Container cranes represent one of the most critical components of ports worldwide. Despite their importance to port operations, the seismic behavior of cranes has been largely ignored. Since the 1960s, industry experts have recommended allowing cranes to uplift, believing that it would limit the amount of seismic loading. However, modern cranes have become larger and more stable, and the industry experts are now questioning the seismic performance of modern jumbo cranes. The main goal of this research was to experimentally investigate the seismic behavior of container cranes from the general elastic behavior through collapse, including non-linear behavior such as buckling and cross section yielding, utilizing the 6 degree-of-freedom shake tables at the University at Buffalo. The testing was divided into two phases. The first phase of testing was conducted on a 1/20th scale model. The second phase of testing was conducted on a 1/10th scale model, which was designed such that no inelastic action would develop prior to uplift (as is the common design practice). In support of the experiments, finite element models were created to determine what simplifications could be made to the structure to aid in testing. The data collected from the testing has been used to validate finite element models, to give a better understanding of the behavior of container cranes under seismic excitations, validate fragility models, and to develop recommendations and guidelines for the design and testing of container cranes.

Pre-existing structural elements can have substantial effects on fracture and fault development in younger strata, especially in areas that undergo significant changes in tectonic setting due to reactivation along older structures. This may affect reservoir permeability, yet remain difficult to detect in subsurface data. The focus of this study centers on two styles of pre-existing structures—Paleozoic thrust belts and Late Triassic rift faults in the Devils River Uplift and Maverick Basin, respectively—which affect the development of faults and fractures in Cretaceous strata. Fault and fracture data were characterized in both the outcrop and within a 3D seismic volume. Furthermore, the role of mechanical stratigraphy on fault and fracture style in both localities was examined. The Pecos River Canyon overlies the Paleozoic Ouachita fold-thrust belt with associated EW and SE-NW trending structures. At the surface, faults are expressed in two predominant orientations (N38E and N70E), which may be predictable angles if the pre-existing structures are reactivated by left lateral oblique slip. Detailed investigation of the fracture development related to these faults was conducted in a dry side canyon along the Pecos River. Mechanical layers were identified and mapped in outcrop to highlight fracture intensity variations between the different layers. The porosity and/or the degree of dolomitization are identified as controls on fracture development, with the lowest strength layer and least fractured being highly dolomitized with the largest porosity of any observed layer in outcrop. Southeast of Lewis Canyon, a 3D seismic of the Maverick Basin reveals linear discontinuities, interpreted as low-offset faults, within the Cretaceous Glen Rose through Austin Chalk that appear similar to those observed in outcrop along the Lower Pecos River. These faults are shown to have an increase in intensity within strata above older Late Triassic-age rift faults. It is proposed that the small faults form during reactivation of the rift faults and exhibit differential degrees of intensity and vertical terminations against six identified mechanical boundaries observed within the 3D seismic volume. / text

The African Methodist Episcopal (A.M.E.) Church, like many historically black denomination over the years, has been actively involved in social change and racial uplift. The concepts of racial uplift and self-determination dominated black social, political, and economic thought throughout the late-eighteenth into the nineteenth century. Having created many firsts for blacks in America, the A.M.E. Church is recognized as leading blacks in implementing the rhetoric of racial uplift and self-determination. Racial uplift was a broad concept that covered issues such as equal rights, moral, spiritual, and intellectual development, and institutional and organizational building. The rhetoric of racial uplift and self-determination help to create many black leaders and institutions such as churches, schools, and newspapers. This is a historical study in which I examined how education and educational institutions sponsored by a black church can be methods of social change and racial uplift. The A.M.E. Church was the first black institution (secular or religious) to create, support, and maintain institutions of higher education for blacks. I explored the question of why before slavery had even ended and it was legal for blacks to learn to read and write, the A.M.E. Church became interested in and created institution of learning. I answer this question by looking at the creation of these institutions as the A.M.E. Church’s way of promoting and implementing racial uplift and self-determination. This examination includes the analysis of language used in articles, sermons, and speeches given by various A.M.E. Church-affiliated persons who promoted education as a method to uplift the Negro race.

