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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Proposta metodológica para análise da capacidade de carga de praias: estudo de caso em três praias do Guarujá (São Paulo) / Methodological proposal for an analysis of the load capacity of beaches: a case study in three beaches of Guarujá (São Paulo)

Silva, Juarez José da 23 November 2012 (has links)
O município do Guarujá, localizado na Região Metropolitana da Baixada Santista (litoral central de São Paulo) tem como principais atividades econômicas o Complexo Portuário-Retroportuário de Santos-Cubatão-Guarujá, o Pólo Polindustrial de Cubatão e o turismo de segunda residência. A cidade recebe, anualmente, grande população turística, cuja quantidade de pessoas pode variar de acordo com os períodos de temporada, feriados prolongados e fins de semana ensolarados. Nos períodos de maior aporte a infra-estrutura local torna-se insuficiente e inadequada para suportar a demanda. O presente estudo visa estudar esses limites e fazer uma análise mais detalhada dos fenômenos socioeconômicos ligados à capacidade de carga de três praias próximas ao centro urbano, Pitangueiras, Astúrias e Tombo, esta última recentemente agraciada com o selo internacional de qualidade Bandeira Azul. A metodologia prevê a avaliação das diferentes capacidades de carga (Capacidades de Carga Física, Capacidade de Carga Econômica, Capacidade de Carga Ecológica, Capacidade de Carga Social e Capacidade de Carga Recreativa), por meio de seus indicadores. / The city of Guarujá, located in the Santos Metrpolitan Region (central coast of São Paulo) has as its maisn economic activities of the Port Complex-Retroportuário Santos-Cubatão-Guarujá, the Pole Poleindustrial Cubatão tourism and second homes. The city receives annually, a large tourist population, which many people may vary according to the periods of the seasons, long weekends and weekends sunn. In peiods of greater contribution to local infrastructure becomes insufficient and inadequate to support the demand. This study aims to study those boundaries and make a more detailed analysis of the socio-economic phenomena related to the load capacity of tree beaches near the city centers. Pitangueiras, Asturias and Tombo, the latter recently awarded the international seal of quality Blue Flag. The methodology provides for the evaluation of different load capacities (Load Capacities Load Capacity Recreation), through its indicators.
2

Proposta metodológica para análise da capacidade de carga de praias: estudo de caso em três praias do Guarujá (São Paulo) / Methodological proposal for an analysis of the load capacity of beaches: a case study in three beaches of Guarujá (São Paulo)

Juarez José da Silva 23 November 2012 (has links)
O município do Guarujá, localizado na Região Metropolitana da Baixada Santista (litoral central de São Paulo) tem como principais atividades econômicas o Complexo Portuário-Retroportuário de Santos-Cubatão-Guarujá, o Pólo Polindustrial de Cubatão e o turismo de segunda residência. A cidade recebe, anualmente, grande população turística, cuja quantidade de pessoas pode variar de acordo com os períodos de temporada, feriados prolongados e fins de semana ensolarados. Nos períodos de maior aporte a infra-estrutura local torna-se insuficiente e inadequada para suportar a demanda. O presente estudo visa estudar esses limites e fazer uma análise mais detalhada dos fenômenos socioeconômicos ligados à capacidade de carga de três praias próximas ao centro urbano, Pitangueiras, Astúrias e Tombo, esta última recentemente agraciada com o selo internacional de qualidade Bandeira Azul. A metodologia prevê a avaliação das diferentes capacidades de carga (Capacidades de Carga Física, Capacidade de Carga Econômica, Capacidade de Carga Ecológica, Capacidade de Carga Social e Capacidade de Carga Recreativa), por meio de seus indicadores. / The city of Guarujá, located in the Santos Metrpolitan Region (central coast of São Paulo) has as its maisn economic activities of the Port Complex-Retroportuário Santos-Cubatão-Guarujá, the Pole Poleindustrial Cubatão tourism and second homes. The city receives annually, a large tourist population, which many people may vary according to the periods of the seasons, long weekends and weekends sunn. In peiods of greater contribution to local infrastructure becomes insufficient and inadequate to support the demand. This study aims to study those boundaries and make a more detailed analysis of the socio-economic phenomena related to the load capacity of tree beaches near the city centers. Pitangueiras, Asturias and Tombo, the latter recently awarded the international seal of quality Blue Flag. The methodology provides for the evaluation of different load capacities (Load Capacities Load Capacity Recreation), through its indicators.
3

