Since the introduction of fiber reinforced polymers (FRP) for the repair and retrofit of concrete structures in the 1980’s, considerable research has been devoted to the feasibility of their application and predictive modeling of their performance. However, the effects of flaws present in the constitutive components and the practices in substrate preparation and treatment have not yet been thoroughly studied. This research aims at investigating the effect of surface preparation and treatment for the pre-cured FRP systems and the groove size tolerance for near surface mounted (NSM) FRP systems; and to set thresholds for guaranteed system performance. The research included both analytical and experimental components. The experimental program for the pre-cured FRP systems consisted of a total of twenty-four (24) reinforced concrete (RC) T-beams with various surface preparation parameters and surface flaws, including roughness, flatness, voids and cracks (cuts). For the NSM FRP systems, a total of twelve (12) additional RC T-beams were tested with different grooves sizes for FRP bars and strips. The analytical program included developing an elaborate nonlinear finite element model using the general purpose software ANSYS. The model was subsequently used to extend the experimental range of parameters for surface flatness in pre-cured FRP systems, and for groove size study in the NSM FRP systems. Test results, confirmed by further analyses, indicated that contrary to the general belief in the industry, the impact of surface roughness on the global performance of pre-cured FRP systems was negligible. The study also verified that threshold limits set for wet lay-up FRP systems can be extended to pre-cured systems. The study showed that larger surface voids and cracks (cuts) can adversely impact both the strength and ductility of pre-cured FRP systems. On the other hand, frequency (or spacing) of surface cracks (cuts) may only affect system ductility rather than its strength. Finally, within the range studied, groove size tolerance of +1/8 in. does not appear to have an adverse effect on the performance of NSM FRP systems.

Prestressed hollow core slabs are essential components in structures such as bridges, parking garages, marine structures, and commercial and industrial buildings. Material degradation and altered functional requirements may seriously threaten the structural integrity of these reinforced concrete structures. Using FRP composites, the NSM strengthening technique presents a viable solution to these challenges. However, further investigation is required to establish comprehensive empirical design guidelines. The intent of this research project is to investigate the NSM technique in conjunction with common design concepts such as prestressed concrete, precast hollow core slabs, the complex behaviour of disturbed regions, and fiber-reinforced composite materials. An experimental program was developed, which included eleven full-scale slab specimens, subject to a four-point load configuration. The main parameters included the prestressing reinforcement ratio, CFRP strengthening ratio, and in-service opening location. Experimental results showed that prestressed concrete strengthened in flexure with NSM-CFRP is a viable technique for lower reinforcement ratios.

L'efficacité de la technique NSM dans la réparation et renforcement des structures est fortement dépendante de la performance d’adhérence entre les joncs de carbone et le béton. De nombreuses études récentes ont été réalisées pour quantifier d’adhérence sur des éprouvettes saines en raison de la complexité de ce problème. Par contre, le comportement des éléments réparés peut être affecté, d’une part, selon les conditions de pré-chargement, et d’autre part, selon l’endommagement spécifique, qui pourraient être rencontrés dans les structures existantes. En effet, un endommagement dans le béton ou dans les armatures peut modifier le comportement global des éléments réparés en réduisant la capacité portante.Tout d’abord, des essais à grande échelle en flexion ont été réalisés pour étudier le comportement des poutres en béton armé. D’une part, différents types d’endommagements ont été considérés tels que la corrosion des aciers et les charges excessives. D’autre part, différentes conditions de pré-chargement incluant les maintiens du chargement à l’heure de la mise en oeuvre de la réparation ont été étudiées. Le comportement de la poutre témoin renforcée se distingue par son côté fragile qui s’accompagne d’une ruine soudaine par pull-out du jonc de carbone de la résine suivie d’éclatement de morceaux de béton dans la zone de béton d’enrobage et d’un écrasement du béton comprimé. Par contre, la ruine de la poutre corrodée et réparée intervient par séparation (délamination) du béton d’enrobage