• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 12
  • 5
  • 4
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 31
  • 31
  • 7
  • 6
  • 6
  • 5
  • 5
  • 5
  • 5
  • 5
  • 5
  • 5
  • 4
  • 4
  • 4
  • 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.
11

Grundförstärkning med pålar i berg : I befintlig konstruktion med begränsat utrymme

Höglund, Madicken, Larsson, Marcus January 2020 (has links)
This study has been done in order to examine which type of pile, pile driving- and waterproofing methodsare most suited for an existing building. A building that will undergo an extensive reinforcement of itsfoundation.The study has been made in regard to the following conditions:● Different types of clay soil (Cohesion soil)● Underlying rock structure with heavy incline (8° slope)● Sensitive environment for vibrations and ground displacements● Limited accessibility (Room and maximum weight)● Compressive and tensile forces● Pool (Water environment)To answer the questions of statement a scientific literature study, interview with a foundation expert,calculations in sizing, but also time and cost analysis has been conducted. A site visit to an object ofreference, Nya Krav Himmerfjärdsverket, occurred where a reconstruction of an existing building withextensive work of reinforcement to its’ foundation was in progress.The steel pipe pile with anchor and steel core pile are the best pile types in such conditions as compressiveand tensile forces, clay soil with underlying inclined rock bed, limited accessibility and sensitivesurrounding environment. Which pile type, pile driving- and waterproofing methods that are most suited forsuch conditions is different for each project. The steel core pile is more suitable for higher loads, rockstructures in incline and when verification of load capacity is not needed. At the same time the steel pipepile is more suited when the underlying rock bed is far below ground level, where you would need manypile elements and joints. In addition, the steel pipe pile is suitable for buildings with a complex loaddistribution, where a greater number of piles with lower load capacities is needed in order to satisfy this.The best pile driving method for drilling in sensitive environment is the water equipped down-the-hole(DTH) drill. This drilling method is gentle to surrounding piles in existing building.In order to minimise the risk of water penetration and then expand the life span of the construction, use ofa combination of different waterproofing systems is to prefer when waterproofing pile heads or pilefoundations.
12

Investigation of nonlinear wave-induced seabed response around mono-pile foundation

Lin, Z., Pokrajac, D., Guo, Yakun, Jeng, D-S., Tang, T., Rey, N., Zheng, J., Zhang, J. 14 January 2017 (has links)
Yes / Stability and safety of offshore wind turbines with mono-pile foundations, affected by nonlinear wave effect and dynamic seabed response, are the primary concerns in offshore foundation design. In order to address these problems, the nonlinear wave effect on dynamic seabed response in the vicinity of mono-pile foundation is investigated using an integrated model, developed using OpenFOAM, which incorporates both wave model (waves2Foam) and Biot’s poro-elastic model. The present model was validated against several laboratory experiments and promising agreements were obtained. Special attention was paid to the systematic analysis of pore water pressure as well as the momentary liquefaction in the proximity of mono-pile induced by nonlinear wave effects. Various embedment depths of mono-pile relevant for practical engineering design were studied in order to attain the insights into nonlinear wave effect around and underneath the mono-pile foundation. By comparing time-series of water surface elevation, inline force, and wave-induced pore water pressure at the front, lateral, and lee side of mono-pile, the distinct nonlinear wave effect on pore water pressure was shown. Simulated results confirmed that the presence of mono-pile foundation in a porous seabed had evident blocking effect on the vertical and horizontal development of pore water pressure. Increasing embedment depth enhances the blockage of vertical pore pressure development and hence results in somewhat reduced momentary liquefaction depth of the soil around the mono-pile foundation. / Energy Technology Partnership (ETP), Wood Group Kenny, and University of Aberdeen; the National Science Fund for Distinguished Young Scholars (51425901) and the 111 project (B12032).
13

A Simple Assessment Of Lateral Pier Response Of Standard Highway Bridges On Pile Foundations

