There has been increasing interest in evaluating the performance of existing reinforced concrete (RC) bridges just after natural disasters or man-made events especially when the defects are invisible, or in quantifying the improvement after rehabilitations. In order to obtain an accurate assessment of the reliability of a RC bridge, it is critical to incorporate information about its current structural properties, which reflects the possible aging and deterioration. This dissertation proposes to develop an adaptive reliability analysis of RC bridges incorporating the damage detection information obtained from nondestructive testing (NDT). In this study, seismic fragility is used to describe the reliability of a structure withstanding future seismic demand. It is defined as the conditional probability that a seismic demand quantity attains or exceeds a specified capacity level for given values of earthquake intensity. The dissertation first develops a probabilistic capacity model for RC columns and the capacity model can be used when the flexural stiffness decays nonuniformly over a column height. Then, a general methodology to construct probabilistic seismic demand models for RC highway bridges with one single-column bent is presented. Next, a combination of global and local NDT methods is proposed to identify in-place structural properties. The global NDT uses the dynamic responses of a structure to assess its global/equivalent structural properties and detect potential damage locations. The local NDT uses local measurements to identify the local characteristics of the structure. Measurement and modeling errors are considered in the application of the NDT methods and the analysis of the NDT data. Then, the information obtained from NDT is used in the probabilistic capacity and demand models to estimate the seismic fragility of the bridge. As an illustration, the proposed probabilistic framework is applied to a reinforced concrete bridge with a one-column bent. The result of the illustration shows that the proposed framework can successfully provide the up-to-date structural properties and accurate fragility estimates.

Glacial isostatic adjustment (GIA) is the process by which the solid Earth responds to past and present-day changes in glaciers, ice caps, and ice sheets. This thesis focuses on vertical crustal motion of the Earth caused by GIA, which is influenced by several factors including lithosphere thickness, mantle viscosity profile, and changes to the thickness and extent of surface ice. The viscosity of the mantle beneath Antarctica is a poorly constrained quantity due to the rarity of relative sea-level and heat flow observations. Other methods for obtaining a better-constrained mantle viscosity model must be investigated to obtain more accurate GIA model predictions. The first section of this study uses seismic wave tomography to determine mantle viscosity. By calculating the deviation of the P- and S-wave velocities relative to a reference Earth model (PREM), the viscosity can be determined. For Antarctica mantle viscosities obtained from S20A (Ekstrom and Dziewonski, 1998) seismic tomography in the asthenosphere range from 1016 Pa∙s to 1023 Pa∙s, with smaller viscosities beneath West Antarctica and higher viscosities beneath East Antarctica. This agrees with viscosity expectations based on findings from the Basin and Range area of North America, which is an analogue to the West Antarctic Rift System. Section two compares bedrock elevations in Antarctica to crustal thicknesses, to infer mantle temperatures and draw conclusions about mantle viscosity. Data from CRUST 2.0 (Bassin et al., 2000), BEDMAP (Lythe and Vaughan, 2001) and specific studies of crustal thickness in Antarctica were examined. It was found that the regions of Antarctica that are expected to have low viscosities agree with the hot mantle trend found by Hyndman (2010) while the regions expected to have high viscosity are in better agreement with the trend for cold mantle. Bevis et al. (2009) described new GPS observations of crustal uplift in Antarctica and compared the results to GIA model predictions, including IJ05 (Ivins and James, 2005). Here, we have generated IJ05 predictions for a three layered mantle (viscosities ranging over more than four orders of magnitude) and compared them to the GPS observations using a χ2 measure of goodness-of-fit. The IJ05 predictions that agree best with the Bevis et al. observations have a χ2 of 16, less than the null hypothesis value of 42. These large values for the best-fit model indicate the need for model revisions and/or that uncertainties are too optimistic. Equally important, the mantle viscosities of the best-fit models are much higher than expected for West Antarctica. The smallest χ2 values are found for an asthenosphere viscosity of 1021 Pa•s, transition zone viscosity of 1023 Pa∙s and lower mantle viscosity of 2 x 1023 Pa∙s, whereas the expected viscosity of the asthenosphere beneath West Antarctica is probably less than 1020 Pa∙s. This suggests that revisions to the IJ05 ice sheet history are required. Simulated annealing was performed on the ice sheet history and it was found that changes to the recent ice load history have the strongest effect on GIA predictions. / Graduate

A RS471/BR153 é uma importante rodovia de integração, pois atravessa o estado do RS diagonalmente (Noroeste – Sudeste). O trecho estudado nesta dissertação localiza-se entre os municípios de Herveiras e Vera Cruz, coincidente com descida do planalto até a região central do estado. Durante o detalhamento do projeto e na construção da obra foram encontrados diversos problemas geotécnicos, os quais são sucintamente descritos. O texto apresenta as condicionantes geotécnicas de três subtrechos: (a) planalto, composto de rochas ácidas de origem vulcânica e grau de fraturamento muito alto; (b) descida da serra, composto pelos derrames da formação Serra Geral (brechas ácidas e basálticas e derrames basálticos) e (c) planície, com a presença de rochas sedimentares e materiais coluvionares. Além disto, há uma região especial onde o traçado atravessa uma sela topográfica coincidente com uma falha regional, com cortes de cerca de 60 m de altura através de rochas ácidas, básicas e brechas vulcânicas. A dissertação apresenta estudos dos processos de quedas de blocos rochosos que têm ocorrido nos cortes da rodovia. Foi