibres available. Pseudo-ductility has been achieved by combining multiple fibre types having different material properties. The work described in this thesis focussed on non-traditional methods for achieving ductility in FRP rebars by taking advantage of the frictional interface of two materials. Two methods were tested. The first employed a solid inner-core with an over-wrap cut at regular intervals and relied on the rebar pulling out of the concrete at sustained load. Rods were tested in concrete beams under bending loads. Sustained load was achieved for significant pull-out. The second method combined continuous fibres with discontinuous meso-rods wherein the continuous fibres provide initial stiffness and maximum strength and the discontinuous meso-rods provide high-ductility via fibre pull-out. A concept model using aligned short steel fibres was manufactured and tested. Load-displacement behaviour showed substantial local elongation. Prototype models using carbon fibres were manufactured and tested. Specimens showed evidence of fibre pull-out. Future specimens should employ an intermediate material with a controlled and repeatable shear strength for the interface.
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Shehata, Emile F. G. "Fibre-reinforced polymer (FRP) for shear reinforcement in concrete structures." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0001/NQ41626.pdf.
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Kiari, Mohamed Ahmed Abubaker. "Novel closed-loop FRP reinforcement for concrete to enhance fire performance." Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/28871.
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The use of fibre-reinforced polymer (FRP) as an internal reinforcement for concrete has many advantages over steel, most notably lack of corrosion which is considered to be a major problem for structures incorporating steel. In Europe alone, it is estimated that the annual repairing and maintenance costs associated with steel corrosion in infrastructure are around £20 billion (Nadjai et al., 2005). Despite of its corrosion resistance, the widespread use of FRP as an internal reinforcement for concrete was hindered due to its relatively weak performance at elevated temperatures, such as in the event of fire. Under heating, the polymer matrix in FRP softens, which causes bond degrading between reinforcement and concrete. The softening of polymer matrices occurs around their glass transition temperatures, which is typically in the range of 65– 150 °C. The sensitivity of FRP bond to temperature is recognised in design guidelines, therefore many advise against utilising FRP as an internal reinforcement for concrete in structures where fire performance is critical. On the other hand, fibres, the other component of FRP, can tolerate temperatures much higher than polymer matrices. This research investigates a new design for FRP internal reinforcement, which exploits the fact that the FRP fibres in general and carbon fibres in particular are capable of sustaining a large proportion of their original strength at high temperatures. Instead of the traditional way of using separate bars, FRP reinforcement was made as closed loops produced through the continuous winding of carbon fibre tows. When the surface bond degrades at elevated temperatures, interaction with concrete can still be provided through bearing at loop ends. The concept of FRP loops was investigated through a series of experimental work. Firstly, the performance of carbon FRP (CFRP) loops was evaluated through a series of push-off tests in which specimens consisting of CFRP loops bridging two concrete cubes were tested in pull-out using hydraulic jacks. Specimens with straight and hooked reinforcement were produced as well for comparison. A total number of 18 specimens were tested at ambient temperature, glass transition temperature (Tg), and above Tg. Results showed that while at ambient temperature there was no distinction in performance. At elevated temperatures, CFRP loops developed strength about three times higher than specimens with straight or hooked bars. Also, while failure mode occurred due to de-bond in the case of straight and hooked reinforcement, rupture failure occurred with CFRP loops. For better demonstration of the concept in more realistic conditions, four-point bending tests were conducted upon 28 beam specimens reinforced either with CFRP loops or straight bars as flexural reinforcement. Beams were tested under monotonic loading at ambient temperature, or under sustained loads with localised heating over the midspan region that contained the reinforcement overlaps. The benefit of CFRP loops became evident in the elevated temperature tests. Beam specimens with spliced straight bars failed due to debonding after a short period (up to 15 minutes) of fire exposure. Conversely, the fire endurance increased four to five times when CFRP loop reinforcement was used. Unlike straight bars, debonding failure was avoided as failure occurred due to reinforcement rupture. The overlap length of the CFRP loops was found to be important in the order for the loop to develop full capacity. Premature failure can occur with short overlap length due to shear off concrete within the overlap zone. The presence of transverse reinforcement increases confinement levels for reinforcement, so the bond failure of straight bars at ambient temperature testing was eliminated when stirrups were provided. However, at elevated temperatures straight bars failed by pull-out even in presence of transverse reinforcement. To facilitate design with CFRP loops, a numerical analysis tool was developed to calculate the bond stress-slip response of reinforcement at ambient and elevated temperatures. A Matlab programme was designed based on a one-dimensional analytical model for steel. The bond law was modified to be used for CFRP reinforcement. Other analytical models from the literature to account for bond degradation with temperature and tensile strength of curved FRP were also utilised. The developed Matlab code has the capability of producing slip, axial stress, and bond stress distribution along reinforcement. The novel FRP loop reinforcement was demonstrated to be a promising solution for enhancing the fire performance of CFRP internal reinforcement at elevated temperatures. It contributes to removing a major obstacle preventing widespread use of FRP-reinforced concrete, and paves the way for CFRP reinforcement to be used in situations where fire performance is critical.
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Lagiň, Juraj. "Řešení vybraných detailů betonových konstrukcí s využitím FRP výztuže." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2020. http://www.nusl.cz/ntk/nusl-409796.
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The diploma thesis is devided into two levels. The Primary part of the thesis is the theoretical part, which is part of project „FV10588 – New generation of spatial prefab made from high-firm concrete with increased mechanical resistence and endurance“, realized in cooperation with Faculty of Civil Engineering at VUT university – Institute of concrete and masonry structures. The project deals with frame corners in the form of steel and composite reinforcement which will compared through experiments and various kind of calculate proceedings. The secondary part of thesis focuses on the static-design project of cooling reservoir, placed under the ground, while is stressed by temperature. The reinforcement of the construction is realized in two ways – steel and composite reinforcement with their effectivity compared.
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Cambridge, Christopher Brian. "Supplementary reinforcement to avoid catastrophic failure in beams with FRP tendons." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0003/MQ44903.pdf.
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Nguyen, Hien V. "Debonding failure of RC beams retrofitted with Near Surface Mounted FRP Reinforcement." Thesis, University of Sheffield, 2016. http://etheses.whiterose.ac.uk/13262/.
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Near Surface Mounted (NSM) Fibre Reinforced Polymer (FRP) reinforcement is an effective rehabilitation solution to strengthen RC structures, as it can enable higher load carrying capacity and ductility than conventional Externally Bonded Reinforcement (EBR). However, the performance of elements strengthened in flexure is still controlled by bond failure between the NSMR system and the concrete substrate. This can reduce both the effectiveness and safety of NSMR systems and should be accounted for in design. The development of high stresses due to the abrupt termination of NSMR is the main cause for the dominant end debonding failure. This type of failure is not well understood and needs to be examined in detail. The aim of this work is to achieve a comprehensive understanding of bond behaviour and debonding mechanisms of the NSMR in flexural strengthening applications both experimentally and theoretically so as to enable the development of practical and reliable design methods for RC beams strengthened in flexure with NSMR. An analytical elastic model is developed to facilitate a fundamental understanding of the distribution of bond stresses along the NSMR, especially in the region around the termination point. The model identifies differences of stress states between EBR and NSMR. However, since it is based on elastic analysis and continuum mechanics, it is unable to represent bond behaviour of NSMR at high load levels. This issue can only be examined in detail via specially developed experimental work. A total of ten RC beams, including two control beams and eight beams strengthened in flexure with CFRP and BFRP bars or strips, are tested to examine the overall structural behaviour of RC beams retrofitted with NSMR of different embedment lengths. Tested beams are heavily instrumented to examine the influence of yield penetration along the internal steel bars on the bond behaviour of the NSM reinforcement within the shear spans and the resulting debonding mechanisms. NSMR enhanced flexural capacity by up to 50% and the dominant failure mode was end debonding after yielding. The experimental results show that yielding of the steel reinforcement penetrates in the shear span much further than predicted through classic section analysis, reaching near or even beyond the termination point. The experimental evidence is used to develop a new simple, yet effective methodology to estimate the minimum embedment length. The new design method is validated against an extensive database collected from literature and is found to provide more accurate and reliable results.
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Lipoldová, Marie. "Studium vlastností ohýbaných FRP výztuží." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2021. http://www.nusl.cz/ntk/nusl-433606.
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The diploma thesis deals with the study of bent FRP reinforcements with the main focus on the methods of production of bent FRP reinforcement, examples of their application in structures. The work also mentions the effects of aggressive environments on the durability of FRP. In the practical part, a search of the possibilities of testing the properties of bent FRP reinforcement. Subsequently, an experiment is designed and performed to monitor changes in the properties of straight and bent FRP reinforcement exposed to the alkaline environment and water at 20 °C and 40 °C. Finally, the evaluation of changes in mechanical properties and observation of reinforcements using optical and scanning electron microscopy is performed.
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Kostova, Kaloyana Zdravkova. "Design and constructability of fabric-formed concrete elements reinforced with FRP materials." Thesis, University of Bath, 2016. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.707574.
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Concrete has many advantages as a low cost and sustainable material. However, more than 5% of the planet’s total carbon emissions are associated with the production of cement, which, in fact, is predominantly due to the large volume of concrete used worldwide. It is known that traditionally designed concrete structures typically use more material than structurally required and, therefore, an important question is whether material demand can be reduced through structural optimisation. A major drawback from optimised design, however, is the cost and complexity of producing conventional rigid moulds. Fabric formwork is emerging as a new method for construction, gaining popularity among architects and engineers for the opportunity to build unique forms and to shape concrete elements efficiently. Porous fabrics, acting as controlled permeability formwork, also have proven effect on the durability characteristics of concrete. While fabric formwork has a profound potential to change the appearance of concrete structures, the shapes cast in fabrics are not defined in advance and have been often created unintentionally. The design of load-bearing reinforced concrete structures, however, requires accurate form-prediction and construction methods for securing steel reinforcement inside flexible fabrics, which presents a number of constructability challenges. For example, cover formers cannot be used to ensure adequate thickness of protective cover, inevitably affecting the acceptance of such structures in practice. This research has demonstrated that non-corrodable FRP reinforcement can be incorporated more easily than steel bars in fabric-formed concrete due to its light weight and flexibility, while it is possible to ensure ductility of such structures through confinement of concrete using FRP helices. A novel splayed anchorage system has been developed to provide end anchorage for optimised sections where standard bends or hooks cannot fit. This work also provides an experimentally verified methodology and guidance for the design and optimisation of fabric-formed elements.
