The introduction of fibre-reinforced polymers (FRPs) to the field of civil engineering has led to numerous research efforts focusing on a wide range of applications where properties such as high strength, light weight or corrosion resistance are desirable. In particular, FRP materials have been especially attractive for use as internal reinforcement in reinforced concrete (RC) structures exposed to aggressive environments due to the rapidly deteriorating infrastructure resulting from corrosion of conventional steel reinforcement. While FRPs have been successfully implemented in a variety of structural applications, little research has been conducted on the use of FRP reinforcement for short span slab bridges. Furthermore, the behaviour of FRP-RC flexural members cast with self-consolidating concrete (SCC) is largely absent from the literature. The present study investigates the behaviour of an all-FRP reinforcement system for slab bridges which combines lower cost glass FRP (GFRP) reinforcing bars with high performance carbon FRP (CFRP) prestressed tendons in SCC to produce a structure which is both cost-efficient and characterized by excellent structural performance at the serviceability, ultimate and fatigue limit states. An extensive experimental program comprised of 57 large or full-scale slab strips was conducted to investigate the effects of reinforcement type, reinforcement ratio, prestressing level and shear reinforcement type on the flexural performance of slab bridges under both monotonic and fatigue loading. The proposed reinforcement system was found to display excellent serviceability characteristics and high load capacities as well as significant deformability to allow for sufficient warning prior to failure. Lastly, the use of post-tensioned CFRP tendons limited the stresses in the GFRP reinforcing bars leading to significantly longer fatigue lives and higher fatigue strengths compared to non-prestressed slabs. Analytical models were used to predict the behaviour of the slab bridge strips at service and at ultimate. Where these models failed to accurately represent the experimental findings, simple modifications were proposed. The results from ancillary tests were also used to modify existing analytical models to predict the effects of fatigue loading on the deflection, crack width, shear resistance and flexural capacity of each of the tested slabs.

No description available.

This thesis investigates the performance of GFRP pretensioned concrete slabs and compares their flexural behaviour with GFRP reinforced and steel prestressed concrete slabs. A total of 12 slabs were cast in this program. The slab mid-span deflections are theoretically predicted and the results indicate that the short-term response of GFRP prestressed concrete slabs can be predicted well by the existing methods. Long-term deflection behaviour has been estimated using the Age Adjusted Effective Modulus Method by incorporating three creep and shrinkage models. A large influence of creep and shrinkage models on the theoretical determination is observed and the use of long term multipliers is not suitable for GFRP prestressed concrete members. The slabs were instrumented for long-term monitoring using strain gauges and fibre-optic sensors. It was concluded that the electrical strain gauges can be successfully used for long-term strain monitoring.

Over the last decade, six major earthquakes that occurred in Turkey dramatically demonstrated the poor performance of the buildings that were designed and constructed far from Turkish seismic code&rsquo / s requirements. The Marmara region, where most of the population and industry is located, is in the active seismic zone. With the rising cost of damages due to earthquakes, the necessity of the cost-benefit analysis for various rehabilitation strategies used in existing buildings has become a major concern for the decision makers who are in the position of making decisions on the building rehabilitation This study evaluates the performance of two different rehabilitation strategies applied to two five-story reinforced concrete buildings and assesses their cost-benefit analyses. These buildings were chosen to be representative of the typical residential To carry out the structural analysis of the buildings, three-dimensional models of the buildings were developed using SAP2000 [6]. Two alternative strengthening methods, insertion of reinforced concrete shear walls and application of Carbon Fiber Reinforced Polymers (CFRP) on hallow clay tile infill walls, were used for both of the buildings. While modeling infill walls strengthened with CFRP, two specific modeling attempts proposed by the researchers at Middle East Technical University were used. Pushover analyses were performed to evaluate seismic performance of the buildings. The Life Safety criterion was chosen as the rehabilitation objective. The global and component response acceptability limits were checked and the cost-benefit analysis was performed in order to determine the most attractive rehabilitation alternative. The results and comparisons given here illustrated that strengthening with shear wall had the most significant improvement on the seismic performance and cost effectiveness of the case study buildings. Outcomes of this study are only applicable to the buildings employed here and are bound by the assumptions made, approximations used and parameters considered in this study. The findings cannot be generalized for the buildings rehabilitated with CFRP due to lack of the consistent models for CFRP application. More research needs to be conducted to provide solid guidelines and reliable models applicable to the CFRP rehabilitated infill walls.