Static, dynamic and levitation characteristics of squeeze film air journal bearing : designing, modelling, simulation and fluid solid interaction

Wang, Chao January 2011 (has links)
Bearings today need to be able to run at very high speed, providing high positional accuracy for the structure that it supports, and requiring very little or no maintenance. For this to happen, bearings must have tight tolerances and very low or zero friction during operation. This pushes many traditional contact-type bearings to their limits as they often fail due to friction, generating heat and causing wear. By comparison, existing non-contact bearings fare better because of their very low or zero friction. But some have their own problem too. For example, the fact that aerostatic bearings require an air supply means having to use a separate air compressor and connecting hoses. This makes the installation bulky. Aerodynamic and hydrodynamic bearings cannot support loads at zero speed. Both hydrodynamic and hydrostatic bearings may cause contamination to the work-pieces and the work environment because of the use of lubricating fluid. A potential solution to the above-mentioned problems is the new squeeze film air bearing. It works on the rapid squeeze action of an air film to produce separation between two metal surfaces. This has the benefit of being compact with a very simple configuration because it does not require an external pressurized air supply, can support loads at zero speed and is free of contamination. For this research, two squeeze film air journal bearings, made from material of Al 2024 - T3 and Cu - C101 with the same geometry, were designed. The bearing is in the shape of a round tube with three fins on the outer surface and the journal, a round rod. When excited at a certain normal mode, the bearing shell flexes with a desirable modal shape for the squeeze film action. The various modes of vibration of Al bearing were obtained from a finite-element model implemented in ANSYS. Two Modes, the 13th and 23rd, at the respective frequencies of 16.320 kHz and 25.322 kHz, were identified for further investigation by experiments with respect to the squeeze film thickness and its load-carrying capacity. For Cu bearing, the two Modes are also 13th and 23rd at the respective frequencies of 12.184 kHz and 18.459 kHz. In order to produce dynamic deformation of the bearings at their modes, a single layer piezoelectric actuator was used as a driver. The maximum stroke length and the maximum blocking force of the single layer piezoelectric actuator were determined using manual calculation and ANSYS simulation. In the coupled-field analysis, the single layer piezoelectric actuator was mounted on the outside surface of the bearing shell and loaded with an AC and a DC voltage in order to produce the static and dynamic deformation. For the static analysis, the maximum deformation of Al bearing shell is 0.124 μm when the actuators are driven at the DC of 75 V. For the dynamic analysis, the actuators are driven at three levels of AC, namely 55, 65 and 75V with a constant DC offset of 75V and the driving frequency coincided with the modal frequency of the bearing. The maximum dynamic deformation of Al bearing shell is 3.22μm at Mode 13 and 2.08μm at Mode 23 when the actuators were driven at the AC of 75 V and the DC of 75 V. Similarly, the FEA simulation was used for analyzing Cu bearing. Furthermore, the dynamic deformation of both Al and Cu bearing at Mode 13 and 23 are validated by experiments. This research developed two theoretical models that explain the existence of a net pressure in a squeeze film for the levitation. The first model uses the ideal gas law as first approximation whilst the second uses the CFX simulation to provide a more exact explanation. In terms of the load-carrying capacity, Mode 13 was identified to be better than Mode 23 for both bearings. However, at Mode 13, Al bearing has a higher load-carrying capacity than Cu bearing. This is due to Al bearing having a higher modal frequency and amplitude. Finally, the coupled-field analysis for fluid solid interaction (FSI) was studied at both Mode 13 and 23 for Al bearing. The findings are that: a) the fluid force in the squeeze film can affect the dynamic deformation of the bearing shell, especially at high oscillation frequency, more at Mode 13 than at Mode 23 due to the relatively high pressure end-leakage in the latter; b) the dynamic deformation of the bearing shell increases with the gap clearance in a logarithmic manner at Mode 13; and c) the micron levels of gap clearance provide a damping effect on the dynamic deformation of the bearing shell at Mode 13 and at Mode 23, though much less dominant.
4

