This thesis consists of the development, trial an application of a computational tool that by the use of the Genetic Algorithm optimization method provides the user with an alternative approach from the traditional trial and error when faced with the challenge of designing end bearing pile groups.The work presents the three main concepts needed for understanding the computational tool as well as the structure of it. The scripting capabilities of a FEM software are exploited in order to automatically generate several design alternatives that are then compared in quality in an iterative way. The developed algorithm succeeds validation against pile group problems with known solutions and is then applied to the analysis of three different real structures with different levels of complexity.The algorithm is suitable for optimizing problems with loading in three directions and several load cases, within a time range consistent with an overnight run, when the density of the pile group is not high. Another potential application is to automatize retaining wall resting on piles type problems within a short amount of computational time. / Denna avhandling består av utveckling och prövning av ett beräkningsverktyg som med hjälp av den genetiska algoritmoptimeringsmetoden ger användaren ett alternativt tillvägagångssätt från den traditionella prövningen när den möter utmaningen att utforma bärande höggrupper.Arbetet presenterar de tre huvudkoncepten som behövs för att förstå beräkningsverktyget och dess struktur. Skriptfunktionerna för en FEM-programvara utnyttjas för att automatiskt generera flera designalternativ som sedan jämförs i kvalitet på ett iterativt sätt. Den utvecklade algoritmen lyckas validera mot höggruppsproblem med kända lösningar och tillämpas sedan för analys av tre olika byggda strukturer med olika nivåer av komplexitet.Algoritmen är lämplig för att optimera problem med belastning i tre riktningar och flera lastfall, inom ett tidsintervall som överensstämmer med en löpning över natten, när täthetsgruppens densitet inte är hög. En annan mycket intressant applikation är att automatisera kvarvarande väggproblem inom en kort tid av beräkningstid.

Yes / This study presents results from laboratory experiments to investigate the wake structure in the lee side of a scaled three-bladed horizontal axis tidal stream turbine with a mono-pile support structure. Experiments are conducted for a range of approaching flow velocity and installation height of rotor. Analysis of the results shows that bed shear stress increases with the increase of approaching velocity and decrease of installation height within 2D (D is the diameter of the rotor) downstream of the rotor. The flow field within 2D downstream of the rotor is greatly influenced by the presence of nacelle and mono-pile. Low stream-wise flow velocity and large turbulence intensity level is detected along the flume center right behind the nacelle and mono-pile from 1D to 2D downstream of the rotor. Stream-wise velocity at the blade tip height lower than the nacelle increases sharply from 1D to 2D and gradually grows afterwards. Correspondingly, the turbulence intensity decreases quickly from 1D to 2D and slowly afterwards. Large bed shear stress is measured from 1D to 2D, which is closely related to turbulence induced by the mono-pile. It is also found that the presence of the mono-pile might make the flow field more ‘disc-shaped’. / National Key Research and Development Program of China (No.2017YFC1404200), the Marine Renewable Energy Research Project of State Oceanic Administration (No.GHME2015GC01), the Fundamental Research Funds for the Central Universities of China (No.2017B696X14) and the Postgraduate Research & Practice Innovation Program of Jiangsu Province, China (No.KYCX17_0448)

Anthropogenic sound in Florida's waters and coastal waterways is most commonly caused by overwater development, marine traffic, and military activity. Overwater construction has increased over the years as a result of aging infrastructure and rising expansions around the United States, including more than forty US Naval facilities containing tens of thousands of feet of pier. Construction methodology, such as pile driving, has risen in shallow waters to build structures such as bridges, piers, and wind farms, with significant consequences for marine life and the environment. More precisely, pile driving activities generate significant decibel levels in the surrounding marine environment. Measurements taken from hydrophones placed in the water near the construction site indicate that the high sound pressure levels produced may be harmful to marine life and the environment. As a result, standards have been established to help alleviate and decrease the possible harm that high decibel sound levels may produce. However, these additional steps increase the overall cost of the construction project. This thesis focuses on replicating the pile driving process using finite element modeling to hydroacoustic parametric study of pile driving-induced anthropogenic sound in neighboring Florida seas, as well as the possible environmental impact of the state's numerous naval base piers. The modeling predictions can then be used to identify the distance from the pile at which marine life and the environment are no longer adversely affected. In addition, computer modeling can reduce construction costs when compared to on-site sensors and monitoring. / Master of Science / Over recent years there has been an increase in the amount of manmade noise in Florida and its coastal waterways due to overwater construction, marine traffic, and military activities. Pile driving construction has increased in shallow waters to build infrastructure, which includes bridges, piers, and wind farms, resulting in a negative impact for marine life and the environment. Federal agencies have established guidelines to ease the harmful effects construction has on marine life and the environment. However, there is concern that these recent guidelines may not properly consider all the geometric and hydrographic variables of manmade noise that affect the high sound exposure levels during pile driving. With a more accurate understanding of the sound generation produced from pile driving, predictions can assist with sound mitigation to ensure less harm to the marine life and environment. In turn, construction companies and government agencies informed with this enhanced understanding can make better decisions that lead to fewer (or possibly eliminate) transmission loss discrepancies and costly noise mitigation measures. Consideration of the marine environment is one of the United States Navy's top priorities with naval stations located throughout the State of Florida that possess thousands of feet of waterfront structures, including piers, requiring routine maintenance and construction. This thesis models the pile driving process through finite element modeling in COMSOL Multiphysics computer software, testing the various parameters that Florida waters may encounter with pile driving on the surrounding coast as well as naval bases.