This research involves the study of the short term loaded behaviour of mechanically degraded reinforced concrete (RC) flexural elements, which are strengthened with fibre reinforced polymer (FRP) composites. The two main objectives have been: (a) to conduct a series of realistic tests, the results of which would be used to establish the design criteria, and (b) to carry out analytical modelling and hence develop a set of suitable design equations. It is expected that this work will contribute towards the establishment of definitive design guidelines for the strengthening of reinforced concrete structures using advanced fibre composites. The experimental study concentrated on the laboratory testing of 30 simply supported, and 4 two-span continuous full size RC beams, which were strengthened by either FRP plates or fabric sheets. The failure modes of these beams, at ultimate limit state, were examined and the influencing factors were identified. A premature and extremely brittle collapse mechanism was found to be the predominant type of failure for beams strengthened with a large area of FRP composites. A modified semi-empirical approach was presented for predicting the failure load of such over strengthened beams. Despite the lack of ductility in fibre composites, it was found that the FRP strengthened members would exhibit acceptable ductile characteristics, if they were designed to be under strengthened. A new design-based methodology for quantifying the deformability of FRP strengthened elements was proposed, and its difference to the conventional concept of ductility was discussed. The available techniques for ductility evaluation of FRP strengthened concrete members were reviewed and a suitable method was recommended for determining ductility level of FRP strengthened members. A non-linear material based analytical model was developed to simulate the flexural behaviour of the strengthened and control beams, the results were seen to match very well. The parametric study provided an insight into the effects of various factors including the mechanical properties and cross sectional area of FRP composites, on the failure modes and ductility characteristics of the strengthened beams. Based on the findings of the experimental and analytical studies, design equations in the BS 8110 format were developed, and design case studies have been carried out. It was concluded that fibre composites could effectively and safely strengthen mechanically degraded reinforced concrete structures if appropriately designed. The modes of failure and the degree of performance enhancement of FRP strengthened beams depend largely on the composite material properties as well as the original strength and stiffness of the RC structure. If the FRP strengthened elements were designed to be under-strengthened, then the premature and brittle failure mode could be prevented and ductile failure mode could be achieved. It was also found that existing steel reinforcement would always yield before the FRP composite reached the ultimate strength. Furthermore, a critical reinforcement ratio, above which FRP strengthening should not be carried out, was defined. It was concluded that FRP strengthening is most suitable for reinforced concrete floor slabs, bridge decks, flanged beams and other relatively lightly reinforced elements. The study also revealed that to avoid a brittle concrete failure, existing doubly reinforced members should not be strengthened by FRP composites.

Engineered wood products (EWP) are becoming extremely popular and a viable material option for the construction of residential, commercial, and hybrid buildings. Cross-laminated timber (CLT) is among one of the many EWP available in North America, which can be utilized for many different applications such as: walls, floors, and roofs. Despite the available requirements in the Canadian blast design standard (CSA, 2012) with regard to the design of wood structures, there are currently no provisions on how to retrofit timber structures to improve their performance when subjected to blast loads. The current study is aimed at investigating the effect of different retrofitting alternatives in order to improve the overall behaviour of CLT when exposed to out-of-plane bending. The experimental program examined the behaviour of seventeen reinforced CLT slabs. Testing was conducted at the University of Ottawa by means of a shock tube capable of simulating high strain rates similar to those experienced during a blast event. The current study was divided into two phases. The first consisted of CLT slabs retrofitted with steel straps where strap spacing, location, and order of installation was investigated. The second phase focused on the development of dynamic properties of CLT panels when reinforced with GFRP. Lay-up configuration and fabric orientation were among the parameters explored. The results from the experimental program show that reinforcing the panels with steel straps had minimal effect on the ultimate strength, but significant levels of post peak resistance and ductility was achieved. The horizontal straps were able to restrict the failure to small regions and to promote flexural failure by preventing rolling shear failure. It also eliminated flying debris and enhanced the ultimate strength, stiffness as well as ductility. Applying GFRP layers enhanced the overall behaviour of the slab resulting in a significant increase in peak resistance, ductility, and stiffness when compared to the dynamic results of an unretrofitted panel. The post peak resistance was also greatly improved. In particular, applying stacked quadraxial lay-up configuration significantly improved the ductility and resulted in the greatest post peak resistance. The effect of steel straps on damaged and retrofitted was relatively minimal, and only partial recovery of the resistance and the stiffness was achieved. GFRP with full confinement yielded better performance compared to the unretrofitted and undamaged counterpart. More work is needed to quantify the benefits of using GFRP in these applications.