utilizado um procedimento que correlaciona as leituras obtidas com o martelo Schmidt (Esclerômetro) e o coeficiente de restituição normal (RN) das rochas em diversos locais. Utilizando estes dados experimentais, foram executadas simulações de queda de blocos em quatro seções transversais bastante distintas com o uso do programa RocFall. Para cada seção foram simulados cinco cenários: (a) a existência de alargamentos para construção de áreas de retenção de blocos, (b) inexistência destas áreas, (c) a existência de preenchimento de uma ou várias banquetas existentes nos taludes de corte, e (d) o abatimento da seção com eliminação das banquetas. Foram também simulados quatro tipos de elementos de proteção: barreiras de baixa altura em concreto, camadas de areia fofa, barreiras metálicas flexíveis e proteção superficial dos taludes. A existência de áreas de retenção de blocos mostrou ser uma ótima medida, com frequências de invasão de pista geralmente abaixo de 1%, podendo chegar a 6,5% em condições de grande acúmulo de material. O melhor desempenho foi obtido pela instalação de camadas de areia fofa, obtendo-se todas as frequências abaixo de 2%. O uso de barreiras rígidas de 81 cm de altura teve um bom desempenho para taludes de baixa altura, chegando a detenções de até 25% dos blocos em trajetória de invasão. As barreiras flexíveis e proteções superficiais geraram resultados satisfatórios, mas que podem ser melhorados com outras modulações e dimensões. / The RS471/BR153 is an important road of integration, that cross RS state diagonally (northwest - southeast). The segment studied on this dissertation is located between the towns of Vera Cruz and Herveiras, coincident with the descent way from the plateau to the central state region. During the design and during the road construction several geotechnical problems were faced, which are briefly described. The text presents the geotechnical constraints of 3 segments: (a) plateau, composed of acid rocks of volcanic origin and very high degree of fracturing, (b) hills of the mountain, made up of volcanic rocks of Serra Geral formation (acid and basaltic breccias, basaltic flows) and (c) the plain, with the presence of sedimentary rocks and colluvial materials. There is also a special region where the road crosses a topographic saddle which it coincides with a regional fault, with cuts of about 60 m high through acid and basic rocks and volcanic breccia. The dissertation presents studies of rock falls that have occurred in the road cuts. A procedure that correlates the readings obtained with the Schmidt hammer (rebound hammer) and the normal coefficient of restitution (RN) of the rocks was carried out for measures taken at several locations. With these experimental data, simulations of falling boulders in four very different cross sections were done using the program RocFall. For each section five situations were simulated: (a) enlargements for the construction of rockfall catchment areas (b) the absence of these areas, (c) the existence of accumulation in the benchs of the cuts, and (d) the reduction of the section with bench removal. Four types of elements of protection were tested: concrete low barriers, layers of sand, flexible metal barriers and slope surface protection. The existence of rockfall catchment areas was shown to be a very good measure with frequencies of track invasion usually below 1% reaching 6.5% on conditions of large material accumulation. The best performance was obtained by the installation of sand layers, with all frequencies below 2%. The use of rigid barriers of 81 cm high had a good performance for low-slope heights, reaching up to 25% block retention. The use of flexible barriers and surface protections also had a good performance. / La RS471/BR153 es una importante carretera de integración, atraviesa el estado de RS diagonalmente (Noroeste-Sureste). El tramo estudiado en esta disertación se localiza entre los municipios de Herveiras y Vera Cruz, y coincide con el descenso desde el altiplano hasta la región central del estado. Durante las etapas de detalle y construcción de la obra fueron encontrados diversos problemas geotécnicos que son brevemente descritos. El texto presenta los condicionantes geotécnicos de tres subtramos: (a) altiplano, compuesto por rocas ácidas de origen volcánico y grado de fracturamiento muy alto; (b) descenso de la sierra, compuesto por los derrames de la formación Serra Geral (brechas ácidas y basálticas e derrames basálticos) y (c) planicie, con rocas sedimentarias y materiales coluviales. Además, hay una región donde el trazado atraviesa una “silla” topográfica que coincide con una falla regional, con cortes de aproximadamente 60 m de altura a través de rocas ácidas, básicas y brechas volcánicas. La disertación presenta estudios de procesos de caídas de rocas que han ocurrido en algunos cortes. Fue utilizado un procedimiento que correlaciona las lecturas obtenidas con el martillo Schmidt (Esclerómetro) y el coeficiente de restitución normal (RN) de las rocas en diferentes lugares. Con estos datos experimentales, fueron ejecutadas simulaciones de caídas de rocas en cuatro secciones transversales bastante distintas usando el programa RocFall. En cada sección fueron simulados cinco escenarios: (a) existencia de sobreanchos para la construcción de áreas de retención de rocas, (b) inexistencia de estas áreas, (c) existencia de relleno en una o más gradas existentes en los taludes de corte, y (d) diminución de la pendiente de los taludes y eliminación de las gradas. También fueron simulados cuatro tipos de elementos de protección: barreras de baja altura en concreto, capas de arena suelta, barreras metálicas flexibles y protección superficial de los taludes. La existencia de áreas de retención de rocas mostro ser una excelente medida, con frecuencias de invasión de pista generalmente inferiores a 1%, pudiendo llegar a 6,5% en condiciones de gran acumulación de material. El mejor desempeño fue obtenido con la instalación de capas de arena suelta, con todas las frecuencias por debajo de 2%. El uso de barreras rígidas de 81 cm de altura tuvo un buen desempeño para taludes de baja altura, llegando a detenciones de hasta 25% de los bloques en trayectoria de invasión. Las barreras flexibles y protecciones superficiales generaron resultados satisfactorios, que podrían ser mejorados con otras modulaciones y dimensiones.

