In an effort to obtain 100-year level hurricane protection for southeastern Louisiana, the U.S. Army Corps of Engineers (USACE) has implemented design guidelines that both levees and structures shall be designed to. Historically, USACE has used concrete piles or steel H-piles as the foundations for these structures. Because of the magnitude of obtaining 100-year level hurricane protection, limited resources, and a condensed timeline, spiral welded pipe piles can be manufactured as an alternative to either the concrete piles or steel H-piles. This research will provide the necessary background for understanding pile foundations, will compare the behaviors of spiral welded pipe piles to that of other piles with respect to geotechnical concerns through a series of pile load tests, and will offer a current cost analysis. This background, testing, and cost analysis will show that spiral welded pipe piles are a viable alternative for USACE structures from a geotechnical and economic perspective.

Deep foundations like auger-cast piles and drilled shafts frequently extend through liquefiable sand layers and bear on non-liquefiable layers at depth. When liquefaction occurs, the skin friction on the shaft decreases to zero, and then increases again as the pore water pressure dissipates and the layer begins to settle, or compact. As the effective stress increases and the liquefiable layer settles, along with the overlaying layers, negative skin from the soil acts on the shaft. To investigate the loss of skin friction and the development of negative skin friction, soil-induced load was measured in three instrumented, full-scale auger-cast piles after blast-induced liquefaction at a site near Christchurch, New Zealand. The test piles were installed to depths of 8.5 m, 12 m, and 14 m to investigate the influence of pile depth on response to liquefaction. The 8.5 m pile terminated within the liquefied layer while the 12 m and 14 m piles penetrated the liquefied sand and were supported on denser sands. Following the first blast, where no load was applied to the piles, liquefaction developed throughout a 9-m thick layer. As the liquefied sand reconsolidated, the sand settled about 30 mm (0.3% volumetric strain) while pile settlements were limited to a range of 14 to 21 mm (0.54 to 0.84 in). Because the ground settled relative to the piles, negative skin friction developed with a magnitude equal to about 50% of the positive skin friction measured in a static pile load test. Following the second blast, where significant load was applied to the piles, liquefaction developed throughout a 6-m thick layer. During reconsolidation, the liquefied sand settled a maximum of 80 mm (1.1% volumetric strain) while pile settlements ranged from 71 to 104 mm (2.8 to 4.1 in). The reduced side friction in the liquefied sand led to full mobilization of side friction and end-bearing resistance for all test piles below the liquefied layer and significant pile settlement. Because the piles generally settled relative to the surrounding ground, positive skin friction developed as the liquefied sand reconsolidated. Once again, skin friction during reconsolidation of the liquefied sand was equal to about 50% of the positive skin friction obtained from a static load test before liquefaction.

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.

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.

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.

[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.

A utilização de estacas helicoidais como fundação de linhas de transmissão de energia elétrica tem aumentando significativamente no Brasil. No entanto, em alguns casos de obra, a camada de solo adequada para se instalarem as hélices da estaca encontra-se em profundidade economicamente inviável para o uso deste tipo de fundação. Esta foi a razão que motivou a presente pesquisa, que tem como objetivo avaliar soluções para a instalação de estacas helicoidais mais curtas, ancoradas em solo de capacidade inferior à necessária para atender às cargas de projeto. Nesta dissertação, foram avaliadas duas soluções alternativas para o aumento de capacidade de carga de fundações por estacas helicoidais, para os casos de carregamento de tração e compressão. A primeira alternativa verificada foi a injeção de calda de cimento em torno das hélices da ponta da estaca. A segunda solução testada foi o preenchimento com argamassa em torno da haste da estaca acima das hélices. Foram realizadas na presente pesquisa nove provas de carga (cinco de tração e quatro de compressão): três em estacas helicoidais convencionais, quatro em estacas helicoidais com injeção de calda de cimento e duas em estacas helicoidais com fuste de argamassa. Após a realização de provas de carga nas estacas, estas foram exumadas para se verificar a forma da coluna de argamassa e as formas de bulbos resultantes das injeções realizadas com calda de cimento. A partir dos resultados dos ensaios, foi verificado que a capacidade de carga da estaca á tração pode ser aumentada usando-se as alternativas testadas. Porém, são necessários mais ensaios para avaliar a eficiência destes procedimentos em diferentes condições de solo e configuração de estacas. / The use of helical piles as foundation for transmission lines has increased significantly in Brazil. However, in some sites, the soil layer suitable for installing the pile helices are considerably deep and it is economically unviable to use this type of foundation. This reason motivated the current study, which aims to evaluate solutions for the installation of helical piles anchored in soil with low capacity. In this research, it was evaluated two alternative solutions to improve the helical pile capacity. The first alternative is injecting a water/ cement mixture which is delivered to the ground throught holes, placed between the upper and bottom helices. The second alternative solution is helical piles with a mortar shaft. Nine pile load tests were performed for the present investigation (five in tension and four in compression): three on conventional helical piles, four on helical piles with injection, and two on helical piles with mortar shaft. After that, the helical piles were exhumed for the verification of the shaft shape and the forms of the bulbs resulting from injections performed with cement mixture. The results of these tests indicated that the uplift capacity of helical piles can be increased by using the alternatives tested. However, more tests are needed to evaluate the effectiveness of these procedures, in different soil conditions and pile configurations.

