A prova de carga dinâmica é freqüentemente utilizada na determinação da capacidade de carga de fundações por estacas cravadas e há relatos de uso com sucesso deste ensaio em estacas escavadas e tubulões. Esta pesquisa envolveu a adaptação e execução da prova de carga dinâmica na placa de aço circular de diâmetro 0,80 m, com o objetivo de inferir a capacidade de carga do sistema placa-solo. Como a prova de carga dinâmica permite que seja feita a comprovação da carga durante a cravação, vislumbra-se também a viabilização desse tipo de ensaio em solos porosos por meio da cravação da placa o necessário para atingir a capacidade de carga exigida em um projeto. Os ensaios foram realizados no campo experimental da USP/São Carlos, com solo superficial não saturado, poroso e colapsível, por isso foram feitas medidas dos valores de sucção matricial, já que esta exerce forte influência sobre a capacidade de carga / The dynamic load test is frequently used in the determination of driven piles foundation bearing capacity. It is also reported the successful use of the test in bored piles and caissons. This research included the adaptation and execution of the dynamic load test in circular steel plate, to verify the bearing capacity of footing foundations. Since the dynamic load tests allow the bearing capacity to be verified during the construction, it is also glimpsed the possibility of using this test in porous soils by penetrating the plate into the soil until the expected bearing capacity is achieved. The tests were held at the USP/São Carlos experimental foundation camp, which has superficial unsaturated, porous and colapsive soil, so matric suction's measurement were made, since it has strong influence on the bearing capacity

Soils, like several other materials, exhibit strong time-dependent behaviour which can be evidenced in terms of creep or strain-rate effects. The degree of this rheological behaviour varies with the type of soil, its structure, and with the stress history. This effect is exacerbated in pile load testing where the procedure duration tends to be shortened under increasing time pressures. The modelling needed to interpret the results therefore becomes more and more complex, including soil viscosity, wave radiation into the soil and other significant phenomena. The objective of the research reported herein is to refine the rheological parameters characterizing the influence of the loading rate within the framework of a relevant pile/soil interaction model fed with dynamic measurements acquired during pile Dynamic Load Tests (DLTs). The final goal is to predict and simulate the quasi-static pile load settlement curve. The pile/soil interaction system is described by a non-linear mass/spring/dashpot system supposed to represent the pile and the soil, with constitutive relationships existing within and between them. These relationships account for the static and the dynamic or rheologic behaviour. A back-analysis process based on a matching procedure between measured and computed quantities allows one to characterize the pile/soil interaction in terms of constitutive and rheologic parameters based on the dynamic measurements. After optimisation of the matching procedure, the parameters obtained are used to simulate the “static” load-settlement curve. The matching procedure is based on an automatic and stochastic parameter perturbation analysis. Since the parameters influence the system response with a relative weight, they are sorted in order to optimise all the parameters by successively retrieving the most influential ones and working on the remaining ones. The back-analysis performed on real dynamic measurements in this research leads to an improved pile/soil interaction model. The slippage between pile and soil along the pile shaft must be explicitly taken into account. This refinement increases the number of degrees of freedom needed to describe the pile/soil system but brings deeper insight into the behaviour of an interfacing zone of limited thickness surrounding the pile shaft.

In order to better understand the behavior of the human brain, it is very important to perform large scale neural network simulation which may reveal the relationship between the whole network activity and the biophysical dynamics of individual neurons. However, considering the complexity of the network and the large amount of variables, researchers choose to either simulate smaller neural networks or use simple spiking neuron models. Recently, supercomputing platforms have been employed to greatly speedup the simulation of large brain models. However, there are still limitations of these works such as the simplicity of the modeled network structures and lack of biophysical details in the neuron models. In this work, we propose a parallel simulator using biophysically realistic neural models for the simulation of large scale neural networks. In order to improve the performance of the simulator, we adopt several techniques such as merging linear synaptic receptors mathematically and using two level time steps, which significantly accelerate the simulation. In addition, we exploit the efficiency of parallel simulation through three parallel implementation strategies: MPI parallelization, MPI parallelization with dynamic load balancing schemes and Hybrid MPI/OpenMP parallelization. Through experimental studies, we illustrate the limitation of MPI implementation due to the imbalanced workload among processors. It is shown that the two developed MPI load balancing schemes are not able to improve the simulation efficiency on the targeted parallel platform. Using 32 processors, the proposed hybrid approach, on the other hand, is more efficient than the MPI implementation and is about 31X faster than a serial implementation of the simulator for a network consisting of more than 100,000 neurons. Finally, it is shown that for large neural networks, the presented approach is able to simulate the transition from the 3Hz delta oscillation to epileptic behaviors due to the alterations of underlying cellular mechanisms.

