Visando o estudo de diversos tipos de fundações implantou-se um Campo Experimental de Engenharia Civil na Unesp, campus de Bauru. Neste local foram realizados inúmeros ensaios de investigação geotécnica cujo solo é uma areia fina argilosa de baixa compacidade, com características colapsíveis, representativo de uma grande área do Estado. Neste trabalho apresentam-se os resultados de trinta provas de carga à compressão, executadas neste campo experimental em dez estacas apiloadas, sendo doze provas em estacas instrumentadas com o uso de strain-gages. Em cada estaca executaram-se três provas de carga, sendo a terceira com inundação prévia do solo, para se verificar o efeito da colapsibilidade na capacidade de carga. A instrumentação permitiu determinar a parcela de carga resistida por atrito e pela ponta da estaca. Os resultados são comparados a métodos empíricos normalmente utilizados no Brasil. Os resultados obtidos servem como subsídios para os projetistas desse tipo de fundação de uso muito freqüente no interior do estado de São Paulo. / In order to study different foundation types, the Unesp (São Paulo State University) in Bauru, created an experimental field in Civil Engineering. In this site an extensive soil investigation program were carried out. The topmost soil is a clayey fine sand with collapsible characteristic. The paper presents the results of thirty compression load tests carried out in ten uncased displacement cast in place piles (pounded piles, called apiloadas in Brazil), where twelve load tests were instrumented with electrical strain gages. In each pile three load test were conducted, two in natural condition and the third after soaking the soil, in order to evaluate the influence of the soil collapsibility in the results. The instrumentation permitted the evaluation of the ultimate bearing, the skin friction, the end-bearing stress and the load transfer distribution along the pile length. Comparation are made between results obtained and predicted by empirical methods that used SPT and CPT results. The results obtained provides the basis for a more rational design procedure and has a major interest for those who are dealing with foundation design of this type, frequently used in the interior of São Paulo State which soil is similar from a geotechnical point of view.

Les inclusions rigides sont un concept récent développé dans le prolongement des fondations mixtes, avec un matelas de transfert de charges entre les colonnes et la structure. Des méthodes de calculs et des concepts de sécurité existent pour ces systèmes combinés, notamment en France où le module pressiométrique mesuré et les recommandations ASIRI (IREX 2012) pour les inclusions rigides sont utilisés. Le dimensionnement classique des pieux basé sur une simple vérification de la portance des colonnes isolées ne peut pas être appliqué à ces systèmes combinés. Les tassements peuvent être plus importants du fait de la part significative de charge reprise par le sol. Le présent travail est une contribution au développement des méthodes de calcul et de dimensionnement en déplacement (préconisé par l'Eurocode 7, EN 1997-1 2004) pour les systèmes combinés sous charge verticale, en particulier au niveau international où des mesures in situ de module de sol ne sont généralement pas disponibles. Les éventuelles particularités de ces systèmes, notamment la sensibilité de colonnes non renforcées de petit diamètre, devaient également être examinées. La méthode de transfert de charge (“load transfer method”, LTM) est identifiée comme un outil d'ingénieur particulièrement adapté au calcul des systèmes combinés présentant une géométrie relativement simple. L'interaction sol-colonne en frottement et en pointe est définie par des courbes de transfert de charge (ou courbes “t-z” et “q-z”). Les méthodes en milieu continu comme la méthode des éléments finis sont à réserver en général aux cas complexes. Le comportement non-linéaire des semelles est examiné sur la base de mesures obtenues dans la littérature. Cette étude aboutit à la proposition d'une courbe charge-tassement hyperbolique pour les semelles. Cette courbe de mobilisation est définie de sorte qu'il y ait concordance avec la méthode linéaire habituelle pour un tiers de la charge ultime de la semelle. Le comportement de pieux isolés est étudié avec de nombreux essais de chargement instrumentés et non-instrumentés pour différents types de pieux et de sol. Une alternative aux courbes de transfert de charge selon Frank et Zhao (1982), basées sur le module pressiométrique, est recherchée. Des courbes de transfert de charge de type racine cubique et hyperbolique sont proposées pour tous types de pieux et de sol. La raideur des courbes proposées dépend d'une bonne estimation des valeurs ultimes de frottement et de résistance de pointe. Au contraire, la raideur initiale