Contexte : Les migrants d'Afrique subsaharienne (ASS) sont particulièrement touchés par l'épidémie de VIH/SIDA en France. Malgré une baisse du nombre de nouveaux diagnostics observés dans la dernière décennie en France, en 2016, les hétérosexuels originaires d'ASS comptent pour trois quarts de nouveaux diagnostics VIH versus un quart seulement pour les migrants hétérosexuels nés dans d'autres pays. Bien que la plupart de personnes concernées soient contaminées dans leurs pays d'origine où la situation épidémiologique de l'infection par le VIH reste préoccupante, des données virologiques et d'enquêtes transversales suggèrent qu'une partie des contaminations a lieu après la migration en France. Ces contaminations post migration peuvent être attribuées à des comportements sexuels à risque dans les réseaux sexuels intra-africains où la prévalence du VIH est élevée. Objectifs : il s'agit ici d'étudier à la fois, les déterminants de la divulgation du statut VIH, les facteurs prédictifs du rebond virologique à l'occasion d'un séjour transitoire en ASS et les facteurs associés aux comportements sexuels à risque. Méthodes : nous avons utilisé les données de l'enquête ANRS-VIHVO réalisée entre 2007- 2009 auprès des migrants d'ASS vivant en France avec une infection par le VIH contrôlée par le traitement antirétroviral, et ayant planifié un séjour transitoire dans leurs pays d'origine pour une durée de 15 jours à 6 mois. Résultats : nous avons trouvé un taux global important de divulgation du statut VIH, 86 % (IC à 95% : 82- 90%). La fréquence de la divulgation du statut VIH au partenaire, composante principale de la stratégie de réduction de risque de transmission du VIH dans les couples est relativement faible, 79% (IC à 95% : 73– 85%) globalement dont 88 % (IC 95% : 82- 94%) en France vs 53% (IC à 95% : 38- 69%)dans le pays d'origine où certaines personnes ont des partenaires sexuels réguliers. Au décours du voyage en ASS, 11,4% (IC à 95% : 7,3- 15,5%)de personnes ont développé un rebond virologique, principalement à cause de la perte d'adhérence à leur traitement antirétroviral pendant le voyage. L'utilisation non systématique du préservatif au cours du dernier mois avec le partenaire est observée chez plus d'un tiers de personnes, soit 38,4%(IC à 95% : 30,0- 46,7%) avec le partenaire régulier et 34,5%(IC à 95% : 21,8- 56,7%) avec le partenaire occasionnel. Plusieurs prédicteurs de la divulgation du statut VIH, de la survenue de rebond virologique au décours du voyage en ASS et de l'utilisation non systématique du préservatif au cours du dernier mois, ont ainsi été identifiés. Conclusion : Une charge virale indétectable tout au long du suivi permet de prévenir la transmission sexuelle du VIH au partenaire. Cette réduction de risque passe à la fois par la divulgation de la séropositivité au partenaire, l'usage du préservatif en cas de charge virale détectable ou de partenaires multiples, et l'adhérence soutenue au traitement antirétroviral / Background: Migrants from sub-Saharan Africa (SSA) are particularly affected by the HIV/ AIDS epidemic in France. Despite a fall in the number of new diagnoses observed in the last decade in France, in 2016 migrants from SSA accounted for 39% of the 6,003 people who discovered their HIV positive status in France. Although the majority of these people are infected in their country of origin because of the epidemiological situation, virological data and cross-sectional surveys suggest that some of the infections occur after migration to France. These post-migration infections can be attributed to risky sexual behavior in intra-African sexual networks where HIV prevalence is high. Objectives: to study at once the determinants of HIV status disclosure, predictive factors of virological rebound during a transitional stay in the country of origin and factors associated with risky sexual behavior. Methods: we used the ANRS-VIHVO survey data set up between 2007- 2009. This cohort studied migrants from SSA living in France with HIV infection managed with antiretroviral therapy, and who had planned a transitional stay in their countries of origin for a period of 15 days to 6 months. Results: Our work highlighted a significant overall rate of HIV status disclosure, 86 % [CI 95%: 82- 90%]. Disclosure to the partner, an important component of the risk reduction strategy of HIV transmission in couples, is relatively low, 79% (95% CI: 73-85%) overall, whose 88% (95% CI: 82-94%) in France vs 53% (95% CI: 38-69%) in the country of origin where some people have regular sex partners. After the trip in ASS, 11.4% (95% CI: 7.3- 15.5%) of people developed a virological rebound mainly due to lack of adherence to treatment during the trip. Non-systematic use of condoms is observed in more than a third of the study subjects, ie, 38.4 % (95% CI: 30.0- 46.7%) with the regular partner and 34.5% (95% CI: 21.8-56.7%) with casual partners. Several predictors of HIV status disclosure, the unsystematic use of condoms and the occurrence of virological rebound after the trip to SSA, were identified in our work. Conclusion: undetectable viral load throughout the follow-up prevents the sexual transmission of HIV to the partner. This risk reduction goes through by the disclosing the HIV status to the partner, condom use in case of detectable viral load or multiple partners, and sustained adherence to antiretroviral therapy

A RS471/BR153 é uma importante rodovia de integração, pois atravessa o estado do RS diagonalmente (Noroeste – Sudeste). O trecho estudado nesta dissertação localiza-se entre os municípios de Herveiras e Vera Cruz, coincidente com descida do planalto até a região central do estado. Durante o detalhamento do projeto e na construção da obra foram encontrados diversos problemas geotécnicos, os quais são sucintamente descritos. O texto apresenta as condicionantes geotécnicas de três subtrechos: (a) planalto, composto de rochas ácidas de origem vulcânica e grau de fraturamento muito alto; (b) descida da serra, composto pelos derrames da formação Serra Geral (brechas ácidas e basálticas e derrames basálticos) e (c) planície, com a presença de rochas sedimentares e materiais coluvionares. Além disto, há uma região especial onde o traçado atravessa uma sela topográfica coincidente com uma falha regional, com cortes de cerca de 60 m de altura através de rochas ácidas, básicas e brechas vulcânicas. A dissertação apresenta estudos dos processos de quedas de blocos