The dissertation details work aimed toward the development and implementation of a 3-D impact fragmentation module to perform rock fall analysis by taking into account impact fragmentation. This fragmentation module is based on a database of a large set of impact simulations using a fully calibrated discrete element model (DEM), and is employed to predict impact fragmentation processes in rockfall analysis by either training a neural network model or linearly interpolating the database. A DEM was employed to model impact fragmentation in the study. A DEM code was developed from scratch. The model was first calibrated and verified with experimental results to demonstrate the capability of modeling both quasi-static and dynamic material behavior. Algorithms to calibrate the model’s micro-parameters against triaxial tests on rocks were presented. Sensitivity analyses were used to identify the deformability micro-parameters by obtaining relationships between microscopic and macroscopic deformability properties. The strength model parameters were identified by a global optimization process aimed at minimizing the difference between computed and experimental failure envelopes. When applied to the experimental results of tested granite, this calibration process produced a good agreement between simulated and experimental results for both deformability and strength properties. Dynamic compression and SHPB tests were performed to verify the dynamic model. A strain-rate-dependent dynamic strength was observed in the experimental results. This strain-rate-dependent dynamic strength was also confirmed by the numerical results. No rate-dependent constitutive model was used in the DEM to simulate dynamic behavior. This simulated rate-dependent dynamic strength can be attributed to material inertia because the inertia inhibits crack growth. Some fundamental mechanisms of impact fragmentation associated with rockfalls were then numerically investigated. The developed DEM code was coupled with a simplified impact model inspired by the theory of dynamic foundations. It has been shown that the magnitude of impact velocity, the angle of the incidence, the ground condition all play very important roles in impact fragmentation. Several case studies were performed to validate the developed impact fragmentation module in rock fall analysis. It has been demonstrated that the developed fragmentation module can reasonably predict impact fragmentation and perform some risk analysis in rock fall analysis. / text

In this study, a total of twelve beams continuous over two spans of 2,800 mm each were constructed and tested to failure. The beams were divided into two series. Series 1 included six T-beams under symmetrical loading, while Series 2 dealt with six rectangular beams under unsymmetrical loading conditions. In Series 1, the test variables included material type, assumed percentage of moment redistribution, spacing of lateral reinforcement in flange, arrangement of shear reinforcement, and serviceability requirements. In Series 2, three different loading cases were considered, I) loading both spans equally, II) loading both spans maintaining a load ratio of 1.5 and III) loading one span only. Under the loading case II, the parameters of reinforcing material type, assumed percentage of moment redistribution and serviceability requirements were investigated. The test results of both series showed that moment redistribution from the hogging to the sagging moment region took place in GFRP-RC beams which were designed for an assumed percentage of moment redistribution. In Series 1, the decrease of the stirrups spacing from 0.24d to 0.18d enhanced the moment redistribution percentage. Also, decreasing the spacing of lateral reinforcement in the flange from 450 to 150 mm improved the moment redistribution through enhancing the stiffness of the sagging moment region. In Series 2, the unsymmetrical loading conditions (loading case II and III) reduced the moment redistribution by reducing flexural stiffness in the heavily loaded span due to extensive cracking. Regarding serviceability in both series, the GFRP-RC beam designed for the same service moment calculated from the reference steel-RC beam, was able to meet the serviceability requirements for most types of the structural applications. / February 2017