dans la zone tendue au niveau à l’insertion du jonc de carbone, qui a commencé entre deux fissures de flexion dans la zone centrale et s’est propagé vers l’appui. Ensuite, afin de comprendre l’origine du mode de ruine de la poutre corrodée et réparée, et d'étudier le comportement global, la rigidité, la ductilité, le mode de ruine, et la capacité portante, des essais expérimentaux ont été réalisés en faisant varier les paramètres relatifs aux conséquences de la corrosion (perte généralisée de la section d’acier tendu, éclatement du béton d’enrobage, détérioration de l’adhérence acier-béton). Cependant, la ruine par la séparation du béton d’enrobage entre deux fissures adjacentes observé sur la poutre corrodée et réparée n’a jamais été obtenue. Pour nos simulations : La ruine a eu lieu par Pull-out du jonc de carbone. Dans tous les cas, la capacité portante mesurée des poutres endommagées puis réparées était supérieure à celle de la poutre témoin (non-renforcée)Finalement, puisque les structures nécessitant de la réparation par application de matériaux composites ne sont pas de récentes, et par conséquent, qui ont déjà subi un certain nombre d’endommagements dus aux contraintes mécaniques (surcharge maintenue à long-terme, charge accidentelle à court-terme), une partie expérimentale s’est intéressée à l'utilisation des joncs de carbone pour la réparation des éléments endommagés par une charge excessive, puis réparés sous ou sans charge maintenue. Un endommagement est capable de réduire légèrement la capacité portante des poutres réparées (moins de 8% par rapport à la poutre témoin renforcée). La réparation des poutres sous charge maintenue a une influence non-significative en diminuant la capacité portante entre 5% et 6% par rapport aux poutres endommagées réparées sans charge maintenue. La ruine des poutres pré-chargées puis réparées a été par l’arrachement du jonc de carbone de la résine « Pull-out » à cause des fissures longitudinales développées dans la résine qui conduit à la perte d'adhérence entre le jonc de carbone et le matériau de scellement en réduisant légèrement leur capacité portante. Par contre, les poutres endommagées par chargement excessif puis réparées ont montré un mode de ruine différent (par écrasement du béton comprimé) mais avec une réduction significative leur capacité portante / The effectiveness of the NSM technique for repairing or strengthening the RC structures is highly dependent on the bond strength behavior between CFRP rods and concrete. Many recent studies have been conducted to evaluate bond strength on undamaged concrete specimens because of the complexity of this problem. On the contrary, the behavior of repaired specimens may be affected, first, by pre-loading conditions, and the other, depending on specific damage that could be encountered in the existing structures. Indeed, damage in concrete or in reinforcement can change the global behavior of repaired elements by reducing the bearing capacity.First, large-scale bending tests were carried out to study the behavior of reinforced concrete beams. On the one hand, various types of damage were considered such as the steel corrosion and excessive loads. On the one hand, different pre-loading conditions including sustaining loads at the time of implementation repair were studied. The behavior of the beam strengthened control is distinguished by its fragile side which is accompanied by sudden failure due to pull-out of the CFRP NSM rod, followed by splitting of concrete pieces in the concrete cover and a crushing of concrete in compressive zone. On the other hand, the failure mode of corroded repaired beam occurred by concrete cover delamination in the tension zone at the level of insertion of CFRP NSM rod that started between two bending cracks in the central area and has spread to the support. Then, in order to understand the origin of the failure mode, global behavior, stiffness, ductility, and bearing capacity of repaired corroded beam, an experimental tests were performed by varying the parameters relating to the consequences of corrosion (such as generalized loss of bottom steel section, concrete cover delamination failure and bond strength failure between concrete and reinforcing steel). However, the failure occurred by the concrete cover delamination between two adjacent bending cracks was never obtained on the repaired corroded beam. For our simulations: The failure was due to pull-out of CFRP rod. In all cases, the bearing capacity measured for repaired damaged beams was greater than that of control beam (non-repaired).Finally, since the structures requiring repair by applying composite materials are not recent, and consequently, number of damages occurred due to mechanical stress (long-term sustained overloading, short term accidental load), an experimental