The Alpine Fault is a major plate boundary structure, which accommodates up to 50-80% of the total plate boundary motion across the South Island of New Zealand. The fault has not ruptured historically although limited off-fault shaking records and on-fault dating suggest large to great (~ Mw 8) earthquakes (every ~100-480 years; most recently in 1717), making it potentially one of the largest onshore sources of seismic hazard in New Zealand. The central section of the Alpine Fault, which bounds the highest elevations in the Southern Alps, is one of the most poorly characterised sections along the fault. On-fault earthquake timing in addition to the amount of dextral slip during major earthquakes was unknown along a 200-km-long section of the central Alpine Fault, while the amount of co-seismic hanging wall uplift was poorly known, prior to the present work. In this thesis I address these knowledge gaps through a combination of light detection and ranging (lidar), field, and stratigraphic mapping along with sample dating to constrain earthquake timing, style of faulting, and hanging wall rock uplift rates. Using lidar data coupled with field mapping I delineated the main trace of the Alpine Fault at Gaunt Creek as a north-striking fault scarp that was excavated and logged; this is part of a 2-km-wide restraining bend dominated by low-angle thrust faulting and without the clear strike-slip displacements that are present nearby (<5 km distant along strike in both directions). Where exposed in this scarp, the fault-zone is characterized by a distinct 5-50 cm thick clay fault-gouge layer juxtaposing hanging wall bedrock (mylonites and cataclasites) over unconsolidated late-Holocene footwall colluvium. An unfaulted peat at the base of the scarp is buried by post-most recent event (MRE) alluvium and yields a radiocarbon age of A.D. 1710–1930, consistent with sparse on-fault data, validating earlier off-fault records that suggest a 1717 MRE with a moment magnitude of Mw 8.1 ± 0.1, based on the 380-km-long surface rupture. Lidar and field mapping also enabled the identification and measurement of short (<30 m), previously unrecognized dextral offsets along the central section of the Alpine Fault. Single-event displacements of 7.5 ± 1 m for the 1717 earthquake and cumulative displacements of 12.9 ± 2 m and 22 ± 2.7 m for earlier ruptures can be binned into 7.1 ± 2.1 m increments of repeated dextral (uniform) slip along the central Alpine Fault. A comparison of these offsets with the local paleoseismic record and known plate kinematics suggests that the central Alpine Fault earthquakes in the past 1.1 ka may have: (i) bimodal character, with major surface ruptures (!Mw 7.9) every 270 ± 70 years (e.g. the 1717 event) and with moderate to large earthquakes (!Mw 7) occurring between these ruptures (e.g. the 1600 event); or (ii) that some shaking data may record earthquakes on other faults. If (i) is true, the uniform slip model (USM) perhaps best represents central Alpine Fault earthquake recurrence, and argues against the applicability of the characteristic earthquake model (CEM) there. Alternatively, if (ii) is true, perhaps the fault is “characteristic” and some shaking records proximal to plate boundary faults do not necessarily reflect plate-boundary surface ruptures. Paleoseismic and slip data suggest that (i) is the most plausible interpretation, which has implications for the understanding of major plate-boundary faults worldwide. Field mapping, geological characterisation, geophysical mapping, and optically stimulated luminescence (OSL) dating of on-fault hanging wall sediments were used to better constrain the geometry and kinematics of Holocene deformation along the rangefront of the Southern Alps at the Alpine Fault near the Whataroa River. The fault here is dextral-reverse, although primarily strike-slip with clear fault traces cutting across older surfaces of varying elevations. Deformational bulges are observed along these traces that are likely thrust-bounded. A terrace of Whataroa River sediments was found on the hanging wall of the Alpine Fault approximately ~ 55-75 m (when considering uncertainties) above the floodplain of the Whataroa River. OSL ages for a hanging wall sediments of 10.9 ± 1.0 ka for the aforementioned terrace, 2.8 ± 0.3 ka for Whataroa River terrace deposits in a deformational bulge, and 11.1 ± 1.2 ka for a rangefront derived fan indicate Holocene aggradation along the rangefront and hanging wall uplift rates of 6.0 ± 1.1 mm/yr. The sub-horizontal, laterally continuous, and planar-bedded Whataroa-sourced terrace deposits suggest that the adjacent bounding faults are steeply-dipping faults without geometries in the shallow subsurface that would tend to cause sedimentary bed rotation and tilting. Using data from the approximately 100-m deep pilot DFDP boreholes together with lidar and field mapping, I present a review of the Quaternary geology, geomorphology, and structure of the fault at Gaunt Creek, and estimate new minimum Late-Pleistocene hanging wall rock uplift rates of 5.7 ± 1.0 mm/yr to 6.3 ± 1.1 mm/yr (without considering local erosion) that suggest that the Southern Alps are in a dynamic steady state here. GPS-derived “interseismic” vertical uplift rates are < 1 mm/yr at the Alpine Fault, so the majority of rock uplift at the rangefront happens during episodic major earthquakes, confirming with on-fault data that slip occurs coseismically. Notably the uplift rates from both Mint and Gaunt Creek are consistent between the two sites although the primary style of faulting at the surface is different between the two sites, suggesting consistent coseisimc uplift of the Southern Alps rangefront along the Alpine Fault in major earthquakes. This thesis collected new on-fault datasets that confirm earlier inferences of plate-boundary fault behaviour. This study of the high-uplift central section of the Alpine Fault provides the first on-fault evidence for the MRE (i.e. 1717) and repeated of dextral slip during the MRE and previous events as well as new hanging wall uplift data which suggests that the majority of rangefront uplift occurs in earthquakes along the Alpine Fault. Because the fault has not ruptured for ~300 years, it poses a significant seismic hazard to southern New Zealand.