des courbes de Frank et Zhao est entièrement définie par le module pressiométrique, ce qui permet d'éviter des erreurs en termes de raideur. Les courbes de mobilisation proposées pour les fondations superficielles et pour les pieux sont combinées et étendues au cas des systèmes combinés. Cette méthode est implémentée comme option LTM dans le programme KID (Keller company 2015). Les prévisions avec le modèle proposé sont en très bonne adéquation avec les mesures effectuées sur 3 sites documentés dans la littérature. Une étude paramétrique montre une transition continue entre la fondation mixte et les inclusions rigides et une possibilité d'optimisation avec une diminution significative des efforts dans les colonnes et dans la fondation superficielle si un matelas est utilisé. En complément, une comparaison avec des calculs en éléments finis en 3D dans un cas théorique de semelle sur colonnes confirme que la méthode de transfert de charge développée est très performante pour des géométries simples. Une analyse de sensibilité est effectuée avec des modèles éléments finis axisymmétriques et 3D avec Plaxis (2013, 2014). Les imperfections géométriques ont principalement une incidence sur l'intégrité structurelle des colonnes non-armées de faible diamètre. Cependant, ces effets sont atténués dans les systèmes combinés en comparaison avec la colonne isolée du fait des possibilités de redistribution des charges dans le système / Rigid inclusions represent a further development of combined pile-raft foundations, comprising a load transfer platform between the columns and the structure. Calculation methods and design concepts are available for such combined systems in particular in France, based on measured pressuremeter modulus values and on the French recommendations ASIRI for rigid inclusions (IREX 2012). The conventional pile design consisting only of a bearing capacity check for the individual column cannot be applied to such combined systems. The expected settlements may be larger due to a significant load proportion supported by the soil. The present work contributes to the development of displacement-based calculation methods (advocated by the Eurocode 7, EN 1997-1 2004) and design methods for combined systems under vertical loads, in particular on an international level where in general no in situ soil modulus values are measured. Possible particularities of such systems, like the sensitivity of unreinforced small-diameter columns, also had to be investigated. The load transfer method (LTM) is identified as a straightforward engineering tool for the calculation of combined systems with relatively simple geometries. The soil-column interaction in terms of skin friction and tip resistance is described by deformation-dependent load transfer curves (or “t-z” and “q-z” curves). Continuum methods like the finite element method should be preferred only for complex cases in general. The non-linear load-settlement behaviour of single footings up to failure is analysed based on measurements given in the literature. This yields the proposal of a hyperbolic load-settlement curve for footings. This mobilization curve is defined in a way to match the linear usual method for one third of the footing ultimate load. The behaviour of single piles is investigated based on numerous available instrumented and non-instrumented pile load tests with different pile and soil types. A reliable alternative to the load transfer curves after Frank and Zhao (1982), which are based on the pressuremeter modulus, is sought. Cubic root and hyperbolic axial load transfer curves are proposed for all pile and ground types. The stiffness accuracy of the proposed curves depends on an accurate estimation of the ultimate skin friction and tip resistance values. On the contrary, the initial stiffness of the Frank and Zhao curves is fully described by the pressuremeter modulus, avoiding thus errors in the stiffness. The proposed mobilization curves for the shallow and pile foundation behaviours are combined and extended for all combined systems. The proposed method is implemented as the LTM option into the software KID (Keller company 2015). The prediction with the developed model matches very well the measurements made for 3 different cases from the literature. A parametric study shows a smooth transition between the combined pile-raft foundation case and the rigid inclusion case and a potential for optimisation with a significant reduction of the internal forces in the columns and in the rigid slab when a load transfer platform is used. In addition, a comparison with 3D finite element calculations for a theoretical footing case with columns confirms that the developed load transfer method is very reliable for simple geometries. Sensitivity investigations using the axisymmetric and 3D finite element method with Plaxis (2013, 2014) are performed. Geometrical imperfections impact mainly the structural integrity of small-diameter unreinforced columns. However, these effects are reduced in combined systems compared to the single column case due to the possibility of redistribution of the loads within the system

