| dc.description.abstract | This paper discusses an approach for the identification of the characteristic responses of jack-up structures during the different phases of using jack-ups (i.e., transport, installation, operations, and retrieval). The approach for identifying the limitations of the use of jack-ups in marine operations is subject to water depth, wind and wave conditions, hydrodynamic factors, and environmental loads, as well as the structural characteristics of the jack-up itself.
The approach used for ULS analysis in the operation phase is to describe the concept of non-linear wave effects on the response of jack-up structures. There are several non-linearities found in the dynamic motions of Jack-up. This demonstrates why time-domain analysis is necessary. Additionally, the strong dynamic amplification highlights how crucial it is to avoid a rise in the natural period as water depths rise. The dynamic response analysis and its non-linearities remain to play an essential role in the assessment of the structure. However, as wind loads increasingly influence the assessment of deep-water jack-up design concerning operation safety, reliability and stability, the conservative projected-area methodology adds a significant amount of unnecessary weight to the evaluation of the structure.
Additionally, to the ULS analysis, discussions on wind and wave conditions during transport and installation of jack-ups are included. Emphasis is on avoidance of resonant wave conditions during installation and retrieval of the jack-ups
Furthermore, reliability assessment of Jack-ups used in the Gulf of Mexico (GoM), on the Norwegian Continental Shelf (NCS) and offshore the West Coast of Nigeria are considered for different levels of dynamic loading. This study established guidelines for selecting Jack-ups for the region under study | |