Date of Award


Degree Type


Degree Name

Doctor of Philosophy


Three main areas are addressed in this study: (1) Statnamic test analysis. In recent years a new type of pile test employing a short-duration load was developed that became known as pile Statnamic test. A method of dynamic analysis has been formulated for this test. The aim of the analysis is twofold: to calculate the pile head displacements in such a way that a satisfactory match with the data measured during the test is obtained; and using the model parameters established from this comparison to predict the pile capacity. The model is one-dimensional and accounts for slip and energy dissipation in the far field. The parameters of the model are, for the most part, directly related to standard geotechnical parameters. The case studies described in this research indicate that the proposed mathematical model works very well and that the Statnamic test may become a useful tool for pile capacity prediction.;(2) Nonlinear behavior of piles. An analysis of pile axial and lateral response to transient dynamic loading and to harmonic loading is presented allowing for nonlinear soil behavior, energy dissipation through radiation damping, soil hysteresis, and the loading rate dependency of the soil resistance. Furthermore, the discontinuity conditions at the pile-soil interface are accounted for. In addition, the effect of neighbouring piles is taken into account for piles in a group. The approach is employed to analyze the pile response to harmonic forces, pile driving, and Statnamic loading and to establish the bearing Capacity and load-deflection curves. Equivalent linear stiffness and damping parameters as well as interaction factors for approximate nonlinear analysis of pile groups are established and presented.;(3) Effect of foundation nonlinearity on offshore tower response. The response of a fixed offshore tower is greatly affected by the nonlinear behavior of the supporting piles. The nonlinear analysis developed in this study is utilized to model the response of foundation piles. A model for the evaluation of wave forces on the tower members that takes into account the spatial incoherence effect on wave forces is described and used in the analysis. The effect of different foundation parameters on the dynamic characteristics of the tower is investigated. Also, the tower response to random wave forces is conducted and the effect of foundation parameters on the tower response is examined. The dynamic characteristics of the tower and its response to wave forces were found to be greatly influenced by the foundation nonlinearity and by the pile-soil-pile interaction as well.



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