[pt] O presente trabalho apresenta os resultados de um programa experimental com o intuito de determinar propriedades de deformabilidade e tensões in-situ em rochas gnáissicas. A determinação das tensões in situ é fundamental para qualquer trabalho em mecânica de rochas, serve como condições de campo em problemas de engenharia e em escalas maiores dá alguns indícios do mecanismo que ocasiona a movimentação de placas tectônicas. O módulo de deformabilidade é um dos principais parâmetros de entrada na análise do comportamento de maciços rochosos que incluem deformações. Este parâmetro geralmente é obtido a partir de ensaios de laboratório em amostras de rochas. Em geral os resultados destes ensaios não representam as propriedades in situ de todo o maciço rochoso, pois uma amostra intacta em laboratório pode ser muito menor que o maciço rochoso que contêm um grande número de planos de fraqueza. A presente pesquisa compreende as etapas de projeto, montagem e aplicação de um pressiômetro como um instrumento para a determinação dos parâmetros de deformabilidade e estado de tensões nos maciços rochosos. Os dados obtidos foram usados para investigar a variação destes parâmetros com o grau de intemperismo. Um sistema de instrumentação foi projetado para tentar monitorar a resposta da rocha às solicitações de carregamento (no caso da determinação do módulo de deformabilidade) e descarregamento (no caso de medição das tensões in situ). A aplicação do pressiômetro foi realizada em maciços rochosos localizados no cidade do Rio de Janeiro afetados por diferentes níveis de intemperismo. Realizaram-se ensaios de pressurização e medição de deslocamentos no momento da escavação dos furos para determinar o estado de tensões da rocha. Os resultados foram processados, interpretados e comparados com ensaios de laboratório anteriormente realizados por outros autores. / [en] This thesis presents the results from an experimental program with intention to determine the properties of deformabilty and in situ stress in gnaissic rocks. The determination of in situ stress is fundamental for any work in rock mechanics, it is use like field conditions at the in engineering problems, and in bigger scales it gives some indications of the mechanics that produce the tectonics plate`s movements. The deformation`s modulus is one of the main parameters in the analysis of the behavior of rocks mass that include deformations. This parameter usually is gotten from laboratory assays in rocks samples. In general the results of these assays do not represent the in situ properties of all the rock mass, therefore an intact rock sample in laboratory could be smaller that the rock mass that contains a great number of weakness planes. This research understands the stages of project, assembly and application of the pressuremeter as an instrument for the determination of the deformability and in situ stress parameters in rock mass. The gotten data had been used to investigate the variation of these parameters with the weathering degree. An instrumentation system was projected to try to monitor the answer of the rock to load (in the case of deformability`s modulus) and unload (in the case of in situ stress measurement). The application of the pressuremeter was carried trough in rock masses located in the Rio de Janeiro city whose were affected by different levels of weathering. Assays of pressurization and measurements of displacements at the moment of the hole drilling in order to determine the in situ stress. The results had been processing, interpreted and compared with laboratory assays previously carried trough by another authors.

