Dissertations / Theses on the topic 'Pile FRP'

This dissertation presents findings from three separate investigations, a laboratory study and two field studies that evaluated the durability of the Fiber Reinforced Polymer (FRP)-concrete bond. The laboratory study explored the role of porosity on CFRP-concrete bond following immersion in warm water. Two disparate field studies measured residual bond after 20 years outdoor exposure of FRP repairs of full-size masonry walls and after 12 years for partially submerged piles supporting the Friendship Trail Bridge, Tampa Bay. The ACI 440 code requires the same surface preparation for all externally bonded FRP concrete repairs. This disregards the role of porosity that is a function of the water / cementitious (w/c) ratio. Concretes with high w/c ratios are low strength concretes, have large voids and a more elaborate capillary pore network compared to low w/c, high strength concretes. Epoxies will therefore penetrate deeper into high porosity concretes. As a result, the performance of low strength, high porosity concrete under moisture exposure can be anticipated to be superior. The laboratory study was intended to determine whether this hypothesis was correct or not. Three different concrete mixes with water / cementitious ratios of 0.73, 0.44 and 0.25 representing high, medium and low porosities were used for the study. The corresponding target compressive strengths were 2,500 psi, 5,000 psi and 7,500 psi respectively. A total of eighteen, 9 in. x 9 in. x 2.5 in. thick slabs, three for each concrete porosity were tested. Slabs were allowed to cure for over 90 days before surfaces were lightly sand blasted to provide the required concrete surface profile (CSP 3). Specimens were then pre-conditioned in an oven for 48 hours to ensure uniform drying. Concrete porosity was characterized using mercury porosimetry, SEM, 3D surface scanning and images obtained using a portable microscope. Two commercially available CFRP materials were bonded to the oven-dried prepared slab surfaces and the epoxy allowed to cure at room temperature for 4 weeks. Twelve FRP bonded slabs were completely submerged in potable water at 30 oC (86 oF) as part of the aging program. The six remaining slabs were used for establishing baseline bond values through destructive pull-off tests. The twelve exposed slabs were similarly tested following 15 weeks of exposure. Results showed minimal degradation in the high porosity, low strength concrete but over 20% reduction in the low porosity, higher strength concrete. Analysis of the failure plane indicated that the lower porosity of the high strength concrete had limited the depth to which the epoxy could penetrate. This was confirmed from magnified images of the bond line taken using a microscope and from a careful assessment of the failure mode. Findings also suggest that the CSP 3 surface profile (light sand blasting) may be adequate for lower strength concrete but not so for higher strength concrete. For applications where FRP concrete repairs of higher strength concrete are permanently or intermittently exposed to moisture, alternative surface preparation may be needed to allow epoxy to penetrate deeper into the concrete substrate. The viscosity of the resin hitherto not considered may be a critical parameter. In 1995, two full-scale concrete masonry walls were repaired using three horizontally aligned 20 in. (508 mm) wide uni-directional carbon fiber sheets using different commercially available epoxies. Twenty years later the CFRP-CMU bond was determined through selective pull-off tests that were preceded by detailed non-destructive evaluation. Results showed that despite superficial damage to the top epoxy coating and debonding along masonry joints, the residual CFRP-CMU bond was largely unaffected by prolonged exposure to Florida’s harsh environment. Therein, 99% of samples exhibited in cohesive failure of the CMU or mortar. Pull-off strength was poorer at mortar joints but because the CFRP was well bonded to the masonry surface, its impact on structural performance of the repair was expected to be minimal. Overall, the repairs proved to be durable with both epoxy systems performing well. The Friendship Trail Bridge linking St. Petersburg to Tampa FL was demolished in 2016. This was the site of three disparate demonstration projects in which 13 corroding reinforced concrete piles were repaired using fiber reinforced polymer (FRP) in 2003-04, 2006, and 2008. The repairs were undertaken using combinations of carbon and glass fiber, pre-preg and wet layup, epoxy and polyurethane resin, and were installed using either shrink wrap or pressure bagging. Residual FRP-concrete bond was evaluated after up to 12 years of exposure through 120 pull-off tests conducted on 10 representative repaired piles. Results showed a wide variation in the measured pull-off strength depending on the type of resin, the number of FRP layers, the prevailing conditions at the time the epoxy was mixed and the method of installation. Epoxy-based systems were found to be sensitive to ambient conditions at installation. Pressure bagging improved performance. The highest residual bond was recorded in pressure bagged piles repaired in 2008. The findings suggest that in marine environments epoxy-based systems installed using pressure bagging can lead to durable repairs.

Fiber Reinforced polymer composite materials offer great potential for waterfront structural applications due to their excellent corrosion resistance, and high strength to weight ratio.
The purpose of this thesis is to develop a deflection based design approach for composite sheet pile wall, based on the traditional free-earth support method, but modified to allow the use of deflection criterion. With a simplified earth pressure loading on the wall, the relationship between maximum bending moment and maximum bending deflection and the relationship between maximum shear force and maximum shear deflection were established. 16 case studies were carried out to include walls ranging from 1.5m to 4.5 m tall and water level to wall height ratio from 0.1 to 0.4. Two deflection limits, L/60 and L/100 were employed in developing the design charts.
To implement the deflection based design, the proper characterization of flexural rigidity (EI) and shear rigidity (KAG) of the sheet pile panels was vital. Tests were conducted on the connected panels to obtain the rigidities. (Abstract shortened by UMI.)