A single-chip, hybrid, heterogeneous, and dynamic shared memory multiprocessor architecture is being developed which may be used for real-time and non-real-time applications. This architecture can execute any application described by a dataflow (process flow) graph of any topology; it can also dynamically reconfigure its structure at the node and processor architecture levels and reallocate its resources to maximize performance and to increase reliability and fault tolerance. Dynamic change in the architecture is triggered by changes in parameters such as application input data rates, process execution times, and process request rates. The architecture is a Hybrid Data/Command Driven Architecture (HDCA). It operates as a dataflow architecture, but at the process level rather than the instruction level. This thesis focuses on the development, testing and evaluation of a new graphic software (hdca) developed to first do a static resource allocation for the architecture to meet timing requirements of an application and then hdca simulates the architecture executing the application using statically assigned resources and parameters. While simulating the architecture executing an application, the software graphically and dynamically displays parameters and mechanisms important to the architectures operation and performance. The new graphical software is able to show system and node level dynamic capability of the HDCA. The newly developed software can model a fixed or varying input data rate. The model also allows fault tolerance analysis of the architecture.

A prova de carga dinâmica é freqüentemente utilizada na determinação da capacidade de carga de fundações por estacas cravadas e há relatos de uso com sucesso deste ensaio em estacas escavadas e tubulões. Esta pesquisa envolveu a adaptação e execução da prova de carga dinâmica na placa de aço circular de diâmetro 0,80 m, com o objetivo de inferir a capacidade de carga do sistema placa-solo. Como a prova de carga dinâmica permite que seja feita a comprovação da carga durante a cravação, vislumbra-se também a viabilização desse tipo de ensaio em solos porosos por meio da cravação da placa o necessário para atingir a capacidade de carga exigida em um projeto. Os ensaios foram realizados no campo experimental da USP/São Carlos, com solo superficial não saturado, poroso e colapsível, por isso foram feitas medidas dos valores de sucção matricial, já que esta exerce forte influência sobre a capacidade de carga / The dynamic load test is frequently used in the determination of driven piles foundation bearing capacity. It is also reported the successful use of the test in bored piles and caissons. This research included the adaptation and execution of the dynamic load test in circular steel plate, to verify the bearing capacity of footing foundations. Since the dynamic load tests allow the bearing capacity to be verified during the construction, it is also glimpsed the possibility of using this test in porous soils by penetrating the plate into the soil until the expected bearing capacity is achieved. The tests were held at the USP/São Carlos experimental foundation camp, which has superficial unsaturated, porous and colapsive soil, so matric suction's measurement were made, since it has strong influence on the bearing capacity