part was interested in the use of CFRP NSM rods to repair of beams damaged by excessive load, and then repaired under or without sustained load. A damage can slightly reduce the bearing capacity of the repaired beams (less than 8% compared to the strengthened control beam). The repair of beams under sustained load has a non-significant effect by reducing the bearing capacity between 5% and 6% compared to the damaged beams repaired without sustained load. The damages of the pre-loaded RC beams repaired with NSM failed by the tearing of the carbon rod "pull-out" due to the longitudinal cracks developed in the epoxy resin volume, which leads to loss of adhesion between the CFRP rod and the sealing material by slightly reducing their bearing capacity. While, the RC beams damaged by overloading which were repaired showed a different mode of failure (crushing of concrete in compression) with also a significant reduction in their ultimate bearing capacity values

Submitted by Maike Costa (maiksebas@gmail.com) on 2017-05-29T13:55:12Z No. of bitstreams: 1 arquivototal.pdf: 5619701 bytes, checksum: 3d5e3403144a3249722499b4dea043e9 (MD5) / Made available in DSpace on 2017-05-29T13:55:12Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 5619701 bytes, checksum: 3d5e3403144a3249722499b4dea043e9 (MD5) Previous issue date: 2016-08-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / It is presented in this thesis, a proposal for solution of engineering problems in heat transfer area using the network simulation method (NSM - Network Simulation Method), which is to solve these problems by analogy between the thermal circuits and electrical circuits. It will be presented to validate the two-dimensional problem of heat conduction in a cylinder in which the solutions obtained by simulation with the solution analytically obtained via Technical Generalized Integral Transform will face (GITT). In the simulations makes up the body discretization study with the aim of establishing a correlation between the amount of cells (the mesh refinement) and the relationship between the radius of the size and length of the cylinder so that the problem solution of heat transfer in the body can be considered one-dimensional. A comparison will be made between the analytical response and obtained by simulation, varying the number of divisions and different relationships between beam dimensions and length of the cylinder. From the solution validated the proposed method, applying the work presented as a generic fabric prepared by the NSM and implementation PSPICE, which serves for solving many problems of heat conduction in a cylindrical geometry. / É apresentada neste trabalho de tese, uma proposta para solução de problemas de engenharia na área de transferência de calor utilizando o método de simulação de rede (NSM – Network Simulation Method), que consiste na resolução destes problemas pela analogia existente entre os circuitos térmicos e os circuitos elétricos. Nele será apresentada a validação do problema bidimensional de condução de calor em um cilindro, no qual, serão confrontadas as soluções obtidas por simulação com a solução obtida analiticamente via Técnica da Transformada Integral Generalizada (GITT). Nas simulações realizadas fazse a discretização do corpo em estudo, com o objetivo de se estabelecer uma correlação entre a quantidade de células (refinamento da malha) e a relação entre o tamanho do raio e comprimento do cilindro para que a solução do problema de transferência de calor no corpo possa ser considerada unidimensional. A comparação se dará entre a resposta analítica e a obtida por simulação, variando o número de divisões e as diferentes relações entre as dimensões raio e comprimento do cilindro. A partir da solução validada pela metodologia proposta, o trabalho apresenta como aplicação, uma malha genérica elaborada através do NSM e implementação no PSPICE, a qual serve para resolução de diversos problemas de condução de calor em geometria cilíndrica.

Ce travail concerne l’étude du renforcement de structures en pierres par matériaux composites. Deux techniques de renforcement sont utilisées. L’un s’agit de renforcement par matrice cimentaire renforcé avec de textile de fibre de verre TRC. L’autre est renforcement par barres de fibre de verre de FRP suivant la technique de NSM (near-surface mounted). La première phase consiste en la caractérisation des matériaux et l’analyse des comportements mécaniques en compression en cisaillement et en traction de petits éléments de maçonnerie composées d’un assemblage de pierre et mortier bâtard. Les valeurs caractéristiques du comportement mécanique de la maçonnerie sont comparées avec les différents modèles dans la littérature qui calculent les paramètres caractéristiques avec une bonne approximation avec les résultats