[pt] Este trabalho é uma pesquisa experimental realizada no Laboratório de Estruturas e Materiais da PUC–Rio, utilizando–se a técnica de aplicação do compósito de fibras de carbono (CFC) colados externamente em consoles curtos de concreto armado. Foram ensaiados seis consoles curtos, sendo: um de referência, três com reforço de CFC na horizontal e dois com reforço de CFC na diagonal. A resistência média do concreto aos 28 dias foi de 30 MPa. A seção transversal do pilar foi de 25 cm × 50 cm e a seção do transversal console foi de 25 cm × 37,5 cm. O diâmetro da armadura tracionada em laço era de 10 mm e o diâmetro da armadura de costura era de 6,3 mm. Os consoles foram instrumentados com extensômetros elétricos de resistência na armadura tracionada, no estribo, no concreto e no CFC. Os ensaios comprovaram um razoável desempenho dessa técnica de reforço. Os resultados experimentais foram comparados com os resultados obtidos no modelo de Bielas e Tirantes e no modelo cinemático da Teoria da Plasticidade, visando a comparação das forças verticais últimas teóricas e experimentais. Foi avaliado o ângulo de inclinação das bielas e o fator de efetividade da deformação específica no reforço de CFC. / [en] This work is an experimental research of concrete short corbels wrapped with Carbon Fiber Reinforced Polymer (CFRP) strips. Different strengthening configurations were used. Was carried out on six corbels strengthened by CFRP. One control specimen without CFRP, three corbels with horizontal CFRP strips and two corbels with diagonal CFRP strips. The concrete had a 28 day compressive strength of 30 MPa. The column cross-section dimensions were 25 cm x 50 cm and the corbel cross-section dimensions were 25 cm x 37,5 cm. The flexural reinforcement consisted of four deformed bars each of diameter 10 mm with four transverse bars of diameter 6,3 mm. The corbels were instrumented with strain gages in flexural reinforcement, stirrup, concrete surface and CFRP strips. The analytical models based on Strut-and-Tie model and in the kinematic model of the Theory of Plasticity, allows one to determine the bearing capacity of corbels. The experimental values are then compared with the analytical results, showing good agreement. The strut angle and the strengthening effectiveness were evaluated.