Shallow geothermal energy (SGE) systems are becoming increasingly popular due to both their environmental and economic value. By using the ground as a source and sink for thermal energy, SGE systems are able to more efficiently heat and cool structures. However, their utility beyond structural heating and cooling is being realized as their applications now extend to slab and pavement heating, grain and agricultural drying, and swimming pool temperature control. Relatively recently, SGE systems have been combined with deep foundations to create a dual purpose element that can provide both structural support as well as thermal energy exchange with the subsurface. These thermo-active foundations provide the benefits of SGE systems without the additional installation costs. One of the novel applications of thermo-active foundations is in bridge deck deicing. Bridge decks experience two main winter weather related problems. The first of which is preferential icing, where the bridge freezes before the adjacent roadway because the bridge undergoes hastened energy loss due to its exposed nature. The second problem is the accelerated deterioration of concrete bridge decks resulting from the application of salts and other chemicals that are used to prevent accumulation and/or melt the frozen precipitation on roads and bridges. By utilizing the foundation of a bridge as a mechanism by which to access the shallow geothermal energy of the subsurface, energy can be supplied to the deck during the winter to melt and/or prevent frozen precipitation. An experimental ground-source bridge deck deicing system was constructed and the performance is discussed. Numerical models simulating the bridge deck and subsurface system components were also created and validated using the results from the numerical tests. Furthermore, the observed loads that result in a foundation from bridge deck deicing tests are shown. In order to better design for these loads, tools were developed that can predict the temperature change in the subsurface and foundation components during operation. Mechanisms by which to improve the efficiency of these systems without increasing the size of the borehole field were explored. Ultimately this research shows that SGE can effectively be used for bridge deck deicing. / Ph. D.

For many aggregate mining facilities, the stockpile is the preferred method of storing rock. In many aggregate mines, as well as other mines using stockpiling techniques, understanding the timing and flow of particles through a stockpile is important for correctly timing samples, making proper process adjustments and overall stockpile safety. Because much of the research of today lacks important information regarding actual interior particle movement within a stockpile, a series of Real Time Distribution (RTD) analyses and stockpile flow models have been prepared and analyzed for this study in order to better understand the flow characteristics of a stockpile. A series of three RTD analyses performed on three separate stockpiles provides information leading to the assumption that stockpiles tend to operate similar to a plug flow system. While conveyor loading techniques may lead to separation of rocks prior to traveling through the stockpile, the majority of the rock particles entering the pile remain near the point of entry, or within the "action" area, and will travel through the pile in a plug flow, rather than a mixed flow, manner. High Peclet number results for each analysis prove this assumption to be accurate. A series of models on three separate stockpiles have been created using PFC3d. Mainly, the simulations prove PFC3d is capable of showing how stockpile particles move in three dimensions while monitoring specific particles within the pile. In addition, these models provide simulation results similar to the results obtained within the RTD analyses. Results show that particles located directly above the discharge point, or "action" area, travel through the pile at a faster rate than particles surrounding this area. Velocity results obtained from the simulations show particles accelerating as they get closer to the discharge points while also providing evidence of "arching" during the simulation process. These findings provide a better understanding of internal flow within the stockpile and ways to possibly predict future stockpile flow issues that may be encountered. / Master of Science