Visando o estudo de diversos tipos de fundações implantou-se um Campo Experimental de Engenharia Civil na Unesp, campus de Bauru. Neste local foram realizados inúmeros ensaios de investigação geotécnica cujo solo é uma areia fina argilosa de baixa compacidade, com características colapsíveis, representativo de uma grande área do Estado. Neste trabalho apresentam-se os resultados de trinta provas de carga à compressão, executadas neste campo experimental em dez estacas apiloadas, sendo doze provas em estacas instrumentadas com o uso de strain-gages. Em cada estaca executaram-se três provas de carga, sendo a terceira com inundação prévia do solo, para se verificar o efeito da colapsibilidade na capacidade de carga. A instrumentação permitiu determinar a parcela de carga resistida por atrito e pela ponta da estaca. Os resultados são comparados a métodos empíricos normalmente utilizados no Brasil. Os resultados obtidos servem como subsídios para os projetistas desse tipo de fundação de uso muito freqüente no interior do estado de São Paulo. / In order to study different foundation types, the Unesp (São Paulo State University) in Bauru, created an experimental field in Civil Engineering. In this site an extensive soil investigation program were carried out. The topmost soil is a clayey fine sand with collapsible characteristic. The paper presents the results of thirty compression load tests carried out in ten uncased displacement cast in place piles (pounded piles, called apiloadas in Brazil), where twelve load tests were instrumented with electrical strain gages. In each pile three load test were conducted, two in natural condition and the third after soaking the soil, in order to evaluate the influence of the soil collapsibility in the results. The instrumentation permitted the evaluation of the ultimate bearing, the skin friction, the end-bearing stress and the load transfer distribution along the pile length. Comparation are made between results obtained and predicted by empirical methods that used SPT and CPT results. The results obtained provides the basis for a more rational design procedure and has a major interest for those who are dealing with foundation design of this type, frequently used in the interior of São Paulo State which soil is similar from a geotechnical point of view.

This master’s thesis is focused on a design of the formula student’s anti-roll bar. The beginning of the thesis is devoted to the introduction of the anti-roll bar function and the explanation of its effect on a vehicle including the analysis of various constructions. Second part deals with the Formula Student competition. There is the analysis of the formula Ford’s anti-roll bar as a starting point for our own design. In the section which deals with the anti-roll bar design several alternatives are designed, the stress analysis of components are made and multi body system models are developed for final solutions. These models serve for further analyses of driving characteristics of the vehicle.

Particulate composites are widely used in many aerospace applications such as protective coatings, adhesives, or structural members of a body and their mechanical properties and behavior have gained increasing significance. The addition of modifiers such as alumina generally leads to improved mechanical properties. This addition also enables the non-invasive study of the load transfer between the particle and the matrix. Understanding the load transfer between the particulate and the matrix material is the first step to understanding the behavior and mechanical properties of the composite as a whole. In this work, samples with an isolated alumina particle embedded in an epoxy matrix were created to replicate the ideal assumptions for many particulate mechanics models. In separate experiments, both photo stimulated luminescent spectroscopy (PSLS) and synchrotron radiation were used to collect the spectral emission and diffraction rings, respectively, from the mechanically loaded samples. The PSLS data and XRD data are shown to be in qualitative agreement that as particle size is increased, the load transferred to the particle also increased for the range of particle sizes tested. This trend of increasing load transfer with increasing particle size is compared with the classical Eshelby model. Results from this work provide experimental insight into the load transfer properties of particulate composites and can serve to experimentally validate the theoretical load transfer models that currently exist.

No description available.