rochosos que têm ocorrido nos cortes da rodovia. Foi utilizado um procedimento que correlaciona as leituras obtidas com o martelo Schmidt (Esclerômetro) e o coeficiente de restituição normal (RN) das rochas em diversos locais. Utilizando estes dados experimentais, foram executadas simulações de queda de blocos em quatro seções transversais bastante distintas com o uso do programa RocFall. Para cada seção foram simulados cinco cenários: (a) a existência de alargamentos para construção de áreas de retenção de blocos, (b) inexistência destas áreas, (c) a existência de preenchimento de uma ou várias banquetas existentes nos taludes de corte, e (d) o abatimento da seção com eliminação das banquetas. Foram também simulados quatro tipos de elementos de proteção: barreiras de baixa altura em concreto, camadas de areia fofa, barreiras metálicas flexíveis e proteção superficial dos taludes. A existência de áreas de retenção de blocos mostrou ser uma ótima medida, com frequências de invasão de pista geralmente abaixo de 1%, podendo chegar a 6,5% em condições de grande acúmulo de material. O melhor desempenho foi obtido pela instalação de camadas de areia fofa, obtendo-se todas as frequências abaixo de 2%. O uso de barreiras rígidas de 81 cm de altura teve um bom desempenho para taludes de baixa altura, chegando a detenções de até 25% dos blocos em trajetória de invasão. As barreiras flexíveis e proteções superficiais geraram resultados satisfatórios, mas que podem ser melhorados com outras modulações e dimensões. / The RS471/BR153 is an important road of integration, that cross RS state diagonally (northwest - southeast). The segment studied on this dissertation is located between the towns of Vera Cruz and Herveiras, coincident with the descent way from the plateau to the central state region. During the design and during the road construction several geotechnical problems were faced, which are briefly described. The text presents the geotechnical constraints of 3 segments: (a) plateau, composed of acid rocks of volcanic origin and very high degree of fracturing, (b) hills of the mountain, made up of volcanic rocks of Serra Geral formation (acid and basaltic breccias, basaltic flows) and (c) the plain, with the presence of sedimentary rocks and colluvial materials. There is also a special region where the road crosses a topographic saddle which it coincides with a regional fault, with cuts of about 60 m high through acid and basic rocks and volcanic breccia. The dissertation presents studies of rock falls that have occurred in the road cuts. A procedure that correlates the readings obtained with the Schmidt hammer (rebound hammer) and the normal coefficient of restitution (RN) of the rocks was carried out for measures taken at several locations. With these experimental data, simulations of falling boulders in four very different cross sections were done using the program RocFall. For each section five situations were simulated: (a) enlargements for the construction of rockfall catchment areas (b) the absence of these areas, (c) the existence of accumulation in the benchs of the cuts, and (d) the reduction of the section with bench removal. Four types of elements of protection were tested: concrete low barriers, layers of sand, flexible metal barriers and slope surface protection. The existence of rockfall catchment areas was shown to be a very good measure with frequencies of track invasion usually below 1% reaching 6.5% on conditions of large material accumulation. The best performance was obtained by the installation of sand layers, with all frequencies below 2%. The use of rigid barriers of 81 cm high had a good performance for low-slope heights, reaching up to 25% block retention. The use of flexible barriers and surface protections also had a good performance. / La RS471/BR153 es una importante carretera de integración, atraviesa el estado de RS diagonalmente (Noroeste-Sureste). El tramo estudiado en esta disertación se localiza entre los municipios de Herveiras y Vera Cruz, y coincide con el descenso desde el altiplano hasta la región central del estado. Durante las etapas de detalle y construcción de la obra fueron encontrados diversos problemas geotécnicos que son brevemente descritos. El texto presenta los condicionantes geotécnicos de tres subtramos: (a) altiplano, compuesto por rocas ácidas de origen volcánico y grado de fracturamiento muy alto; (b) descenso de la sierra, compuesto por los derrames de la formación Serra Geral (brechas ácidas y basálticas e derrames basálticos) y (c) planicie, con rocas sedimentarias y materiales coluviales. Además, hay una región donde el trazado atraviesa una “silla” topográfica que coincide con una falla regional, con cortes de aproximadamente 60 m de altura a través de rocas ácidas, básicas y brechas volcánicas. La disertación presenta estudios de procesos de caídas de rocas que han ocurrido en algunos cortes. Fue utilizado un procedimiento que correlaciona las lecturas obtenidas con el martillo Schmidt (Esclerómetro) y el coeficiente de restitución normal (RN) de las rocas en diferentes lugares. Con estos datos experimentales, fueron ejecutadas simulaciones de caídas de rocas en cuatro secciones transversales bastante distintas usando el programa RocFall. En cada sección fueron simulados cinco escenarios: (a) existencia de sobreanchos para la construcción de áreas de retención de rocas, (b) inexistencia de estas áreas, (c) existencia de relleno en una o más gradas existentes en los taludes de corte, y (d) diminución de la pendiente de los taludes y eliminación de las gradas. También fueron simulados cuatro tipos de elementos de protección: barreras de baja altura en concreto, capas de arena suelta, barreras metálicas flexibles y protección superficial de los taludes. La existencia de áreas de retención de rocas mostro ser una excelente medida, con frecuencias de invasión de pista generalmente inferiores a 1%, pudiendo llegar a 6,5% en condiciones de gran acumulación de material. El mejor desempeño fue obtenido con la instalación de capas de arena suelta, con todas las frecuencias por debajo de 2%. El uso de barreras rígidas de 81 cm de altura tuvo un buen desempeño para taludes de baja altura, llegando a detenciones de hasta 25% de los bloques en trayectoria de invasión. Las barreras flexibles y protecciones superficiales generaron resultados satisfactorios, que podrían ser mejorados con otras modulaciones y dimensiones.