The global stiffness behaviour of modular-based two storey timber structures was studied under prescribed horizontal displacements at the upper corners of the volume modules. To be able to study this behaviour, a numerical finite element model was created in Abaqus. A parametric study was performed in which the geometry and spring stiffness of joints were varied until the enough stiff module was attained for safe transfer of shear forces through the module structure. The FE-model was parameterized to have possibility to vary positions of door and window openings in the volume modules. These openings had influence on the global structural behaviour of the two storey module structure since the side wall with two openings showed less reaction forces at its top corner point A compared to the other wall point B. In addition, the module#3 was assigned with small spring stiffness in x-direction representing friction in the joint between the volume modules. This was done without uplift plates and angle brackets. The findings showed that there was significant slipdeformation between the volume modules and small reaction forces at points A and B. The spring stiffness value in x-direction was varied until large value was obtained which resulted in overall shear deformations of the walls in both volume modules. When the angle bracket and the uplift plates were introduced between the modules when small spring stiffness along the joint between the volume modules was used, the results showed that most of the shear forces were transferred through the angle brackets instead of the fastener joints between the modules. Moreover, the results showed that the reaction forces at the points A and B increased when the angle brackets were assigned in the module. Furthermore, the results also showed that uplift plates used in the model worked well for simulations with low vertical spring stiffness between the modules.

Os arenitos fluviais e eólicos da Formação Sergi (Jurássico – Cretáceo) são os reservatórios mais importantes da Bacia do Recôncavo, nordeste do Brasil. Um estudo detalhado utilizando Microscopia Eletrônica de Varredura, Microscopia Ótica, Difração de Raios-X e Espectroscopia de Infravermelho revelou a ocorrência de dickita, um argilomineral indicativo de soterramento profundo (T >100oC), nos campos de óleo de Buracica (630 a 870 m) e Água Grande (1300 a 1530 m). A dickita ocorre distribuída irregularmente em arenitos com grande permeabilidade e porosidade intergranular da seqüência estratigráfica média da Formação Sergi, como agregados vermiculares e booklets substituindo grãos de feldspato e preenchendo poros gerados por dissolução de feldspatos e poros intergranulares adjacentes. O hábito vermicular da dickita é um produto da transformação pseudomórfica da caolinita durante o soterramento, provavelmente sob influência de condições ácidas relacionadas a ácidos orgânicos gerados da evolução térmica do querogênio nas rochas geradoras rift. A presença de dickita concorda com a intensidade de compactação, com a relativamente abundante cimentação pós-compactacional de quartzo, e com os valores de isótopos estáveis de oxigênio dos cimentos de calcita pós-compactacional, que correspondem a temperaturas de até 116oC. Essas evidências sugerem que os arenitos foram submetidos a temperaturas substancialmente mais altas que aquelas correspondentes a sua atual profundidade. Entretanto, um fluxo de calor ou de fluidos mais acentuado não pode ser invocado para a área para explicar as altas temperaturas. A ocorrência de dickita, associada a outras evidências petrológicas para condições de soterramento profundo, bem como análises de traços de fissão em apatitas de outras áreas na bacia, indicam que a área central da Bacia do Recôncavo sofreu soerguimento e erosão de pelo menos 1 km (provavelmente mais que 1500 m). Este evento não foi anteriormente detectado por modelos estruturais e estratigráficos convencionais. / Fluvial and aeolian sandstones of the Sergi Formation (Jurassic-Cretaceous) are the most important reservoirs of the Recôncavo Basin, northeastern Brazil. A detailed study through optical and electronic microscopy, X-ray diffraction and infra-red spectroscopy revealed the occurrence of dickite, a clay mineral indicative of deep burial conditions (T > 100oC), in the shallow Buracica (630 to 870 m) and Água Grande (1300 to 1530 m) oilfields. Dickite occurs irregularly distributed in sandstones with larger intergranular porosity and permeability of the middle, coarser stratigraphic sequence of Sergi Formation, as vermicular and booklet aggregates replacing feldspar grains, and filling pores generated by feldspars dissolution and adjacent intergranular pores. The vermicular habit of dickite is a product of pseudomorphic kaolinite transformation during burial, presumably under influence of acidic conditions related to organic acids generated from the thermal evolution of kerogen in the rift source rocks. The presence of dickite agrees with the intensity of compaction, relatively abundant post-compactional quartz cementation, and stable oxygen isotope values of the post-compactional calcite cements, corresponding to temperatures as high as 116ºC. This set of evidence suggests that the sandstones were subjected to temperatures substantially higher than those corresponding to their present burial depths. However, no enhanced thermal or hydrothermal fluid flow can be invoked in the area to be accounted for the interpreted high temperatures. The occurrence of dickite and other petrologic evidence for deep burial conditions, as well as apatite fission tracks analyses from other areas in the basin, indicate that an uplift and erosion of at least 1 km and probably more than 1500 m has affected the central part of Recôncavo Basin, and very likely the whole region, what was not previously detected by conventional structural and stratigraphic models.