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Morphy, Ryan David. "Behaviour of fibre-reinforced polymer (FRP) stirrups as shear reinforcement for concrete structures." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0002/MQ45102.pdf.
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Riccardi, Francesco. "Experimental and numerical investigation of the interaction between concrete and FRP reinforcement anchorages." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPAST065.
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Des opérations de renforcement ou réparation sont souvent nécessaires pour garantir l’intégrité des structures en Béton Armé (BA) vis-à-vis du risque sismique. Dans ce cadre, le Polymère Renforcé de Fibres (PRF) stratifié au contact a démontré son efficacité pour améliorer le comportement en flexion des éléments de structures tant en termes de résistance que de ductilité. Afin d’en améliorer la liaison en proximité des jonctions, les ancrages noyés dans le béton représentent une solution avantageuse en termes de performances et de facilité de mise en place. Néanmoins, leur comportement mécanique est fréquemment associé à des mécanismes locaux de déformation qui peuvent affecter la réponse globale de la structure. Un nouveau montage expérimental a été donc conçu pour réaliser des essais de flexion in-situ sur des poutres renforcées de petite échelle avec l’utilisation de la tomographie 3D et étudier l’interaction entre le béton et les ancrages. L’objectif principal est de suivre grâce à la Corrélation d’Images Volumiques (CIV) l’évolution de la dégradation du matériau pendant le chargement et de reconstruire la cinématique de la zone renforcée. D’un point de vue numérique, un modèle éléments finis enrichis inspiré par la Méthode des Discontinuités Fortes (SDA) a été développé dans le but d’améliorer la représentation de l’interface. De cette façon, des comportements mécaniques complexes comme les phénomènes d’arrachement peuvent être facilement reproduits, en limitant en même temps le coût de calcul. La calibration du comportement d’interface est faite enfin grâce aux résultats des essais in-situ qui permettent de valider le modèle dans le cas de problèmes non-linéaires<br>Strengthening and retrofitting techniques are often required for guaranteeing the integrity of Reinforced Concrete (RC) structures to prevent seismic risk. In such a framework, Externally Bonded (EB) FRP strengthening systems have proven their effectiveness in enhancing the flexural performances of structural members both in terms of bearing capacity and ductility. In order to improve the bond in the vicinity of RC joints, embedded anchors represent an attractive solution in terms of both performances and ease of installation. Nevertheless, their mechanical behaviour is often associated with localised deformation mechanisms that can strongly affect the overall structural response. A novel experimental apparatus has therefore been designed in order to carry out in-situ bending tests on small-scale strengthened beams in conjunction with 3D tomography and study the interaction between concrete and anchors. The main goal is to track the evolution of material degradation over the entire loading history by means of Digital Volume Correlation (DVC) and to reconstruct the kinematics of the strengthened region. From a numerical point of view, an enriched finite element model inspired by the Strong Discontinuity Approach (SDA) has been developed with the aim of improving the interface representation. By means of a kinematic enrichment, this strategy allows, on the one hand, to account for complex mechanical behaviours such as pull-out deformation modes and debonding mechanisms, on the other hand, to limit the computational effort. The calibration of the interfacial behaviour is then realised by means of the in-situ experimental results which allow to validate the model in the case of non-linear problems
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El-Nemr, Amr Maher. "Serviceability of concrete members reinforced with FRP bars." Thèse, Université de Sherbrooke, 2013. http://hdl.handle.net/11143/6124.
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La détérioration des infrastructures au Canada due à la corrosion des armatures est l'un des défis majeurs de l'industrie de la construction. Les progrès récents dans la technologie des polymères ont conduit au développement d'une nouvelle génération de barres d'armature à base de fibres renforcées de polymères (PRF), (en particulier les fibres de verre). Ces barres, résistant à la corrosion, ont montré un grand potentiel d'utilisation pour mieux protéger les infrastructures en béton armé contre les effets dévastateurs de la corrosion. Avec la publication du nouveau code S807-10 "Spécifications pour les polymères renforcés de fibres" et la production de barres en PRF de très haute qualité, celles-ci représentent une alternative réaliste et rentable par rapport à l'armature en acier pour les structures en béton soumises à de sévères conditions environnementales. La conception des éléments en béton armé de barres en PRF est généralement gouvernée par l'état de service plutôt que l'état ultime. Par conséquent, il est nécessaire d'analyser les performances en flexion et le comportement en service en termes de déflexion et de largeur de fissures des éléments en PRF sous charges de service et de vérifier que ces éléments rencontrent les limites des codes. Aussi, de récents développements dans l'industrie des PRF ont conduit à l'introduction des barres en PRF avec des configurations de surface et des propriétés mécaniques différentes. Ces développements sont susceptibles d'affecter leur performance d'adhérence et, par conséquent, la largeur des fissures dans les éléments en PRF. Cependant, les codes de conception et les guidelines de calcul fournissent une valeur unique pour le coefficient d'adhérence (k[indice inférieur b]) en tenant compte des configurations de surface et en négligeant le type de barre en PRF, le diamètre de la barre, et le type de béton et de sa résistance. En outre, le code canadien S807-10 "Spécifications pour les polymères renforcés de fibres" fournit une étape en classant les barres en PRF par rapport à leur module d'élasticité (E[indices inférieurs frp]). Ces classifications ont été divisées en trois classes : Classe I (E[indices inférieurs frp]<50 GPa), Classe II (50 GPa [plus petit ou égal] E[indices inférieurs frp]< 60 GPa) et Classe III (E[indices inférieurs frp] [plus grand ou égal] 60 GPa). Ce programme de recherche vise à étudier expérimentalement le comportement en flexion des éléments en béton en service armé avec différents paramètres sous charges statiques. Le programme expérimental est basé sous plusieurs paramètres, dont les différents ratios de renforcement, différents types de barres (différentes classes comme classifiées par le CAN/CSA S807-10), le diamètre et la surface de la barre, la configuration ainsi que la résistance du béton. De plus, les recommandations actuelles de design pour les valeurs de k[indice inférieur b] et la vérification de la dépendance des valeurs de k[indice inférieur b] sur le type de barres (verre ou carbone), le diamètre des barres et le type de béton et sa résistance ont été étudiées. Le programme expérimental comprenait la fabrication et les essais sur 33 poutres à grande échelle, simplement appuyées et mesurant 4250 mm de long, 200 mm de large et 400 mm de hauteur. Vingt et sept poutres en béton ont été renforcées avec des barres en PRF à base de verre, quatre poutres en béton ont été renforcées avec des barres de PRF à base de carbone, et deux poutres ont été renforcées avec des barres en acier. Toutes les poutres ont été testées en flexion quatre points sur une portée libre de 3750 mm. Les paramètres d'essai étaient: le type de renforcement, le pourcentage d'armature, le diamètre des barres, configurations de surface et la résistance du béton. Les résultats de ces essais ont été présentés et discutés en termes de résistance du béton, de déflection, de la largeur des fissures, de déformations dans le béton et l'armature, de résistance en flexion et de mode de rupture. Dans les trois articles présentés dans cette thèse, le comportement en flexion et la performance des poutres renforcées de barres en PRFV et fabriquées avec un béton normal et un béton à haute performance ont été investigués, ainsi que les différentes classes de barres en PRFV et leurs configurations de surface. Les conclusions des investigations expérimentales et analytiques contribuent à l'évaluation des équations de prédiction de la déflection et des largeurs de fissures dans les codes de béton armé de PRF, pour prédire l'état de service des éléments en béton renforcés de PRF (déflection et largeur de fissures). En outre, à la lumière des résultats expérimentaux de cette étude, les équations de service (déflection et largeur des fissures) incorporées dans les codes et guidelines de design [ACI 440.1R-06, 2006; ISIS Manual No.3, 2007; CAN/CSA-S6.1S1, 2010; CAN/CSA-S806, 2012] ont été optimisées. En outre, les largeurs de fissures mesurées et les déformations ont été utilisées pour évaluer les valeurs courantes de k[indice inférieur b] fournies par les codes et les guidelines de calcul des PRF. En outre, les conclusions ne prennent pas en charge la valeur unique de k[indice inférieur b] pour les barres en PRF de types différents (carbone et verre) avec des configurations de surface similaires et s'est avéré être dépendant du diamètre de la barre.
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Eitel, Amy Katherine. "Performance of a GFRP reinforced concrete bridge deck." online version, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=case1102014072.
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Rizkalla, Natalie Sami. "Partial bonding and partial prestressing using stainless steel reinforcement for members prestressed with FRP." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0015/MQ53022.pdf.
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DeYoung, Kenneth Lee. "Flexure shear response in fatigue of fiber reinforced concrete beams with FRP tensile reinforcement." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/4894.
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Thesis (M.S.)--University of Missouri-Columbia, 2007.<br>The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on March 24, 2008) Includes bibliographical references.
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Soeira, Lucas Emanuel. "Projeto e elaboração de um dispositivo para remodelagem de fibras como subsistema do processo de enrolamento filamentar." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/18/18146/tde-27102009-192514/.