A deformabilidade é a característica que permite ao eritrócito normal de 7 a 8 micrômetros (m) circular por capilares de até 3m de diâmetro. Esse fenômeno depende da geometria celular, da viscosidade interna e das propriedades visco-elásticas da membrana eritrocitária. Dentre as várias técnicas de estudo da deformabilidade eritrocitária (DE), como: a aspiração por micropipeta, a filtração e a reoscopia, destaca-se a ectacitometria. Essa técnica utiliza um viscosímetro de fluxo laminar onde as modificações de forma dos eritrócitos são monitoradas continuamente por um feixe de raio LASER, processadas por microcomputador e inseridas em gráfico para posterior análise. A ectacitometria fornece o Índice de Deformabilidade (ID), o qual proporciona a medida da eliptocitogênese dos eritrócitos quando submetidos a uma força denominada shear stress. A anemia ferropriva é uma patologia muito freqüente na prática médica. Apresenta anormalidades morfológicas expressivas como: microcitose, hipocromia, ovalócitos, eliptócitos e hemácias em alvo. Alterações de deformabilidade eritrocitária foram descritas em diversas situações como na esferocitose hereditária, eliptocitose hereditária e anemias hemolíticas auto-imune. Na anemia ferropriva os trabalhos de deformabilidade eritrocitária são controversos. O presente estudo avalia a DE, utilizando a técnica da ectacitometria, em 21 pacientes portadores de anemia ferropriva documentada, antes e depois do tratamento com sais de ferro. Embora o tratamento da anemia tenha sido eficaz (Hb antes- 8,52 g/dl e Hb depois -12,74 g/dl), alguns pacientes persistiram com morfologia eritrocitária alterada. Os resultados demonstram DE diminuída em pacientes portadores de anemia ferropriva, quando comparada ao grupo controle (p< 0,0007). A ausência de normalização e manutenção da diferença estatística após a terapêutica (p< 0,03), em baixos valores de shear stress, pode ser atribuida à manutenção das alterações morfológicas eritrocitárias. Não foi verificada correlação entre o grau da anemia e a redução da DE. A diminuição da DE apresenta maior correlação com a microcitose, sendo que a hipocromia parece não interferir de maneira importante. A concomitância dos dois fatores pode somar ou anular os seus efeitos sobre a DE. O presente estudo sugere que o fator responsável pela diminuição da DE na anemia ferropriva é a microcitose. Recentemente, relatos de anemia ferropriva associada a fenômenos trombóticos aumentaram o interesse no estudo da DE para melhor compreensão desses casos. / The deformability allows the 7 to 8 cm red cell to circulate through capillaries of 3 cm. This phenomenon depends on cellular geometry, internal viscosity and viscoelastic properties of the membrane. Among the various techniques of erytrocyte deformability (ED) analysis such as: micropipette aspiration, filtration and reoscopy, we chose ektacytometry. This technique uses a laminar flow viscometry, where red cell shape changes are continuously monitorated by LASER, processed by a computer and inserted in a graphic for further analysis. Ektacytometry measures the Deformability Index (DI), which shows the size of eliptocytogenesis of the eritrocyte under shear stress force. Iron deficiency anemia is a very frequent disease in medical practice. It presents expressive morphologic alterations such as microcytosis, hypocromy, ovalocytosis, eliptocytosis and target cells. Erytrocyte deformability has been described in a number of situations like hereditary spherocytosis, hereditary elitptocytosis and autoimmune hemolytic anemia. Concerning iron deficiency anemia, authors are controversial. The present study evaluates erytrocyte deformability, using ectacytometry in 21 patients carrying documented iron deficiency before and after therapeutics with iron components. Although the anemia treatment proved to be efficient (before Hb- 8,52 g/dl and after Hb- 12,74 g/dl), some patients persisted with erytrocyte alteration morfology. Results demonstrate diminished erytrocyte deformability in people with iron deficiency anemia, when compared with the control group (p< 0,0007). The absence of regularization and maintenance of statistical difference after treatment (p< 0,03) in low shear stress can be attributed to the persistence of red cell anomalies. There is no relation between the level of anemia and reduced ED. The erytrocyte deformability diminished is greatly related to microcitosys, even if hipocromy seems to not interefere importantly. The two factors altogether can either sum or nulify the effects over erytrocyte deformability. The present study suggests that the responsible factor for diminished erytrocyte deformability is microcitosys. Recently, iron deficiency anemia has been associated to thrombotic phenomenon has raised interest in the studying of erytrocyte deformability, in order to understand such cases.