Yuksekol, Umit Taner 01 February 2007 (has links) (PDF)
Group of piles are widely used deep foundation systems to resist lateral and vertical loads. Seismic and static performance of pile groups mostly depend on soil type, pile spacing and pier rigidity. Not many pile lateral load tests have been performed due to high costs. Advanced and complex analytical methods were developed over the years to assess nonlinear lateral pile response. This research is conducted aiming at developing a practical analysis method to verify the lateral performance of pile groups and its effect on overall response of bridge utilizing the available pile lateral load test data. Empirical constants derived from evaluation of lateral load tests are used in a simple formulation to define the nonlinear behavior of the pile-soil system. An analysis guideline is established to model the nonlinear soil-bridge interaction by the help of a general purpose structural analysis program comprising recommendations for various cases. Results of the proposed method is compared to the results of industry accepted advanced methods using response spectrum and nonlinear time history analyses to assess the suitability of this new application. According to the analysis results, proposed simple method can be used as an effective analysis tool for the determination of response of the superstructure.
14

Estudo da incorporação de resíduos de cerâmica vermelha na composição de concreto para uso em estacas moldadas in loco /

Wada, Patrycia Hanna. January 2010 (has links)
Orientador: Antonio Anderson da Silva Segantini / Banca: Adriano Souza / Banca: David de Carvalho / Resumo: A preocupação com o meio ambiente tem estimulado o interesse por pesquisas voltadas para o desenvolvimento sustentável. O presente trabalho objetivou estudar o reaproveitamento de resíduos de cerâmica vermelha (RCV) na composição de concreto, em substituição em massa ao agregado miúdo (areia), visando a sua utilização em estacas do tipo moldadas in loco. Foram confeccionados concretos com substituição de 20%, 40%, 60% e 80% de areia natural (em massa) pelo RCV. Realizaram-se ensaios de compressão simples e de módulo de elasticidade em todos os traços no estado endurecido e, no estado fresco, ensaios de incorporação de ar e de massa específica. Visando avaliar o seu comportamento em condições de campo, frente às ações de trabalho, foram confeccionadas três estacas de concreto com 40% de RCV, as quais foram submetidas à prova de carga por meio de ensaio rápido. Os resultados das provas de carga foram comparados com os de outros ensaios realizados no mesmo local, porém com estacas de concreto convencional. Concluiu-se que o reaproveitamento do RCV melhorou as características físicas e mecânicas do concreto e possibilitou a sua aplicação nas estacas em estudo. / Abstract: Concern for the environment has stimulated interest in research for sustainable development. The present work aimed investigated the reuse of red ceramic waste (RCW) in the concrete composition, replacing in weight to fine aggregate (sand) and proposing his application in cast-in-place piles foundations. Were made compositions with 20%, 40%, 60% and 80% of sand by RCW replacement. Compressive strength tests and modulus of elasticity were performed for all compositions of hardened concrete. Testing of air entraining and density were also made in the concrete in its fresh state. In order to evaluate his behavior under field conditions, on work load situation, three foundation piles were made, which were submitted the quick load test. The piles were made with 20.0 cm diameter and 4.50 m length using concrete with 40% replacement. The results obtained were compared with others load test carried at the same place, however with conventional concrete piles. It was concluded that reuse of RCW improved the physical characteristics and mechanics of concrete and its possible application in the piles foundation in study. / Mestre
15

Zajištění stavební jámy a založení objektu SONO v Brně / Sekuring of Foundation Pit in Brno

Ondráček, Jaroslav January 2012 (has links)
It is project of securing foundation pit and foundation for SONO building realized in Brno in Veveří street. It is required to desing economical and safety construction.A calculation was performed by program FINE GEO 5 - Student version.
16

Numerical Modeling of Helical Pile-to-Foundation Connections subjected to Monotonic and Cyclic Loads

Chiluwal, Sundar January 2019 (has links)
No description available.
17

Сравнительный анализ возведения ленточного и свайного фундаментов гражданского здания : магистерская диссертация / Comparative analysis of the construction of strip and pile foundations of a civil building

Чжао, Ж., Zhao, R. January 2023 (has links)
В работе выполнен сравнительный анализ свайных и ленточных фундаментов гражданского здания. Сравнение выполнено по стоимости и трудоемкости изготовления фундаментов для определенных инженерно-геологических условий с учетом действующих нагрузок. / The work performed a comparative analysis of pile and strip foundations of a civil building. The comparison was made based on the cost and labor intensity of manufacturing foundations for certain engineering-geological conditions, taking into account the existing loads.
18