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Essa dissertação trata da modelagem física de filamentos de fibras visando adequá-las a aplicações em equipamentos de enrolamento filamentar - filament winding. No decorrer do trabalho é abordada a criação do subsistema para condução e posicionamento dos fios que compõem as bobinas - rovings. São feitas análises por elementos finitos e realizados testes de bancada com os componentes mecânicos visando validar o subsistema como parte integrante das máquinas de filament winding. É estudada a forma de impregnação dos fios, a tensão e o grau de espalhamento dos fios no decorrer da sua passagem pelo sistema, o qual é composto por um conjunto de polias, um tracionador e um enrolador desses fios.<br>This dissertation deals with the use of fiber reinforcements, in order to improve its appliance in filament winding machines. Throughout this work it is created a mechanism system to remodel the fiber filaments from rovings to the part that is been produced. Finite element analyses and experimental tests are performed to validate the system as part of the filament winding machines. Its is studied the impregnation characteristics, the tensioning and the spreading of the fibers along the designed system, which is composed by a set of pulleys and tensioners. The system is built and satisfactory results are obtained. The results obtained as well as proposals to improve the system are presented and the results discussed.
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Boyd, Curtis Barton. "A Load-Deflection Study of Fiber-Reinforced Plastics as Reinforcement in Concrete Bridge Decks." Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/9591.
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Approximately fifty percent of the bridges in the United States are considered deficient. The deterioration of the concrete components is a leading cause of the problem. The deterioration of concrete bridge decks is due primarily to corrosion of the reinforcing steel in the concrete. A promising solution to the problem is the use of fiber reinforced plastics (FRP) as a replacement for reinforcing steel. The use of FRP as reinforcement has the following advantages of lightweight, high tensile strength, corrosion resistance, flexibility, and electromagnetic resistance. This paper looks at the use of FRP as reinforcement in concrete beams and compares the information from deflection measurements of different configurations. Also, a material cost comparison is made to determine the cost of using the FRP reinforcement over standard steel reinforcement. Concrete bridge deck systems are designed using steel and fiber-reinforced plastics and allowable stress and load resistance factor methods. Recommendations for further study and uses of FRP are made.<br>Master of Science
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Fawwaz, Maha, and Adnan Hanna. "Structural behavior of notched glulam beams reinforced by means of plywood and FRP." Thesis, Linnéuniversitetet, Institutionen för teknik, TEK, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-19479.
Full textAbstract:
Nowadays, timber is widely used in construction industry thanks to its availability and good properties. The use of solid (sawn) timber is not always proper since it is only available up to certain dimensions. Therefore, the so-called Engineered WoodProducts (EWPs) have been introduced to cope with the different design needs of structures. The Glued laminated Timber (glulam) is a type of EWPs that consists of smallsections of timber laminates glued together to form beams and columns. Glulam can be manufactured in almost any size and shape; it can also be tapered or notched. However, notching a beam at its end leads to a stress concentration at the re-entrantcorner of the notch due to the sudden change in the notched beam’s cross section. The concentration of shear and tensile stresses perpendicular to the grain can lead to a catastrophic brittle failure caused by the crack propagation from the notch corner. Crack opening due to tensile stresses perpendicular to grain is the most common failure at the notch corner and it is always taken into design consideration. However,shear component is usually exists and must be also considered in design to guarantee the safety of the structure. Currently, only the normal forces perpendicular to the beam’s axis are considered in the design of the reinforcement in design handbooks. The aim of this thesis was to study the structural behavior of notched glulam beams reinforced by adhered plywood panels and FRP. The carrying capacity of the notched glulam beams at their ends is the main subject of this thesis. In addition, a review of the notched beams design, reinforcements, and analysis theories are included. Experimental series of three point bending tests with notched glulam beams withdifferent configurations of reinforcement was carried out in lab. Deformations and forces were measured both with conventional techniques and with contact-free measurement systems - ARAMIS. On the other hand, a simple model of two dimensional plane stress element has been created of the unreinforced notchedbeam in ABAQUS. The normal and shear stresses were calculated for a horizontalpath of 100 mm in length starting from the notch tip. Afterwards, the mean stresseswere determined for the same path and have been used in calculations. The Mean Stress Approach has been adopted in the hand calculations to calculate the crack length and the failure load according to the ABAQUS model. Accordingly, the failure load was about 40 kN for the unreinforced beams. Also, Eurocode 5 has been used to calculate the failure load which gave a value of 20.2 kN for the unreinforced beams. The average maximum applied load in tests was 30 kN for the unreinforced beams while it reached about two and a half times this value for the CF-reinforced and the plywood-reinforced beams.<br>Tack vare sina goda egenskaper används trä i byggnadskonstruktioner i allt storeomfattning. Konstruktionsvirke (sågade trävaror) kan dock inte alltid användas pågrund av de begränsade dimensioner som finns tillgängliga. På grund av bl a dettahar ett flertal så kallade engineer wood products (EWP) utvecklats. Limträ är en typav EWP som består av sammanlimmade lameller som bygger upp tvärsnitt i balkareller pelare. Limträ kan tillverkas i nästan godtycklig storlek och form och kan enkeltförses med t ex urtag. Vid urtag i balkändar nära upplag uppstår högaspänningskoncentrationer vid urtagets horn på grund av geometrin. Koncentrationenav normalspänningar och skjuvspänningar kan leda till plötsligt brott på grund avsprickpropagering från urtagets hörn, något som måste tas hänsyn till viddimensionering. Dagens dimensioneringsmetoder är baserade på att man tar hänsyntill enbart normalspänningarna vinkelrät fiberriktningen.Målet med detta arbete har varit att studera beteendet hos limträbalkar med urtag vidupplag som förstärkts med fiberarmering eller plywood. Huvudmålet har varit attbestämma balkarnas bärförmåga, vilket skett genom att genomföra försök med olikakonfigurationer vad gäller förstärkningsmaterial och dess utformning. Vidare harolika dimensioneringsmetoder från litteraturen studerats.Kraft och förskjutning under provningarna uppmättes dels med traditionellamätmetoder, men deformationerna mättes även med beröringsfri metod, ARAMIS.En enkel tvådimensionell finit elementmodell skapades och analyserades i ABAQUSför analys av oförstärkt balk. Normalspänningar och skjuvspänningar beräknades ochmedelspänningarna längs en på förhand definierad sträcka beräknades.Medelspänningskriteriet användes sedan för att uppskatta balkens bärförmåga.Enligt FE-beräkningarna uppskattades bärförmågan för de oförstärkta balkarna till ca40 kN. Provningarna gav ett medelvärde på balkarnas bärförmåga på ca 30 kN,medan de förstärkta balkarna hade en 2,5 gånger högre bärförmåga. Skillnadenmellan FE-beräkningarna och provningarna kan förklaras med den osäkerhet somfinns vad gäller det aktuella trämaterialets egenskaper.Beräkningar enligt Eurokod 5 gav en karakteristisk bärförmåga på 20,2 kN.
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Sabri, Amirreza. "Seismic Retrofit of Load Bearing URM Walls with Internally Placed Reinforcement and Surface-Bonded FRP Sheets." Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/40675.
Full textAbstract:
Concrete block masonry is a common building material used worldwide, including Canada. Reinforced masonry buildings, designed according to the requirements of recent building codes, may result in seismically safe structures. However, unreinforced masonry (URM) buildings designed and constructed prior to the development of modern seismic design codes are extremely vulnerable to seismic induced damage. Replacement of older seismically deficient buildings with new and seismically designed structures is economically not feasible in most cases. Therefore, seismic retrofitting of deficient buildings remains to be a viable seismic risk mitigation strategy. Masonry load bearing walls are the most important elements of such buildings, potentially serving as lateral force resisting systems.
A seismic retrofit research program is currently underway at the University of Ottawa, consisting of experimental and analytical components for developing new seismic retrofit systems for unreinforced masonry walls. The research project presented in this thesis forms part of the same overall research program. The experimental component includes design, construction, retrofit and testing of large-scale load bearing masonry walls. Two approaches were developed as retrofit methodologies, both involving reinforcing the walls for strength and deformability. The first approach involves the use of ordinary deformed steel reinforcement as internally added reinforcement to attain reinforced masonry behaviour. The second approach involves the use of internally placed post-tensioning tendons to attain prestressed masonry behaviour. The analytical component of research consists of constructing a Finite Element computer model for nonlinear analysis of walls and conducting a parametric study to assess the significance of retrofit design parameters. The results have led to the development of a conceptual retrofit design framework for the new techniques developed, while utilizing the seismic provisions of the National Building Code of Canada and the relevant CSA material standards.
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Amico, Ross Dominick. "Shear Strength and Strength Degradation of Concrete Bridge Decks with GFRP Top Mat Reinforcement." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/33899.
Full textAbstract:
The primary objective of this research was to investigate the shear strength of concrete bridge decks with GFRP top-mat reinforcement. Several models currently exist to predict the shear strength during the design process; however, previous research at Virginia Tech indicates that the existing equations are overly conservative. For this research, a series of concrete decks with varying lengths were tested in a laboratory environment in a two-span continuous configuration, during which data was collected on deflections, rebar strain, crack widths, and ultimate load. It was concluded that the existing equations, particularly the guidelines of ACI 440, are grossly over-conservative for GFRP-reinforced concrete bridge decks continuous over multiple supports. It was suggested that this is due to multiple factors, including additional support provided by the typically-neglected steel reinforcement in the bottom mat and a higher shear strength of the uncracked portion of concrete due to higher compressive stresses in the section as a result of the continuous deck configuration.
The second objective of this research was to investigate the effects of environmental exposure on the composite deck and the individual GFRP rebar. Three deck specimens were subjected to differing environmental conditions, including one that was placed into service at an interstate weigh station. All three decks were tested in the same manner as those in the shear investigation. Additionally, live load tests were conducted on the weigh station deck during the time it was in place and tensile tests were conducted on rebar that were extracted from the concrete decks. In the live load testing, the GFRP strains increased by more than 200% over the period of service, which was likely due to a combination of a reduction in GFRP stiffness and a greater amount of cracking. During the laboratory tests on the decks, no clear correlation between conditioning and deflections or cracking was found. The ultimate strength actually increased with conditioning, with the weigh station specimen exhibiting the highest shear strength. Finally, the results of the rebar tensile tests suggested a decrease in both modulus of elasticity and ultimate tensile strength of the GFRP with environmental exposure when compared to unconditioned bars.<br>Master of Science
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Januš, Ondřej. "Navrhování konstrukcí s FRP výztuží." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2016. http://www.nusl.cz/ntk/nusl-240234.