Analytical Modeling of Wood Frame Shear Walls Subjected to Vertical Load

Nguyendinh, Hai 2011 May 1900 (has links)
A nonlinear automated parameter fitted analytical model that numerically predicts the load-displacement response of wood frame shear walls subjected to static monotonic loading with and without vertical load is presented. This analytical model referred to as Analytical Model of wood frame SHEar walls subjected to Vertical load (AMSHEV) is based on the kinematic behavior of wood frame shear walls and captures significant characteristics observed from experimental testing through appropriate modeling of three failure mechanisms that can occur within a shear wall under static monotonic load: 1) failure of sheathing-to-framing connectors, 2) failure of vertical studs, and 3) uplift of end studs from bottom sill. Previous models have not accounted for these failure mechanisms as well as the inclusion of vertical load, which has shown to reveal beneficial effects such as increasing the ultimate load capacity and limiting uplift of the wall as noted in experimental tests. Results from the proposed numerical model capture these effects within 7% error of experimental test data even when different magnitudes of vertical load are applied to predict the ultimate load capacity of wood frame shear walls.
5

Instalação e capacidade de carga axial de estacas modelo fluidizadas em solos arenosos / Installation and axial load capacity of fluidized model piles in sandy soils

Passini, Larissa de Brum January 2015 (has links)
O objetivo desta tese foi verificar a viabilidade de utilização de jatos de água verticais circulares, únicos e contínuos, provenientes da ponteira de uma estaca torpedo, para auxiliar sua instalação por peso próprio no leito marinho, através da fluidização do solo. Foram realizados ensaios de laboratório, em modelo reduzido, utilizando hastes para simular estacas torpedo (sem aletas) seguindo a lei de semelhança pelo número de Froude. Os ensaios de instalação por peso próprio, com e sem fluidização, ocorreram sem altura de queda, com a estaca modelo em contato com a superfície do leito. Trabalhou-se com três diâmetros de estacas, seis massas, quatros vazões e areia fina saturada compactada em duas densidades relativas iniciais (média e densa). Os ensaios de arrancamento, em leito arenoso fluidizado e não fluidizado, foram realizados imediatamente, 4, 24 e 48 horas após a instalação dos modelos. A metodologia de instalação proposta mostrou-se viável, quando o jateamento é aplicado desde a superfície em solo arenoso. As profundidades instaladas atingidas por fluidização (L/de > 50) foram consideravelmente superiores às profundidades cravadas por apenas peso próprio (L/de < 5). A geometria da zona perturbada durante a instalação por fluidização dos modelos, permaneceu constante e paralela ao fuste, com geometria de aproximadamente 2de em relação ao modelo, independentemente da vazão aplicada e da densidade relativa inicial do solo. A partir das leis de análise dimensional, uma expressão para a profundidade instalada das estacas modelo foi proposta, mostrando que a mesma é função do peso e da geometria do modelo, das propriedades físicas do solo e do fluido, e de sua vazão. Quanto maior a massa do modelo e a vazão aplicada e menor a densidade relativa, maior a profundidade atingida e maior a velocidade inicial de instalação. Constatou-se que a capacidade de carga axial dos modelos depende da densidade relativa, do diâmetro do modelo e do método de instalação (com e sem fluidização). Independentemente da densidade relativa inicial, o solo fluidizado convergiu para a mesma densidade relativa final, próxima as suas condições no estado crítico. As estacas em solo fluidizado apresentaram ganho resistência com o tempo (efeito de setup), com capacidade de carga inferior às estacas cravadas em solo não fluidizado. / The aim of this thesis was to investigate the feasibility of using circular vertical water jets, single and continuous, from the tip of a torpedo pile, to assist its installation by own weight on the seabed, through soil fluidization. Laboratory model tests were carried out, using tubes to simulate torpedo piles (without wings) following the law of similarity defined by the Froude number. The installation tests by the pile own weight, with and without fluidization, occurred without drop height, with the piles in contact with the surface of the bed. Three diameters of model piles and six masses, four flow rates and saturated sand at two initial relative densities (medium and dense) have been used in this set of experiments. Pullout tests in fluidized and nonfluidized soils were performed immediately, 4, 24 and 48 hours after the installation of the models. The proposed installation methodology proved to be feasible when the fluidization is applied from the surface in sandy soils. The installation depths achieved by fluidization (L/de > 50) were significantly higher than the depths reached by pile own weight (L/de < 5). The geometry of the perturbed zone during model installation by fluidization remained constant and parallel to the shaft in a geometry of about 2de of the pile model, regardless of the applied flow rate and the initial relative density of the soil. Following the laws of dimensional analysis, an expression for the embedment of fluidized piles is derived, showing that the penetration depth is a function of pile weight and geometry, fluidized water jet flow rate and velocity, as well as the soil and fluid properties. Increasing the model mass and fluidized flow rate and decreasing the relative density leads to an increase in the depth reached and the initial speed of installation. The axial load capacity of the models depends on the soil relative density, piles diameter and installation method (with and without fluidization). Regardless the initial relative density, the fluidized soil converged to the same final relative density, near its conditions of critical state. Piles installed in fluidized soil presented gain of axial capacity over time (setup effect) with lower resistance than piles driven in nonfluidized soil.
6