Fibre reinforced polymer (FRP) composites represent an alternative construction material for deep foundations that have the potential to eliminate most of the durability concerns associated with traditional piling materials. Research studies and database related to the use FRP composite material as piling foundation is very limited. This research project was undertaken to investigate the structural and geotechnical behaviour of FRP composite piles. The originality of this study rests on the following pillars:• Presenting a new understanding for the factors controlling the compressive strength of FRP tube confined concrete. • Introducing the concept of constitutive interface surface which considers the effect of surface hardness and relative roughness on the interface shear coefficient. • Studying the evolution of FRP pile surface roughness during the driving process. • Investigating the effect of harsh environments on the shear behaviour of FRP-granular interface. • Conducting an extensive experimental and numerical study to characterize the FRPs and soil parameters that control the behaviour of axially and laterally loaded FRP composite pile. Experimental testing program was conducted in this study to examine the behaviour of two different FRPs tubes confined concrete under axial compression, and flexural load. Based on the experimental results of this study and test results available in the literature, a new design chart was proposed to predict the strength enhancement based on concrete strength and FRP lateral confinement. An extensive laboratory study was conducted to evaluate the interface friction behaviour between granular materials and two different FRP materials. The interface test results obtained from experiment were used to examine a number of parameters known to have an effect on the interface friction coefficient. Furthermore, to investigate the evolution of FRP pile surface roughness during the driving process laboratory tests were also conducted to quantify the interface shear induced surface roughness changes under increased normal stress levels. Moreover, interface tests were also conducted using three more counterface materials to define schematically the constitutive interface shear surface (CISS) in the three dimensional domain of surface roughness, surface hardness, and interface shear coefficient. The long-term experimental program was also conducted in this study to assess the effect of different ageing environment conditions on FRP-granular interface shear coefficient. Acidic and alkaline aging environments were adopted in this study. The experimental program involved assessing the ageing effect on the testing FRP materials in terms of the changes in their hardness and surface roughness properties. Furthermore, the interface shear tests were conducted, using the unaged and aged FRP materials, to evaluate the effect of aging environments on FRP-granular interface shear coefficient. A small-scale laboratory pile loading tests were carried out to assess the FRP pile behaviour under axial and lateral loads. The laboratory test results were used to verify/validate a numerical model developed by the commercial finite element package ABAQUS (6.11). Additional numerical analyses using the verified model were conducted to investigate the effect of different the FRPs and soil parameters on the engineering behaviour of FRP pile.