A utilização de estacas helicoidais como fundação de linhas de transmissão de energia elétrica tem aumentando significativamente no Brasil. No entanto, em alguns casos de obra, a camada de solo adequada para se instalarem as hélices da estaca encontra-se em profundidade economicamente inviável para o uso deste tipo de fundação. Esta foi a razão que motivou a presente pesquisa, que tem como objetivo avaliar soluções para a instalação de estacas helicoidais mais curtas, ancoradas em solo de capacidade inferior à necessária para atender às cargas de projeto. Nesta dissertação, foram avaliadas duas soluções alternativas para o aumento de capacidade de carga de fundações por estacas helicoidais, para os casos de carregamento de tração e compressão. A primeira alternativa verificada foi a injeção de calda de cimento em torno das hélices da ponta da estaca. A segunda solução testada foi o preenchimento com argamassa em torno da haste da estaca acima das hélices. Foram realizadas na presente pesquisa nove provas de carga (cinco de tração e quatro de compressão): três em estacas helicoidais convencionais, quatro em estacas helicoidais com injeção de calda de cimento e duas em estacas helicoidais com fuste de argamassa. Após a realização de provas de carga nas estacas, estas foram exumadas para se verificar a forma da coluna de argamassa e as formas de bulbos resultantes das injeções realizadas com calda de cimento. A partir dos resultados dos ensaios, foi verificado que a capacidade de carga da estaca á tração pode ser aumentada usando-se as alternativas testadas. Porém, são necessários mais ensaios para avaliar a eficiência destes procedimentos em diferentes condições de solo e configuração de estacas. / The use of helical piles as foundation for transmission lines has increased significantly in Brazil. However, in some sites, the soil layer suitable for installing the pile helices are considerably deep and it is economically unviable to use this type of foundation. This reason motivated the current study, which aims to evaluate solutions for the installation of helical piles anchored in soil with low capacity. In this research, it was evaluated two alternative solutions to improve the helical pile capacity. The first alternative is injecting a water/ cement mixture which is delivered to the ground throught holes, placed between the upper and bottom helices. The second alternative solution is helical piles with a mortar shaft. Nine pile load tests were performed for the present investigation (five in tension and four in compression): three on conventional helical piles, four on helical piles with injection, and two on helical piles with mortar shaft. After that, the helical piles were exhumed for the verification of the shaft shape and the forms of the bulbs resulting from injections performed with cement mixture. The results of these tests indicated that the uplift capacity of helical piles can be increased by using the alternatives tested. However, more tests are needed to evaluate the effectiveness of these procedures, in different soil conditions and pile configurations.

Rate-dependent effects introduced during rapid and/or dynamic events have typically been oversimplified to compensate for deficiencies in present analyses. As load test results are generally considered as the basis of performance from which foundations can be designed, it is imperative that the analyzed load test data be as accurate as possible. In an attempt to progress the state of load test data regression, this dissertation addresses two common assumptions made during the regression process: (1) the statnamic damping coefficient is constant throughout the entire load test and (2) the concrete stress-strain relationship is linear-elastic. Also presented is a case study where the inherent features of a rapid load test proved useful in identifying the occurrence and proximity of a structural failure within a drilled shaft.

There is ussualy used the Masopust's method to assessment the piles in Czech Republic. This method is based on statistical processing of large data set of load piles tests. Due to the using of regression coefficients this method is relatively complicated and not very transparent. Instead, foreign standards ussualy use direct the values of limit stress on the base of piles and unit friction capacity. Procedure for determining the bearing capacity of the piles is thus considerably simplified. In this thesis the Masopust's method is compared with the methods used in Germany and Austria. This comparison provides insight to the safety level that include various approaches.