Afin de prolonger leur durée de vie et d'assurer la sécurité des usagers, les structures en béton peuvent nécessiter un renforcement au cours de leur durée de service. La technique de renforcement par collage externe, en surface, de composites renforcés de fibres de carbone, de verre ou d'aramide à l'aide de résines durcissant à température ambiante est largement employée pour son efficacité et sa facilité de mise oeuvre. Toutefois l'utilisation à la fois de fibres synthétiques et de matrices polymères produit un impact écologique non négligeable. L'objectif de ce travail de recherche est d'examiner la possibilité d'utiliser des fibres de lin pour le renforcement externe de structures en béton. Les propriétés mécaniques spécifiques et le bilan environnemental avantageux des fibres de lin en font une alternative intéressante aux fibres de verre. Cependant leur origine naturelle conduit à une plus grande variabilité des propriétés, à un comportement en traction non linéaire et une sensibilité accrue à l'humidité. Les principaux objectifs du travail de thèse portent ainsi sur la sélection des matériaux et la mise en oeuvre les plus adaptés, sur l'évaluation des performances du matériau et de son adhérence au support béton et sur une évaluation de la durabilité des propriétés du système. Dans une première partie expérimentale deux méthodes de mise en oeuvre du renfort à fibres de lin (stratification au contact et collage de lamelles rigides) sont développées et caractérisées. Des observations tomographies X confirment la bonne imprégnation des fibres et la cohésion des composites. Les essais de traction révèlent un comportement en traction bilinéaire comme décrit dans la littérature, avec des propriétés d'effort par largeur de bande comparables aux composites de renfort à fibres de verre. La caractérisation des interfaces composite/béton menée par tests de cisaillement à double recouvrement confirme une bonne adhérence qui se traduit par une rupture cohésive dans le substrat béton. La nature des fibres ne semble pas influencer le comportement de l'interface. Les systèmes de renforcement à fibres de lin sont donc capables de reprendre des efforts transmis par cisaillement de façon comparable aux matériaux de renfort à fibres de verre. Dans une deuxième partie des essais exploratoires de durabilité ont ensuite été menés pour vérifier la pérennité des propriétés de ces deux composites de renfort dans un environnement de service. Un vieillissement accéléré artificiel en enceinte climatique est mis en place tandis que des composites à fibres de lin stratifié au contact sont exposés pendant un an à l'environnement extérieur. Un second vieillissement hygrothermique à 70°C est mené pendant 4 semaines. Les dégradations des propriétés des composites à fibres de lin sont comparables à celles de certains composites de renfort à fibres de verre. Malgré la nature hydrophile des fibres de lin, les premiers essais ne montrent pas de dégradations des propriétés qui rendraient le composite impropre à une utilisation comme renfort extérieur de structures en béton / To extend their life and ensure the safety of users, concrete structures may need strengthening during their service life. The technique of strengthening by external bonding of composites carbon, glass or aramid composites using polymer that are cured at room temperature is widely used for its effectiveness and ease of implementation. Yet the uses of both synthetic fibers and polymer matrices have a significant environmental impact. The objective of this research is to examine the possibility of using flax fibers for the external strengthening of concrete structures. Their high specific mechanical properties and positive environmental balance make them an interesting alternative to the glass fibers. However, they also present a larger variability in properties, a non-linear tensile behavior and high sensitivity to humidity. The main objectives of this thesis involve the selection of the materials and the most suitable implementation, the evaluation of the materials’ performances and adherence to concrete support and a sustainability assessment of those properties. In a first experimental section, two methods of implementation of the flax fiber reinforcement are developed and characterized: by wet lay-up and by bonding of pre-hardened. Tomography observations confirm the good fiber impregnation and cohesion of the composites. The tensile tests show a bilinear tensile behavior as described in the literature, with stress per width at failure comparable to glass fibres strengthening systems. The characterization of composite/concrete interfaces is conducted by double overlap shear tests and confirms a good adhesion which results in concrete failure before the failure of the reinforcement system. The nature of the fibers does not appear to influence the shear behavior of the interface. For glass or flax wet lay-up systems, failure can occur with failure of the composite. Flax fiber reinforcement systems can take up the forces transmitted by shear in a manner comparable to glass composites. In the second part, sustainability tests were conducted to ensure the sustainability of the properties of these two composite reinforcements in a service environment. An artificial accelerated aging test in a climatic chamber is set up while wet lay-up flax fiber composites are exposed to the external environment during a year. A second hydrothermal aging test is conducted for 4 weeks at 70°C. The degradations of the properties of the flax composites are comparable to those of some glass reinforcement composites. Despite the hydrophilic nature of the flax fibers the first tests show no degradation of properties that would make the composite unsuitable for an external reinforcement of concrete structures