Full textAbstract:
The diploma thesis presents design of construction with FRP reinforcement. Including design process of cross-section with FRP reinforcement exposed to bending moment and shear force at ultimate limite state according to given standards and guidelines. Long term physical and mechanical properties of FRPs are taking into account. There are also compared load capacities of cross-section exposed to combination of bending moment and axial force, which were designed according to mentioned standards. In another part of diploma thesis there is a design of construction (precast gatehouse) with FRP reinforcement and steel reinforcement with ordinary and lightweight concerete.
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Matušíková, Anna. "Navrhování konstrukcí s FRP výztuží." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2012. http://www.nusl.cz/ntk/nusl-225478.
Full textAbstract:
This diploma thesis presents available FRP software for calculating load bearing capacity of the structures reinforced with FRP and compares them between each other. Furthermore theory and algorithm of my own software is presented here. Load bearing capacity of structures which are reinforced with non-metallic reinforcement and loaded by combination of normal force and bending moment can be solved by my programme. Effects of high temperatures on the concrete structures can be included in the calculation. In the second part of the thesis is calculated load-bearing capacity and deflection of the real beam reinforced with FRP reinforcement and load-bearing capacity of member with FRP reinforcement with effect of elevated temperature. This has been done using my software. Comparison of results from hand calculation and laboratory load-bearing testing is done at the end. This laboratory testing was accomplished by Institute of Concrete and Mansory Structures at our faculty.
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Cawrse, Jason Kyle. "Laboratory Tests of a Bridge Deck Prototype With Glass Fiber Reinforced Polymer Bars as the Top Mat of Reinforcement." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/35262.
Full textAbstract:
The primary objective of this project was to test a full-scale prototype of an actual bridge deck containing GFRP bars as the top mat of reinforcement. The purpose of the tests was to verify that the design would resist the loads for which it was designed and provide assurance that the deck would not unexpectedly fail due to the use of this new material. Behavior of the bridge and deck, such as failure load, failure mode, cracking load, crack widths, deflections, and internal stresses, were examined. Four tests were performed on the deck, all of which tested the deck in negative moment regions. From the tests, it was concluded that the design of the deck was very conservative and that unexpected failure should be of no concern.
The secondary objective of this project was to comment on the construction of a bridge deck reinforced with GFRP bars and to note its advantages and disadvantages along with a critique of the current state-of-the-art of designing bridge decks with FRP reinforcement. It was found that the advantages of construction with GFRP bars far outweighed the disadvantages, and that the placing of the top mat of GFRP bars was much easier than the placing of the bottom mat of steel bars. It was also concluded that the current state-of-the-art of designing bridge decks reinforced with GFRP is, for the most part, inaccurate in its prediction of behavior and that more research is needed to create more accurate design equations and procedures. Although current methods do not result in accurate predictions of behavior, they do, as mentioned above, result in conservative designs.<br>Master of Science
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Eredini, Rewan. "Reinforced Concrete Beams Strengthened with Side Near Surface Mounted FRP : A parametric study based on finite element analysis." Thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-60412.
Full textAbstract:
Most of the today’s concrete structures are older than tenyears, and the need to strengthening existing structures is growing steadily. This is due to various reasons such as degradation due to ageing, environmentally induced degradation, poor initial design or construction and lack of maintenance, to name a few. Among the benefits of strengthening existing structures are; less impacts on the environmental and financial benefits. Therefore, there is a need to find alternative ways to strengthen concrete structures more effectively. For the past decades, several different strengthening methods have been studied. Two examples are externally bonded reinforcement (EBR) and near surface mounted reinforcement (NSM). The outcome of these studies has shown a significant enhancement to the structures. Steel plates and rebar have been used to strengthen concrete structures and have shown good increases in flexural capacity. For this purpose, resins have been used to implement the steel plates and rebar, e.g. shotcrete and epoxy. Due to the weight of steel and its sensitivity to corrosion, new materials have been sought. A promising material for this use is the fiber reinforced polymers (FRP). There are several types of FRP such as, carbon fiber reinforced polymer (CFRP), glass fiber reinforced polymer (GFRP) and aramid fiber reinforced polymer (AFRP). These new material has shown a better performance, due to their light weight, resistance to corrosion,etc. NSM and EBR perform extremely well in practice as long as sufficient anchorage is provided. However, a premature debonding has been observed by several researchers. This report will study an alternative method to reinforce existing concrete structures called “Side Near Surface Mounted Reinforcement (S-NSMR)” in association with a project run by Gabriel Sas at Luleå University of Technology. This is compared to Bottom Near Surface Mounted Reinforcement (B-NSM), which is a well-established method. It is assumed that the fiberutilisation will increase in NSM applied on the side of the beam. If this hypothesis is proven correct, the proposed method will also solve a major constrain in the utilisation of the NSM technique. In certain cases, the bottom of a beam is not fully accessible for strengthening using bottom Applied NSM techniques due to e.g. partition walls or beam-column joints. To test the effect of S-NSMR seven concrete beams, one reference beam with no fiberreinforcement and two sets of three, for S-NSMR and B-NSMR respectively with different CFRP-rebar length, were tested in the laboratory. An analytical calculation has also been carried out. In this thesis, a parametric study is performed with FEM software Atena. The thesis begins with a study of the failure phenomena occurring in the earlier mentioned strengthening method. A benchmark model is then modelled with a good comparison to the experimental results. An idealised model of the steel reinforcement in the concrete beam is used according to Eurocode 2. Material parameters in concrete are calculated according to Atena theory documents. The influence of creep and shrinkage are considered by reducing the elastic modulus of concrete by 25 %, reducing the tensile strength by 50 % and fracture energy accordingly. Thereafter, three additional parameters were chosen to continue the parametric study with Atena, 1) CFRP with E-modulus 160 GPa, 2) two different position in cross-section height of S-NSM and 3) five shorter CFRP-rebar each 100 mm smaller than the previous rebar. The behaviour of the two reinforcing types is then compared. The first parameter is, CFRP with a smaller E-modulus. It could be observed that all beams lost their stiffness, especially after yielding of the steel reinforcement. A small improvement in ductility could also be observed. The utilisation rate of CFRP increased by 13-16% in the case of S-NSM and 18-20% in the case of B-NSM. The second parameter is, different position of CFRP along the height of the beams cross-section in S-NSM beams. The positions of the CFRP was lowered in two steps. In each case an increase in stiffness and a decrease in ductility could be observed. However, the increase of the stiffness was still smaller than the stiffness in the B-NSM, in all cases. The failure mode changed from a ductile (concrete crushing) type to a more brittle kind (peeling-off concrete), due to large flexural cracks at the end of the CFRP-rebar. The utilisation rate of CFRP-rebar, is decreased in each S-NSM beam except for S-NSM 2 with the height 25 mm. The reduction in the utilisation rate of the CFRP is 7-32 % and in S-NSM 2 with the height H25mm showing an increased in utilisation rate by 7 %. The third is parameter, different length of CFRP-rebar. In the case of S-NSM, the failure mode changed from a ductile failure mode to a brittle failure mode. The utilisation rate decreased with the decrease in CFRP length. In three of five cases, the S-NSM shows a higher ultimate load-displacement relation, and in all five cases the maximum tensile strains in the CFRP were higher in S-NSM than B-NSM. Even though the stiffness in the S-NSM is lower than the B-NSM, it would be more preferable to use the S-NSM than B-NSM, because of its higher ultimate load and lower displacements.
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Mičkal, Petr. "Odolnost FRP kompozitních materiálů vůči působení vybraných agresivních prostředí." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-295666.
Full textAbstract:
This thesis deals with monitoring of the durability of FRP reinforcements in alkaline environments with differing temperature exposures. The theoretical part of the thesis consists of a general description of the FRP composites, the manufacturing of these FRP reinforcements using pultrusion technology, the resistance of these composites in aggressive alkaline environments, and the influence of temperature on the speed and manner of degradation. In the experimental part of this thesis, the FRP reinforcements were placed in an alkaline environment tempered at different temperatures (20 °C, 40 °C, 60 °C). Subsequently, any optical physical changes of the reinforcements were described and evaluated by the use of optical microscopy and the destructive tests of these reinforcements.
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Tavares, Danusa Haick. "Análise teórica e experimental de vigas de concreto armadas com barras não metálicas de GFRP." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-22062006-105650/.
Full textAbstract:
A substituição do aço pela armadura não metálica objetiva o aumento da durabilidade de estruturas sujeitas à corrosão e a campos eletromagnéticos. Mas, a inserção de um novo material na construção civil demanda especificação de sua composição, comportamento e procedimentos de sua utilização. Este trabalho analisa o comportamento à flexão de vigas de concreto armadas com barras não metálicas. Para esta finalidade foram realizados, uma revisão bibliográfica considerando os trabalhos publicados desde o início das pesquisas até os mais recentes e ensaios dos materiais e de vigas de concreto armado. Os ensaios de determinação das propriedades das barras da armadura não metálica de GFRP (glass fiber polymer polímero reforçado com fibra de vidro) englobam a determinação do diagrama tensão-deformação e capacidade resistente. As vigas armadas com barras de GFRP foram ensaiadas à flexão em quatro pontos e os resultados comparados com o de uma viga armada com barras de aço CA-50 também ensaiada a flexão. Nos modelos pôde-se perceber a influência das propriedades das barras de GFRP no comportamento geral da estrutura. Por exemplo, as grandes deformações nas barras longitudinais e os deslocamentos dos modelos foram determinados pelo baixo módulo de elasticidade das barras de GFRP. É evidente a necessidade de continuação dos estudos envolvendo barras de GFRP. Estas pesquisas poderão desenvolver meios de se utilizar as propriedades do material em favor do melhor funcionamento da estrutura<br>Steel reinforcement replacement aims an increase at the durability of structures with corrosion and electrical magnetic problems. But, inserting a new material at the civil construction industry demands specifications of its composition, behavior and procedures for its utilization. This work is a flexural behavior analysis of reinforced concrete beams reinforced with GFRP bars. To make this, a technical literature research was made considering the pioneer until the most recent researches, and components and concrete reinforced beams tests were done. GFRP bars properties tests went from the determination of its strains X stress diagram to its tension resistance. GFRP reinforced beams were submitted to four points flexural tests and the results compared with a CA-50 steel reinforced beam also submitted to the flexural test. The specimens showed the influence of GFRP properties at the behavior of the structure. For example, longitudinal bars large strains and the large displacement of the beam were determined by GFRP bars low longitudinal elastic modulus. Continuing the studies evolving GFRP bars is certainly a need. New researches might be able to design a way to use the composite properties to improve the structure behavior
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Tascioglu, Cihat. "Impact of Preservative Treatments and Fungal Exposure on Phenolic Fiber Reinforced Polymer (FRP) Composite Material Utilized in Wood Reinforcement." Fogler Library, University of Maine, 2002. http://www.library.umaine.edu/theses/pdf/TasciogluC2002.pdf.