Engenheiros geotécnicos, defrontam-se frequentemente com solos de baixa capacidade de suporte. Para viabilizar projetos nestes materiais, pode-se utilizar fundações com grandes dimensões e/ou melhorar a propriedades mecânicas destes solos. Fundações de grandes dimensões podem ser extremamente onerosas e gerar impactos ambientais indesejáveis provocados por grandes movimentações de solo. Em contrapartida, o melhoramento das propriedades mecânicas do solo pode ser obtido por meio de tratamento com agentes cimentantes. Esta técnica tem-se mostrado bastante promissora nas diversas subáreas da geotecnia, como por exemplo, leito e subleito de pavimentação, estabilidade de taludes e terrenos para assentamento de fundações à compressão. A utilização desta técnica em fundações escavadas submetidas à tração ainda é incipiente. Até meados dos anos 1950, os métodos de previsão de desempenho consideravam somente o peso do solo contido em uma superfície ruptura somado ao peso da fundação, como contribuindo na capacidade de carga ao arrancamento. Estudos recentes passaram a incluir uma terceira parcela de resistência devido à resistência ao cisalhamento do solo. A partir de então diversos autores passaram a estudar técnicas de melhoramento e reforços dos reaterros. Num primeiro momento, foi estudada a influência das técnicas de compactação do reaterro e a substituição do material por outro com melhores propriedades. Atualmente, os estudos concentram-se no reforço dos reaterros com geossintéticos e adição de agentes cimentícios. Neste contexto, o objetivo deste trabalho é realizar um estudo avaliando os benefícios gerados pelo aumento da capacidade de carga, de fundações escavadas e reaterradas com areia fina e homogênea (proveniente da cidade de Osório/RS), cimentada, avaliando sua influência em termos das propriedades geométricas (diâmetro das fundações, profundidade de assentamento e diâmetro de tratamento) e geotécnicas (coesão, ângulo de atrito e módulo de elasticidade, influenciados pelo teor de cimento). Para tanto foram realizadas provas de carga à tração, variando-se o diâmetro (30 e 45 cm), profundidades de embutimentos (entre 0,5 e 2,0), e teores de cimento (0%, 3% e 7%). Através das provas de carga, verificou-se que o aumento do teor de cimento e da profundidade de assentamento aumentam a capacidade de carga à tração. Os resultados experimentais foram reproduzidos pelo método de elementos finitos por meio de retroanálise. A partir do modelo numérico gerado pela retroanálise, foram executadas duas análises paramétricas. Na primeira foram definidos os parâmetros significativos – coesão e embutimento – e determinada uma equação adimensional para determinação da carga máxima para tratamento de uma camada infinita. Na segunda análise foram definidos ábacos para determinação da perda de carga em função da redução do diâmetro de tratamento, para três níveis de cimentação – baixa, média e alta. / Geotechnical engineers frequently have to deal with soils that have reduced strength. In order to carry out the design of footings in such materials, their base has to be quite large and/or mechanical properties of the soils have to be improved. Shallow foundations of large dimensions can be extremely expensive and generate undesirable environmental impacts due to large soil movements. As an alternative, the improvement of mechanical properties of the local soil can be obtained by treating it with cementitious agents. Such technique has been used with success in several earthworks such as the improvement of base and sub-base of pavements, slope stability and particularly as a soil-cement mixture of a compacted layer over a low bearing capacity soil. The use of such technique in footings subjected to pullout forces is still insipient. Until middle 1950’s, pullout design methodologies of shallow foundations embedded in soil backfills considered only the weight of the soil contained inside a specific failure surface plus the foundation self-weight as the pullout failure load. Further studies included the shear strength of the soil at the failure surface. Since then several authors considered several techniques to improve and/or reinforce the backfills. At first the influence of backfill compaction and material substitution to improve soil properties were considered. Nowadays, studies concentrate in the reinforcement of backfills with geosynthetics