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environment. This reduces their dynamic response to such environment and

extends the applicability of fixed platform to deeper water such as 1000 m.

Figure 4.4 – Launch simulation of a self-upending jacket

* A compliant tower structure can be divided into four basic structural

components:

* The foundation piles,

* The base section,

* The tower section(s). Depending on the water depth and the means of

transport, the tower can be made in one or more sections,

* The deck.

* The base and the tower sections are lattice space structures fabricated from

tubular steel members and thus termed the jacket base and the jacket tower

sections. Normally the tower section is much larger than the base section.

4.2.3 Gravity Base Structures

* Gravity base structures (GBS) are very large structures that sit on the seabed

and resist sliding and overturning loads by friction and soil bearing capacity.

The hull of a GBS is made of several tanks that are used to store oil and

ballast. The lightship displacement of the gravity based structures can be of
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