This study is carried out on the analysis and design methodologies for tension leg platforms(TLP). It is composed of two parts. The first is the identification of the essential technologies for analysis and design of TLP's, and the second is the dynamic analysis of tethers. In the first part, the study is carried out on six sub-subjects as follows ; (1) wave and wave loadings (2) TLP motion (3) TLP tethers (4) TLP structure (5) tether foundation and (6) installation and operation. In the second part, the dynamic analysis of tethers is carried out for wave loadings. The tethers are modelled using 2-D beam elements. The effect of parametric excitation caused by the vertical motion of the TLP is investigated. Example analysis is carried out for several cases of tethers in different water depths and for different values of mean top tensions. Dynamic response of tether is obtained for three wave conditions are considered : i.e. moderate, severe and extreme wave conditions.