Instalação e capacidade de carga axial de estacas modelo fluidizadas em solos arenosos / Installation and axial load capacity of fluidized model piles in sandy soils

Passini, Larissa de Brum January 2015 (has links)
O objetivo desta tese foi verificar a viabilidade de utilização de jatos de água verticais circulares, únicos e contínuos, provenientes da ponteira de uma estaca torpedo, para auxiliar sua instalação por peso próprio no leito marinho, através da fluidização do solo. Foram realizados ensaios de laboratório, em modelo reduzido, utilizando hastes para simular estacas torpedo (sem aletas) seguindo a lei de semelhança pelo número de Froude. Os ensaios de instalação por peso próprio, com e sem fluidização, ocorreram sem altura de queda, com a estaca modelo em contato com a superfície do leito. Trabalhou-se com três diâmetros de estacas, seis massas, quatros vazões e areia fina saturada compactada em duas densidades relativas iniciais (média e densa). Os ensaios de arrancamento, em leito arenoso fluidizado e não fluidizado, foram realizados imediatamente, 4, 24 e 48 horas após a instalação dos modelos. A metodologia de instalação proposta mostrou-se viável, quando o jateamento é aplicado desde a superfície em solo arenoso. As profundidades instaladas atingidas por fluidização (L/de > 50) foram consideravelmente superiores às profundidades cravadas por apenas peso próprio (L/de < 5). A geometria da zona perturbada durante a instalação por fluidização dos modelos, permaneceu constante e paralela ao fuste, com geometria de aproximadamente 2de em relação ao modelo, independentemente da vazão aplicada e da densidade relativa inicial do solo. A partir das leis de análise dimensional, uma expressão para a profundidade instalada das estacas modelo foi proposta, mostrando que a mesma é função do peso e da geometria do modelo, das propriedades físicas do solo e do fluido, e de sua vazão. Quanto maior a massa do modelo e a vazão aplicada e menor a densidade relativa, maior a profundidade atingida e maior a velocidade inicial de instalação. Constatou-se que a capacidade de carga axial dos modelos depende da densidade relativa, do diâmetro do modelo e do método de instalação (com e sem fluidização). Independentemente da densidade relativa inicial, o solo fluidizado convergiu para a mesma densidade relativa final, próxima as suas condições no estado crítico. As estacas em solo fluidizado apresentaram ganho resistência com o tempo (efeito de setup), com capacidade de carga inferior às estacas cravadas em solo não fluidizado. / The aim of this thesis was to investigate the feasibility of using circular vertical water jets, single and continuous, from the tip of a torpedo pile, to assist its installation by own weight on the seabed, through soil fluidization. Laboratory model tests were carried out, using tubes to simulate torpedo piles (without wings) following the law of similarity defined by the Froude number. The installation tests by the pile own weight, with and without fluidization, occurred without drop height, with the piles in contact with the surface of the bed. Three diameters of model piles and six masses, four flow rates and saturated sand at two initial relative densities (medium and dense) have been used in this set of experiments. Pullout tests in fluidized and nonfluidized soils were performed immediately, 4, 24 and 48 hours after the installation of the models. The proposed installation methodology proved to be feasible when the fluidization is applied from the surface in sandy soils. The installation depths achieved by fluidization (L/de > 50) were significantly higher than the depths reached by pile own weight (L/de < 5). The geometry of the perturbed zone during model installation by fluidization remained constant and parallel to the shaft in a geometry of about 2de of the pile model, regardless of the applied flow rate and the initial relative density of the soil. Following the laws of dimensional analysis, an expression for the embedment of fluidized piles is derived, showing that the penetration depth is a function of pile weight and geometry, fluidized water jet flow rate and velocity, as well as the soil and fluid properties. Increasing the model mass and fluidized flow rate and decreasing the relative density leads to an increase in the depth reached and the initial speed of installation. The axial load capacity of the models depends on the soil relative density, piles diameter and installation method (with and without fluidization). Regardless the initial relative density, the fluidized soil converged to the same final relative density, near its conditions of critical state. Piles installed in fluidized soil presented gain of axial capacity over time (setup effect) with lower resistance than piles driven in nonfluidized soil.
7