Pour évaluer la résistance mécanique du béton dans un ouvrage existant, la méthodologie courante combine des mesures non destructives (CND) comme le rebond ou/et la vitesse des ondes ultrasoniques avec la technique destructive (carottes) afin de produire une relation‘‘modèle de conversion” entre la résistance mécanique et les mesures CND. Le modèle de conversion est utilisé pour estimer la valeur locale de résistance mécanique à chaque emplacement de test en utilisant la valeur CND correspondante. Ensuite, on calcule les estimations de la résistance moyenne et/ou de l’écart-type de la résistance (variabilité de la résistance du béton). Cependant, la fiabilité d’estimation est toujours discutable en raison des incertitudes associées à l’évaluation de la résistance basée sur les mesures CND. Pour améliorer la fiabilité, les incertitudes doivent être réduites en spécifiant et en contrôlant leurs facteurs d’influence. Par conséquent, l’objectif de cette thèse est d’analyser la méthodologie d’évaluation courante afin de fournir des recommandations pratiques qui peuvent améliorer la fiabilité de l’évaluation de la résistance in-situ du béton dans les ouvrages existantes par des tests non destructifs et des carottes.Pour ce but, un simulateur a été construit afin d’analyser les effets des facteurs les plus influents en utilisant une vaste campagne de données provenant de sources différentes (études in situ ou en laboratoire et données synthétiques générées). La première contribution de ce travail est le développement d’une nouvelle approche d’identification du modèle ‘‘bi-objectif” qui peut efficacement capturer la variabilité de la résistance mécanique en plus de la moyenne. Après avoir étudié l’effet du mode de sélection des emplacements pour les carottes, une méthode a été proposée pour sélectionner ces emplacements en fonction des mesures CND ‘‘sélection conditionnelle” qui améliore la qualité de l’évaluation sans coût supplémentaire. Une dernière innovation est l’établissement de courbes de risque qui quantifient la relation entre le nombre de carottes et la précision de l’estimation. Enfin, des recommandations ont été formulées afin de fournir des estimations plus fiables. / To assess concrete strength in an existing structure, the current methodology combines nondestructive measurements (NDT) like rebound hammer or/and pulse velocity with destructive technique (cores) in order to implement a relationship ‘‘conversion model” between the compressive strength and NDT measurements. The conversion model is used to estimate the local strength value at each test location using the corresponding NDT value.Then the estimated mean strength and/or estimated strength standard deviation (concrete strength variability) values are calculated. However, the reliability of these estimated values isalways a questionable issue because of the uncertainties associated with the strength assessment based upon NDT measurements. To improve the reliability, the uncertainties must be reduced by specifying and controlling their influencing factors. Therefore, the objective of this thesis is to analyze the current assessment methodology in order to provide practical recommendations that can improve the reliability of assessing the in-situ strength in existing concrete structures by nondestructive tests and cores.To this end, a simulator was built in order to analyze the effects of the most influencing factors using a large campaign of datasets from different sources (in-situ or laboratory studies,and generated synthetic data).The first contribution of this work is the development of a new model identification approach“bi-objective” that can efficiently capture the strength variability in addition to the mean strength. After studying the effect of the way of selection the core locations, a method was proposed to select these locations depending on the NDT measurements “conditional selection” that improves the quality of assessment without additional cost. A third innovation was the development of a procedure to identify the relation between the number of cores and the accuracy of the estimation. Finally recommendations were derived in order to providemore reliable estimated values.