L'étude des systèmes pieux-sol est d'une importance capitale dans le domaine de l'ingénierie géotechnique, car elle est directement liée à la stabilité et à la fiabilité des structures et des infrastructures. Ce travail étudie le comportement mécanique des systèmes pieux-sol, en mettant l'accent sur les pieux en polymère renforcé de fibres (FRP) et les mélanges caoutchouc-sol (RSM). Trois aspects principaux sont étudiés à l'aide de simulations de dynamique moléculaire (MD). Tout d'abord, les propriétés de frottement à l'interface entre le pieu FRP et l'argile sont étudiées à l'aide d'un modèle kaolinite-époxy, qui donne une valeur calculée de 159 mJ/m2 pour le travail d'adhésion. Les coefficients de cisaillement interfaciaux maximaux diminuent de manière non linéaire avec l'augmentation de la contrainte normale. Le processus de frottement interfacial est caractérisé par le fait qu'il dépend de la vitesse avec des plages de vitesse distinctes, et ces caractéristiques sont prises en compte par la théorie de Bell étendue. On observe que le mouvement de stick-slip se manifeste exclusivement dans les scénarios où les vitesses de glissement sont faibles. Cette tendance à l'augmentation des barrières énergétiques avec l'augmentation des contraintes normales met en évidence l'augmentation des forces de traction nécessaires pour induire le glissement du PRFV le long de l'interface avec l'argile dans des conditions de contraintes normales plus élevées.Deuxièmement, les simulations MD étudient la friction interfaciale à l'interface pieu-sable FRP dans diverses conditions de sécheresse, d'eau pure et d'eau salée. Une résine époxy réticulée est synthétisée pour étudier ses interactions avec la silice cristalline. Les relations force-déplacement de frottement présentent des phases non linéaires et stables distinctes. Les profils de rigidité tangentielle, en particulier à des niveaux de contrainte normale plus faibles, montrent des réductions plus rapides pour atteindre l'état d'équilibre. Les molécules d'eau agissent comme des lubrifiants, les ions NaCl affectant leur efficacité. Les systèmes secs ont le coefficient de frottement le plus élevé, suivis par les systèmes à l'eau salée et à l'eau pure.Troisièmement, l'interaction à l'interface caoutchouc/sol est étudiée dans le cadre de la RSM à l'aide de simulations MD. La force de frottement augmente avec la distance de glissement et la contrainte normale, ce qui est cohérent avec le comportement de frottement entre les sols naturels. Le compactage du caoutchouc et de l'argile augmente les forces de frottement et améliore les propriétés techniques. Les particules de caoutchouc réduisent le mouvement de glissement à l'interface montmorillonite-caoutchouc, en fournissant un effet d'amortissement qui réduit l'intensité des vibrations de glissement pendant le glissement. Les paramètres interfaciaux et les coefficients de frottement sont déterminés et concordent avec les données expérimentales, ce qui améliore la compréhension du comportement du RSM et les applications dans les fondations des sols.Enfin, cette étude introduit un élément intégré pieu-sol efficace pour simuler le comportement des pieux tout en tenant compte de la non-linéarité du sol et du matériau du pieu à l'échelle macroscopique. Les charnières plastiques et les ressorts du sol sont intégrés dans les formulations d'éléments proposées, de sorte qu'un seul type d'élément suffit pour simuler commodément les interactions non linéaires entre le pieu et le sol. Un programme Python a été développé sur la base de la méthode des éléments finis (FE), et la procédure d'analyse détaillée est donnée. La validation à l'aide d'essais sur le terrain démontre la précision de l'analyse du comportement des pieux sous des charges latérales et axiales
The study of pile-soil systems is of paramount importance in the field of geotechnical engineering, as it is directly related to the stability and reliability of structures and infrastructure. This work investigates the mechanical behavior in pile-soil systems, with emphasis on fiber-reinforced polymer (FRP) piles and rubber-soil mixes (RSM). Three main aspects are investigated using molecular dynamics (MD) simulations. First, friction properties at the FRP pile-clay interface are studied using a kaolinite-epoxy model, which yields the calculated work of adhesion value of 159 mJ/m2. The peak interfacial shear coefficients decrease nonlinearly with increasing normal stress. The interfacial friction process is characterized by its velocity-dependent with distinct velocity ranges, and these characteristics are captured by the extended Bell theory. It is observed that stick-slip motion manifests itself exclusively in scenarios with lower sliding velocities. This observed trend of increasing energy barriers with increasing normal stresses highlights the increased pulling forces required to induce FRP sliding along the clay interface under higher normal stress conditions. Second, MD simulations investigate the interfacial friction at the FRP pile-sand interface under various dry, pure water, and salt water conditions. A cross-linked epoxy resin is synthesized to study its interactions with crystalline silica. Friction force-displacement relationships show distinct nonlinear and steady-state phases. Tangential stiffness profiles, especially at lower normal stress levels, show faster reductions to reach the steady-state. Water molecules act as lubricants, with NaCl ions affecting their effectiveness. Dry systems have the highest coefficient of friction, followed by salt water and pure water systems.Third, the interaction at the rubber/soil interface is studied within RSM using MD simulations. Friction force increases with sliding distance and normal stress, which is consistent with the friction behavior between natural soils. Compaction of rubber and clay increases friction forces and improves engineering properties. Rubber particles reduce stick-slip motion at the montmorillonite-rubber interface, providing a damping effect that reduces stick-slip vibration intensity during sliding. Interfacial parameters and friction coefficients are determined and agree with experimental data, improving the understanding of RSM behavior and applications in soil foundations.Finally, this study introduces an efficient integrated pile-soil element to simulate pile behavior while accounting for soil and pile material nonlinearity at the macroscale. The plastic hinges and soil springs are integrated into the proposed element formulations, so that one element type is sufficient to conveniently simulate the nonlinear pile-soil interactions. A Python program has been developed based on the finite element (FE) method, and the detailed analysis procedure is given. Validation with field tests demonstrates accuracy for the analysis of pile behavior under lateral and axial loads

Thesis (Ph. D.) -- University of Maryland, College Park, 2005.
Thesis research directed by: Civil Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.

The structural behaviour of FRP-composite (E-glass/polyester) sheet pile panels subjected to uniform pressure load was investigated. Single, connected and concrete-filled 2.13 m panels were tested to failure with the objective of determining their moment capacity and failure mechanism. As the uniform load test procedure utilized in this study allowed for the prevention of premature local crushing behaviour within the span, the average moment capacity obtained in this study was more than double that found in prior studies of FRP sheet pile panels, averaging 11.15 kN.m in single panel tests and 9.32 kN.m in connected panel tests. Single panels exhibited little difference in moment capacity whether tested in the upright or inverted orientation and there was no apparent reduction in capacity when a single panel was subjected to repeated load cycles. Failure of both single and connected panels was generally attributable to local buckling and invariably occurred at a deflection of about 50mm, indicating that deflection limits may govern design. No joint failure was observed in connected panels. (Abstract shortened by UMI.)