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Harlan, Matthew. "Field Test of a Bridge Deck with Glass Fiber Reinforced Polymer Bars as the Top Mat of Reinforcement." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/9987.
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The primary objective of this research project was to perform live load tests on a bridge deck with GFRP reinforcement in the field under service conditions. The strains and deflections in the span reinforced with GFRP in the top mat were recorded under a series of truck crossings, and these were compared to the span reinforced with all steel bars under identical loading conditions, as well as design values and other test results. Transverse strains in the GFRP bars, girder distribution factors, girder bottom flange strains, dynamic load allowances, and weigh-in-motion gauge results were examined. From the live load tests, it was concluded that the bridge was designed conservatively for service loads, with measured strains, stresses, distribution factors, and impact factors below allowables and design values.
The second objective was to monitor the construction of the bridge deck. To carry out this objective, researchers from Virginia Tech were on site during the bridge deck phase of the construction. The construction crews were observed while installing both the all-steel end span and the steel bottom/GFRP top end span. The installation of the GFRP bars went smoothly when compared to that of the steel bars. The workers were unfamiliar with the material at first, but by the end of the day were handling, installing, and tying the GFRP bars with skill. It was concluded that GFRP bars are an acceptable material in bridge deck applications with respect to constructibility issues.
The third objective was to set up the long term monitoring and data collection of the bridge deck. Electrical resistance strain gauges, vibrating wire strain gauges, and thermocouples were installed in the deck prior to concrete casting to provide strain and temperature readings throughout the service life of the bridge. It was concluded that the span reinforced with GFRP was instrumented sufficiently for long-term health monitoring.<br>Master of Science
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Ručinskas, Artūras. "Comparative analysis of stress-strain calculation methods and algorithms for concrete members reinforced with FRP re-bars." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2011. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2011~D_20110620_141822-28189.
Full textAbstract:
The final thesis consists of three main parts, each covering a certain aspect of investigation.
First chapter presents an extensive literature review, covering such aspects as: application of
FRP (fiber reinforced polymer) materials in modern-day civil engineering, characteristics of
FRP reinforcement for reinforced concrete structures, advantages and drawbacks of FRP rebars
compared to traditional materials, peculiarities of flexural behavior of FRP reinforced
members, review of existing empirical stress-strain calculation algorithms and building codes
for concrete members reinforced with FRP.
Second part aims at presenting gathered experimental data consisting of 51 FRP reinforced
flexural members under 4 point bending scheme. Taking into account such parameters as
reinforcement ratio, load intensity and elasticity modulus of FRP reinforcement, statistical
analysis on a number of calculation algorithms and building codes is performed in order to
evaluate their credibility and reliability for use in real-world structures.
The final part of the work presents a Simplified Discrete Crack model developed in VGTU
Department of Bridges and Special Structures. The model is applied for a series of collected
beams. The results are compared with theoretical predictions made by different design codes
and experimental values.
The final thesis consists of: 90 pages of text (without appendixes), 46 pictures, 17 tables. 3
appendixes are included. Literature list consisting of 82... [to full text]<br>Baigiamąjį magistro darbą sudaro trys pagrindinės dalys. Pirmajame skyriuje pateikiama literatūros apžvalga, kurioje nagrinėjamos temos susijusios su pluoštinės armatūros panaudojimu lenkiamiems betoniniams elementams. Apžvelgiamos tokių elementų panaudojimo galimybės, privalumai ir trūkumai, deformacijų skaičiavimo metodai bei matematiniai modeliai. Antrajame skyriuje nagrinėjama surinkta polimerine armatūra armuotų sijų eksperimentinių duomenų imtis. Siekiant įvertinti skirtingų skaičiavimo metodų patikimumą ir pritaikomumą ne plienine armatūra armuotiems elementams, atliekama lyginamoji statistinė analizė. Jos metu įvertinama armavimo procento, apkrovimo lygio bei pluoštinės armatūros tamprumo modulio įtaka. Trečiojoje darbo dalyje surinktai eksperimentinių duomenų imčiai pritaikytas VGTU Tiltų ir Specialiųjų Statinių Katedroje sukurtas Diskrečiųjų plyšių modelis. Gautos priklausomybės palygintos su kitų skaičiavimo normų rezultatais bei eksperimentiniais duomenimis. Gauti rezultatai parodė, kad pritaikius tikslesnius praslydimo bei armatūros ir betono sąveikos ruožuose tarp plyšių modelius, diskrečiųjų plyšių modelis gali būti sėkmingai taikomas polimerine armatūra armuotų elementų elgsenai prognozuoti.
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Attia, Abdelgayed Abdelgawad Sharaky Ibrahim. "A study of the bond and flexural behaviour of reinforced concrete elements strengthened with near surface mounted (NSM) FRP reinforcement." Doctoral thesis, Universitat de Girona, 2013. http://hdl.handle.net/10803/128331.
Full textAbstract:
The main objective of the thesis is to study the bond behaviour of NSM FRP reinforcement in concrete elements. With this aim an extensive program of experimental tests complemented with numerical analysis has been performed to study the effect of the variables affecting this technique. In the first part of this thesis the modified pull-out test is carried out. A Finite Element Analysis (using the program FEMIX V.4) was used to perform several trials to fit as much as possible (inverse analysis) the force versus loaded end slip responses obtained experimentally in direct pullout tests. In the second part of this thesis an experimental program of flexural tests on RC beams strengthened with NSM FRP has been carried out to study the effect on the flexural behaviour of some of the previous variables studied in the first part<br>L’objectiu principal d’aquesta tesi és l’estudi del comportament adherent entre el reforç NSM FRP i l’element de formigó. D’aquesta manera s’ha realitzat un extens programa d’assajos experimentals complementat amb anàlisis numèriques per tal d’estudiar les variables que incideixen en aquesta tècnica. En la primera part de la tesi es fa un estudi de l’adherència emprant l’assaig de pull-out modificat. S’ha realitzat una anàlisi amb el MEF (emprant el programa FEMIX V.4) per tal de fer diverses proves per ajustar amb la màxima precisió possible (anàlisi inversa) la resposta força-lliscament de l’extrem carregat de la barra obtinguda experimentalment en els assajos de pull-out. A la segona part de la tesi s’ha portat a terme un programa d’assajos a flexió d’elements de formigó armat reforçats amb NSM FRP per tal d’estudiar l’efecte d’algunes de les variables analitzades en la primera part
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Choo, Ching Chiaw. "Investigation of rectangular concrete columns reinforced or prestressed with fiber reinforced polymer (FRP) bars or tendons." Lexington, Ky. : [University of Kentucky Libraries], 2005. http://lib.uky.edu/ETD/ukycien2005d00258/ChooPhDDissertation%5FFinal.pdf.
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Thesis (Ph. D.)--University of Kentucky, 2005.<br>Title from document title page (viewed on November 7, 2005). Document formatted into pages; contains xi, 139 p. : ill. Includes abstract and vita. Includes bibliographical references (p. 130-139).
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Phillips, Kimberly Ann. "Performance of a Bridge Deck with Glass Fiber Reinforced Polymer (GFRP) Bars as the Top Mat of Reinforcement." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/36296.
Full textAbstract:
The purpose of this research was to investigate the effectiveness and durability of GFRP bars as reinforcement for concrete decks. Today's rapid bridge deck deterioration is calling for a replacement for steel reinforcement. The advantages of GFRP such as its high tensile strength, light weight, and resistance to corrosion make it an attractive alternative to steel.
The first objective of this research was to perform live load testing on a bridge deck reinforced with GFRP in one span and steel in the other. The results were compared to the findings from the initial testing performed one year earlier. The strains and deflections of the bridge deck were recorded and the two spans compared. Transverse stresses in the GFRP bars, girder distribution factors, and dynamic load allowances were calculated for both spans. From the live load tests, it was concluded that the GFRP-reinforced span results were within design parameters. The only concern was the increased impact factor values.
The second objective was to perform live load tests on a slab reinforced with GFRP installed at a weigh station. Two live load tests were performed approximately five months apart. Peak strains in the GFRP and steel bars were recorded and compared. The peak stresses had increased over time but were within design allowable stress limits.
The third objective of this research was to investigate the long term behavior and durability of the GFRP reinforcing bars cast in a concrete deck. The strain gauges, vibrating wire gauges, and thermocouples in the bridge deck were monitored for approximately one year using a permanent data acquisition system. Daily, monthly, and long term fluctuations in temperature and stresses were examined. It was concluded that the vibrating wire gauges were more reliable than the electrical resistance strain gauges. It was further observed that the main influence over strain changes was temperature fluctuations.<br>Master of Science
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Darabi, Mohammadali. "Long-Term Deflection Of One-Way Concrete Slab Strips Containing Steel And GFRP Reinforcement." Thesis, Fredericton: University of New Brunswick, 2011. http://hdl.handle.net/1882/35382.