Fosfogesso é um resíduo sólido poluente resultante da produção de ácido fosfórico, principal componente de fertilizantes fosfatados. Esse resíduo é gerado no mundo a uma taxa de 180 milhões de toneladas por ano, originando problemas sérios de armazenagem em vários países. As restrições de leis ambientais e o aumento do custo de espaço para a armazenagem do fosfogesso têm estimulado pesquisadores a encontrarem aplicações para este resíduo. Uma delas é a sua utilização como material de construção de bases rodoviárias. O objetivo principal deste trabalho é avaliar a influência do tipo de cimento Portland na resistência e deformabilidade das misturas de fosfogesso e cimento, com vistas à sua utilização em construção rodoviária. O comportamento mecânico foi analisado através de ensaios de compressão simples de corpos de prova compostos de fosfogesso e cimento, variando-se o tipo de cimento (CP III 40, CP V ARI e CP II-E 32), o teor de cimento (5%, 10% e 15%), a energia de compactação (normal e modificada), a condição de ensaio dos corpos de prova (sem imersão e após imersão em água por 4 horas) e o período de cura (1, 3, 7, 28, 84 e 210 dias). Realizou-se também uma comparação entre os desempenhos das misturas de fosfogesso e cimento e de solo-cimento. Os resultados mostram que o tipo de cimento não tem efeito predominante no comportamento da mistura, se comparado com os efeitos das outras variáveis. Entretanto, observou-se que, a longo prazo, os cimentos CP II-E 32 e CP V ARI, com teores elevados de aluminato tricálcico (C3A) em sua composição, 5% e 7,5%, respectivamente, conduzem à diminuição de resistência e rigidez da mistura; ao contrário do cimento CP III 40, com baixo teor de C3A, 2,4%, que forneceu, até os 210 dias, o aumento das mesmas. Além disto, o aumento do teor de cimento, da energia de compactação e do tempo de cura conduz ao crescimento, e a imersão dos corpos de prova em água a uma queda, da resistência e rigidez das misturas. No estudo comparativo, as misturas de fosfogesso e cimento apresentam resistência e rigidez, respectivamente, da ordem de ¼ e ½ da resistência e rigidez das misturas de solo-cimento. Finalmente, conclui-se que as misturas de fosfogesso e cimento têm potencial para serem usadas em construção rodoviária. / Phosphogypsum is a pollutant solid by-product resulting from the production of phosphoric acid, a major constituent of phosphate fertilizers. The annual worldwide production of this by-product is approximately 180 millions tons a year, causing serious problems in several countries due to its disposal. Environmental pressures as well as increased land costs associated with stockpiling phosphogypsum have stimulated researchers to find applications for this material. One of them is its use as road base material. The main objective of this research is to evaluate the influence of Portland cement type on the strength and deformability of cement-stabilized phosphogypsum mixtures for use in road construction. Thus the mechanical behavior of the mixtures was analyzed through unconfined compression testing of specimens composed by phosphogypsum and cement, varying the cement type (CP III 40, CP V ARI and CP II-E 32), the cement content (5%, 10% and 15%), the compaction energy (standard and modified Proctor), the testing conditions (without immersion and after immersion in water) and the curing time (1, 3, 7, 28, 84 and 210 days). A comparative study of performance between cement-stabilized phosphogypsum and cement-soil mixtures was also carried out. The laboratory results indicated the cement type has no significant effect in the mechanical behavior of the mixtures, if compared with the effects of the other parameters. However, it was observed in long-term periods that thecement types CP II-E 32 and CP V ARI, with 5% and 7,5% tricalcium aluminate (C3A) contents in their chemical composition, respectively, lead to decreasing strength and stiffness of the mixture; unlike the cement type CP III 40, with lower C3A content, 2,4%, that leads to increasing strength and stiffness of the mixture up to 210 day. In addition, the strength and stiffness of the mixtures increase with increasing cement content, compaction energy and curing period before testing, but decrease with immersion test condition. In the comparative study, the cement-stabilized phosphogypsum mixtures has strength and stiffness of about ¼ e ½ of the strength and stiffness of the cement-soil mixtures, respectively. Finally, it was concluded that the cement-stabilized phosphogypsum mixtures have potential application for road construction.

O crescimento do número de Barragens de Enrocamento com Face de Concreto (BEFC) no Brasil e no mundo e os problemas relacionados com a movimentação da face motivaram o desenvolvimento deste estudo sobre o comportamento mecânico do enrocamento. Geralmente, as previsões dos movimentos diferenciais do maciço são feitas com base nas características de deformabilidade do material. Este trabalho apresenta um estudo de tensão-deformação de enrocamento baseado em análise numérica de uma seção de barragem de grande altura, com o objetivo de definir o estado e as trajetórias de tensões que influenciam os valores dos parâmetros de deformabilidade. Baseado nas condições de carregamento previstas para o maciço de enrocamento, foi desenvolvida a programação e as metodologias dos ensaios laboratoriais. A partir dos resultados destes ensaios foi possível estimar os parâmetros de deformabilidade do enrocamento a serem utilizados em estudos tensão-deformação. / The important growth in the number of Concrete Face Rockfill Dams (CFRD\'s) in Brazil and in the World, and the reported problems related to movements of the concrete slab, motivated the present study of mechanical behavior of the rockfill. In general, predictions of the differential movements within the rockfill mass are based on the deformation properties of the rockfill materials. This work presents a stress-strain study of the rockfill mass, based on a numerical analysis of a high dam cross section, aiming to define the stress state and stress paths that influence the deformability parameters. Based on the loading condition estimated for the rockfill mass, the program and the methodology for the laboratorial tests was set. From these test results it was possible to estimate the deformability parameters of the rockfill to be used in stress-strain analysis.