Typically, foundation piles are made of materials such as steel, concrete, and timber. Problems associated with use of these traditional pile materials in harsh marine environments include steel corrosion, concrete deterioration, and marine borer attack on timber piles. It has been estimated that the U.S. spends over $1 billion annually in repair and replacement of waterfront piling systems. Such high repair and replacement costs have led several North American highway agencies and researchers to investigate the feasibility of using composite piles for load bearing applications, such as bridge substructures. As used here, the term â composite pilesâ refers to alternative pile types composed of fiber reinforced polymers (FRPs), recycled plastics, or hybrid materials. Composite piles may exhibit longer service lives and improved durability in harsh marine environments, thereby presenting the potential for substantially reduced total costs. Composite piles have been available in the North American market since the late 1980â s, but have not yet gained wide acceptance in civil engineering practice. Potential disadvantages of composite piles are high initial cost and questions about engineering performance. At present, the initial cost of composite piles is generally greater than the initial cost of traditional piles. Performance questions relate to driving efficiency, axial stiffness, bending stiffness, durability, and surface friction. These questions exist because there is not a long-term track record of composite pile use and there is a scarcity of well-documented field tests on composite piles. This research project was undertaken to investigate the engineering performance of composite piles as load-bearing foundation elements, specifically in bridge support applications. The objectives of this research are to: (1) evaluate the soil-pile interface behavior of five composite piles and two conventional piles, (2) evaluate the long-term durability of concrete-filled FRP composite piles, (3) evaluate the driveability and the axial and lateral load behavior of concrete-filled FRP composite piles, steel-reinforced recycled plastic composite piles, and prestressed concrete piles through field tests and analyses, and (4) design and implement a long-term monitoring program for composite and conventional prestressed concrete piles supporting a bridge at the Route 351 crossing of the Hampton River in Virginia. A summary of the main findings corresponding to each of these objectives is provided below. A laboratory program of interface testing was performed using two types of sands and seven pile surfaces (five composite piles and two conventional piles). The interface behavior of the different pile surfaces was studied within a geotribology framework that investigated the influence of surface topography, interface hardness, and particle size and shape. In general, the interface friction angles, both peak and residual, were found to increase with increasing relative asperity height and decreasing relative asperity spacing. The interface shear tests for the three pile types tested at the Route 351 bridge showed that, for medium dense, subrounded to rounded sand, with a mean particle size of 0.5 mm, the residual interface friction angles are 27.3, 24.9, and 27.7 degrees for the FRP composite pile, the recycled plastic pile, and the prestressed concrete pile, respectively. Interface shear tests on these same piles using a medium dense, subangular to angular sand, with a mean particle size of 0.18 mm, resulted in residual interface friction angles of 29.3, 28.8, and 28.0 degrees for the FRP composite pile, the recycled plastic pile, and the prestressed concrete pile, respectively. A laboratory durability study was completed for the FRP shells of concrete-filled FRP composite piles. Moisture absorption at room temperature caused strength and stiffness degradations of up to 25% in the FRP tubes. Exposure to freeze-thaw cycles was found to have little effect on the longitudinal tensile properties of saturated FRP tubes. Analyses were performed to investigate the impact of degradation of the FRP mechanical properties on the long-term structural capacity of concrete-filled FRP composite piles in compression and bending. The impact was found to be small for the axial pile capacity due to the fact that the majority of the capacity contribution is from the concrete infill. The impact of FRP degradation was found to be more significant for the flexural capacity because the FRP shell provides most of the capacity contribution on the tension side of the pile. Full-scale field performance data was obtained for two composite pile types (concretefilled FRP composite piling and steel-reinforced recycled plastic piling), as well as for conventional prestressed concrete piles, by means of load test programs performed at two bridge construction sites: the Route 351 bridge and the Route 40 bridge crossing the Nottoway River in Virginia. The field testing at the two bridges showed no major differences in driving behavior between the composite piles and conventional prestressed concrete piles. Pile axial capacities of the composite piles tested at the Route 351 bridge were between 70 to 75% of the axial capacity of the prestressed concrete test pile. The FRP and prestressed concrete piles exhibited similar axial and lateral stiffness, while the steel-reinforced plastic pile was not as stiff. Conventional geotechnical analysis procedures were used to predict axial pile capacity, axial load-settlement behavior, and lateral load behavior of the piles tested at the Route 351 bridge. The conventional analysis procedures were found to provide reasonable predictions for the composite piles, or at least to levels of accuracy similar to analyses for the prestressed concrete pile. However, additional case histories are recommended to corroborate and extend this conclusion to other composite pile types and to different soil conditions. A long-term monitoring program for composite and conventional prestressed concrete piles supporting the Route 351 bridge was designed and implemented. The bridge is still under construction at the time of this report, therefore no conclusions have been drawn regarding the long-term performance of concrete-filled FRP composite piles. The longterm monitoring will be done by the Virginia Department of Transportation. In addition to the above findings, initial cost data for the composite piles and prestressed concrete piles used in this research were compiled. This data may be useful to assess the economic competitiveness of composite piles. The initial unit cost of the installed composite piles at the Route 40 bridge were about 77 % higher than the initial unit cost for the prestressed concrete piles. The initial unit costs for the composite piles installed at the Route 351 bridge were higher than the initial unit cost of the prestressed concrete piles by about 289% and 337% for the plastic and FRP piles, respectively. The cost effectiveness of composite piles is expected to improve with economies of scale as production volumes increase, and by considering the life-cycle costs of low-maintenance composite piles.
Ph. D.