Em obras de fundações por estacas cravadas, os diferentes comprimentos finais das estacas refletem a variabilidade natural do terreno, e variam de acordo com o critério de paralização da cravação, normalmente baseado em medidas de nega e repique elástico. Pouco se tem aproveitado desses registros para o controle da resistência mobilizada na fundação ao final da cravação, devido à limitação da aplicação das fórmulas dinâmicas e ao desconhecimento de alguns parâmetros. Em muitos casos de controle de capacidade de carga, apenas é realizada a aferição de um fator de segurança pontual, obtido via prova de carga. Neste trabalho, é apresentado um procedimento de controle de capacidade de carga de fundações por estacas cravadas, baseado em registros de nega e repique elástico, a partir de fórmulas dinâmicas, que possibilitam a estimativa da resistência mobilizada ao final da cravação em todo o universo de estacas de uma obra. Este procedimento proposto foi aplicado em um estudo de caso de uma obra em um porto em Santa Catarina. Nesta obra foram cravadas 2506 estacas pré-moldadas de concreto, controladas por nega e repique elástico, registrados em todas as estacas no final da cravação. Neste conjunto de estacas foram executadas 74 provas de carga dinâmica, com energia crescente, e quatro provas de carga estática. Neste caso de obra controlada, os resultados mostraram que o procedimento adotado, baseado na utilização de fórmulas dinâmicas, com parâmetros calibrados a partir dos resultados das provas de carga dinâmica, permitiu estimar valores de resistência mobilizada ao final da cravação das 2506 estacas da obra, que apresentaram um valor médio próximo ao valor médio encontrado nas 74 estacas ensaiadas. Além disso, o coeficiente de variação dos valores de resistência mobilizada de todas as estacas da obra foi da ordem de 16,0%, similar ao coeficiente de variação de 14,7%, obtido nos resultados das provas de carga dinâmica. / The different final lengths of driven piles reflect the natural variability of the soil, and are dependent of the driving controls based in the measurements of the final set and elastic rebound. Normally these measurements are not used to predict the ultimate capacity of pile foundations, at the end of driving, due to the limitation of the dynamic formulas and the lack of some parameters. In many cases, the pile capacity control is based on a determination of a single safety factor, obtained from pile load tests. In this work, it is proposed a procedure to control the ultimate capacity of driven piles, based on the results of the final set and the elastic rebound, and dynamic formulas, which allow the estimation of the mobilized resistance at the end of driving of all piles driven in a particular project. This procedure was applied in a case study of a port in Santa Catarina. In this case, 2506 precast concrete piles were driven, and controlled by the elastic rebound, recorded at the end of driving. Also, dynamic load tests, with increasing energy, were performed on 74 piles, and static load tests were carried out on four piles. The results showed that this procedure adopted, based on the use of dynamic formulas calibrated using the results of dynamic load tests, is capable to estimate the values of mobilized resistance along all piles at the end of driving. The average result of the mobilized resistance of the 2506 piles was close to the average value found by the results of the 74 pile dynamic load tests. Also, the coefficient of variation of the mobilized resistance of all piles was around 16.0%, similar to the coefficient of variation of 14.7%, obtained by the dynamic load tests.

Pavement roughness has been found to have an effect on the coefficient of friction measured with the Locked-Wheel Skid Tester (LWT) with measured friction decreasing as the long wave roughness of the pavement increases. However, the current pavement friction standardization model adopted by the American Society for Testing and Materials (ASTM), to compute the International Friction Index (IFI), does not account for this effect. In other words, it had been previously assumed that the IFI's speed constant (SP), which defines the gradient of the pavement friction versus speed relationship, is an invariant for any pavement with a given mean profile depth (MPD), regardless of its roughness. This study was conducted to quantify the effect of pavement roughness on the IFI's speed constant. The first phase of this study consisted of theoretical modeling of the LWT using a two-degree of freedom vibration system. The model parameters were calibrated to match the measured natural frequencies of the LWT. The calibrated model was able to predict the normal load variation during actual LWT tests to a reasonable accuracy. Furthermore, by assuming a previously developed skid number (SN) versus normal load relationship, even the friction profile of the LWT during an actual test was predicted reasonably accurately. Because the skid number (SN) versus normal load relationship had been developed previously using rigorous protocol, a new method that is more practical and convenient was prescribed in this work. This study concluded that higher pavement long-wave roughness decreases the value of the SP compared to a pavement with identical MPD but lower roughness. Finally, the magnitude of the loss of friction was found to be governed by the non-linear skid number versus normal load characteristics of a pavement.

Esta tesis analiza los métodos estáticos, los cuales comprenden los métodos analíticos y semi empíricos que son utilizados para determinar la capacidad de carga teórica en pilotes, y los compara con las pruebas de carga dinámica, las cuales brindan el resultado real de la capacidad de carga de un pilote. El análisis realizado recopila las teorías de Therzaghi, Hansen, Meyerhof y Bowles, en cuanto a los modelos analíticos, y las teorías de Aoki Velloso, Decourt Quaresma, Pedro Paulo Velloso y Texeira, por parte de las teorías semi empíricas. / This thesis analyzes the static methods, which include the analytical and semi-empirical methods that are used to determine the theoretical load capacity in piles, and compares them with the dynamic load tests, which provide the real result of the load capacity of a pile. The analysis compiles the theories of Therzaghi, Hansen, Meyerhof and Bowles, regarding the analytical models, and the theories of Aoki Velloso, Decourt Quaresma, Pedro Paulo Velloso and Texeira, by the semi-empirical theories. / Tesis

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