and in the addition of cementitious agents. In such context, the main aim of present work is to carry out a research evaluating the benefits towards the improvement of uplift performance of footings embedded in cemented stabilized backfill, analyzing the influence of the geometrical characteristics of the problem (diameter of the footings, depth of embedment and size of the improved area) and geotechnical properties of the backfill (cohesion intercept, friction angle and Young’s modulus), the latter influenced by the amount of cementitious agents inserted on the soil. For doing so, several pullout tests were carried out varying foundation diameter (0.30 and 0.45 m), embedment depth according foundation diameter (ranging from 0.5 e 2.0) and cement contents (0%, 3% and 7%) in the stabilized backfill. Results of pullout tests have shown that the increase of cement content and embedment depth of the backfill increased uplift capacity. Field results were reproduced through a back-analysis using the finite element technique. In the sequence, two distinct parametrical analyses were also carried out. In the first analysis the parameters that show significance were cohesion intercept and embedment depth – a non-dimensional equation determining the failure pullout load (considering infinite horizontal improvement) was determined. In the second analysis distinct abacus were produced to allow considering reduction of horizontal treatment area for three cementation levels – low, medium e high.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A geotecnia constitui uma disciplina relativamente recente na área da engenharia civil, e dessa disciplina faz parte um capítulo ainda menos estudado que trata de fundações submetidas a esforços de tração. O presente trabalho deriva do conjunto de provas de cargas realizado para um importante projeto de linhas de transmissão que permitiu a aferição da teoria de capacidade de carga à tração da Universidade de Grenobel, cujos estudos comparativos mostram bons resultados para fins de aplicações práticas. De posse da extensa documentação técnica produzida e documentada por esse estudo foi possível comparar os resultados obtidos pelas provas de cargas e os resultados teóricos com os resultados das modelagens 2D axisimetricas por elementos finitos. Além dessas análises, foi possível verificar a variação da resistência à tração através de análises paramétricas realizadas a partir da variação da coesão e do ângulo de atrito. Os estudos apresentados reafirmam a confiabilidade das teorias da Universidade de Grenoble, que contemplam a simplicidade desejada às aplicações de cunho prático, com resultados satisfatórios em relação àqueles obtidos nos ensaios de tração. Por outro lado, as análises paramétricas realizadas indicaram a tendência de comportamento que a resistência à tração deve apresentar para diferentes parâmetros do solo. O conhecimento dessas tendências permite ao projetista avaliar os fatores de segurança sob ponto de vista probabilístico, ou seja, permite o emprego de fatores de segurança com o conhecimento da probabilidade de ruína associada. As análises probabilísticas foram traçadas a partir do emprego de funções genéricas de várias variáveis no formato FOSM (First Order Second Moment) que fornecem soluções aproximadas para o cálculo de desvio padrão quando não existe uma amostragem representativa. Ao término das análises, obteve-se como resultado, o mapa comparativo da probabilidade de ruína para os mesmos fatores de segurança empregados com base em resistências estimadas através de diferentes métodos de cálculos (Universidade de Grenoble e modelagem computacional). / Geotechnical engineering is a relatively recent area of civil engineering, which comprises the much less studied topic of foundations under tensile loads. Based on an extensive literature review this paper presents a set of foundation uplift tests carried out for an important transmission line project that allowed to compare the test results with the theory developed at the University of Grenoble, with fairly good results for practical purposes. The test results have also been compared to axisymmetric finite element analysis, also with satisfactory results. This study also presents parametric variations of the soil strength parameters to estimate the variation of the tensile foundation capacity based on sequentially increasing values of cohesion and friction angle. The parametric variation of the soil strength parameters was intended to provide the necessary insight to a complementary probabilistic analysis presented at the end of this dissertation. This work confirms the adequacy and simplicity of the theoretical framework developed at the University of Grenoble comparably to more refined techniques such as finite element analysis, providing a valuable tool for practical design applications. The probabilistic analysis was based on standard FOSM (First Order Second Moment ) approximation, providing estimates of the standard deviation of the tensile foundation capacities to better understand expected variations of the foundation uplift capacity in practical problems.