The buckling behaviour of fibre reinforced polymer (FRP) sheet pile panels subjected to a uniform lateral pressure was investigated. Based on the previous full scale tests by Shanmugan in year 2003 (Shanmugan, 2004), the critical load at buckling initiation was first determined through experimental data analysis, and the theoretical modeling was then followed in an attempt to predict the buckling initiation and understanding the failure mechanism. The behavior of the panels loaded in upright position and inverted position was studied.
The local buckling of the compressive flanges was monitored by the strain measurements, which demonstrated that when tested in upright position, the panel failed immediately after local buckling of compressive flange, and when tested in inverted position, the panels could be able to carry the load into post buckling region. The stresses and corresponding axial forces at buckling were calculated by the classical beam flexure formula but taking into consideration the reduction of flexure rigidity and neutral axis shifting. The axial force calculated from the beam flexure formula was comparable with that from stain gauge measurements. The axial force was not uniformly distributed along the width of the compressive flange at upright position and was about zero at the free edge. When tested in inverted position, the neutral axis distance and the flexure rigidity kept almost as a constant. The sheet pile panels were with a uniform axial force along the width of the compressive flange.
An analytical modeling was performed to predict the buckling initiation. The buckling of the panel was simplified as the buckling of the compressive flange with various boundary conditions. The differential equation of the compressive flange was established based on the assumption that the flange was subjected to an in-plane axial force and an out-of-plane lateral pressure simultaneously. It was found that the lateral pressure did not have direct effect on the critical load. It was the compressive axial force that determined the local buckling of the flange. Kollar's explicit expressions were also applied but only valid for long plate loaded by uniform axial force.
The buckling load obtained by solving the differential equation for the inverted panel compared well with that from the experimental results. However, for the flange in a pile at an upright position, the theoretical prediction was far less than the experimental value which might be attributed to the non uniform axial force on the flange. Energy method was applied to estimate the range of the buckling load of a plate loaded by a linearly distributed axial force. The upper bound value was obtained from fixed boundary condition and the lower bound from simply supported assumption. The experimental result was found in between the two bounds and was in favour of the lower bound as a conservative estimation of critical load for upright panel.

El presente estudio es realizado en el Hospital Central de Aeronáutica donde se atiende población militar y civil (familiares directos de estos, y un escaso número de personal ajeno a la institución pero que voluntariamente solicita atención en dicho establecimiento), en donde la raza predominante es la mestiza, aunque existe un número relativamente considerable de personas que tienen fenotipo con riesgo de melanoma maligno, de acuerdo con lo mencionado antes; principalmente el personal de oficiales y/o sus familiares cercanos. Debido al considerable aumento progresivo de casos de melanoma maligno cutáneo, esta patología se está convirtiendo en un importante problema de salud pública en los países con la más alta incidencia de esta enfermedad. Por esta razón y para evaluar cómo es el comportamiento de esta entidad en la población que se atiende en el Hospital Central de la Fuerza Aérea, el cual es un centro asistencial de nivel IV, es que me motiva a realizar el presente estudio retrospectivo correspondiente a los últimos 10 años.
Tesis de segunda especialidad

Descrizione dei vantaggi della tecnologia delle fondazioni da pozzo per le pile da ponte. Analisi dei carichi di un viadotto esistente a struttura mista e studio agli stati limite delle più svantaggiose condizioni di carico. Analisi sismica della pila. Progetto e verifica della pila, del plinto e del pozzo nelle diverse fasi di realizzazione e per le combinazioni di carico considerate. Verifiche del terreno, con riferimento ai criteri di dimensionamento del Prof. Jamiolkowski. Analisi tenso-deformativa del terreno con software Plaxis2D e Midas-GTS (3D). Confronti fra il metodo analitico adottato nelle verifiche ed i risultati numerici. Norme di riferimento: NTC2008, Istruzione N°I/SC/PS-OM/2298, Ordinanza 3274 come modificato dall'OPCM 3431

Les infections à Pseudomonas aeruginosa chez l’homme représentent un problème de santé publique important car elles sont souvent graves et peu de solutions thérapeutiques sont disponibles face aux souches multi-résistantes isolées de façon extrêmement fréquente. La multi-résistance de cette bactérie et sa persistance est connue maintenant pour être associée à sa capacité à vivre en communauté in vivo comme c’est le cas par exemple dans les voies aériennes des patients atteints de mucoviscidose. Dans ce contexte, P. Aeruginosa s’établit sous forme de microcolonies dont le regroupement va résulter dans la formation d’un biofilm structuré, auquel différents acteurs moléculaires participent de façon séquentielle et synergique ou antagoniste. Parmi ceux-ci, une machinerie d’assemblage de pili de type IVb codée par 12 gènes formant le locus tad, assemble des appendices formés par l’oligomérisation de sous-unités pilines Flp, et confère à la bactérie la capacité à former des agrégats et à initier un biofilm. Mon travail de thèse a permis d’identifier les conditions d’expression chromosomique de la sous-unité Flp qui se révèlent être optimales en phase tardive de croissance et en conditions aérobies. La présence dans le locus d’un couple de gènes codant pour un système à deux composants (TCS) classique, le TCS PprA-B suggérait qu’il pouvait avoir un rôle dans l’expression du locus tad. Le régulateur de réponse PprB contrôle l’expression des 5 unités transcriptionnelles du locus tad. TadF correspond à l'unique piline mineure du système, et n’est pas essentielle à la formation du pilus. La protéine RcpC, qui n’est présente qu’au sein des machineries Tad, semble impliquée dans la modification post-traductionnelle de la sous-unité Flp et module le phénotype d’adhérence des bactéries aux cellules épithéliales bronchiques. Le pilus Flp n’est qu’un des acteurs moléculaires de l’adhérence et de la formation du biofilm. Le second axe de ma thèse a été la mise au point d’une puce dédiée à l’étude de la transcription de ces gènes ou « adhésome ». Elle permettra d’avoir une vue globale de l’expression de ces systèmes au cours des différentes étapes du développement du biofilm et de l’infection ex vivo comme chez les patients atteints de mucoviscidose
Human P. Aeruginosa infections have become a serious threat to public health because they are often serious and very difficult to treat due to the emergence of strains resistant to all known antibiotics. Multi-resistance and persistence of this bacterium is known to be associated with its capacity to live within a sedentary community lifestyle in vivo, called biofilm, as it is the case in the airways of cystic fibrosis patients. In the biofilm, bacteria are associated in microcolonies which grow within an autoproduced matrix and lead to a highly structured community. A large number of macromolecular systems are expressed in a sequential manner and probably act in synergy or antagonism. Among them, the Tad machine encoded by the tad locus constituted of 12 genes, assembles Flp type IVb pili at the surface of the bacteria and helps bacteria to aggregate and to initiate biofilm formation. During my PhD work, we identified the conditions of chromosomal production of the Flp pilin subunit, which is highly produced in the very late stationary growth phase and under aerobic conditions. The identification of two genes encoding a classical two-component system within the tad locus, PprAB, suggested that it could play a role in the control of tad genes. The response regulator, PprB, positively controls the expression of the five transcriptional units forming this tad locus. TadF is the unique minor pilin of the Tad system but no implication in Flp pilus biology could be unravelled. The RcpC protein, which is unique to Tad machines, controls an Flp pilin post-translational modification but not its assembly into pilus. The RcpC-dependent Flp pilin modification which could be a glycosylation, affects the efficiency of the Flp-host receptor interaction. The type IVb Flp pilus is not the unique macromolecular system involved in the adhesion and P. Aeruginosa biofilm structuring. A second axis of my PhD period was devoted to the development of a dedicated chip (ADH chip) with the aim to obtain a global view of the expression of these systems during the formation of a biofilm in vitro and ex vivo in a large number of clinical strains isolated during the infection in the lungs of cystic fibrosis patients