Fosfogesso é um resíduo sólido poluente resultante da produção de ácido fosfórico, principal componente de fertilizantes fosfatados. Esse resíduo é gerado no mundo a uma taxa de 180 milhões de toneladas por ano, originando problemas sérios de armazenagem em vários países. As restrições de leis ambientais e o aumento do custo de espaço para a armazenagem do fosfogesso têm estimulado pesquisadores a encontrarem aplicações para este resíduo. Uma delas é a sua utilização como material de construção de bases rodoviárias. O objetivo principal deste trabalho é avaliar a influência do tipo de cimento Portland na resistência e deformabilidade das misturas de fosfogesso e cimento, com vistas à sua utilização em construção rodoviária. O comportamento mecânico foi analisado através de ensaios de compressão simples de corpos de prova compostos de fosfogesso e cimento, variando-se o tipo de cimento (CP III 40, CP V ARI e CP II-E 32), o teor de cimento (5%, 10% e 15%), a energia de compactação (normal e modificada), a condição de ensaio dos corpos de prova (sem imersão e após imersão em água por 4 horas) e o período de cura (1, 3, 7, 28, 84 e 210 dias). Realizou-se também uma comparação entre os desempenhos das misturas de fosfogesso e cimento e de solo-cimento. Os resultados mostram que o tipo de cimento não tem efeito predominante no comportamento da mistura, se comparado com os efeitos das outras variáveis. Entretanto, observou-se que, a longo prazo, os cimentos CP II-E 32 e CP V ARI, com teores elevados de aluminato tricálcico (C3A) em sua composição, 5% e 7,5%, respectivamente, conduzem à diminuição de resistência e rigidez da mistura; ao contrário do cimento CP III 40, com baixo teor de C3A, 2,4%, que forneceu, até os 210 dias, o aumento das mesmas. Além disto, o aumento do teor de cimento, da energia de compactação e do tempo de cura conduz ao crescimento, e a imersão dos corpos de prova em água a uma queda, da resistência e rigidez das misturas. No estudo comparativo, as misturas de fosfogesso e cimento apresentam resistência e rigidez, respectivamente, da ordem de ¼ e ½ da resistência e rigidez das misturas de solo-cimento. Finalmente, conclui-se que as misturas de fosfogesso e cimento têm potencial para serem usadas em construção rodoviária. / Phosphogypsum is a pollutant solid by-product resulting from the production of phosphoric acid, a major constituent of phosphate fertilizers. The annual worldwide production of this by-product is approximately 180 millions tons a year, causing serious problems in several countries due to its disposal. Environmental pressures as well as increased land costs associated with stockpiling phosphogypsum have stimulated researchers to find applications for this material. One of them is its use as road base material. The main objective of this research is to evaluate the influence of Portland cement type on the strength and deformability of cement-stabilized phosphogypsum mixtures for use in road construction. Thus the mechanical behavior of the mixtures was analyzed through unconfined compression testing of specimens composed by phosphogypsum and cement, varying the cement type (CP III 40, CP V ARI and CP II-E 32), the cement content (5%, 10% and 15%), the compaction energy (standard and modified Proctor), the testing conditions (without immersion and after immersion in water) and the curing time (1, 3, 7, 28, 84 and 210 days). A comparative study of performance between cement-stabilized phosphogypsum and cement-soil mixtures was also carried out. The laboratory results indicated the cement type has no significant effect in the mechanical behavior of the mixtures, if compared with the effects of the other parameters. However, it was observed in long-term periods that thecement types CP II-E 32 and CP V ARI, with 5% and 7,5% tricalcium aluminate (C3A) contents in their chemical composition, respectively, lead to decreasing strength and stiffness of the mixture; unlike the cement type CP III 40, with lower C3A content, 2,4%, that leads to increasing strength and stiffness of the mixture up to 210 day. In addition, the strength and stiffness of the mixtures increase with increasing cement content, compaction energy and curing period before testing, but decrease with immersion test condition. In the comparative study, the cement-stabilized phosphogypsum mixtures has strength and stiffness of about ¼ e ½ of the strength and stiffness of the cement-soil mixtures, respectively. Finally, it was concluded that the cement-stabilized phosphogypsum mixtures have potential application for road construction.

