It is evident from several studies that ultimate bearing capacities calculated by traditional methods are conservative and subjective. For large civil structures founded on spread footings, cost-effective and safer foundation could be achieved by adopting optimum ultimate bearing capacity values that are based on an objective and pragmatic analysis. There is a pressing need to modify the existing methods for accurate estimation of the bearing capacities of rocks for spread footings. In practice, foundation bearing capacities of rock masses are often estimated using the presumptive values from Building Officials Code Administrators, National Building Code, and methods adopted by the American Association of State Highway and Transportation Officials. However, the estimated values are often not realistic, and site-specific analyses are essential. In this study, geotechnical reports and drill-log data from successful geotechnical design projects founded on a wide range of granites in eastern Tennessee were consulted. Different published methods were used to calculate ultimate bearing capacity of rock mass. These methods included Peck, Hansen and Thornburn, Hoek and Brown, Army Corps of Engineers, Naval Facilities Engineering Command, and Terzaghi's general bearing capacity equations. Wide variation was observed in the calculated ultimate bearing capacity values, which ranged over about two orders of magnitude. Only two of the methods provided realistic results when validated with plate-load test data from similar rocks.

The methods of analysis used to determine ultimate bearing capacity of piles are applied to a field case in Turkey. During the pile driving works of the Atat&uuml / rk Culture Center in Samsun, Delmag D22-13 and Delmag D-15 diesel pile driving hammers have been used. The ultimate bearing capacity and skin friction values calculated using static formulas have been given as input to the wave equation pile analysis program FADWAVE written by J.E.Bowles. The analytical method used in this program was based on the wave propagation in solids originated in 1962 by E.A.L.Smith. The results obtained from the program are compared with each other.

Esta tese aplica o conceito de energia complementar para a determinação da capacidade de carga última de estaca cravada no ensaio de carregamento dinâmico de energia crescente. O ensaio de carregamento dinâmico com impactos de energia constante só permite obter a resistência estática mobilizada do modelo de CASE ou de SMITH com base na teoria da equação da onda e no Pile Driving Analyzer. A aplicação de impactos de energia crescente mostra que a curva de resistência estática - deslocamento dinâmico apresenta: a) trecho linear crescente seguido de trecho que se curva até que a tangente se torna vertical ou b) trecho crescente quase linear até um pico de resistência, seguido de uma curva de descarga até um determinado valor que corresponde à tangente vertical ou, c) trecho linear crescente seguido de trecho curvo cuja tangente não se verticaliza e onde a resistência volta a crescer. A ruptura do sistema estaca - maciço de solos é caracterizada pela energia complementar que passa em um máximo sempre que a resistência mobilizada atinge um pico. No pós-ruptura o excesso de energia aplicada e o excesso de trabalho das forças de amortecimento do impacto, em relação ao pico máximo, crescem linearmente com o nível de energia cinética aplicada. / This thesis suggests how to evaluate the ultimate bearing capacity of driven piles by using dynamic load tests with increasing energy. The dynamic load test with constant energy blows only allows the determination of the mobilized static resistance (CASE and SMITH\'s model), by using the wave equation theory and the Pile Driving Analyzer. The application of increasing energy blows shows that this static resistance: a) increases with increasing energy and then becomes constant or; b) increases with increasing energy up to a peak resistance and thereafter first decreases and then becomes constant or, c) starts to increase with increasing energy, then remains constant and after some blows starts to increase again. lt is shown that the rupture of the pile-soil system is characterized by the kinetic complementary energy reaching an upper limit when the impact mobilizes the maximum static pile capacity. All the energy or work done by damping forces, in excess of this maximum or peak situation, increases linearly with increasing energy.

Esta tese aplica o conceito de energia complementar para a determinação da capacidade de carga última de estaca cravada no ensaio de carregamento dinâmico de energia crescente. O ensaio de carregamento dinâmico com impactos de energia constante só permite obter a resistência estática mobilizada do modelo de CASE ou de SMITH com base na teoria da equação da onda e no Pile Driving Analyzer. A aplicação de impactos de energia crescente mostra que a curva de resistência estática - deslocamento dinâmico apresenta: a) trecho linear crescente seguido de trecho que se curva até que a tangente se torna vertical ou b) trecho crescente quase linear até um pico de resistência, seguido de uma curva de descarga até um determinado valor que corresponde à tangente vertical ou, c) trecho linear crescente seguido de trecho curvo cuja tangente não se verticaliza e onde a resistência volta a crescer. A ruptura do sistema estaca - maciço de solos é caracterizada pela energia complementar que passa em um máximo sempre que a resistência mobilizada atinge um pico. No pós-ruptura o excesso de energia aplicada e o excesso de trabalho das forças de amortecimento do impacto, em relação ao pico máximo, crescem linearmente com o nível de energia cinética aplicada. / This thesis suggests how to evaluate the ultimate bearing capacity of driven piles by using dynamic load tests with increasing energy. The dynamic load test with constant energy blows only allows the determination of the mobilized static resistance (CASE and SMITH\'s model), by using the wave equation theory and the Pile Driving Analyzer. The application of increasing energy blows shows that this static resistance: a) increases with increasing energy and then becomes constant or; b) increases with increasing energy up to a peak resistance and thereafter first decreases and then becomes constant or, c) starts to increase with increasing energy, then remains constant and after some blows starts to increase again. lt is shown that the rupture of the pile-soil system is characterized by the kinetic complementary energy reaching an upper limit when the impact mobilizes the maximum static pile capacity. All the energy or work done by damping forces, in excess of this maximum or peak situation, increases linearly with increasing energy.

The master thesis consists of a theoretical part and a practical part. In the theoretical part jet-grouting technology is described briefly. Mechanical properties of jet-grouted piles were characterized. Various estimation methods of ultimate pile bearing capacity are described in this thesis – analytical calculation of ultimate bearing capacity for bored piles and estimation of ultimate pile bearing capacity by analysis of load-displacement curve defined by CHIN (1970; 1972). Load transfer method for piles and hyperbolic load-transfer curve are introduced. As a part of the load-trasfer method analysis, a method of estimating ultimate pile shaft friction called beta method is defined. In the practical part were evaluated several static load tests of jet-grouted piles and were constructed their load-displacemnt curves. Then reverse analysis of the results from static load tests was performed using load-transfer method. Then ultimate pile bearing capacity was estimated using analytical calculation of pile bearing capacity for bored piles and using analysis of load-displacement curve with method by CHIN (1970; 1972). By evaluation of load transfer method and beta method ultimate shaft resistence for each pile was estimated. Results and load-displacement curves were compared.