Cette thèse porte sur les instruments de politique publique permettant de réduire les émissions de CO2 liées à l’usage des véhicules particuliers. La mise en place de ces instruments est légitime et nécessaire compte tenu de la contribution de ces véhicules au changement climatique (17% des émissions de CO2 en France en 2010). Dans le cadre d’une modélisation théorique en équilibre partiel et statique du marché automobile, les travaux considèrent deux leviers de réduction d’émissions : l’amélioration de la performance énergétique des véhicules et la diminution des distances parcourues. Dans un premier Chapitre consacré à l’analyse côté offre du système automobile, la question de recherche est de déterminer si, d’une part, une coopération entre acteurs de la filière automobile conduit à la production de véhicules plus économes en carburant qu’en l’absence de coopération, et d’autre part, si cette coopération est un substitut ou non à l’intervention publique. L’impact de la demande de véhicules économes en carburant sur les décisions d’investissement et de coopération des producteurs est démontré, ce qui justifie la mise en place d'outils de politique publique stimulant la demande. Aussi, le deuxième Chapitre est consacré à l’analyse de la demande de véhicules et de kilomètres. L’accent est mis sur l’interdépendance entre ces deux demandes, qui est à l’origine du phénomène bien connu d’effet rebond. Il est question d’étudier l’impact de cet effet rebond sur l’efficacité des taxes différenciées à l’achat et des taxes à l’usage des véhicules. Enfin, l’ambition du dernier Chapitre est tenir compte des effets de ces instruments sur l’utilité des ménages et le profit pour la filière automobile. L’objectif plus large est de déterminer si les décideurs publiques sont à mêmes de lutter contre les émissions de CO2 des véhicules tout en augmentant le bien-être de la population et la croissance économique. / This Thesis analyses public economic policies enabling to reduce CO2 emissions from car use. Implementing these tools is legitimate and necessary because of the high contribution of passenger vehicles to climate change (17% of CO2 emissions in France in 2010). Within a partial and static equilibrium model of the car market, the present research considers two distinct levers to cut CO2 emissions from car use: the improvements of passenger vehicles energy-efficiency, and a reduction in miles driven. In the first Chapter dedicated to an analysis of the supply-side of the automotive system, the research question consists in investigating on the one hand whether a cooperation among actors of the automotive sector leads to the production of vehicles that are less fuel-consuming than without the cooperation; and on the other hand whether this cooperation could be a substitute to a policy intervention. The impact of the demand for low fuel-consuming vehicles on the producers’ decision to invest and to cooperate is demonstrated; this justifies the implementation of policy tools stimulating demand. Hence, the second Chapter is dedicated to an analysis of the demand for vehicles and kilometres. Emphasis is placed on the interdependency between car choice and car use, which is at the root of the well-known phenomenon of rebound effect. The aim is to study the impact of that rebound effect on the efficiency of differentiated car purchase taxes and car use taxes. Lastly, the ambition of the last Chapter is to take the impacts of the latter pricing tools on households’ utility and automotive sector’s profit into account. More generally, the purpose is to investigate whether public decision-makers are able to mitigate CO2 emissions from car use while improving households’ well-being and economic growth.

A RS471/BR153 é uma importante rodovia de integração, pois atravessa o estado do RS diagonalmente (Noroeste – Sudeste). O trecho estudado nesta dissertação localiza-se entre os municípios de Herveiras e Vera Cruz, coincidente com descida do planalto até a região central do estado. Durante o detalhamento do projeto e na construção da obra foram encontrados diversos problemas geotécnicos, os quais são sucintamente descritos. O texto apresenta as condicionantes geotécnicas de três subtrechos: (a) planalto, composto de rochas ácidas de origem vulcânica e grau de fraturamento muito alto; (b) descida da serra, composto pelos derrames da formação Serra Geral (brechas ácidas e basálticas e derrames basálticos) e (c) planície, com a presença de rochas sedimentares e materiais coluvionares. Além disto, há uma região especial onde o traçado atravessa uma sela topográfica coincidente com uma falha regional, com cortes de cerca de 60 m de altura através de rochas ácidas, básicas e brechas vulcânicas. A dissertação apresenta estudos dos processos de quedas de blocos rochosos que têm ocorrido nos cortes da rodovia. Foi utilizado um procedimento que correlaciona as leituras obtidas com o martelo Schmidt (Esclerômetro) e o coeficiente de restituição normal (RN) das rochas em diversos locais. Utilizando estes dados experimentais, foram executadas simulações de queda de blocos em quatro seções transversais bastante distintas com o uso do programa RocFall. Para cada seção foram simulados cinco cenários: (a) a existência de alargamentos para construção de áreas de retenção de blocos, (b) inexistência destas áreas, (c) a existência de preenchimento de uma ou várias banquetas existentes nos taludes de corte, e (d) o abatimento da seção com eliminação das banquetas. Foram também simulados quatro tipos de elementos de proteção: barreiras de baixa altura em concreto, camadas de areia fofa, barreiras metálicas flexíveis e proteção superficial dos taludes. A existência de áreas de retenção de blocos mostrou ser uma ótima medida, com frequências de invasão de pista geralmente abaixo de 1%, podendo chegar a 6,5% em condições de grande acúmulo de material. O melhor desempenho foi obtido pela instalação de camadas de areia fofa, obtendo-se todas as frequências abaixo de 2%. O uso de barreiras rígidas de 81 cm de altura teve um bom desempenho para taludes de baixa altura, chegando a detenções de até 25% dos blocos em trajetória de invasão. As barreiras flexíveis e proteções superficiais geraram resultados satisfatórios, mas que podem ser melhorados com outras modulações e dimensões. / The RS471/BR153 is an important road of integration, that cross RS state diagonally (northwest - southeast). The segment studied on this dissertation is located between the towns of Vera Cruz and Herveiras, coincident with the descent way from the plateau to the central state region. During the design and during the road construction several geotechnical problems were faced, which are briefly described. The text presents the geotechnical constraints of 3 segments: (a) plateau, composed of acid rocks of volcanic origin and very high degree of fracturing, (b) hills of the mountain, made up of volcanic rocks of Serra Geral formation (acid and basaltic breccias, basaltic flows) and (c) the plain, with the presence of sedimentary rocks and colluvial materials. There is also a special region where the road crosses a topographic saddle which it coincides with a regional fault, with cuts of about 60 m high through acid and basic rocks and volcanic breccia. The dissertation presents studies of rock falls that have occurred in the road cuts. A procedure that correlates the readings obtained with the Schmidt hammer (rebound hammer) and the normal coefficient of restitution (RN) of the rocks was carried out for measures taken at several locations. With these experimental data, simulations of falling boulders in four very different cross sections were done using the program RocFall. For each section five situations were simulated: (a) enlargements for the construction of rockfall catchment areas (b) the absence of these areas, (c) the existence of accumulation in the benchs of the cuts, and (d) the reduction of the section with bench removal. Four types of elements of protection were tested: concrete low barriers, layers of sand, flexible