Modelagem e mapas de capacidade suporte de carga de solos cultivados com cana-de-açúcar

Miranda, Elka Élice Vasco de [UNESP] 09 June 2006 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:31:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-06-09Bitstream added on 2014-06-13T19:01:58Z : No. of bitstreams: 1 miranda_eev_dr_botfca.pdf: 1324011 bytes, checksum: a567d708b4146a28712b92024a4d7865 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / New studies must consider and quantify the load level that a determined soil can receive and in what management condition this soil can be handled without suffering physical alterations and additional compaction. The objectives of this work were to quantify the preconsolidation pressure, suggesting it as a quantitative indicator of the soil structural sustentabilidade cultivated with sugar cane; to get models that allow to predict the behavior of the soil structure cultivated with sugar cane in function of the preconsolidation pressure and the water content; to get agricultural traffic maps in function of water content and the preconsolidation pressure of the soil using geostatistics resources; and to evaluate the soil mechanical resistance, based on cone index and water content variation under several types of soils. Soil samples from several soil classes were collected cropped with sugar cane and areas that varied from 4.88 and 17.86 ha. The maps that illustrated the spatial variability of the several physical attributes were made using statistical and geostatistical resources. The models of the soil load capacity satisfactory modeled the behavior of the soil structure in function of the water content and depth, helping the maximum load prediction that this soil can receive without compromising its structure. The obtained models were sensible to identify the consolidation structure, identifying the layers and grids with huge mechanical resistance. The use of geostatistical tools and mapping the studied attributes showed a promising tool to take decisions about the system, aiming at, over all the soil structure sustentation. The maps of the soil load capacity constituted an efficient tool to locate 4 areas into the field with compromised structure, making possible to plan the correct dimension of the machinery... (Complete abstract, click electronic access below)
8

Instalação e capacidade de carga axial de estacas modelo fluidizadas em solos arenosos / Installation and axial load capacity of fluidized model piles in sandy soils