Modélisation du comportement des sables sous la condition de cisaillement simple et applications au calcul des pieux / Mechanical modelling of sand considering simple shear condition and its application to pile foundation

Wu, Zexiang 13 December 2017 (has links)
La thèse vise à étudier le comportement mécanique des sables sous la condition de cisaillement simple et à son application au calcul des pieux. Tout d'abord, un modèle de sable récemment développé (SIMSAND) prenant en compte l'état critique est introduit avec une procédure directe de détermination des paramètres. Le modèle est implanté dans un code de calcul aux éléments finis qui a fait l’objet de différentes validations. Ensuite, le modèle est amélioré en considérant l'anisotropie inhérente lors de la rotation des contraintes principales sous la condition de cisaillement simple et a été validé en utilisant les résultats des essais tri axiaux et de cisaillement simple sur le sable de Fontainebleau. Les essais de cisaillement simple sont analysés en imposant les conditions de sollicitations réelles tridimensionnelles appliquées par l’appareillage utilisé. L'inhomogénéité de l'échantillon avec l'effet de la taille de l'échantillon est également étudiée. Puis, des essais de cisaillement simple cycliques drainés et non-drainés sur le sable de Fontainebleau sont effectués pour étudier les caractéristiques sous charges cycliques, telles que la dégradation de la contrainte normale effective et l'accumulation de la déformation volumique, compte tenus de certains facteurs comme l’indice des vide initial, la contrainte normale appliquée, le rapport de contrainte de cisaillement cyclique et le rapport de contrainte de cisaillement moyenne. Sur la base de ces résultats, deux modèles analytiques sont proposés pour prédire la dégradation à long terme de la contrainte normale effective et l'accumulation des déformations volumiques en fonction du nombre de cycles. En outre, les essais cycliques de cisaillement simple sont simulés par le modèle SIMSAND amélioré en utilisant une technique d'inversion de contrainte. Enfin, on simule une série de pieux modèles sous charges monotone et cyclique pour laquelle la résistance en pointe du pieu est évaluée ainsi que la réponse du sol entourant le pieu. / The thesis aims to study the mechanical behaviour of sand under simple shear condition and to apply the results to the numerical simulation of pile foundation. First, a recently developed critical state sand model (SIMSAND) is introduced with a straight forward procedure of parameters determination, implemented into a finite element code and then subjected to a series of validations. Then, the model is enhanced by considering the inherent anisotropy during the principal stress rotation under the simple shear condition and validated by using results of both triaxial tests and simple shear tests on Fontainebleau sand. Simple shear tests are analysed by simulating in three-dimensions the real conditions imposed by the simple shear apparatus. The inhomogeneity of the samples with the effect of sample size is also investigated. Furthermore, undrained and drained cyclic simple shear tests on Fontainebleau sand are conducted to investigate the cyclic responses, such as the effective normal stress degradation and the volumetric strain accumulation, respectively, considering some impact factors such as the initial void ratio, the normal stress, the cyclic shear stress ratio and the average shear stress ratio. Based on these results, two analytical models are proposed to predict the long-term degradation of the effective normal stress and the accumulation of the volumetric strain with the number of cycles. Moreover, the cyclic simple shear tests are simulated by the enhanced SIMSAND model by incorporating the stress reversal technique. Finally, a series of model pile tests under monotonic and cyclic loadings are simulated based on which the cone resistance of the piles is evaluated as well as the response of the soil surrounding the pile.
19

Metodologia semiempírica unificada para a estimativa da capacidade de carga de estacas. / Unified semiempirical methodology for estimating the load capacity of piles.

Amann, Kurt André Pereira 27 August 2010 (has links)
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.
20

Metodologia semiempírica unificada para a estimativa da capacidade de carga de estacas. / Unified semiempirical methodology for estimating the load capacity of piles.

Kurt André Pereira Amann 27 August 2010 (has links)
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.

Page generated in 0.1097 seconds