Date of Award
Doctor of Philosophy
This study comprises three main parts: (1) Pile Driving Analysis. The conventional one dimensional wave equation analysis of the pile driving problem suffers from the empirical representation of the soil parameters. In this study, an improved one dimensional wave equation model is developed which accounts for wave propagation in the soil mass and thus gives more realistic prediction of the pile displacements. A three dimensional finite element analysis of the problem is also formulated and its results are compared with those of the one dimensional analysis. The finite element analysis is computationally very expensive which is not justified due to its sensitivity to the input parameters. (2) Modelling of Wave Forces. Lack of spatial correlation of short crested waves is accounted for using a coherence function model and the wave forces estimated using this model are compared with those estimated using the directional spectrum model. Both models are found to give comparable resultant wave forces and their attenuation with separation if their parameters are properly chosen. The error resulting from assuming a constant water particle velocity along the tributary length is examined and appears to be small. (3) Response of Fixed Offshore Towers to Random Wave Forces Accounting for Pile-Soil-Pile Interaction. Dynamic pile-soil-pile interaction under the effect of wave forces is usually neglected in the design of offshore towers. It is examined and found to have a significant effect on the response of the tower to random waves. It is incorporated in the analysis using dynamic interaction factors which consider pile-soil separation. The response of the tower is found to be greatly influenced by pile-soil-pile interaction which is attributed to the increase in flexibility and damping of the tower.
Mitwally, Hisham Mohammed, "Dynamic Analysis Of Offshore Structures" (1987). Digitized Theses. 1603.