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Jack-up units have considerable economic significance because they are used to carry out a large proportion of the world's oil and gas exploration in water depths less than 90.0m. Due to the increase in use of jack-ups in harsher environments, analysis techniques assuming quasi-static and linear structural behaviour have had to be reassessed. This thesis is concerned with non-linear dynamic analysis methods appropriate for a jack-up assessment. Jack-up modelling requires realistic representation of the structure, the foundations and the environmental loading, together with the implementation of appropriate dynamic analysis algorithms. Techniques for each of these aspects of jack-up analysis are reviewed and the implementation of several of the methods in an advanced plane frame analysis program called JAKUP is described. Geometric non-linearity in the structure and work hardening plasticity at the foundations are accounted for in the program. Test cases are presented to verify the implementation of the methods and then some illustrative plane frame quasi-static and dynamic analyses are described. These simple models highlight the importance of accounting for dynamic motions in a jack-up analysis. For the quasi-static analyses, the assumption of pinned footing behaviour is seen to always result in the most conservative displacement and moment predictions. However, the analyses show that this is not always the case when dynamic amplification is accounted for.

The goal of this study was to identify areas in which an influenza immunization campaign for seniors, sponsored by a health maintenance organization (HMO), could be improved. This study was conducted at Group Health Cooperative of Puget Sound (GHC), serving approximately 470,000 enrollees in Washington State. A survey was administered to two groups of seniors drawn at random--those who received influenza vaccine and those who did not, during the fall and winter of 1991. Immunization rates were almost 75 percent for "well" seniors and 85 percent for "chronically ill" seniors. Bivariant analysis showed that two activities of the influenza campaign were associated with vaccine compliance: a provider-generated recruitment letter and exposure to an immunization article in the enrollee newsletter. Using a broader framework for predicting vaccine compliance, logistic regression showed that vaccine compliance was associated positively with previous immunizations and belief that "my doctor wants me to get a shot," and negatively with fear of adverse reaction and belief that the vaccine is ineffective. There were few suggestions for improving the immunization program, among both vaccinated and unvaccinated enrollees. Approximately two-thirds of unvaccinated enrollees said there was nothing GHC could do to convince them to be vaccinated. These findings suggest high vaccine compliance and satisfaction with an HMO-sponsored influenza campaign. Strategies and potential to further increase vaccination rates are discussed.