Engenheiros geotécnicos, defrontam-se frequentemente com solos de baixa capacidade de suporte. Para viabilizar projetos nestes materiais, pode-se utilizar fundações com grandes dimensões e/ou melhorar a propriedades mecânicas destes solos. Fundações de grandes dimensões podem ser extremamente onerosas e gerar impactos ambientais indesejáveis provocados por grandes movimentações de solo. Em contrapartida, o melhoramento das propriedades mecânicas do solo pode ser obtido por meio de tratamento com agentes cimentantes. Esta técnica tem-se mostrado bastante promissora nas diversas subáreas da geotecnia, como por exemplo, leito e subleito de pavimentação, estabilidade de taludes e terrenos para assentamento de fundações à compressão. A utilização desta técnica em fundações escavadas submetidas à tração ainda é incipiente. Até meados dos anos 1950, os métodos de previsão de desempenho consideravam somente o peso do solo contido em uma superfície ruptura somado ao peso da fundação, como contribuindo na capacidade de carga ao arrancamento. Estudos recentes passaram a incluir uma terceira parcela de resistência devido à resistência ao cisalhamento do solo. A partir de então diversos autores passaram a estudar técnicas de melhoramento e reforços dos reaterros. Num primeiro momento, foi estudada a influência das técnicas de compactação do reaterro e a substituição do material por outro com melhores propriedades. Atualmente, os estudos concentram-se no reforço dos reaterros com geossintéticos e adição de agentes cimentícios. Neste contexto, o objetivo deste trabalho é realizar um estudo avaliando os benefícios gerados pelo aumento da capacidade de carga, de fundações escavadas e reaterradas com areia fina e homogênea (proveniente da cidade de Osório/RS), cimentada, avaliando sua influência em termos das propriedades geométricas (diâmetro das fundações, profundidade de assentamento e diâmetro de tratamento) e geotécnicas (coesão, ângulo de atrito e módulo de elasticidade, influenciados pelo teor de cimento). Para tanto foram realizadas provas de carga à tração, variando-se o diâmetro (30 e 45 cm), profundidades de embutimentos (entre 0,5 e 2,0), e teores de cimento (0%, 3% e 7%). Através das provas de carga, verificou-se que o aumento do teor de cimento e da profundidade de assentamento aumentam a capacidade de carga à tração. Os resultados experimentais foram reproduzidos pelo método de elementos finitos por meio de retroanálise. A partir do modelo numérico gerado pela retroanálise, foram executadas duas análises paramétricas. Na primeira foram definidos os parâmetros significativos – coesão e embutimento – e determinada uma equação adimensional para determinação da carga máxima para tratamento de uma camada infinita. Na segunda análise foram definidos ábacos para determinação da perda de carga em função da redução do diâmetro de tratamento, para três níveis de cimentação – baixa, média e alta. / Geotechnical engineers frequently have to deal with soils that have reduced strength. In order to carry out the design of footings in such materials, their base has to be quite large and/or mechanical properties of the soils have to be improved. Shallow foundations of large dimensions can be extremely expensive and generate undesirable environmental impacts due to large soil movements. As an alternative, the improvement of mechanical properties of the local soil can be obtained by treating it with cementitious agents. Such technique has been used with success in several earthworks such as the improvement of base and sub-base of pavements, slope stability and particularly as a soil-cement mixture of a compacted layer over a low bearing capacity soil. The use of such technique in footings subjected to pullout forces is still insipient. Until middle 1950’s, pullout design methodologies of shallow foundations embedded in soil backfills considered only the weight of the soil contained inside a specific failure surface plus the foundation self-weight as the pullout failure load. Further studies included the shear strength of the soil at the failure surface. Since then several authors considered several techniques to improve and/or reinforce the backfills. At first the influence of backfill compaction and material substitution to improve soil properties were considered. Nowadays, studies concentrate in the reinforcement of backfills with geosynthetics and in the addition of cementitious agents. In such context, the main aim of present work is to carry out a research evaluating the benefits towards the improvement of uplift performance of footings embedded in cemented stabilized backfill, analyzing the influence of the geometrical characteristics of the problem (diameter of the footings, depth of embedment and size of the