Passini, Larissa de Brum January 2015 (has links)
O objetivo desta tese foi verificar a viabilidade de utilização de jatos de água verticais circulares, únicos e contínuos, provenientes da ponteira de uma estaca torpedo, para auxiliar sua instalação por peso próprio no leito marinho, através da fluidização do solo. Foram realizados ensaios de laboratório, em modelo reduzido, utilizando hastes para simular estacas torpedo (sem aletas) seguindo a lei de semelhança pelo número de Froude. Os ensaios de instalação por peso próprio, com e sem fluidização, ocorreram sem altura de queda, com a estaca modelo em contato com a superfície do leito. Trabalhou-se com três diâmetros de estacas, seis massas, quatros vazões e areia fina saturada compactada em duas densidades relativas iniciais (média e densa). Os ensaios de arrancamento, em leito arenoso fluidizado e não fluidizado, foram realizados imediatamente, 4, 24 e 48 horas após a instalação dos modelos. A metodologia de instalação proposta mostrou-se viável, quando o jateamento é aplicado desde a superfície em solo arenoso. As profundidades instaladas atingidas por fluidização (L/de > 50) foram consideravelmente superiores às profundidades cravadas por apenas peso próprio (L/de < 5). A geometria da zona perturbada durante a instalação por fluidização dos modelos, permaneceu constante e paralela ao fuste, com geometria de aproximadamente 2de em relação ao modelo, independentemente da vazão aplicada e da densidade relativa inicial do solo. A partir das leis de análise dimensional, uma expressão para a profundidade instalada das estacas modelo foi proposta, mostrando que a mesma é função do peso e da geometria do modelo, das propriedades físicas do solo e do fluido, e de sua vazão. Quanto maior a massa do modelo e a vazão aplicada e menor a densidade relativa, maior a profundidade atingida e maior a velocidade inicial de instalação. Constatou-se que a capacidade de carga axial dos modelos depende da densidade relativa, do diâmetro do modelo e do método de instalação (com e sem fluidização). Independentemente da densidade relativa inicial, o solo fluidizado convergiu para a mesma densidade relativa final, próxima as suas condições no estado crítico. As estacas em solo fluidizado apresentaram ganho resistência com o tempo (efeito de setup), com capacidade de carga inferior às estacas cravadas em solo não fluidizado. / The aim of this thesis was to investigate the feasibility of using circular vertical water jets, single and continuous, from the tip of a torpedo pile, to assist its installation by own weight on the seabed, through soil fluidization. Laboratory model tests were carried out, using tubes to simulate torpedo piles (without wings) following the law of similarity defined by the Froude number. The installation tests by the pile own weight, with and without fluidization, occurred without drop height, with the piles in contact with the surface of the bed. Three diameters of model piles and six masses, four flow rates and saturated sand at two initial relative densities (medium and dense) have been used in this set of experiments. Pullout tests in fluidized and nonfluidized soils were performed immediately, 4, 24 and 48 hours after the installation of the models. The proposed installation methodology proved to be feasible when the fluidization is applied from the surface in sandy soils. The installation depths achieved by fluidization (L/de > 50) were significantly higher than the depths reached by pile own weight (L/de < 5). The geometry of the perturbed zone during model installation by fluidization remained constant and parallel to the shaft in a geometry of about 2de of the pile model, regardless of the applied flow rate and the initial relative density of the soil. Following the laws of dimensional analysis, an expression for the embedment of fluidized piles is derived, showing that the penetration depth is a function of pile weight and geometry, fluidized water jet flow rate and velocity, as well as the soil and fluid properties. Increasing the model mass and fluidized flow rate and decreasing the relative density leads to an increase in the depth reached and the initial speed of installation. The axial load capacity of the models depends on the soil relative density, piles diameter and installation method (with and without fluidization). Regardless the initial relative density, the fluidized soil converged to the same final relative density, near its conditions of critical state. Piles installed in fluidized soil presented gain of axial capacity over time (setup effect) with lower resistance than piles driven in nonfluidized soil.
9

Capacidade de carga de um modelo de fundação superficial em solo arenoso fofo com reforço de geotêxtil / Bearing capacity of a superficial foundation model in soft sand reinforced with geotextiles

Constancio, Lucas Amarante 16 August 2018 (has links)
Orientador: Pérsio Leister de Almeida Barros / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-16T06:19:41Z (GMT). No. of bitstreams: 1 Constancio_LucasAmarante_M.pdf: 4405049 bytes, checksum: 0e339df263cb9591f816add6ac404af7 (MD5) Previous issue date: 2010 / Resumo: Este trabalho visa avaliar o ganho de capacidade de carga de uma fundação superficial em areia fofa, através da inclusão de reforço de material geossintético. Para tanto, propõe-se observar o aumento da capacidade de carga do solo, com uma única camada de reforço em geotêxtil tecido, para uma fundação superficial do tipo sapata corrida. Através de um modelo reduzido que atende os critérios para atingir o estado plano de deformação, avalia-se a capacidade de carga do solo sem reforço, com reforço planar horizontal e faz-se uma nova proposta de disposição geométrica de tal elemento, buscando maior ganho de capacidade de carga e atenuação de deformações. O modelo reduzido é ensaiado no interior de um tanque que permite o acompanhamento das deformações através de sua face translúcida, além da aquisição dos dados de carga aplicada e recalque da fundação. Com a aquisição dos dados, é possível estabelecer comparações entre as diferentes situações analisadas, através da análise dos gráficos de carga-recalque. O trabalho mostra que é possível obter-se um ganho na capacidade de carga com inclusão do reforço e também que é possível chegar a capacidades de carga ainda maiores, apenas readequando a geometria do posicionamento do reforço com uma angulação do geotêxtil. Por fim, este trabalho contribui para a compreensão dos fatores envolvidos na complexa interação entre solo e reforço para fundações apoiadas sobre solos reforçados, campo este, que ainda precisa de refinamento, pesquisa, novas abordagens e contribuições / Abstract: This study aims to evaluate the gain in bearing capacity of a shallow foundation on a soft sand, through the inclusion of geosynthetic reinforcement. For this, the bearing capacity of a soft sandy soil carrying a shallow strip footing, without any reinforcement, and with a single layer of reinforcement of a woven geotextile is observed. Through the use of a reduced model, which satisfy the criteria for reaching a plane strain state, the bearing capacity of the unreinforced soil, the soil reinforced with planar horizontal and the soil reinforced with a new proposed geometric arrangement seeking greater gain of bearing capacity and the attenuation on deformation are evaluated. The reduced model is placed in a tank which allows the monitoring of deformations through its translucent face, and acquisition of applied load and foundation settlement data. After the acquisition of data it is possible to make comparisons between the different situations analyzed by examining the plots of load versus settlement. The results show that it is possible to obtain a gain in capacity with the inclusion of reinforcement and that it is possible to reach even higher bearing capacity just adjusting the geometry of the reinforcement placement, providing an inclination to the geotextile sheet. Finally, this work adds to the understanding of the different factors affecting the complex iteration mechanisms involved in foundations over reinforced soils, a field that still needs refinement and research, new approaches and contributions / Mestrado / Geotecnia / Mestre em Engenharia Civil
10