metal barriers and slope surface protection. The existence of rockfall catchment areas was shown to be a very good measure with frequencies of track invasion usually below 1% reaching 6.5% on conditions of large material accumulation. The best performance was obtained by the installation of sand layers, with all frequencies below 2%. The use of rigid barriers of 81 cm high had a good performance for low-slope heights, reaching up to 25% block retention. The use of flexible barriers and surface protections also had a good performance. / La RS471/BR153 es una importante carretera de integración, atraviesa el estado de RS diagonalmente (Noroeste-Sureste). El tramo estudiado en esta disertación se localiza entre los municipios de Herveiras y Vera Cruz, y coincide con el descenso desde el altiplano hasta la región central del estado. Durante las etapas de detalle y construcción de la obra fueron encontrados diversos problemas geotécnicos que son brevemente descritos. El texto presenta los condicionantes geotécnicos de tres subtramos: (a) altiplano, compuesto por rocas ácidas de origen volcánico y grado de fracturamiento muy alto; (b) descenso de la sierra, compuesto por los derrames de la formación Serra Geral (brechas ácidas y basálticas e derrames basálticos) y (c) planicie, con rocas sedimentarias y materiales coluviales. Además, hay una región donde el trazado atraviesa una “silla” topográfica que coincide con una falla regional, con cortes de aproximadamente 60 m de altura a través de rocas ácidas, básicas y brechas volcánicas. La disertación presenta estudios de procesos de caídas de rocas que han ocurrido en algunos cortes. Fue utilizado un procedimiento que correlaciona las lecturas obtenidas con el martillo Schmidt (Esclerómetro) y el coeficiente de restitución normal (RN) de las rocas en diferentes lugares. Con estos datos experimentales, fueron ejecutadas simulaciones de caídas de rocas en cuatro secciones transversales bastante distintas usando el programa RocFall. En cada sección fueron simulados cinco escenarios: (a) existencia de sobreanchos para la construcción de áreas de retención de rocas, (b) inexistencia de estas áreas, (c) existencia de relleno en una o más gradas existentes en los taludes de corte, y (d) diminución de la pendiente de los taludes y eliminación de las gradas. También fueron simulados cuatro tipos de elementos de protección: barreras de baja altura en concreto, capas de arena suelta, barreras metálicas flexibles y protección superficial de los taludes. La existencia de áreas de retención de rocas mostro ser una excelente medida, con frecuencias de invasión de pista generalmente inferiores a 1%, pudiendo llegar a 6,5% en condiciones de gran acumulación de material. El mejor desempeño fue obtenido con la instalación de capas de arena suelta, con todas las frecuencias por debajo de 2%. El uso de barreras rígidas de 81 cm de altura tuvo un buen desempeño para taludes de baja altura, llegando a detenciones de hasta 25% de los bloques en trayectoria de invasión. Las barreras flexibles y protecciones superficiales generaron resultados satisfactorios, que podrían ser mejorados con otras modulaciones y dimensiones.

La Côte Nord de l’Estuaire et du Golfe du St. Laurent (Québec, Canada) est caractérisée par une série de complexes deltaïques mis en place en contexte de chute de Niveau Marin Relatif (NMR) forcée par le rebond glacio-isostatique, lors du retrait des marges de l’Inlandsis Laurentidien. L’étude de trois complexes deltaïques montre qu’un motif d’évolution morphostratigraphique contrôlé par le retrait des marges glaciaires prévalait au premier ordre. Le premier stade de sédimentation se caractérise par la mise en place de cônes d’épandage juxtaglaciaires sous-aquatiques. Leur localisation au front de la marge glaciaire fait que la répartition spatiale des corps sédimentaires montre localement un empilement en rétrogradation. Dès l’émergence d’un front glaciaire continental, des deltas proglaciaires se développent en contexte de chute de NMR, formant des lobes dont l’altitude décroît vers le bassin. Ces derniers sont initialement associés à un système fluviatile en tresse alimenté en sédiments glaciogéniques par les marges glaciaires en retrait. Malgré des taux de chute de NMR de plusieurs cm/an, aucune incision fluviatile n’est observée à ce stade et la dynamique de transfert est prédominante du fait des forts taux d’apports sédimentaires. Plus tard, à la suite du retrait des marges glaciaires hors des bassins versants, le remaniement paraglaciaire se développe du fait de la réduction drastique des apports en eaux et sédiments. Le système fluviatile, devenu méandriforme, s’encaisse dans les anciens dépôts deltaïques maintenant inactifs et les bordures de deltas sont remaniées par les processus littoraux (plages soulevées, terrasses marines). Cette étude révèle que la majorité du volume de ces complexes deltaïques (10-20 km3) est mis en place en quelques milliers d’années seulement, immédiatement après la déglaciation ; le remaniement paraglaciaire n’ayant contribué à l’accrétion deltaïque que très marginalement. La modélisation numérique (Dionisos) valide les différents forçages identifiés par l’analyse morphosédimentaire. Une synthèse des complexes deltaïques à l’échelle de toute la Côte Nord du St. Laurent a permis de catégoriser 21 complexes deltaïques en 4 scénarios d’évolution morphosédimentaire, directement liés à la dynamique de retrait de la marge glaciaire. Leur décryptage offre une clef de lecture originale pour l’historique du retrait des marges glaciaires de l’Inlandsis Laurentidien sur la période 12-7.5 ka cal BP. / The North Shore of the St. Lawrence Estuary and Gulf is characterized by the presence of deltaic complexes that were emplaced under falling Relative Sea Level (RSL) forced by the glacio-isostatic rebound, immediately after the retreat of the Laurentide Ice Sheet (LIS) margin. The study of three deltaic complexes reveals that a common morphostratigraphic evolution forced by the retreat of the LIS prevailed for the edification of these structures, reflecting the retreat of the LIS margin. The emplacement of subaqueous outwash fans beyond the retreating or stillstanding glaciomarine margin constitutes the first stage of this evolution. As tied to the ice-margin position, these fans are characterized in places by a backstepping stacking pattern, in spite of the forced regressive setting. From the emergence of a continental ice front, the proglacial deltaic system develops and forms lobes staged accordingly to the RSL fall. These deltaic systems actively prograde at that time because they are fed in glaciogenics by the retreating LIS margin through braided meltwater streams. In spite of the RSL fall reaching several centimeters per years, no fluvial entrenchment occurs mainly owing to the significant amount of sediment supply. Later, when the LIS margin retreats from the drainage basins of feeding rivers, fluvial systems experience a drastic drop in sediment supply that forced the interruption of the deltaic progradation and the onset of paraglacial reworking. The paraglacial reworking consists in the entrenchment of a meandering fluvial system within former deltaic deposits and shows the prevalence of shallow-marine processes (waves, tides) at the delta rim (raised beaches, marine terraces). This study reveals that the bulk of the deltaic volume (c.a. 10-20 km3) for each complex was emplaced in only a few thousands of years following the LIS margin retreat when the latter was still located in the drainage basin. The paraglacial reworking had a minor influence on the deltaic accretion. A forward stratigraphic model (Dionisos) is used to validate the variety of forcing as understood from the sedimentary analysis. A synthesis including 21 deltaic complexes of the St. Lawrence North Shore allowed the establishment of a fourfold categorization. This scheme of deltaic evolution was used in order to refine the position of the LIS margin retreating upland for a period ranging from 12 to 7.5 ka cal BP.