Les défaillances des logiciels dans les systèmes temps réel strict peuvent avoir des conséquences graves (pertes économiques, mise en danger de la vie humaine). La vérification des contraintes temporelles d'un système temps réel strict dépend de la connaissance du pire temps d'exécution des tâches a priori. Cependant, déterminer le pire temps d'exécution d'une tâche seule n'est pas trivial sur lesarchitectures des processeurs actuels. L'utilisation de mécanismes matériels complexes a un grand impact sur la prévisibilité des performances. Ce document se focalise sur les problèmes de l'analyse temporelle des accès mémoire vers les données des programmes qui s'exécutent sur une architecture munie d'une hiérarchie mémoire (mémoire cache ou mémoire sur-puce, nommée communément mémoire scratchpad). Plusieurs approches sont proposées pour la prévisibilité et l'amélioration du pire temps d'exécution des tâches qui s'exécutent sur une architecture munie d'une hiérarchie mémoire
Software failures in hard real-time systems can have serious consequences (economic risks, human life losses). The verification of timing constraints of a real-time system depends on the safe estimation of the worst-case execution time (WCET) of tasks. However, the estimation of the individual task's worst-case execution time is not trivial. The uses of complex mechanisms in computer architectures have a significant impact on the execution time predictability. This document focuses on the problems of timing analysis of data memory accessesfor computer architecture with a memory hierarchy (a scratchpad memory or a cache memory). We propose approaches to improve the worst-case execution time of the tasks and to tackle the lack of predictability of the memory hierarchy

Guiron le courtois, vaste roman de chevalerie en prose composé du Roman de Meliadus et du Roman de Guiron a été copié, remanié, compilé dans de nombreux manuscrits depuis sa création, entre 1235-1240, jusqu’à la fin du Moyen Âge. Sa matière ouverte à toutes les continuations en fait une œuvre aux contours flous. Le manuscrit BnF fr. 340 (fin XIVe-début XVe siècle), associant le Roman de Meliadus et la Compilation de Rusticien de Pise, forme un ensemble où se dessine la chevalerie errante des pères des grands héros arthuriens, animée par la violence des combats, l’abondance du sang versé, mais aussi par la joie des rencontres et de la parole échangée. C’est cette communauté vivante que cette thèse entreprend d’analyser, à travers l’exploration conjointe du texte et de l’image du manuscrit BnF fr. 340, dont l’analyse iconographique sera ouverte à d’autres programmes de manuscrits de la même période
Guiron le courtois—a vast chivalric novel written in prose and composed of the Roman de Meliadus and of the Roman de Guiron—was copied, redrafted, compiled in various manuscripts since its creation spanning from 1235-1240 to the end of the Middle Ages. Its material allows all kinds of continuations which makes it a work with blurred outlines. The manuscript BnF fr. 340 (End of 14th-Beginning 15th Century) associates the Roman de Meliadus and the Compilation of Rusticien de Pise; it forms a whole in which can be seen wandering knights, namely the fathers of the great Arthurian heroes driven by violent fights and a desire to shed blood abundantly, but also by merry encounters and word exchanges. This thesis ends at analysing this lively community through the exploration of both text and imagery in the manuscript BnF Fr 340; this iconographic analysis leads to the study of new programs of manuscripts dating back to the same period