As some companies in the paper industry struggle to shift from commodity grades to value added products, technical challenges and opportunities have grown tremendously. These new products require more stringent manufacturing specifications and improved performance relative to those of lignocellulosic fibers currently being produced. Hence, topochemical and mechanical modifications of pulp fibers have moved to the forefront of many corporate strategies. Researchers are beginning to develop new tools to help better understand the fundamental mechanisms of fiber modifications and how to most efficiently apply them. Two novel approaches are presented. First, a new method to observe single fiber crossings is developed. It was found that refining reduces the stepheight in the fiber crossing for both hardwood and softwood kraft pulps by increasing the tendency of the fibers to collapse, deform, and assume a lens like shape. The effect of pulp type, bleaching, drying, wet pressing, and fiber charge were also investigated. Graphs of stepheight versus freespan were linear through the origin suggesting that the freespan (flexibility) of the crossing fiber is largely unimportant to the formation of fiber crossings. Quite surprisingly, the ratio of stepheight to freespan remained relatively constant no matter the treatment. Only bleaching and the addition of surface charge via CMC had any independent impact on freespan. The data do not fit bending or shear mechanisms that have been developed in the literature suggesting that another mechanism may be responsible for the deformation behavior of single fiber crossings. Also, a method employing fluorescence microscopy and fluorescence resonance energy transfer is used to image the areas of a fiber-fiber interface while they were bonded. Analysis of the FRET signal from fiber crossings indicate that wet pressing increased the FRET occurring between the two dyed fiber surfaces. The results are consistent with the increased amount of interdiffusion expected with higher levels of wet pressing. Two novel techniques are used to investigate fundamental aspects of fiber deformation behavior and fiber-fiber bond formation. As these methods are further refined and utilized they will provide new avenues for researchers to explore and expand the property space of fibers and paper sheets.

Performance of bridges during previous earthquakes has demonstrated that many structural failures could be attributed to seismic deficiencies in bridge columns. Lack of transverse reinforcement and inadequate splicing of longitudinal reinforcement in potential plastic hinge regions of columns constitute primary reasons for their poor performance. A number of column retrofit techniques have been developed and tested in the past. These techniques include steel jacketing, reinforced concrete jacketing and use of transverse prestressing (RetroBelt) for concrete confinement, shear strengthening and splice clamping. A new retrofit technique, involving fibre reinforced polymer (FRP) jacketing has emerged as a convenient and structurally sound alternative with improved durability. The new technique, although received acceptance in the construction industry, needs to be fully developed as a viable seismic retrofit methodology, supported by reliable design and construction procedures. The successful application of externally applied FRP jackets to existing columns, coupled with deteriorating bridge infrastructure, raised the possibility of using FRP reinforcement for new construction. Stay-in-place formwork, in the form of FRP tubes are being researched for its feasibility. The FRP stay-in-place tubes offer ease in construction, convenient formwork, and when left in place, the protection of concrete against environmental effects, including the protection of steel reinforcement against corrosion, while also serving as column transverse reinforcement. Combined experimental and analytical research was conducted in the current project to i) improve the performance of FRP column jacketing for existing bridge columns, and ii) to develop FRP stay-in-place formwork for new bridge columns. The experimental phase consisted of design, construction and testing of 7 full-scale reinforced concrete bridge columns under simulated seismic loading. The columns represented both existing seismically deficient bridge columns, and new columns in stay-in-place formwork. The existing columns were deficient in either shear, or