Page 148 - Marine Structural Design

124 Part I Structural Design Principles

A floating installation may be designed to function in a number of modes, e.g. transit,
operational, and survival. The limiting design criteria include relevant considerations
regarding the following items:
structural strength in intact condition,
structural strength in damaged condition,
airgap,
compartmentalization and stability.
For novel designs, where limited or no direct experience exists, relevant analysis and model
testing should be conducted to demonstrate that an acceptable level of safety is obtained.
The structure should be designed to resist relevant actions associated With conditions that may
occur during all stages of the life cycle of the unit, including:
Fabrication,
Sitemoves,
Mating,
Sea transportation,
Installation,
Decommissioning.
It is generally more practical and efficient to analyze different action effects via a range of
models, with the responses superimposed from each model, factored as relevant.

Figure 6.6 Example of Global Analysis Model (NTS, 1998)
A simplified model may be applied for the preliminary design to establish the approximate
design responses and to get a feel for how the structure will behave.