Résumé : Afin de contribuer dans la réponse latérale des pieux sous sollicitations latérales et notamment prendre en compte des plusieurs paramètres en relation avec les pieux (matériau, diamètre, rigidité, inclinaison) et le sol (nature, rigidité), des analyses numériques en différences finies 2D et 3D ont été réalisées en considérant des pieux chargés latéralement et ancrés dans des sols sableux, argileux et même sableux-argileux. Des modèles numériques simulés avec les codes en différences finies FLAC pour l’analyse 2D et FLAC[indice supérieur 3D] pour l’analyse 3D ont été inspirés des modèles de pieux réduits et en vraie grandeur, faisant l’objet de publications. Des enregistrements du déplacement latéral ou/et de la capacité latérale ou/et du moment fléchissant des pieux considérés ont été pris lors de ces essais. Ces modèles numériques ont été validés à travers diverses comparaisons entre les mesures, les calculs de FLAC et/ou FLAC3D et dans des cas les calculs d’autres méthodes utilisées dans la pratique. Une comparaison entre l’analyse 2D et l’analyse 3D de la réponse latérale d’un pieu rigide chargé latéralement dans un sol cohérent, a été réalisée dans le but de connaître les limites de l’analyse 2D et la possibilité de corréler ses résultats à ceux de l’analyse 3D. L’influence de la charge verticale sur la réponse latérale (capacité latérale et moment fléchissant maximal) d’un pieu en béton, chargé latéralement dans des sols sableux et argileux, a été étudiée avec une analyse numérique 3D. Il a été démontré que pour le cas des sols sableux, la charge verticale n’a pas un effet considérable sur la réponse latérale des pieux soumis à des charges latérales. Par contre, la charge verticale conduit à une diminution significative de la capacité latérale des pieux dans des sols argileux. Il est également constaté que l'influence des charges verticales sur la réponse latérale du pieu installé dans une argile surconsolidée avec une résistance au cisaillement non drainée proportionnelle à la profondeur et un OCR variant de 1,5 à 4,0 est très différent de celle correspondante à une résistance au cisaillement non drainée constante quelle que soit la valeur d’OCR. Des analyses 3D ont été, également, effectuées pour étudier la réponse latérale de pieux inclinés et chargés latéralement. La capacité latérale des pieux inclinés dans les sols sableux est considérablement augmentée avec l’augmentation de la valeur de l’inclinaison du pieu correspondante à la direction opposée à la direction de la charge latérale, et la densité du sable. Mais lorsque la direction de l’inclinaison du pieu et la même que celle correspondante à la charge latérale, cette capacité latérale est légèrement à modérément augmentée tout dépendamment de la valeur et le signe de l'angle ainsi que de la densité du sable. L’influence de l’angle d’inclinaison associé avec la charge verticale sur la capacité latérale de pieux inclinés est aussi très importante pour les sols sableux. Pour les sols argileux, l'influence de l'angle d’inclinaison sur la capacité latérale dépend seulement de l'angle d’inclinaison. En effet, la capacité latérale est modérément augmentée. Par contre, L'effet combiné de l’angle et la charge verticale est assez important. // Abstract : This thesis pertains to numerical analyses conducted primarily to evaluate the lateral response of piles and the contribution of several parameters related to piles (e.g., material, diameter, stiffness, inclination) and the soil (e.g., type, rigidity). Numerical finite differences analysis in 2D and 3D have been performed modelizing laterally loaded piles in sandy, clayey, and even sandy-clayey soils. Numerical models, simulated with finite difference codes FLAC for analysis in 2D and FLAC[superscript 3D] for 3D analysis, were inspired from experimental laboratory and full scale models available in literature. Measurements of lateral deflection and/or lateral capacity and/or bending moment of tested piles were recorded during these tests. These numerical models have been validated through comparison between the various measurements, predictions with FLAC and/or FLAC3D and for some cases the calculations with other methods used in practice. Comparison between 2D and 3D analyses of the response of laterally loaded rigid piles in cohesive soils, was performed in order to investigate the 2D analysis limitations and the possibility of correlating the 2D results with those of 3D analysis. A series of 3D finite differences analyses is also conducted to evaluate the influence of vertical loads on the lateral response of pile foundations. Numerical results have shown that the lateral resistance of the piles does not appear to vary considerably with the vertical load in sandy soil especially at loosest stat. However, vertical load leads to a significant decrease in lateral capacity of piles in homogeneous and inhomogeneous clay layers. It is also found that the influence of vertical loads on the lateral response of pile installed in over-consolidated clay with undrained strength proportional to depth and different OCR in the range of 1.5 to 4.0 is quite different from that with constant undrained strength regardless the adopted OCR value. The 3D finite difference analyses have been, also, carried out to investigate the lateral response of battered piles. The lateral capacity of the battered piles in sandy soils is considerably increased when the value of pile inclination corresponding to the opposite direction of the lateral load increases and when the sand density increases. But in the case of pile inclination corresponding to the same direction of the lateral load, the lateral capacity is slightly increased regardless to the adopted value of batter angle and the sand density. In clayey soil, it was found that the influence of the batter angle on the lateral capacity of piles depends only on the batter angle and not on the clay rigidity. For the case of pile inclination corresponding to the opposite direction of the lateral load, the lateral capacity is moderately increased and for the other case of inclination, the effects are not significant. The influence of both batter angle and vertical load on lateral capacity of battered pile in clayey soils is moderately pronounced.