expérimentales. En plus, le comportement de matériaux de renforcement sont testés en traction ainsi que le comportement de l’adhésion entre le renfort et la maçonnerie est étudié. La deuxième phase se concentre sur le renforcement de murs de maçonnerie soumis sur deux types de chargement. L’un s’agit de cisaillement dans le plan des murs effectué avec l’essai de compression diagonale. Le deuxième représente des charges de flexion à 3 points hors plan des murs accompagné par des forces de compression axiale qui provoque une contrainte de compression de 0.2 MPa. L’essai de cisaillement s’est réalisé sur des murs carrés de cinq rangées de pierres avec mortier. Le renforcement par deux barres verticales de NSM FRP améliore significativement la ductilité et le module de cisaillement des murs, ainsi que le renforcement avec deux couches orthogonales de TRC améliore la résistance au cisaillement. Enfin l’application de modèles analytiques a permet de comparer les résultats expérimentaux aux résultats donnés avec les modèles. En plus, l’essai de flexion à 3 points est effectué sur des murs composés de douze rangées de pierres avec mortier. Le renforcement avec deux barres verticales et deux barres transversales a plus augmenté la rigidité élastique. En revanche, le renforcement avec TRC composé d’une seule couche de textile accompagné avec une barre verticale de FRP n’augmente pas la résistance de mur par rapport à la résistance du mur renforcé avec une seule couche de textile ou avec une barre verticale seule / This work concerns the study of the reinforcement of stone structures with composite materials. Two reinforcing techniques are used. One is reinforcement by cement matrix reinforced with textile TRC of glass fiber. The other is by reinforcing FRP fiberglass rods according to NSM technique (near-surface mounted). The first phase consists of materials characterization and analysis of mechanical behavior in compression shear and tensile of small masonry specimens made of stone and mortar. The characteristic values of the mechanical behavior of the masonry are compared with the different models in the literature which calculate the characteristic parameters and give a good approximation with the experimental results. In addition, the behavior of reinforced materials is tested in tension and the behavior of the adhesion between the reinforcement and the masonry is studied. The second phase focuses on strengthening masonry walls subjected to two types of loading. One is in-plane shear of walls made with the diagonal compression test. Represents the second bending loads to 3 points out of plane walls accompanied by axial compression forces which cause a compressive stress of 0.2 MPa. The shear test was performed on square walls of five rows of stones with mortar. Strengthening by two vertical bars NSM FRP significantly improves the ductility and shear modulus of the walls and the reinforcement with two orthogonal layers TRC improves shear strength. Finally the application of analytical models used to compare the experimental results with the results given by the models. In addition, the bending test with 3-point is carried out on walls composed of twelve rows of stones with mortar. The reinforcement with two vertical bars and two crossbars increased more elastic stiffness. However, the reinforcement with TRC composed of a single layer of textile accompanied with a vertical bar FRP does not increase the resistance of the wall relative to the resistance of the reinforced wall with a single layer of textile or with a simple vertical bar

Ενίσχυση σε κάμψη στοιχείων οπτοπλινθοδομής με τη χρήση συνθέτων υλικών ανόργανης μήτρας και με την τοποθέτηση σύνθετων ράβδων σε εγκοπές. Περιγραφή διαδικασίας ενισχύσεων, πειραματικής διαδικασίας, πειραματικών αποτελεσμάτων και θεωρητική ανάλυση. / Reinforcement of masonry using TRM(Textiles Reinforced with mortar)and NSM.

The study involved Indigenous communities of Saskatchewan and Alberta which are adversely impacted by industrial activities in their traditional territory. The overall goal of this study is: the assessment of social media in risk studies among Indigenous communities of western Canada. The methods used were: interviews, focus group discussion (FGD), and net-mapping. Results showed that the majority of youths communicated around risk using new social media (NSM) in event of risk outbreak, while Indigenous Elders, communicated face-to-face and via cell-phone. Results also showed that youths use Traditional Knowledge learnt from the Elders to understand Chronic wasting disease (CWD) risk, interpret, communicate and mobilize around mitigation. The study concluded that the use of NSM is becoming increasingly important for scoping information around wildlife decline and emergency in these Indigenous communities.