L'avancée de la technologie des PRF a suscité l'intérêt de l'introduction de nouvelles fibres, comme la fibre de basalte, qui a un potentiel d'offrir une solution efficace, lorsqu’utilisée dans les structures en béton, soit sur la résistance à la corrosion, la durabilité et la rentabilité. En outre, les codes et les guides disponibles, ne fournissent pas de recommandations pour l'utilisation de barres en PRFB puisque les recherches passées dans ce domaine sont limitées. Donc, des travaux de recherche sont nécessaires pour caractériser et comprendre le comportement des barres de PRFB dans les éléments en béton armé. En conséquence, les objectifs principaux sont d'évaluer les caractéristiques à court et long terme des barres de PRFB nouvellement développées, ainsi que d'évaluer les performances structurales de ces nouvelles barres comme renforcement interne dans les poutres et les dalles de pont et d'introduire ce nouveau renforcement dans les codes et les guides de dimensionnement. Les tests expérimentaux ont été faits en trois parties. La première partie porte sur le développement de trois nouvelles barres et tendons en PRFB pour déterminer leurs propriétés physiques et mécaniques. Les performances à long terme et de durabilité ont été réalisées en conditionnant les barres de PRFB dans une solution alcaline simulant les conditions humides dans le béton pour déterminer la compatibilité comme renforcement interne dans les éléments en béton. Par la suite, les propriétés ont été déterminées et comparées avec des spécimens non conditionnés (référence). La seconde partie a porté sur sept dalles de pont en béton armé grandeur réelle avec les bords restreints, simulant les tabliers de pont les plus utilisés en Amérique du Nord, pour évaluer la performance des dalles renforcées de PRFB et d'acier. Les dalles mesurent 3000 mm de long × 2500 mm de large × 200 mm d'épaisseur. Les dalles ont été testées jusqu'à la rupture sous une charge concentrée au centre de celles-ci simulant l'empreinte d'une roue d'un camion. Les capacités en poinçonnement sont prédites en utilisant les exigences réglementaires disponibles, et sont comparées aux résultats expérimentaux. La troisième partie de cette étude portait sur les essais de 14 poutres en béton de 3100 mm de long × 200 mm de large × 300 mm de profond pour examiner le comportement en flexion et les performances en service des barres de PRFB avec deux états de surfaces: fini sablé et crénelé. Les poutres ont été testées en flexion en quatre points avec une portée libre de 2700 mm jusqu'à la rupture. Les résultats sont introduits et discutés en terme : du comportement de la fissuration, des flèches, de la capacité en flexion et des modes de ruptures. De plus, le coefficient d'adhérence (kb) des barres de PRFB est déterminé et comparé avec les recommandations des codes et guides actuels. Les résultats sont introduits et discutés en terme : du comportement de la fissuration, des flèches, de la capacité en flexion et des modes de ruptures. De plus, le coefficient d'adhérence des barres de PRFB est déterminé et comparé avec les recommandations des codes et guides actuels. Les résultats de l'étude concluent sur la viables pour la production des barres de PRFB pour respecter les exigences des codes actuelles. Également, les résultats d'essai indiquent que les barres de PRFB ont de bonnes propriétés mécaniques et peuvent être placées dans la même catégorie que les barres de PRFV, soit grade III. De plus, le comportement des poutres et des dalles de pont renforcées de PRFB est similaire que pour un renforcement en PRFV et PRFC et les exigences réglementaires sont applicables pour les barres de PRFB. / Abstract: The advances in fiber-reinforced-polymer (FRP) technology have spurred interest in introducing new fibers, such as basalt FRP (BFRP), which has the potential to offer an efficient solution when implemented in concrete structure, such as corrosion resistant, durable and cost-effective. Furthermore, the available design codes and guides do not provide any recommendations for the use of BFRP bars since fundamental studies and relevant applications are still limited. Therefore, investigations are needed to characterize and understand the behavior of BFRP bars in concrete members. Consequently, the main objectives of this experimental investigation are to evaluate the short- and long-term characteristics of newly developed BFRP bars, as well as evaluate the structural performance of these new bars as internal reinforcement for concrete