No description available.

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.

No description available.

[pt] Este trabalho consiste na determinação dos valores e da distrbuição dos módulos de elasticidade com a profundidade de maciços de solo estratificados através de retroanálises de provas de carga em estaca instrumentada, com medição de recalques no topo e na base, publicadas na literatura para depósito de solos resuduais, argila rija e areia. Nas retroanálises utilizou-se um programa computacional baseado numa versão simplificada do método dos elementos de contorno, sugerida por Poulos (1968), com adaptações da formulação de Mindlin (1936) para permitir também a consideração de maciços estratificados. Seus resultados foram comparados com aqueles obtidos por vários tipos de ensaios de campo ou de laboratório, com o objetivo de indicar quais destes ensaios são os mais adequados para a determinação dos parâmetros de deformação do solo, visando o cálculo do recalque de estacas. Os valores de módulo de elasticidade computados nas retroanálises compararam-se satisfatoriamente com aqueles determinados com base nos ensaios que, durante a execução, induzem pequenas deformações no solo, ocorrendo, por outro lado, uma significativa subestimativa destes valores quando determinados em ensaios envolvendo grandes deformações. Este comportamento permitiu então concluir que uma escolha adequada do nível de deformações associada ao tipo de ensaio é essencial para a determinação das características de compressibilidade do solo na engenharia de fundações. / [en] This work consists of the determination of values and distribution of the modulus of elasticity with depth in layered soils through backanalysis of instrumented pile load tests, published in literature for residual soils, stiff clay and sand. In the backanalysis was used a simplified version of the boundary element method, originally introduced by Poulos and Davis (1968), with adaptations of Mindlin´s formulation to allow for the consideration of layered soils. The results of the backanalysis were compared with those obtained through many ´in situ´ and laboratory tests, with the aim of indicating which of those tests are more suitable for the determination of the deformation parameters of the soil, to be used in the evaluation of pile settlement. The values of elasticity modulus computed in the backanalysis agreed well with those determined from the tests which transmit small strains to the soil during its execution. On the other hand, these values were subestimated when obtained from tests that involve high strains. This behavior permitted the conclusion that an appropriate choice of the strain level, associated to the type of the test, is essential to the determination of the compressibility characteristics of the soil in foundation engineering problems. / [es] Este trabajo aborda la determinación de los valores de los módulos de elasticidad con profundidad de macizos de suelo estratificados así como su distribución. Dicha determinación se efectua a través de retroanálisis de pruebas de carga en estaca instrumentada, que aparecen publicadas en la literatura para depósito de suelos residuales, arcilla dura y arena. En el retroanálisis se utilizó un programa computacional basado en una versión simplificada del método de los elementos de contorno, sugerida por Polos (1968), con adaptaciones de la formulación de Mindlin (1936) que permiten considerar macizos estratificados. Con el objetivo de indicar cuál de estos ensayos resulta más adecuado para la determinación de los parámetros de deformación del suelo y para el cálculo del recalque de estacas, se compararon sus resultados con los obtenidos por varios tipos de ensayos de campo o de laboratorio. Los valores de módulo de elasticidad computados en el retroanálisis se compararan satisfactoriamente con los determinados con base en los ensayos que, durante la ejecución, inducen pequenas deformaciones en el suelo, teniendo, por otro lado, una significativa subestimación de estos valores cuando son determinados en ensayos con grandes deformaciones. Este comportamiento permitió entonces concluir que una selección adecuada del nível de deformación asociada al tipo de ensayo es esencial para la determinación de las características de compresibilidad del suelo en la ingeniería de fundaciones.