Arbeitswissenschaftliche digitale Menschmodelle werden als Werkzeuge virtueller Ergonomie zur Gestaltung menschengerechter Produkte und Arbeitsplätze genutzt. Der bislang nur qualitativ beschriebene Praxiseinsatz wird durch theoretische Analysen und eine empirische Studie systematisiert und darauf aufbauend werden die Schwachstellen der Systeme erörtert. Ein wesentlicher Ansatzpunkt für Weiterentwicklungen ist die Erarbeitung ergonomischer Bewertungsverfahren bzw. -modelle, insbesondere für Belastungen aufgrund von Bewegungen. Digitale Menschmodelle bieten das Potenzial, aus simulierten Bewegungsdaten und den damit zusammenhängenden Belastungen eine Bewertung der Arbeitsvorgänge zu generieren. In dieser Arbeit wird daher ein neues arbeitswissenschaftliches Bewertungsmodell für muskuläre Beanspruchungen erforscht, d.h. methodisch hergeleitet und evaluiert. Dazu ist ein Versuchsstand zur Standardisierung und Belastungserzeugung notwendig. In der darauffolgenden Laborstudie werden die Belastungsparameter statischer Momentanteil, Winkelgeschwindigkeit und Momentrichtung variiert und die daraus entstehende Veränderung der muskulären Beanspruchung von Probanden erforscht. Ein dafür benötigtes, neues Verfahren zur Normalisierung wird vorgestellt. Die Laborstudie zeigt, dass der statische Momentanteil linear steigend mit der Arbeitsbeanspruchung zusammenhängt. Die durchschnittliche Winkelgeschwindigkeit beeinflusst die Arbeitsbeanspruchung je nach Muskeltyp entweder linear steigend oder ohne Zusammenhang. / Digital human models for human factors are used as tools for virtual ergonomics and the design of products and workplaces. In this work the use of the systems is analysed with theoretical models and an empirical study. Therefore, disadvantages of the systems are identified. A main idea for further developments is the research on ergonomic approaches and models, especially for movements and the strain caused by movements. Digital human models are capable to assess work processes based on data from simulations. In this work a new human factors orientated rating model for muscular strains is developed and evaluated. A test stand generates and standardizes the stress. In a laboratory survey the stress parameters are analysed. The variation of the static torque part, the angular velocity and the torque direction cause changes in the muscular strains. Hence, these muscular strains are measured electromyographically. A new normalisation method, the normalized standard movement, is introduced. The survey shows the existence of a correlation of static torque part and work strain. Depending on the muscle type, the angular velocity either affects the work strain linear increasing or does not affect it.

Chapter 3 Groundnut Bud Necrosis Virus (GBNV) is a tripartite ambisense RNA plant virus that belongs to serogroup IV of Tospovirus genus. Non-Structural protein-m (NSm), which functions as movement protein in tospoviruses, is encoded by the M RNA. In this chapter, we demonstrate that despite the absence of any putative transmembrane domain, GBNV NSm associates with membranes when expressed in E. coli as well as in N. benthamiana. Incubation of refolded NSm with liposomes ranging in size from 200-250 nm resulted in changes in the secondary and tertiary structure of NSm. A similar behaviour was observed in the presence of anionic and zwitterionic detergents. Furthermore, the morphology of the liposomes was found to be modified in the presence of NSm. Deletion of coiled coil domain resulted in the inability of in planta expressed NSm to interact with membranes. Further, when the C-terminal coiled coil domain alone was expressed, it was found to be associated with membrane. These results demonstrate that NSm associates with membranes via the C-terminal coiled coil domain and such an association may be important for movement of viral RNA from cell to cell. Further NSm was shown to be phosphorylated by N. benthamiana and tomato crude sap as observed in other movement proteins. Chapter 4 This chapter deals with localization of NSm to PD and identification of domain involved in localization. For this purpose NSm and its mutants were cloned in pEAQ:GFP vector and transiently expressed in N. benthamiana by infiltration of transformed Agrobacteria. The GFP tagged NSm was visualized by confocal microscopy. The results demonstrated that NSm forms punctate structures and localizes to PD as confirmed by colocalization of mCherry: PDLP1a, a PD marker which resides in PD, with GFP:NSm. To find out the domain involved in PD localization, sequential deletion mutants were made. It was found that C-terminal domain is involved in PD localization. On the other hand, N-terminal unfolded region was dispensable for PD localization. This is the first report of a coiled coil domain shown to be involved in PD localization. It has also been demonstrated that GBNV NSm interacts with NP. Further, membrane floatation assay carried in presence of NP suggested that interaction of NSm and NP affected membrane association of NSm. These results were further confirmed by localization studies of NSm in presence of NP. It was found that there was considerable relocalization of both NSm and NP. NSm was observed to be present in cytoplasm as well as on the