Full textAbstract:
Fibre reinforced polymers (FRP’s) are considered an alternative to steel reinforcement in concrete structures because of their noncorrosive nature and nonmagnetic properties. FRP materials are, however, brittle and have a lower stiffness compared to steel. The latter property can lead to deflection and crack control problems in FRP-reinforced concrete flexural members under service loads. A considerable amount of information is available for short-term deflection of FRP-reinforced concrete members, but data on long-term deflections are scarce.
This study presents the results of monotonic (short-term) and sustained (long-term)
loading tests of 12 concrete shallow beams reinforced with either steel or glass FRP
(GFRP) bars. The short-term load-deflection responses of the members are evaluated
using existing deflection prediction models (Branson’s and Bischoff’s), and the long-term deflection results (monitored over a period of one year) are used to evaluate the existing ACI code and CSA standard approaches for estimating long-term deflection. The GFRP-reinforced concrete beams exhibited greater amounts of both immediate deflection (under sustained load) and long-term deflections over time, than the steel-reinforced concrete beams. The long-term deflections of both the steel- and GFRP-reinforced concrete beams are overestimated when using the ACI and CSA approaches. Although ACI Committee 440 recommends use of lower values of the long-term deflection multiplier for GFRP-reinforced concrete beams, results obtained from this study suggest that the same longterm multiplier values may be used for GFRP- and steel-reinforced concrete beams loaded at between 115 to 157 days of concrete age.
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Le, Nguyen Khuong. "Contribution à la compréhension du comportement des structures renforcées par FRP sous séismes." Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0020/document.
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Dans le cadre de la mise à niveau sismique des bâtiments existants, la technique de renforcement par placage et enrobage de polymères renforcés de fibres (FRP) offre une réponse pertinente. L’objectif de cette thèse est de proposer une modélisation fiable pour la détermination de la réponse quasi-statique et dynamique d’une grande variété d’éléments de structure et d’identifier les apports possibles d’une telle modélisation à la conception. Les stratégies de modélisation s’appuient sur l’utilisation d’éléments finis massifs ou basés sur une cinématique simplifiée (coques multicouches et poutres multifibres), associés à des modèles locaux d’endommagement et de plasticité pour les matériaux en présence (béton, armatures et FRP). L’hypothèse d’adhérence parfaite, d’une part, entre les armatures et le béton, et d’autre part, entre les bandes de FRP et le béton, permet de calculer efficacement les cas des poteaux courants, des poteaux courts, des voiles longs et courts, dans les régimes quasi-statique (pushover) et dynamique. Le renforcement par placage et enrobage FRP pour des structures en béton armé, est reproduit au sein de la modélisation par un apport de matière (éléments de type barre avec les caractéristiques propres des FRP) et des modifications des paramètres de la loi de comportement du béton, justifiées par l’expérimentation et la littérature. La pertinence de l’approche est finalement démontrée en confrontant la réponse temporelle de structures à l’échelle 1, de type ossature ou de type contreventé par des voiles, aux résultats expérimentaux issus de benchmarks internationaux<br>In the context of the building’s protection against seismic risk, the strengthening technique by FRP (Fiber Reinforced Polymers) plating and wrapping provides a relevant solution. The objective of this thesis is to propose a reliable modeling for determining the quasi-static and dynamic responses of a wide variety of structural elements and to draw advantage in design. The modeling strategies make use of 3D elements or finite elements based on simplified kinematics (multilayer shells or multifiber beams), associated with local damage and plasticity laws for the constitutive materials (concrete, rebar and FRP). The perfect bond assumption between steel-concrete and FRP-concrete allows efficiently calculating the quasi-static and dynamic behaviors of short and slender columns, as well as short and slender walls. The mechanical contribution of FRP plating and wrapping is reproduced in the modeling by adding material (bar type elements with FRP characteristics) and by changing the parameters of the concrete model on the basis of the experience and analytical formula issued from the literature. The relevance of the approach is finally highlighted by comparing the time-history response of real braced frame or wall structures with the experimental results
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Kratochvílová, Denisa. "Vlastnosti kompozitů s polymerní matricí a dlouhovláknovou výztuží." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-392350.
Full textAbstract:
Because FRP composites have high fiber strength and good durability, they are increasingly used for repairs, modernisation and reconstruction of concrete structures. In practice, however there is a risk of premature separation of FRP reinforcement from concrete. This can be avoided by appropriate selecting the fibers and the matrix and the appropriate shape of the reinforcement. The actual materials and consistency of FRP reinforcement with concrete are also covered by this diploma thesis.
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Allen, Christine. "Role of end peeling in behavior of reinforced concrete beams with externally bonded reinforcement." Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/33982.
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Aging bridges in the United States demand effective, efficient, and economical strengthening techniques to meet future traffic requirements. One such technique is to bond steel or fiber reinforced polymer (FRP) plates to the tension faces of reinforced concrete bridge beams with adhesives to strengthen them in flexure. However, beams that have been flexurally strengthened in this manner often fail prematurely, in particular by plate end peeling.
The benefits of flexural strengthening by externally bonded reinforcement can only be fully realized by preventing premature failure modes so as to allow the development of composite action between the beam and the external reinforcement. With this goal in mind, several critical limit states of externally reinforced beams are examined in this thesis. Models developed by Roberts (1989) and by Colotti, Spadea, and Swamy (2004) that predict premature plate end debonding are examined in depth using data from previously conducted experimental programs that employed both steel and FRP external reinforcement. In addition, various parameters of the concrete beam, adhesive, and external reinforcement are analyzed in each model to determine the role of each parameter in failure prediction.
A critical appraisal of the performance of the models using existing experimental data leads to the selection of the Roberts (1989) model. This model is used to develop recommended design guidelines for flexurally strengthening reinforced concrete bridge beams with externally bonded FRP plates and for preventing premature plate peeling.
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Dagdony, Masara, and Toba Rashid. "Kolfiberförstärkning av betongkonstruktioner med avseende på böjningoch tvärkraft : En hypotetiskt plattrambro modellerad i Brigade Standard och en T-balk." Thesis, KTH, Byggteknik och design, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-215098.
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Samhället ändras konstant men detta innebär inte bara en förändring för människorna i samhället utan också att nya krav ställs på konstruktionen som brukas av människorna. Många byggnadskonstruktioner kan därmed behöva en förstärkning efter en viss tid. Behovet av en förstärkning kan bero på flera orsaker exempelvis ändrat nyttjande. Det är mer fördelaktigt med en förstärkning av konstruktionen än att den rivs ner och byts ut för att klara av dagens krav. Syftet med detta examensarbete är att undersöka förstärkning av betongkonstruktioner med hjälp av kolfiberkomposit. I rapporten presenteras beräkningar som gjordes för att undersöka tillökningen i böjoch tvärkraftskapacitet efter en utförd förstärkning. Parallellt med beräkningarna kontrollerades och utvecklades befintliga mallar som finns för denna metod. För att kunna uppnå syftet undersöktes två hypotetiska betongkonstruktioner. Ena konstruktionen är en plattramsbro som modellerades i FEM programmet Brigade Standard. Beräkningar på plattramsbron gjordes med avseende på böjande moment. Den andra konstruktionen som undersöktes är en T-balk som är en del utav ett bjälklag. På T-balken granskades tvärkraftskapaciteten innan och efter en utförd förstärkning med kolfiber. I resultatet redovisas mängden kolfiber som erfordras för att uppnå önskad kapacitet hos konstruktionerna. I resultatet redogörs också kapaciteten som uppnås efter kolfiberförstärkningen.<br>The society changes constantly, but this does not only affect the inhabitants of the society, but also that new demands are made on the construction used by the people. Many constructions may therefore require reinforcement after a certain amount of time. The need for reinforcement may be due many different reasons for example to altered use, corrosion to internal reinforcement or may be due to design errors, accidents or new standards. It is more beneficial to reinforce the structure than to tear it down and replace it to meet current requirements. The purpose of this thesis is to investigate carbon fiber reinforced polymer, CFRP, as a method to strengthen concrete structures. The report presents calculations that were made to investigate the increase in bending and shear capacity after a performed reinforcement. Alongside the calculations, existing templates for this method were checked and developed. In order to achieve the purpose, two hypothetical concrete structures were investigated. One design is a frame bridge modeled in the FEM program Brigade Standard. Calculations on the frame bridge were made with respect to bending. The other construction that was investigated is a T-beam. On the Tbeam, shear capacity was examined before and after reinforced carbon fiber reinforcement. The result present the amount of carbon fiber required to achieve the desired capacity of the structures. The result also describes the capacity achieved after carbon fiber reinforcement.
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Syed, Shah Taqiuddin Q. "An Alternative Strengthening Technique using a Combination of FRP Sheets and Rods to Improve Flexural Performance of Continuous RC Slabs." University of Toledo / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1469151846.
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Macháček, Jan. "Využití moderních kompozitních materiálů při návrhu betonových konstrukcí." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-391937.
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The diploma thesis deals with the design of concrete structures reinforced by FRP according to ACI, fib, CSA and EC2 regulations, which are stressed by a shear force. The diferences between steel rebar and FRP reinforcement were described, in particular its mechanical degradation over time and a different stress-strain diagram. Furthermore, shear capacity calculations were performed according to the regulations and compared with the real tests. Then the parametric analysis of shear strength was performed. In the practical part, the design of concrete floor slab structure supported by the pillars and walls was performed. The upper reinforcement of this slab was designed with FRP and the lower with steel rebar. Double-headed studs were used as a punching shear reinforcement.
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Tmej, Patrik. "Zesílení ŽB oblouku pomocí kompozitní výztuže." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2016. http://www.nusl.cz/ntk/nusl-240182.
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The aim of the thesis is the strengthening and resistance of concrete construction. At the beginning is described composite reinforcement and their specific properties. The thesis specifically follows behavior concrete vault and the effects of load. Resistance vault is calculated by S&T model – strut and tie. Finally, the thesis contain strengthening construction by composite reinforcement. Strengthening is considered by two ways - strengthening by cohesive reinforcement and strengthening by incoherent reinforcement (wrapping).
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Sarr, Cheikh Ahmed Tidiane. "Vers une auscultation par acousto-ultrasons des renforcements par composites collés de structures du génie civil." Thesis, Ecole centrale de Nantes, 2022. http://www.theses.fr/2022ECDN0005.