Os primeiros estudos sobre pavimentos de concreto continuamente armados (PCCA) foram desenvolvidos em zonas cujo clima característico é o temperado (EUA, Holanda e Bélgica), não se tendo estudos técnicos acerca do comportamento do pavimento em ambiente tropical. A premissa de funcionamento do PCCA está baseada na não execução de juntas de retração, obrigatórias em pavimentos de concreto simples (PCS), ou seja, as fissuras devido à retração do concreto ocorrem aleatoriamente, sendo controladas pela elevada taxa de armadura longitudinal disposta longitudinalmente ao longo de toda a extensão do pavimento. Como essa armadura não possui função estrutural, pois é colocada acima da linha neutra da placa, no banzo comprimido, sua função é manter as fissuras fortemente apertadas, garantindo suavidade ao rolamento e elevada transferência de carga (LTE), a qual ocorre pelo intertravamento dos agregados nas faces fissuradas, proporcionando assim um pavimento de alta durabilidade e que dispende baixíssimos custos com manutenção. No Brasil, a primeira experiência com PCCA teve início no ano de 2010, quando foram construídas quatro seções de 50 m de extensão cada, consideradas curtas em comparação aos 400 m de extensão de um PCCA rodoviário que podem ser alcançados ao final de um dia de trabalho. O monitoramento contínuo de tais seções mostrou haver uma diferença muito significativa de comportamento, comparado aos PCCA tradicionais, no que tange o tempo decorrido para estabelecimento do padrão de fissuração (a primeira fissura surgiu um ano após a construção), bem como espaçamento médio entre as fissuras, devido à curta extensão das placas e a inexistência de um sistema de ancoragem nas extremidades. Assim, para melhor compreender o comportamento de pavimentos de concreto com armadura contínua com padrões condizentes à realidade rodoviária em ambiente tropical, em janeiro de 2016, foi construído no campus da Universidade de São Paulo o primeiro PCCA de longa extensão do Brasil, com 200 m de comprimento. Foram empregados quatro diferentes tipos de concreto, variando o tipo de cimento e o tipo de agregado, bem como foram empregados aço galvanizado e aço comum. Para entender o comportamento do pavimento sob as condições climáticas brasileiras foram realizados três estudos: levantamento de fissuras (espaçamento e abertura), modelagem analítica do espaçamento entre fissuras através de modelos de previsão de retração em concreto e testes com FWD para avaliação da eficiência de transferência de carga (LTE) entre as fissuras. A análise do padrão de fissuração mostrou que o desenvolvimento das fissuras aconteceu conforme a literatura técnica, tendo início na primeira semana após a concretagem e atingindo aproximadamente 60% do número total de fissuras antes do primeiro mês. As seções centrais possuem o maior número de fissuras, pois estão ancoradas pelas seções de extremidade, onde o surgimento das fissuras é mais lento por conta da falta de ancoragem. As aberturas das fissuras mostraram-se maiores nas posições com aço galvanizado devido à menor aderência aço-concreto nesse caso, em comparação às posições com aço comum. O modelo de previsão de retração no concreto que melhor se aproximou do espaçamento médio desenvolvido em campo foi o modelo do Eurocode 2, com diferenças em torno de 30%, aproximadamente. As análises de LTE mostraram um desempenho muito satisfatório, apesar de a LTE nas regiões com aço galvanizado ter resultado menor do que a LTE nas regiões com aço comum. / The first studies on continuously reinforced concrete pavements (CRCP) were developed in areas in which the typical weather is temperate (United States, Netherlands and Belgium), with no technical studies carried out in tropical weather. CRCP structural premise is based on a slab without construction joints which are required in jointed plain concrete pavements (JPCP); i.e., CRCP cracks due to concrete shrinkage occur randomly being controlled by the high longitudinal reinforcement percentage, positioned longitudinally along the pavement length. As the longitudinal reinforcement has no structural role, because it is placed above the slab neutral