improved area) and geotechnical properties of the backfill (cohesion intercept, friction angle and Young’s modulus), the latter influenced by the amount of cementitious agents inserted on the soil. For doing so, several pullout tests were carried out varying foundation diameter (0.30 and 0.45 m), embedment depth according foundation diameter (ranging from 0.5 e 2.0) and cement contents (0%, 3% and 7%) in the stabilized backfill. Results of pullout tests have shown that the increase of cement content and embedment depth of the backfill increased uplift capacity. Field results were reproduced through a back-analysis using the finite element technique. In the sequence, two distinct parametrical analyses were also carried out. In the first analysis the parameters that show significance were cohesion intercept and embedment depth – a non-dimensional equation determining the failure pullout load (considering infinite horizontal improvement) was determined. In the second analysis distinct abacus were produced to allow considering reduction of horizontal treatment area for three cementation levels – low, medium e high.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A geotecnia constitui uma disciplina relativamente recente na área da engenharia civil, e dessa disciplina faz parte um capítulo ainda menos estudado que trata de fundações submetidas a esforços de tração. O presente trabalho deriva do conjunto de provas de cargas realizado para um importante projeto de linhas de transmissão que permitiu a aferição da teoria de capacidade de carga à tração da Universidade de Grenobel, cujos estudos comparativos mostram bons resultados para fins de aplicações práticas. De posse da extensa documentação técnica produzida e documentada por esse estudo foi possível comparar os resultados obtidos pelas provas de cargas e os resultados teóricos com os resultados das modelagens 2D axisimetricas por elementos finitos. Além dessas análises, foi possível verificar a variação da resistência à tração através de análises paramétricas realizadas a partir da variação da coesão e do ângulo de atrito. Os estudos apresentados reafirmam a confiabilidade das teorias da Universidade de Grenoble, que contemplam a simplicidade desejada às aplicações de cunho prático, com resultados satisfatórios em relação àqueles obtidos nos ensaios de tração. Por outro lado, as análises paramétricas realizadas indicaram a tendência de comportamento que a resistência à tração deve apresentar para diferentes parâmetros do solo. O conhecimento dessas tendências permite ao projetista avaliar os fatores de segurança sob ponto de vista probabilístico, ou seja, permite o emprego de fatores de segurança com o conhecimento da probabilidade de ruína associada. As análises probabilísticas foram traçadas a partir do emprego de funções genéricas de várias variáveis no formato FOSM (First Order Second Moment) que fornecem soluções aproximadas para o cálculo de desvio padrão quando não existe uma amostragem representativa. Ao término das análises, obteve-se como resultado, o mapa comparativo da probabilidade de ruína para os mesmos fatores de segurança empregados com base em resistências estimadas através de diferentes métodos de cálculos (Universidade de Grenoble e modelagem computacional). / Geotechnical engineering is a relatively recent area of civil engineering, which comprises the much less studied topic of foundations under tensile loads. Based on an extensive literature review this paper presents a set of foundation uplift tests carried out for an important transmission line project that allowed to compare the test results with the theory developed at the University of Grenoble, with fairly good results for practical purposes. The test results have also been compared to axisymmetric finite element analysis, also with satisfactory results. This study also presents parametric variations of the soil strength parameters to estimate the variation of the tensile foundation capacity based on sequentially increasing values of cohesion and friction angle. The parametric variation of the soil strength parameters was intended to provide the necessary insight to a complementary probabilistic analysis presented at the end of this dissertation. This work confirms the adequacy and simplicity of the theoretical framework developed at the University of Grenoble comparably to more refined techniques such as finite element analysis, providing a valuable tool for practical design applications. The probabilistic analysis was based on standard FOSM (First Order Second Moment ) approximation, providing estimates of the standard deviation of the tensile foundation capacities to better understand expected variations of the foundation uplift capacity in practical problems.