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Un rapport sénatorial de Juin 2019 estime le parc d’ouvrages vieillissants de la France à plus de 25000 ponts routiers. Une des solutions préconisées pour éviter la ruine de ces structures est leur renforcement par collage de matériaux composites. Cette solution technique permet d’augmenter la durée de vie des ouvrages tout en prenant en compte de nouvelles sollicitations (augmentation drastique du trafic et risques sismiques). Cependant, elle est efficace que lorsque le joint de colle est bien exécuté et exempt de tout défaut ou endommagement. Ainsi, son utilisation est limitée par une méconnaissance de la qualité réelle des joints de colle sur site. L’objectif de cette thèse est de proposer à partir d’une technique non destructive, les acoustoultrasons, une méthodologie de détection et d’identification des principaux types de défauts rencontrés dans des assemblages collés. Les deux types de substrats les plus communément utilisés en génie civil à savoir l’acier et le béton ont été étudiés dans cette thèse. Par le biais d’une analyse monoparamétrique et d’une analyse statistique en composantes principales (ACP), l’ensemble des défauts créés dans des assemblages d’acier-composite et de béton-composite ont été détectés avec succès. L’identification de ces défauts a été obtenue grâce aux outils de l’intelligence artificielle (IA) à travers l’algorithme de classification de la forêt d’arbres décisionnels. Les facteurs pouvant influencer cette méthodologie ont été passés en revue avant qu’elle ne soit validée sur des échantillons de plus grande échelle, proches des réalisations sur site. Enfin, via une simulation par éléments finis de la propagation du signal dans un assemblage collé, nous soulignons les perspectives que peut offrir cette technique dans la constitution de bibliothèques d’apprentissage pour l’application des techniques de l’IA au diagnostic et au pronostic de l’état de joints de colle<br>A Senate report from June 2019 estimates France’s ageing structures at more than 25,000 road bridges. One of the recommended solutions to prevent the collapse of these structures is their bonding reinforcement of composite materials. This technical solution allows us to increase their lifeservice by taking into account new acquired stresses (drastic increase in traffic and seismic risks). However, the reinforcing is effective only when the adhesively bonded joint is well executed and free of defects or damages. Thus, the use of this method is limited by a lack of knowledge of the real quality of adhesive joints on site. The objective of this thesis is to propose from a nondestructive technique, the acousto-ultrasonics, a methodology of detection and identification of all types of defects encountered in adhesively bonded assemblies.We studied the most common types of substrates used in civil engineering: steel and concrete. Through a mono-parametric analysis and a statistical principal components analysis (PCA), all the elaborated defects in compositesteel and composite-concrete assemblies were successfully detected. The identification of these defects was obtained using Machine Learning tools through the Random Forest classification algorithm. The factors that could influence this methodology were studiedbefore it was validated on specimens of a larger scale, closer to the on-site achievements. Finally, through a finite element simulation of signal propagation in a bonded assembly, we underline the perspectives that this technique can offer in building learning libraries for the application of Machin Learning techniques to the diagnosis and prognosis of the state of adhesively bonded joints
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Mohamed, Khaled Ahmed. "Performance and strut efficiency factor of concrete deep beams reinforced with GFRP bars." Thèse, Université de Sherbrooke, 2015. http://hdl.handle.net/11143/7613.
Full textAbstract:
Abstract : Deep reinforced concrete beams are commonly used as transfer girders or bridge bents, at which its safety is often crucial for the stability of the whole structure. Such elements are exposed to the aggressive environment in northern climates causing steel-corrosion problems due to the excessive use of de-icing salts. Fiber-reinforced polymers (FRP) emerged as non-corroded reinforcing materials to overcome such problems in RC elements. The present study aims to address the applicability of concrete deep beams totally reinforced with FRP bars. Ten full-scale deep beams with dimensions of 1200 × 300 × 5000 mm were constructed and tested to failure under two-point loading. Test variables were shear-span depth ratio (equal to 1.47, 1.13, and 0.83) and different configurations of web reinforcement (including vertical and/or horizontal web reinforcement). Failure of all specimens was preceded by crushing in the concrete diagonal strut, which is the typical failure of deep beams. The test results indicated that, all web reinforcement configurations employed in the tested specimens yielded insignificant effects on the ultimate strength. However, strength of specimens containing horizontal-only web reinforcement were unexpectedly lower than that of specimens without web reinforcement. The web reinforcement’s main contribution was significant crack-width control. The tested specimens exhibited reasonable deflection levels compared to the available steel-reinforced deep beams in the literature. The development of arch action was confirmed through the nearly uniform strain distribution along the length of the longitudinal reinforcement in all specimens. Additionally, the basic assumption of the strut-and-tie model (STM) was adequately used to predict the strain distribution along the longitudinal reinforcement, confirming the applicability of the STM for FRP-reinforced deep beams. Hence, a STM based model was proposed to predict the strength of FRP-reinforced deep beams using the experimental data, in addition to the available experimentally tested FRP-reinforced deep beams in the literature. Assessment of the available STMs in code provisions was conducted identifying the important parameters affecting the strut efficiency factor. The tendency of each parameter (concrete compressive strength, shear span-depth ratio, and strain in longitudinal reinforcement) was individually evaluated against the efficiency factor. Strain energy based calculations were performed to identify the appropriate truss model for detailing FRP-reinforced deep beams, hence, only four specimens with vertical web reinforcement exhibited the formation of two-panel truss model. The proposed model was capable to predict the ultimate capacity of the tested deep beams. The model was also verified against a compilation of a data-base of 172 steel-reinforced deep beams resulting in acceptable level of adequacy. The ultimate capacity and performance of the tested deep beams were also adequately predicted employing a 2D finite element program (VecTor2), which provide a powerful tool to predict the behavior of FRP-reinforced deep beams. The nonlinear finite element analysis was used to confirm some hypotheses associated with the experimental investigations.<br>Résumé : Les poutres profondes en béton armé (BA) sont couramment utilisées comme poutre de transfert ou coude de pont, comme quoi sa sécurité est souvent cruciale pour la sécurité de l’ensemble de la structure. Ces éléments sont exposés à un environnement agressif dans les climats nordiques causant des problèmes de corrosion de l’acier en raison de l’utilisation excessive de sels de déglaçage. Les polymères renforcés de fibres (PRF) sont apparus comme des matériaux de renforcement non corrodant pour surmonter ces problèmes dans les BA. La présente étude vise à examiner la question de l'applicabilité des poutres profondes en béton complètement renforcées de barres en PRF. Dix poutres profondes à grande échelle avec des dimensions de 1200 × 300 × 5000 mm ont été construites et testées jusqu’à la rupture sous chargement en deux points. Les variables testées comprenaient différents ratios de cisaillement porté/profondeur (égal à 1.47, 1.13 et 0.83) ainsi que différentes configurations d’armature dans l’âme (incluant un renforcement vertical avec ou sans renforcement horizontal). La rupture de tous les spécimens a été précédée par l’écrasement du béton dans le mât diagonal, ce qui est la rupture typique pour les poutres profondes en BA. Les résultats ont révélé que toutes les configurations de renforcement de l’âme employées dans les spécimens d'essais avaient un effet négligeable sur la résistance ultime. Toutefois, la résistance des spécimens contenant uniquement un renforcement horizontal était étonnamment inférieure à celle des spécimens sans renforcement. La contribution principale du renforcement de l’âme était dans le contrôle de la largeur de fissuration. Les spécimens examinés présentaient une déflexion raisonnable par rapport à ce qui est disponible pour les poutres profondes renforcées en acier dans la littérature. Le développement de l'effet d'arche a été confirmé par la distribution quasi uniforme des déformations le long du renforcement longitudinal dans tous les spécimens. En outre, l'hypothèse de base du modèle des bielles et tirants (MBT) a été utilisée adéquatement pour prédire la distribution de déformation le long du renforcement longitudinal, confirmant l'applicabilité du MBT pour les poutres profondes armées de PRF. Par conséquent, un modèle basé sur un MBT a été proposé afin de prédire la résistance des poutres profondes renforcées de PRF en utilisant les données expérimentales en plus de la mise à l'épreuve expérimentalement des poutres profondes renforcées de PRF trouvées dans la littérature. Une évaluation des MTB disponibles dans les dispositions des codes a été menée afin de déterminer les paramètres importants affectant le facteur d'efficacité de la bielle. La tendance de chaque paramètre (la résistance à la compression du béton, le ratio de cisaillement porté/profondeur, et la déformation dans le renforcement longitudinal) a été évaluée individuellement contre le facteur d'efficacité. Des calculs basés sur l’énergie des déformations ont été effectués pour identifier le modèle de treillis approprié afin de détailler les poutres profondes renforcées de PRF. Par conséquent, seulement quatre spécimens avec un renforcement vertical dans l’âme présentaient la formation de modèles avec deux panneaux de treillis. Le modèle proposé a été capable de prédire la capacité ultime des poutres profondes testées. Le modèle a également été vérifié contre une base de données de 172 poutres profondes renforcées en acier aboutissant en un niveau acceptable de pertinence. La capacité ultime et la performance des poutres profondes testées ont été également adéquatement prédites employant un programme d'éléments finis en 2D (VecTor2), ce qui fournira un puissant outil pour prédire le comportement des poutres profondes renforcées de PRF. L'analyse non linéaire par éléments finis a été utilisée afin de confirmer certaines hypothèses associées à l'étude expérimentale.
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Bártová, Denisa. "Využití moderních kompozitních materiálů při návrhu betonových konstrukcí." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2020. http://www.nusl.cz/ntk/nusl-409787.