axis, in the compression zone, its main function is to keep cracks strongly tight, ensuring a smooth ride and high load efficiency transfer (LTE) at cracks, which occurs through aggregates interlocking, thereby providing a highly durable pavement with low maintenance costs. The first experience with CRCP in Brazil started in 2010, when four experimental sections were constructed. Each section is 50 meters long, short when compared to the traditional CRCP that can extend for over 400 meters providing that concrete pouring does not stop. Continuous monitoring of these sections has shown that the short CRCP behaves differently from traditional CRCP, regarding the time taken for the cracking pattern full development (the first crack was visible on the surface one year after the construction), as well as average cracking space due to the slab\'s short extension and lack of anchorage. Therefore, in order to fully analyze the behavior of a traditional CRCP under tropical weather, in January 2016, the first long extension CRCP in Brazil was built, at the University of São Paulo campus, with 200 meters length. Four types of concrete were applied in the construction, varying cement and aggregate type. Galvanized and ordinary steel were used as well. To analyze the pavement behavior under Brazilian climatic conditions, three studies were carried out: cracks surveys (spacing and width), analytical modeling crack spacing through shrinkage prediction models and Falling Weight Deflectometer testing to evaluate the crack\'s load transfer efficiency (LTE). Cracking pattern analysis has shown cracks development consistent with technical literature. The first cracks appeared during the first week after concrete placement and, before the first month, about 60% of the total cracks number had developed. Central sections presented greatest number of cracks as they are anchored by the outer sections, where cracking occurs slower due to the lack of anchorage. Cracks width was higher in areas with galvanized steel due to the weaker steel-concrete bond, when compared to areas with common steel. The shrinkage prediction model for concrete that better approached the average field crack spacing was the Eurocode 2, with mean difference of 30%. LTE analysis has shown a quite satisfactory performance, even though LTE in areas with galvanized steel is lower than LTE in areas with common steel.

Este trabalho se propõe a analisar os efeitos produzidos pela inundação do solo em estacas escavadas, isoladas, submetidas a esforços de compressão. Os resultados obtidos referem-se à execução de três provas de carga lentas em estacas com diâmetros de 0,40 m e 0,50 m (2 provas de carga distintas) e comprimentos de 10,0 m, submetidas anteriormente a uma série de carregamentos (duas provas de carga rápidas e duas lentas). Os resultados relativos aos deslocamentos medidos no topo das estacas e os obtidos pela instrumentação instalada ao longo do fuste são então comparados com a sequência dos resultados anteriores, para avaliação do efeito de umedecimento no comportamento \"carga x recalque\" e nos mecanismos de transferência de carga. É feita ainda uma descrição minuciosa do processo utilizado para inundação do solo e uma breve consideração sobre os efeitos da não reposição de cargas em ensaios lentos, de longa duração. / This work intends to analyze the effects produced by the flooding of the soilexcavated piles, isolated, subjected to compression efforts. The results refer to the execution of three slow load tests on piles with diameters of 0.40 m and 0.50 m (2 distinct load tests) and 10.0 m lengths, submitted previously to a number of shipments (two slow and two quick load). The results concerning offsets measured at the top of the stakes and those obtained by the instrumentation installed along the forend are then compared with the sequence of the previous results, to evaluate the effect of damping in behavior \"load x settlement\" and load transfer mechanisms. It was also made a thorough description of the process used to flood the ground and a brief consideration of the effects of non-replacement of loads in slow, long-term trials.