[en] NUMERICAL EVALUATION OF LOAD CAPACITY OF CORRODED PIPES / [pt] AVALIAÇÃO NUMÉRICA DA CAPACIDADE DE CARGA DE DUTOS CORROÍDOS

JOABSON LIMA ALVES 17 July 2002 (has links)
[pt] Dutos são sistemas amplamente utilizados para o transporte de óleo e gás. Desta forma, é importante que o mesmo opere com eficiência e segurança. Com o passar do tempo os dutos podem sofrer danos que podem causar prejuízos à sua integridade estrutural e, consequentemente, prejuízo financeiro às indústrias que os operam. Uma das formas mais comuns de danos presentes nos dutos é a corrosão. Esta pode comprometer a sua capacidade de carga. Com isto, a determinação da resistência remanescente de dutos corroídos tornou-se objeto de estudo de vários pesquisadores em todo o mundo. Métodos empíricos utilizados para esta determinação foram desenvolvidos e estão disponíveis na literatura, e muitos deles são aplicáveis apenas em dutos submetidos à pressão interna. Entretanto estes métodos se mostram, em geral, bastante conservadores nesta determinação. Assim, métodos alternativos têm sido desenvolvidos baseados no método dos elementos finitos. Este trabalho tem como objetivo avaliar a capacidade de carga de dutos corroídos submetidos a carregamentos combinados que tentam simular os que ocorrem no campo. Estes carregamentos são: pressão interna, momento fletor e cargas axiais. Carregamentos axiais são provenientes da variação de temperatura e do efeito Poisson existente nas extremidades dos dutos devido à pressão interna. Neste trabalho realizou-se a modelagem de dutos submetidos à carregamentos combinados, onde se tentou reproduzir ao máximo as condições de ensaio. Tomou-se como base ensaios experimentais e numéricos encontrados na literatura. Aspectos globais sobre a modelagem são detalhados. A modelagem dos exemplos aqui apresentados foi desenvolvida no programa comercial ABAQUS Versão 6.1. / [en] Pipelines are widely employed systems by the transport of oil and gas. Due to its great extensions and to economic and environmental reasons it is important to assure safe and efficient operation of the pipelines. After some time of operation the pipes can present damage that can affect its structural integrity, and require for repair and even operation interruption with consequently financial losses for the pipeline operating industries.One of the most commonly registered defects by pipes is corrosion. The determination of the residual load capacity of corroded pipes is object of study of many researchers all over the world. With this effort empirical methods were developed and are widely employed. Most of these methods are however applicable to pressure loaded pipes, and do not take into account more complex combined loading. Additionally highly conservative results are obtained by these methods. Alternative methods have been developed based on the finite element method.The objective of this work is to evaluate the load capacity of corroded pipes subjected to combined loading, which simulates the loads in field. These include internal pressure, bending due to soil settlement and axial load representing thermal effects. In this work the pipe model was developed in order to reproduce the experimental end field conditions. Global aspects of pipe modeling are discussed. Experimental test results and numerical analysis present in the literature are taken for comparison.The examples were analyzed with the commercial finite element code ABAQUS version 6.1.

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