beams and bridge-deck slabs to introduce these new reinforcing bars to the design codes and guides. The experimental tests were completed through three parts. The first part was conducted on three newly developed BFRP bars and tendons to investigate their physical and mechanical properties. Durability and long-term performance were assessed by conditioning the BFRP bars in an alkaline solution simulating the moist concrete environment to determine their suitability as internal reinforcement for concrete elements. Thereafter, the properties were assessed and compared with the unconditioned (reference) values. The second part of this study was conducted on seven full-scale edge-restrained concrete bridge-deck slabs simulating actual slab-on-girder bridge-deck that is commonly used in North America to evaluate the performance of concrete bridge-deck slabs reinforced with BFRP and steel bars. The deck slabs measured 3000 mm long × 2500 mm wide × 200 mm deep. The slabs were tested up to failure under single concentrated load acting on the center of each slab simulating the footprint of sustained truck wheel load. The punching shear capacities were predicted using the available provisions, and compared with the experimental results. The third part of this study included testing of fourteen concrete beams of 3100 mm long × 200 mm wide × 300 mm deep to investigate the flexural behavior and serviceability performance of sand-coated and ribbed BFRP bars in concrete beams. The beams were tested under four-point bending over a clear span of 2700 mm until failure. The results are introduced and discussed in terms of cracking behavior, deflection, flexure capacity, and failure modes. In addition, the bond-dependent coefficient (kb) of the BFRP bars was determined and compared with the recommendations of the current FRP design codes and guides. The findings of this study concluded the feasibility of producing BFRP bars meet the requirements of the current FRP standards. Also, the test results revealed that the BFRP bars had good mechanical behavior and could be placed in the same category as grade II and grade III GFRP bars. Moreover, the behavior of the concrete bridge-deck slabs and beams reinforced with BFRP bars was quite similar to the counterparts reinforced with glass- and carbon-FRP bars and the available FRP provisions are applicable for BFRP bars. The beam test results yielded an average bond-dependent coefficient (kb) of 0.76±0.03 and 0.83±0.03 for the sand-coated and ribbed BFRP bars, respectively.

La consommation globale de plastique renforcé de fibres de carbone (PRFC) est en constante augmentation, ce qui induit la nécessité de créer un secteur de recyclage capable de traiter l’ensemble des fibres de carbone actuellement consommées et qui représente la quantité de déchets à traiter en devenir. Cette thèse porte sur le développement et l'application d’une méthodologie d’évaluation multicritère du développement durable pour la création d’une filière de recyclage des plastiques renforcés de fibres de carbone (PRFC) issus du secteur aéronautique, mais aussi des autres secteurs consommateurs de fibres de carbone tels que l’automobile et l’éolien. Cette méthodologie a pour but d’identifier les indicateurs les plus pertinents ainsi que les méthodes qui leurs sont associés, c'est-à-dire qu’elle vise à la création et l’adaptation d’indicateurs clé de performance du développement durable pour caractériser au mieux les impacts environnementaux et sociaux-économique de cette filière de recyclage. Le résultat final de ce travail est la création d’une méthodologie d’évaluation du développement durable dédiée à la filière de recyclage des fibres de carbone par la considération des différents aspects de celui-ci. Cette méthodologie, aidant à l’identification et la définition des indicateurs clé de performances du développement durable peut être aussi appliquée à d’autres secteurs souhaitant s’implanter en suivant les principes de ce développement. / The global consumption of carbon-fiber reinforced plastic (CFRP) is constantly growing since the last decade, leading to the need to create a recycling sector able to manage the amount of carbon fibers currently consumed and representing the amount of waste to be treated in the future. This thesis focus on the creation of a methodology for evaluating the sustainability potential for the implementation of a carbon fiber reinforced plastics recycling (CFRP) sector. CFRP coming from the aeronautics sector as well as other sectors such as the automobile and wind-energy industries. This methodology aims at identifying the most relevant indicators and associated methods, but also aims at the creation and adaptation of indicators to best assess the environmental and socioeconomic impacts of this recycling sector. The final result of this work, is the creation of a sustainability assessment methodology dedicated to the carbon fiber recycling sector, considering the different sustainability pillars. However this methodology also define more widely a tool that helps to identify sustainability performance indicators and that can be applied to other sectors if necessary.