L’information des patients est devenue un enjeu de santé publique et une composante essentielle de la relation médecin patient. De nombreux auteurs s’accordent à dire que l’information écrite est un complément indispensable à l’obligation d’information orale car elle améliore la qualité des soins et l’adhérence du patient à sa prise en charge. Malgré l’existence de nombreuses Fiches d’Information Patient (FIP), le médecin a du mal à se les approprier. Elles sont souvent non validées, peu lisibles, difficiles à stocker, sans références, sources ni dates de rédaction. La première étape de notre travail a consisté à proposer une méthode pour élaborer des fiches d’information du patient (FIP) et à partir d’elle, 125 FIP concernant des motifs de consultation les plus fréquents en soins primaires. Une étude observationnelle réalisée dans 26 cabinets de médecine générale auprès de 350 patients, a montré d’une part que les patients sont demandeurs de FIP et qu’elles sont appréciées des patients. Et d’autre part, que la compréhension des maladies aiguës est plus limitée que celles des maladies chroniques ou situations de prescription chez les patients à faible niveau scolaire. Une étude interventionnelle randomisée en clusters réalisée dans 24 cabinets de médecine générale auprès de 400 patients, nous a permis de montrer que les FIP permettaient aux patients d’améliorer leur niveau de connaissances sur les pathologies et de modifier positivement leur comportements de santé, y compris pour les patients à faible niveau scolaire. Néanmoins, il n’était pas possible de comparer ces résultats à ceux de la littérature, les protocoles de recherche étant trop hétérogènes (critères de jugement spécifiques d’une situation clinique donnée).Pour surmonter cette difficulté, nous basant sur une « revue des revues » de la littérature, nous avons proposé un modèle théorique décrivant les modalités d’action des FIP au cours de la consultation, à partir duquel nous avons élaboré trois scores génériques utilisables pour tout type de consultation : un score de Communication Médecin Malade (CMM), un score de satisfaction et un score d’adhérence globale. Une fois les propriétés psychométriques de ces scores validés, nous avons étudié leurs déterminants. En situation aiguë, le seul déterminant de la CMM était la qualité de l’information reçu (quoi et que faire multipliant la probabilité d’une bonne communication par 11.9), les caractéristiques du patient n’influençant pas la CMM. L’adhérence globale est déterminée par le type de pathologie (paramètre inflexible) et par la qualité de la CMM. Enfin, la satisfaction, bien que tout autant liée à l’infrastructure, à l’équipe paramédicale et à l’équipe médicale, est également améliorée par une CMM de bonne qualité. En situation aiguë, la CMM est donc primordiale et impacte sur les indicateurs santé usuels que sont la satisfaction et l’adhérence des patients.Enfin, nous avons évalué avec ces nouveaux outils l’impact de 6 FIP sur la CMM, l’adhérence globale du patient et la satisfaction dans deux services d’urgences auprès de 324 patients. Cette étude interventionnelle avant-après nous a permis de montrer que les FIP améliorent: la CMM, la satisfaction vis-à-vis des professionnels de santé, le comportement des patients (qui respectent mieux les modalités de prises des médicaments et reconsultent moins dans les services d’urgences pour une même pathologie) et le comportement des médecins (qui prescrivent moins médicaments et davantage d’examens complémentaires). En situation aiguë, un outil simple pour améliorer la CMM est l’usage de FIP délivrée en complément de l’information orale.La CMM est un critère de jugement fondamental qu’il conviendra à l’avenir d’utiliser plus souvent, notamment pour évaluer les interventions thérapeutiques non pharmacologiques en plein essor, et pour lesquelles la communication est probablement un déterminant majeur de l’efficacité
Patient information has become a public health issue and an essential component of Doctor-Patient communication (DPC). Many authors agree that written information is an indispensable complement to the obligatory oral information, since it improves the quality of care and the patient adherence. Despite the existence of numerous Patient Information Leaflets (PILs), physicians have difficulty appropriating them; they are often not validated, hard to read, difficult to store, without references, sources and dates of writing. The first step in our work was to propose a methodology for developing PILs and from there, design 125 PILs for the most common reasons for consultation in primary care. An observational study carried out in 26 general practice offices with 350 patients showed that patients appreciate PILs. On the other hand, the understanding of Acute Conditions (AC) is more limited than that of chronic diseases or prescription situations, particularly patients with a low school level. A cluster randomized interventional study performed in 24 general practice offices with 400 patients showed that PILs allowed patients to improve their knowledge about pathologies and modify their health behaviors positively, independently of their level of education. Nevertheless, the heterogeneity of the research protocols made it impossible to compare our results with those of the literature.To overcome this scientific hurdle and continue our work on the assessment of PILs, we performed a review of the literature on the subject, constructed a theoretical model describing the various effects of PILs and created three generic scales usable for evaluating the impact of PILs on any type of condition (scales of Doctor-Patient Communication, satisfaction and overall adherence). An observational study carried out in 2 Emergency Departments (ED) allowed us to validate the 3 scores, assess the psychometric properties and elucidate their determinants. In the context of AC, the only determinant of the DPC was the quality of the information received (both information "what to do" and "when to reconsult" have an adjusted Odds Ratio 11.9. Characteristics of the patient did not influence the DPC score. The overall adhesion is determined by the type of pathology (inflexible parameter) and by the quality of the DPC. Finally, although satisfaction was strongly associated with the hospital infrastructure and the attitude of the paramedical and medical staff, a high DPC score multiplied the probability of having a good satisfaction score. In a context of emergency consultations, the DPC is paramount and has an impact on the usual health indicators: satisfaction and adherence.Finally, a before-after intervention study conducted in two ED showed that PILs improve DPC, satisfaction with healthcare professionals, and adherence to medication regimens. PILs decrease the number of reconsultations for the same pathology, in particular return to the ED. They reduce the number of drug prescriptions given by the doctor in favor of complementary examinations and specialized advice. In a context of AC, a PIL given by the doctor improves DPC, the patient’s satisfaction with healthcare professionals and improves both the doctor’s and the patient’s behaviors.The DPC is a fundamental outcome that will need to be measured more frequently in the future, including in acute situations