A pesquisa parte do fato de que os métodos semiempíricos de estimativa da capacidade de carga de estacas não devem ser empregados indiscriminadamente em qualquer região do país sem as devidas adequações às características do solo local. Constata-se, com isso, que não existem metodologias específicas para proceder tais adequações e que o meio técnico acaba por realizar a mera classificação dos métodos em conservador ou contra a segurança, o que se constitui num certo paradigma. Assim, o presente trabalho propõe uma Metodologia Semiempírica Unificada (MSU), em três etapas. Na primeira delas, o projetista estima a capacidade de carga a partir da otimização das melhores práticas adotadas pelos diversos métodos semiempíricos utilizados no Brasil. Discutem-se ainda o embutimento da ponta e a criação de novos métodos semiempíricos. Na segunda etapa, realiza-se a verificação de desempenho com base nos critérios de ruptura aplicados à curva carga-recalque de provas de carga. Nessa etapa, as imprecisões do dito paradigma são apontadas e faz-se uma nova proposta de aplicação dos critérios de ruptura. Na terceira etapa, faz-se uma retroanálise para aferição da estimativa semiempírica unificada da primeira etapa. Propõe-se, assim, o uso da separação das parcelas de atrito e ponta por meio de métodos de transferência de carga, bem como pela proposta de ajustes polinomiais, no caso de ensaios instrumentados. A análise crítica desse processo gerou a proposta de uma nova abordagem matemática da transferência de carga. A correção dos valores adotados para os coeficientes semiempíricos de cada camada, individualmente, é feita pela proposta de aplicação do conceito de Hierarquia dos Solos (AMANN, 2000). Os resultados de correção dos métodos semiempíricos, contudo, são específicos para o solo de cada local em estudo. Assim, são utilizados, como exemplo, ensaios em diversas regiões do país, o que permite a verificação da aplicabilidade da metodologia proposta. / The research starts from the fact that the semiempirical methods for estimating the pile load capacity shouldn\'t be used indiscriminately in any country\'s region without making proper adjustments to the local soil characteristics. It is verified, from this, that there are no specific methodologies to make such adjustments and the geotechnical engineers find themselves forced to perform a simple classification of the methods in \"conservative\" or \"against the safety\", which constitutes a form of paradigm. In this context, this paper proposes a Unified Semiempirical Methodology (MSU) in three steps. In the first, the designer estimates the foundation load capacity from the optimization of best practices adopted by different semiempirical methods used in Brazil. A discussion is also made the toe embedment and the creation of new semiempirical methods. In the second step, the verification of the foundation performance is carried out, based on the failure criteria applied to the load-settlement curve of load tests. At this step, the inaccuracies from that paradigm are outlined and a new proposal is made for applying the failure criteria. In the third step, a backanalysis is accomplished to admeasure the unified semiempirical estimative from the first step. It is, thus, proposed to separate both shaft friction and toe resistance from the total load, by means of load transfer methods, and by the proposal of polynomial adjustments in the case of instrumented piles. With the critical analysis of this process, a new mathematical approach to load transfer is presented. The correction of the coefficients of the semiempirical methods is made by the application of the Soils\'s Hierarchy concept (AMANN, 2000). The results of semiempirical methods correction, however, are specific to the soils of each particular site. The applicability, of the proposed methodology, is illustrated using pile load tests from various parts of the country.

Este trabalho se propõe a analisar os efeitos produzidos pela inundação do solo em estacas escavadas, isoladas, submetidas a esforços de compressão. Os resultados obtidos referem-se à execução de três provas de carga lentas em estacas com diâmetros de 0,40 m e 0,50 m (2 provas de carga distintas) e comprimentos de 10,0 m, submetidas anteriormente a uma série de carregamentos (duas provas de carga rápidas e duas lentas). Os resultados relativos aos deslocamentos medidos no topo das estacas e os obtidos pela instrumentação instalada ao longo do fuste são então comparados com a sequência dos resultados anteriores, para avaliação do efeito de umedecimento no comportamento \"carga x recalque\" e nos mecanismos de transferência de carga. É feita ainda uma descrição minuciosa do processo utilizado para inundação do solo e uma breve consideração sobre os efeitos da não reposição de cargas em ensaios lentos, de longa duração. / This work intends to analyze the effects produced by the flooding of the soilexcavated piles, isolated, subjected to compression efforts. The results refer to the execution of three slow load tests on piles with diameters of 0.40 m and 0.50 m (2 distinct load tests) and 10.0 m lengths, submitted previously to a number of shipments (two slow and two quick load). The results concerning offsets measured at the top of the stakes and those obtained by the instrumentation installed along the forend are then compared with the sequence of the previous results, to evaluate the effect of damping in behavior \"load x settlement\" and load transfer mechanisms. It was also made a thorough description of the process used to flood the ground and a brief consideration of the effects of non-replacement of loads in slow, long-term trials.