membrane. At the same time, NP was observed on membrane apart from being present in the cytoplasm. When N-terminal 50 amino acids (unfolded) region of NSm was deleted and colocalization studies were carried out, it was found that NSm and NP do not colocalize, suggesting that NSm interacts with NP via the unfolded region and helps in the relocalization of NP to the membrane. Chapter 5 This chapter deals with the pathway of targeting NSm to PD. To decipher the pathway, followed by NSm, an inhibitor of endomembrane or vesicle mediated transport, Brefeldin A (BFA) was used. When GFP-NSm was expressed it was observed to form punctate structure at PD as before. Upon treatment with BFA, green islands were observed in the cytoplasm suggesting that ER was involved in targeting NSm to PD. Similarly, LatB, inhibitor of actin mediated targeting of protein to membrane, also abrogated the localization of NSm to PD. In order to further understand the role of ER in targeting NSm to PD, an ER marker, ER-GFP (GFP fused to HDEL peptide that directs it to ER) was coexpressed with GBNV NSm fused to mCherry. It was observed that NSm colocalizes with ER-GFP as yellow puncta on PD. The puncta appeared as patches and the whole ER-network was converted to vesicles. This was further confirmed by coexpressing ER-GFP with NSm without any tag. The green fluorescent vesicles were observed preferentially near cell membrane. To delineate the region of NSm involved in vesicle formation, point mutants and deletion mutants of NSm were generated without the tag and coexpressed with ER-GFP. When N-terminal 203 amino acids were deleted, NSm was able to transform ER membranes to vesicles suggesting that these residues are dispensable for vesicle formation. Interestingly, the deletion of coiled coil domain leads to cytosolic location of NSm. Furthermore, the C-terminal coiled coil domain when expressed alone was capable of inducing vesicle formation. This is the first report of involvement of such a domain in ER membrane association and vesicle formation.

Most reinforced concrete (RC) structures are continuous in some way, and many of these structures are strengthened using fibre-reinforced polymer (FRP) materials as a routine basis. The problem of how to exploit moment redistribution in FRP-strengthened continuous RC structures is still unresolved. Reduction in ductility has been recognised in such structures. However, FRP-strengthening is introduced as an effective method to enhance the strength and load bearing capacity of RC structures. As a result, design guidelines worldwide employ conservative guidance for design, such that they limit the potential exploitation of moment redistribution in FRP-strengthened members. To date, limited research has been conducted into the redistribution of bending moment in such structures. Previous theoretical studies have not yet led to a reliable and rigorous solution for quantifying moment redistribution throughout the loading cycle. In addition, a wide scatter of moment redistribution percentage findings, from zero to 56%, has been reported in previous experimental studies. This demonstrates the need for further research to effectively characterise the circumstances under which moment redistribution can be relied on, both into and out of FRP-strengthened zones in continuous RC flexural members. This research aims to encourage the use of FRP for strengthening existing RC structures in a more efficient manner. The findings help to better understand restrictions on moment redistribution into and out of FRP-strengthened zones, effect of mechanical anchorage of the FRP on the degree of moment redistribution, and the extent to which moment redistribution can be relied on. A new analytical model, only based on structural mechanics, is developed in this research. A comprehensive set of large-scale structural testing is undertaken to validate the analytical model under various strengthening circumstances. The analytical and experimental results show that moment redistribution can occur into FRP-strengthened zones to full capacity without any limitation, even if the FRP is unanchored. Further, bending moment can also be redistributed out of strengthened zones to a considerable extent (up to 20%), depending on the quantity and stiffness of the FRP, and provided that the FRP is fully anchored. A set of parametric studies is conducted to investigate the effectiveness of different parameters on the level of moment redistribution. The major parameters include compressive strength of concrete, steel reinforcement proportion, steel yield strength, FRP quantity and stiffness, ultimate strain of the FRP, strengthening configuration, load position, beam shape, and curvature ductility. The outcomes demonstrate that it is not only the curvature ductility of FRP-strengthened sections that is important to the capacity for moment redistribution (out of such zones), but also the mode of failure, strength of the other critical zones, the ratio of stiffness between the critical zones, and the loading arrangement. It is concluded that moment redistribution in continuous FRP-strengthened concrete structures should be permitted both into and out of strengthened zones, provided that the criteria for such redistribution are met.