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This diploma thesis deals with the design of FRP reinforced concrete structures. The theoretical part is focused mainly on the punching shear of a flat two way slab according to ACI, fib Bulletin, CSA, and JSCE standards. This thesis also includes a description of the punching shear resistance according to Eurocode 2. FRP reinforcement, its mechanical properties, and their behaviour in time are also described. Next, a parametric study was performed that examines the effects of various parameters on the punching shear resistance according to the standards mentioned above. At the end a non-linear analysis using the ATENA software was performed. The practical part includes a structural design of a flat two way slab. The slab uses a steel reinforcement at the bottom, while the top is reinforced with FRP reinforcement. The punching shear design is also included. In the last chapter the serviceability limit state is checked, specifically the slab long-term deflection. The thesis also includes drawings. All calculations were performed in accordance with Eurocode 2 and fib Bulletin No. 40.
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Abdallah, Mohammad. "Flexural strengthening of RC continuous beams with FRP reinforcements according to the NSM and EB techniques : experimental, analytical and numerical (FE) study." Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0156.
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Cette thèse est composée de quatre parties, chacune présente plusieurs éléments de recherche en fonction du sujet abordé. Chaque partie a été structurée de sorte à aborder et analyser un problème de flexion spécifique concernant le renforcement des poutres en béton armé avec des matériaux composites (Fibre Reinforced Polymer (FRP)). L’objectif de cette thèse est l’étude expérimentale, analytique et numérique par Eléments Finis (EF) des techniques de renforcement et de réparation par l’insertion des joncs composites (Near Surface Mounted reinfocement (NSM)) ou par le collage des tissues ou des lamelles composites (Externally Bonded (EB)) des poutres continues à deux travées. Le programme expérimental dans cette thèse comprend vingt et une-poutres: six poutres de trois mètres de longueur chacune simplement appuyées, et quinze poutres continues de 6 mètres de longueur avec deux travées de 2,8 mètres. Les approches analytiques et de dimensionnement ainsi que la modélisation par EF ont été développées et utilisées dans certaines parties en fonction de leur importance et de leur nécessité. - La première partie concerne la possibilité de renforcer les poutres en Béton Armé (BA) par l’insertion de joncs de carbone (CFRP) dans les faces latérales des poutres (technique de SNSM) au lieu de leur faces inférieure ou supérieure tendues. Par conséquent, la technique de SNSM a été proposée et étudiée sur six poutres simplement appuyées: une poutre témoins sans renforcement et cinq autres renforcées avec deux joncs CFRP de 6mm de diamètre. - La deuxième partie présente des études expérimentale et analytique concernant l'évaluation de l'utilisation de la technique NSM pour le renforcement en flexion des poutres continues en BA. Le programme expérimental de cette partie comporte six poutres de 6 m de longueur à deux travées de 2,8m : une poutre témoin et cinq autres poutres renforcées avec des joncs composites dans la région du moment positif (sagging) ainsi que celle du moment négatif (hogging). - La troisième partie présente une étude comparative entre les techniques de renforcement NSM et SNSM des poutres continues en BA à deux travées. L'étude comprend deux sections principales; une section expérimentale et une section modélisation par EF. - La quatrième partie présente une étude expérimentale menée principalement afin d’essayer de combler les lacunes dans la littérature concernant le renforcement des poutres continues en BA avec la technique EB. Cette partie est composée de trois sections principales. Dans la première section, sept poutres continues de 6 m de longueur à deux travées de 2,8 m sont étudiées statiquement: une poutre témoin (de la deuxième partie) et six poutres renforcées avec des tissus ou des lamelles CFRP. La deuxième section de cette partie évalue l'efficacité des règlements de conception actuels pour déterminer la résistance à la flexion des poutres continues en BA renforcées à l'extérieur avec des tissus ou des lamelles. Enfin, la troisième section évalue et compare les efficiences des techniques EB et NSM. A cet effet, deux autres poutres (de la troisième partie) renforcées par les techniques NSM et SNSM sont testées et présentées<br>This thesis is composed of four parts. Each part contains several research items according to the structural topic planned to be studied. Although the logical sequence was preserved in the thesis, each part was structured to discuss and address a specific flexural issue regarding strengthening reinforced concrete (RC) beams with fiber-reinforced polymers (FRPs). In general, the thesis experimentally, analytically, and numerically studies the possibility of using near surface mounted (NSM) and externally bonded (EB) techniques for strengthening and repairing continuous two-span beams. In summary, the experimental scheme of this thesis comprised 21 beams: six beams were simply supported with a 3-m length each, and 15 beams were continuous over two spans with a 6-m total beam length and 2.85-m span length each. The analytical analysis and design approaches as well as the finite element (FE) numerical models were developed or/and utilized in some parts according to their importance and necessity.- The first part studies the possibility of strengthening RC beams on their side surfaces instead of their soffits. Therefore, the side near surface mounted (SNSM or side-NSM) technique was proposed and investigated on six simply supported beams: one control beam and five others initially strengthened with 2∅6 carbon-FRP (CFRP) bars.-The second part presents an experimental and analytical study regarding the assessment of using the NSM technique for flexural strengthening of continuous RC beams. The experimental program of this part consists of six full-scale two-span beams: one control beam and five others strengthened with FRP bars in both hogging and sagging regions.-The third part presents a comparison between the NSM and side-NSM techniques for strengthening continuous two-span RC beams with CFRP rods. The study comprises two main sections: an experimental section and a FE section.-The fourth part presents an experimental study that was primarily conducted to fill in the gaps in the literature regarding strengthening continuous RC beams with EB-CFRP. Generally, this part consists of three main sections. In the first section, seven large-scale two-span beams are statically investigated: one control beam (from part two) and six beams initially strengthened in terms of bending with CFRP sheets or plates. The second section evaluates the effectiveness of the current design codes in determining the flexural strength of continuous beams strengthened externally with CFRP sheets or plates. Finally, the third section assesses and compares the efficiencies of the EB and NSM techniques
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Sambrook, Thomas. "An electrophysiological investigation of reward prediction errors in the human brain." Thesis, University of Plymouth, 2015. http://hdl.handle.net/10026.1/3462.
Full textAbstract:
Reward prediction errors are quantitative signed terms that express the difference between the value of an obtained outcome and the expected value that was placed on it prior to its receipt. Positive reward prediction errors constitute reward, negative reward prediction errors constitute punishment. Reward prediction errors have been shown to be powerful drivers of reinforcement learning in formal models and there is thus a strong reason to believe they are used in the brain. Isolating such neural signals stands to help elucidate how reinforcement learning is implemented in the brain, and may ultimately shed light on individual differences, psychopathologies of reward such as addiction and depression, and the apparently non-normative behaviour under risk described by behavioural economics. In the present thesis, I used the event related potential technique to isolate and study electrophysiological components whose behaviour resembled reward prediction errors. I demonstrated that a candidate component, “feedback related negativity”, occurring 250 to 350 ms after receipt of reward or punishment, showed such behaviour. A meta-analysis of the existing literature on this component, using a novel technique of “great grand averaging”, supported this view. The component showed marked asymmetries however, being more responsive to reward than punishment and more responsive to appetitive rather than aversive outcomes. I also used novel data-driven techniques to examine activity outside the temporal interval associated with the feedback related negativity. This revealed a later component responding solely to punishments incurred in a Pavlovian learning task. It also revealed numerous salience-encoding components which were sensitive to a prediction error’s size but not its sign.
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Knight, Daniel. "The generic simulation of reinforced concrete beams with prestressing and external reinforcement." Thesis, 2014. http://hdl.handle.net/2440/85233.
Full textAbstract:
This thesis presents a series of journal papers in which a new segmental moment-rotation (M/Ө) approach is developed for simulating the instantaneous and sustained loading behaviour of reinforced concrete (RC) beams with prestressing and external reinforcement. The M/Ө approach is formed on the fundamental Euler-Bernoulli postulation that plane sections remain plane, but not necessarily on the Euler-Bernoulli corollary of a linear strain profile. Further adaption of the well-established mechanics of partial-interaction (PI) theory introduces a fundamental baseline concept in which residual strains due to time-effects, thermal gradients and prestressing are accounted for in simulating the formation and gradual widening of cracks and the associated effects of tension-stiffening allowing for bond-slip. The effects of concrete softening are incorporated into the M/Ө approach through a size dependent concrete stress-strain relationship based on the mechanics of shear-friction theory which simulates the behaviour of a member once a concrete softening wedge forms. The approach is shown to be able to quantify segmental equivalent flexural rigidities for both instantaneous and time-dependent behaviour, thus removing the reliance on empiricism in quantifying the effects of concrete cracking and softening. In defining the segmental equivalent flexural rigidities of RC beams with both post-tensioned and pre-tensioned reinforcement it is shown how the approach is used to quantify the load-deflection behaviour of the entire member through the application of conventional analysis techniques. The established M/Ө approach is then generically applied to RC beams with both prestressed fibre reinforced polymer (FRP) and steel reinforcement in quantifying the beams instantaneous and sustained loading behaviour through being able to accommodate any conventional method of quantifying the time-dependent parameters. Thus the broad application of the M/Ө approach provides a novel method of simulating, through mechanics, the full-range of behaviour of a prestressed beam, that is from prestress application through serviceability loading and to collapse. Moreover, the reliance on empiricisms, as typically relied upon in standard analysis methods, are removed with the only empirical components required being in defining the material properties. Having established the M/Ө approach for the instantaneous and sustained loading of conventional prestressed beams, the approach is extended to simulate the behaviour of RC beams with unbonded post-tensioned FRP and steel tendons. Through understanding the individual segmental behaviour, a global approach is introduced in which the behaviour of the unbonded reinforcement can be quantified from the deformation based analysis. The approach is then further extended to incorporate the analysis of RC beams with mechanical-fastened (MF) FRP allowing for the PI behaviour at the fasteners. This extension forms the basis of a generic technique which can subsequently be used in the design of MF systems, with and without prestress, and therefore provide the foundation in developing design guidelines. The universal application of the developed residual strain PI M/Ө approach provides a novel technique in simulating what is observed in practice for RC beams with prestressing and external reinforcement. The approach is a useful extension to the current analysis techniques in which the reliance on defining empiricisms through vast experimental testing procedures is removed.<br>Thesis (Ph.D.) -- University of Adelaide, School of Civil, Environmental and Mining Engineering, 2014