ICT has become so deeply embedded into the fabric of European society – in economic, political, and socio-cultural narratives, practices, and structures – that it has been constructed as holding tremendous untapped and inestimable potential for instigating and unleashing far-reaching societal transformation, addressing key societal challenges, and solving all societal problems. It has recently been seen, given its ubiquity, as a critical driver and powerful catalyst for sustainable urban development due to its potential to enable substantial energy savings and GHG emissions reductions in most urban sectors, especially buildings. However, related to this ubiquity, there are also a lot of visions (of limited modern applicability), hopes, myths, fallacies, and oxymora, which applies for the environmental subsystem of information society where debates focus on whether ICT can advance environmental urban sustainability. There are intricate relationships and tradeoffs among the multidimensional effects of ICT for the environment that flow mostly from the use and application of ICT – e.g. energy efficiency technology - throughout the urban sphere. Regardless, the technological orientation and framing of the sustainable city and the green economy has gained dominance in European society and become prevalent in what has come to be identified or known as the discourse of ICT for sustainable urban development (ICT4SUD). The aim of this study is to carry out a critical reading of the social construction of ICT4SUD, the underlying ideology about the ICT potential in advancing environmental urban sustainability. To achieve this aim, a Foucauldian-Faircloughian discursive approach is employed to examine the selected empirical material. This approach consists of nine stages: (1) surface descriptors and contextual elements; (2) historical-diachronic dimension; (3) epistemic and cultural frames; (4) discursive constructions and discourses; (5) social actors and framing power; (6) discursive strategies; (7) discursive mechanisms; (8) political practice, knowledge, and power; and (9) ideological standpoints.As a scholarly discourse, ICT4SUD is inherently part of and influenced by economic, societal, and political structures, and produced in social interaction. ICT4SUD is thus neither paradigmatic nor value-free, but rather socio-politically situated. It is shaped by cultural frames that are conventionalized by European society and attuned to its values, and it is a matter of a pre-intellectual space where ICT and sustainability constitute salient defining factors of the dominant configuration of knowledge, institutions, and material forces of European society. Indeed, ICT4SUD is impacted by earlier representations of reality and how they were reproduced in relation to the significance of discursive constructions of ICT and sustainability issues in the broader context of European culture. Moreover, the ICT4SUD discourse plays a major role in (re)constructing the image of the ICT industry as a social actor and in defining its identity and relation with other constituents of society, in that it is relocated new roles and attributed new societal missions. The dominant framing of the reports is clearly the one advanced by the ICT industry: it is constituted into the main definer of the represented reality. Further, positioning the ICT industry as the driver of the low-carbon city/economy aids the construction of an image of leadership in creating a low carbon society. The reports’ construction of energy efficiency technology is a powerful legitimation of the ICT industry’s views and actions. In addition, the ICT4SUD discourse is exclusionary, namely a number of facts and issues pertaining to structural, indirect, and systemic effects of ICT and the associated rebound effects are left out, concealed, or neglected. Also, the discourse is inclined to be deterministic, i.e. it postulates that ICT, supported by policy, will achieve SUD while it falls short in considering social behaviour and socio-economic relationships. It moreover tends to be rhetorical – that is, it promises environmentally SUD without really having a holistic strategy to achieve that goal. Furthermore, given the scientific discourse and the legitimation capacity of computing, climatology, and sustainability indicators, one can subsume a range of social and political effects under the category of discourse mechanisms through which ICT4SUD operates, which both show the power of discourse and potentially empower the ICT industry and its cohorts. There are different justifications for the development of energy efficiency technology in relation to decision-making processes. Plus, politics, as a consequence of its interaction with ICT4SUD, forces, though different mechanisms, the emergence and development of the ICT4SUD discourse, which is, simultaneously, influenced by the power/knowledge relations established in European society that bounds or expands its success. Finally, as to ideological reproduction, the ICT4SUD discourse reconstructs cultural claims, conveys ideological messages, and reproduces and legitimizes power structures.