碩士
國立海洋大學
造船工程學系
86
FRP管榫條式接合，是將一條狀榫條，插入由管材鐘口管和插口管上 榫條溝槽所構成的通道內，而達到接合的目的，當接頭承受一軸向力時， 榫條接合部份會產生極大應力，因此對於接頭榫條接合部份需要做一受力 後破壞模式的分析。 本文主要是使用有限元素分析軟體ANSYS，對於此 項榫條式接頭進行彈塑性分析，首先由拉力試驗取得所需的接頭材料性質 ，然後改變一些參數，包括榫條截面高度和寬度以及管材間的間隙，於 ANSY中分別建立模型進行分析，針對分析結果，加以評估比較，分析結果 可做為日後接頭加工及設計時的基本參考。 由ANSY分析後的應力分 佈情形，可以瞭解接頭的破壞模式，發現會在榫條鐵氟隆部份受到嚴重的 擠壓，並且產生遠久變形的破壞模式。 Locking joint is realized by inserting a cable which blocks the bell to the spigot on the sleeve to the FRP pipe. This block transfers the axial stresses along the pipes and therefore it requires very high mechanical characteristics, so we must perform a fracture analysis of Locking joint of the FRP pipe. The analysis is performed by using the software package of a Finite Element Methods, ANSYS. First, find the material properties of the coupling by tension test, then change the height and width of key lockcross section to establish the model. It has great advantages to design aLocking Coupling by performing a preliminary analysis. After performing the ANSYS analysis, we can find the fracture mode of the coupling, which is the permanent deformation in theTEFLON key lock.

As vast networks of high pressure buried energy pipelines traverse North America and other continents, the stability of such essential buried infrastructure must be maintained under a variety of earth loading conditions. The pipe-soil interaction and the longitudinal behaviour of buried pipes due to relative ground movements is poorly understood. This thesis presents full scale testing and numerical modeling of steel and Glass Fibre Reinforced Polymer (GFRP) pipelines to better understand the flexural performance of buried pipes subjected to lateral earth movement. For the experimental phase of the study, a series of pipe bending experiments have been conducted on 102 mm nominal diameter and 1830 mm long steel and GFRP pipes buried in dense sand. Pipe loading was carried out by pulling pipe ends using two parallel cables attached to a spreader beam outside the test region, using a hydraulic actuator. The different tests covered burial depth-to-diameter (H/D) ratios of 3, 5 and 7. During the steel pipe testing phase, special consideration was given to assess the effect of boundary limits, friction within the pulling mechanism, and consistency of results using repeated tests. For the GFRP pipes, the experimental work investigated the effect of the laminate structure of the pipes, including both cross-ply and angle-ply laminates. Test results showed that burial depth significantly influenced the ultimate pulling forces, longitudinal strains, and pipe net deflection at mid-span. The results were also compared between the two types of pipes. The failure mechanism for all tests was consistently governed by soil failure, except for the angle-ply GFRP pipe that failed at a burial depth of H/D=7. For the numerical analysis, the study presents the development and verification of two and three-dimensional numerical models including material constitutive models for both the pipe and for the soil using a stress-dependent modulus. Calculations are presented for different burial depths and are compared to experimental data. It was shown that the numerical model can successfully capture the pipe-soil interaction behaviour for both pipe types in terms of load-displacement responses and net bending deflection. Also, the effect of material variation and laminate structure were in agreement with test data.
Thesis (Ph.D, Civil Engineering) -- Queen's University, 2013-04-18 22:21:53.025

碩士
國立暨南國際大學
土木工程學系
96
Corrosion and deterioration of concrete piles are common problems for wharf structures. Wave impacts, cyclic wetting and drying due to tidal action, and high concentration of chlorine ions result in accelerated deterioration of marine concrete piles. Retrofit schemes for corroded marine concrete piles are similar to those for reinforced concrete (RC) columns. Among the popular retrofit methods, FRP jacketing has been attracting intensive interests in research as well as in practical application. Despite the rapid development of research and application of FRP jacketing for RC column retrofit, study on FRP jacketing for marine concrete piles is rare. As the corrosion condition facing marine piles is much different from that for RC columns, the effectiveness of the retrofit technique for corroded marine piles needs to be re-examined. A case of corrosion of prestressed concrete (PC) piles supporting landing stage structures in a harbor of Taiwan was investigated. A series of 7 reduce-scaled PC pile specimens simulating the corroded and the FRP-repaired PC piles were tested to investigate the lateral load-carrying behavior of the PC piles for the landing stage structures. The present thesis presents the analytical study on the experiments. The forced-based finite fiber element (FFE) model that has been built in the OpenSees software framework is employed. Each specimen is modeled by a forced-based FFE, which consists of 8 controlled cross sections. Each of the controlled sections is sub-divided into a number of fibers that represent the stress-strain behavior of the constituent materials, concrete or reinforcing steel, of the cross section. Two models for stirrup-confined concrete and three models for FRP-confined concrete are used and evaluated to model the uniaxial stress-strain behavior of concrete. By using OpenSees cyclic static analyses of the force-based FFE are conducted to analytically simulate the cyclic tests of the pile specimens. The analytical results are compared with the experimental curves to validate the analytical models.