ABSTRACT
Offshore steel jacket structures have been commonly used for oil and gas fields for decades. These structures contribute to about 90% of the world’s offshore platforms and are appropriate for relatively shallow water depth. In this study, nonlinear dynamic analysis is performed on a 3-D model of a jacket-type fixed offshore platform for North Sea conditions. The structure is modeled, analyzed and designed using finite element software-Structural Analysis Computer System (SACS). The behaviour of jacket under wave load and seismic load are examined separately. Further, by varying the leg batter values of the platform, weight optimization is carried-out. Soil-structure interaction effect is considered in the analyses and these results are compared with the hypothetical fixed-support end condition. From the analyses, it is found that the optimum leg batter value for the chosen jacket structure is 16 and 2% of weight saving is achieved.