flexure, where the flexural deficiencies stemmed from lack of concrete confinement and/or use of inadequately spliced longitudinal reinforcement. The test parameters included cross-sectional shape (circular or square), reinforcement splicing, column shear span for flexure and shear-dominant behaviour, FRP jacket thickness, as well as use of FRP tubes as stay-in-place formwork, with or without internally embedded FRP crossties. The columns were subjected to a constant axial compression and incrementally increasing inelastic deformation reversals. The results, presented and discussed in this thesis, indicate that the FRP retrofit methodology provides significant confinement to circular and square columns, improving column ductility substantially. The FRP jack also improved diagonal tension capacity of columns, changing brittle shear-dominant column behavior to ductile flexure dominant response. The jackets, when the transverse strains are controlled, are able to improve performance of inadequately spliced circular columns, while remain somewhat ineffective in improving the performance of spliced square columns. FRP stay-in-place formwork provides excellent ductility to circular and square columns in new concrete columns, offering tremendous potential for use in practice. The analytical phase of the project demonstrates that the current analytical techniques for column analysis can be used for columns with external FRP reinforcement, provided that appropriate material models are used for confined concrete, FRP composites and reinforcement steel. Plastic analysis for flexure, starting with sectional moment-curvature analysis and continuing into member analysis incorporating the formation of plastic hinging, provide excellent predictions of inelastic force-deformation envelopes of recorded hysteretic behaviour. A displacement based design procedure adapted to FRP jacketed columns, as well as columns in FRP stay-in-place formwork provide a reliable design procedure for both retrofitting existing columns and designing new FRP reinforced concrete columns.

La capacité des globules rouges à modifier leur forme en fonction de conditions externes spécifiques représente une propriété fondamentale permettant aux cellules de traverser des capillaires de diamètres plus petits que leur propre diamètre. L’ektacytométrie est une technique utilisée pour mesurer la déformabilité des globules rouges en exposant un échantillon très dilué de sang à des contraintes de cisaillement et en mesurant l’élongation resultante des globules par l'analyse de la figure de diffraction laser. Ce travail contribue à la conception et l’évaluation d’un nouveau dispositif de diagnostic basé sur la méthode microfluidique d'ektacytométrie à gradient osmolaire. Elle permet de mesurer la déformabilité d'une population de globules rouges (RBC), en fonction de l'osmolalité de milieu. Cette mesure permet un diagnostic différentiel d'un certain nombre de troubles de globules rouges présentant des symptômes similaires. Elle permet également de suivre les effets de certains traitements. Des aspects théoriques qui s’appuient sur les équations des écoulements et une preuve de principe sont discutés. Cette nouvelle technique ouvre la possibilité de construire un instrument simple et peu encombrant, décrit dans ce travail, ne nécessitant qu'un prélèvement de sang au bout du doigt / The ability of red blood cells (RBC) to change their shape under varying conditions is a crucial property allowing these cells to go through capillaries narrower than their own diameter. Ektacytometry is a technique for measuring deformability by exposing a highly diluted blood sample to shear stress and evaluating the resulting elongation in RBC shape using a laser diffraction pattern. This work contributes to the design and evaluation of a new diagnostic technique based on osmotic scan ektacytometry, using a microfluidic method. It allows the measurement of deformability of an RBC population, as a function of varying medium osmolality. This measurement makes possible a differential diagnosis for any one of a number of RBC disorders presenting similar symptoms. It also permits the physician to follow the effects of treatments. Both theoretical aspects based on flow equations and a proof of principle are discussed. This new technique opens up the possibility of building a simple, small footprint instrument described in this work that can be used with finger prick amounts of blood